Development of Medical Equipment to Make Colonoscopy Procedures Safer For

Development of Medical Equipment to make Colonoscopy Procedures Safer for

Physicians: Control Head Holder and Splatter Shield

A thesis presented to

the faculty of

the Russ College of Engineering and Technology of Ohio University

In partial fulfillment

of the requirements for the degree

Master of Science

Rajesh Ravindra Shanbhag

December 2014

This thesis titled

Development of Medical Equipment to make Colonoscopy Procedures Safer for

Physicians: Control Head Holder and Splatter Shield

RAJESH RAVINDRA SHANBHAG

has been approved for

the Department of Mechanical Engineering

and the Russ College of Engineering and Technology by

JungHun Choi

Assistant Professor of Mechanical Engineering

Dennis Irwin

Dean, Russ College of Engineering and Technology 3

ABSTRACT

SHANBHAG, RAJESH RAVINDRA, M.S., December 2014, Mechanical Engineering

Development of Medical Equipment to make Colonoscopy Procedures Safer for

Physicians: Control Head Holder and Splatter Shield

Director ofThesis: JungHun Choi

The physicians performing colonoscopy are at risk due to the occupational overuse injuries and exposure to infectious splatters from the patient’s anus. The objective of this thesis is to develop medical equipment to make the colonoscopy procedure safer and more comfortable for performing physicians. To understand the problem well, the colonoscopy procedure was directly observed. Additionally, physicians were questioned to better comprehend safety issues associated with the procedure.

Subsequently, two devices were developed in an attempt to make the procedure safer for the physicians[1]. The Control Head Holder (CHH) holds the control head of the colonoscopy equipment, which provides the physician with less fatigue during the procedure. A splatter shield was also developed to mitigate the physician’s exposure to bodily fluids. The splatter shield provides added advantage of a holder for the insertion tube of the colonoscope which grants the physician the extra freedom to perform activities that may require two hands. A proof of concept prototype of the CHH and the shield with the Tube Holder (TH) was fabricated as per the requirements. The shield was then subjected to drop test and drop ball test to validate the desired deliverables. The force required to initiate slipping from the TH was determined using a force sensor. The

CHH was checked for fatigue reduction with medical students through surface 4

Electromyography (sEMG). The equipment was also evaluated by a group of students and experts who performed the procedure on the Active Colonoscopy Training Model

(ACTM) simulator while monitoring space preservation, ease of use, clarity, degree of freedom and overall rating. The results of this research suggest that the implementation of the CHH is a positive value addition for the comfort of physicians performing colonoscopy. However, further research is necessary to enhance the capability of the developed equipment for serving physicians better.

ACKNOWLEDGMENTS

Above all, I give complete gratitude and appreciation to my advisor, Dr. JungHun

Choi for his interest, patience and motivation he extended throughout the duration of my

Masters degree. Without Dr. Choi’s support, I would not have been able to complete my

Masters degree in such a timely manner.

I thank Dr. David Drozek for allowing me to gain experience by letting me shadow multiple colonoscopy procedures at Doctor’s Hospital, Nelsonville, Ohio. I also would like to acknowledge him for his time and valuable inputs for the development of my equipment and giving me the necessary information to have a complete understanding of a basic colonoscopy. I would also like to thank Dr. Crystal Mills for providing ideas and guidance for my research.

I would like to thank Dr. Brain Clark for letting me use his OMNI TMS laboratory for my experimentation and advising me throughout my research. I would also like to thank Dr. Niladri Kumar Mahato for guiding me throughout the medical trials and his knowledge in statistical data analysis played a major part in my thesis. If it was not for his guidance in writing the analysis section, I would have struggled greatly, and for that I am grateful.

I also would like to thank Dr. Kremer for guiding me and helping me understand the deliverables through the validation of developed prototype.

I would also take this opportunity to thank Mr. Thomas Joseph Boyle for his time and help in fabricating the prototype. It was his knowledge and assistance which made me successfully build the proof of concept prototype. 6

Lastly, I must recognize all the support and encouragement given by the administrative staff and faculty members of Mechanical Engineering Department, Ohio

University.

TABLE OF CONTENTS

Abstract ...... 3 Acknowledgments...... 5 List of Tables ...... 9 List of Figures ...... 10 Chapter 1: Introduction ...... 12 1.1 Literature Review...... 13 1.1.1 Colonoscopy Overview ...... 13 Chapter 2: Endoscopist Risks Involved in Colonoscopy ...... 16 2.1 Forces Involved in Colonoscopy ...... 17 2.2 Risks Involved in Colonoscopy ...... 19 2.3 Equipment Which Aid Physicians ...... 21 2.4 Surface Electromyography and Muscle Fatigue ...... 24 2.5 Thesis Objectives ...... 25 Chapter 3: Development of the Equipment ...... 27 3.1 Requirements for the Developed Proof of Concept Prototype ...... 27 3.2 Development of the Proof of Concept Prototype ...... 34 3.3 Failure Mode Effect and Analysis ...... 46 Chapter 4: Methods of Study...... 55 4.1 Testing of the CHH ...... 55 4.1.1 Test of Fatigue Through Surface Electromyography...... 55 4.2 Testing of the Splatter Shield...... 58 4.2.1 Drop Test ...... 58 4.2.2 Drop Ball Test ...... 60 4.3 Testing of the TH ...... 62 4.3.1 Compliance of a Colonoscope Insertion Tube ...... 62 4.3.2 Force Test of the TH ...... 66 4.4 Equipment Evaluation Through Survey...... 67 Chapter 5: Results and Discussions...... 70 5.1 Validation of the CHH ...... 70 5.1.1 Test for Fatigue Reduction Using Surface Electromyography ...... 71 5.2 Validation of Splatter Shield ...... 89 5.2.1 Drop Test ...... 89 5.2.2 Drop Ball Test ...... 90 5.3 Validation of the TH ...... 91 5.3.1 Force Test of the TH ...... 92 5.4 Equipment Evaluation Through Survey...... 94 8

Chapter 6: Conclusions ...... 99 6.1 Evaluation of Thesis Objectives ...... 99 Chapter 7: Future Work ...... 103 Bibliography ...... 106 Appendix A – Bill of Materials of the Developed Equipment ...... 110 Appendix B - Survey Questions for Equipment Evaluation Survey ...... 116 Appendix C – Equipment Used for the Research ...... 118

LIST OF TABLES

Page Table 1 Anthropomorphic data of human hip ...... 30 Table 2 Anthropomorphic data of factor 31 and 20 ...... 39 Table 3 The anthropomorphic data of factors 24 and 42...... 40 Table 4 Failure mode effect and analysis of the CHH...... 47 Table 5 Failure mode effects and analysis of the Splatter shield...... 51 Table 6 Failure mode effect and analysis of the TH...... 53 Table 7 Classification of groups for the surface electromyography test...... 72 Table 8 MVC values recorded for biceps brachii at pre and post procedure for with support (WS) and without support (WOS) conditions...... 73 Table 9 Sphericity tests for the one way repeated measures ANOVA...... 75 Table 10 MVC values recorded for flexor carpi radialis at pre and post procedure for with support (WS) and without support (WOS) conditions...... 79 Table 11 Sphericity tests for the one way repeated measures ANOVA...... 81 Table 12 Percentage RMS EMG activity of biceps brachii recorded at the last minute of the trial to the MVC recorded with support (WS) and without support (WOS)...... 84 Table 13 Sphericity tests for the one way repeated measures ANOVA for muscle activity of biceps brachii ...... 86 Table 14 Percentage RMS EMG activity of flexor carpi radialis recorded at the last minute of the trial to the MVC recorded with support (WS) and without support (WOS) – flexor carpi radialis...... 87 Table 15 Drop test results conducted on the prototype shield ...... 90 Table 16 Results of the drop ball test on the shield ...... 91 Table 17 Forces recorded at 3 positions for 3 trials on colonoscope of sizes 12.45mm diameter and 13.7 diameter ...... 93 Table 18 Factor of Safety for the force grip imparted by the TH for tube diameters 12.5mm and 13.7mm respectively...... 94 Table 19 Bill of materials of the CHH...... 110 Table 20 Bill of materials of the Splatter Shield...... 112 Table 21 Bill of materials of TH...... 115

LIST OF FIGURES

Page

Figure 1 Colonoscopy clinical support [2]...... 14 Figure 2 Devices that aid colonoscopy – (Right to left, CW) The neck harness, the colonoscope holder and insertion tube holder [29]–[31]...... 23 Figure 3 Anthropomorphic data (factor 19) of human hip [39]...... 30 Figure 4 Modelled CHH in Unigraphics NX and the proof of concept prototype...... 35 Figure 5 Modelled shield in Unigraphics NX and proof of concept prototype...... 35 Figure 6 Working Model 2D simulation of tipping load of the CHH...... 36 Figure 7 Encircled region indicates the region of gripping by the CHH...... 37 Figure 8 Developed ball joint of the CHH...... 38 Figure 9 Factors 31 and 20 from the Human data digest [39]...... 39 Figure 10 Factors 21 and 42 taken from the Human data digest [39]...... 39 Figure 11 Rack and pinion arrangement of the CHH...... 40 Figure 12 Developed linear actuator for the Splatter shield...... 41 Figure 13 Developed lock to hold the shield firmly on the bed...... 43 Figure 14 Modelled and fabricated Tube Holder...... 44 Figure 15 Pictorial depiction of the drop test...... 59 Figure 16 Shield which is fastened together for drop test...... 60 Figure 17 (a) Drop test apparatus (b) The ball impactor...... 61 Figure 18 Experimental setup to determine the Compliance of the insertion tube of CF140L...... 63 Figure 19 Cross section with markings of positions on the colonoscope insertion tube. . 63 Figure 20 Moment vs. Radius of curvature of the insertion tube...... 64 Figure 21 Moment vs radius of curvature for positions A, B, C and D (clockwise)...... 65 Figure 22 Force sensor arrangement for the force impart test of TH...... 67 Figure 23 ACTM - Active Colonoscopy Training Model...... 68 Figure 24 Plot of fatigue induced in biceps brachii for both events - with support (WS) and without support (WOS)...... 74 Figure 25 MVC of biceps pre and post procedure for without support condition...... 76 Figure 26 MVC of biceps pre and post procedure for with support condition...... 77 Figure 27 Percentage of fatigue induced in the twelve subjects for without support (WOS) and with support (WS) conditions for biceps brachii...... 77 Figure 28 Plot of fatigue induced in flexor carpi radialis for both events - with support (WS) and without support (WOS)...... 78 Figure 29 MVC of forearms pre and post procedure for without support condition...... 82 Figure 30 MVC of forearms pre and post procedure for with support condition...... 82 Figure 31 Percentage of fatigue induced in the twelve subjects for without support (WOS) and with support (WS) conditions for flexor carpi radialis...... 83 Figure 32 RMS EMG values at the last minute of the trial in comparison with the RMS EMG values recorded at MVC for with CHH (WS) and without CHH (WOS) conditions - biceps brachii...... 85 11

Figure 33 Biceps muscle activity of 12 subjects at the last minute of the trial in comparison to the muscle activity at the MVC (time interval = 0.5 sec) for with support (WS) and without support (WS) conditions...... 86 Figure 34 RMS EMG values at the last minute of the trial in comparison with the RMS EMG values recorded at MVC for with CHH (WS) and without CHH (WOS) conditions – flexor carpi radialis...... 88 Figure 35 Flexor carpi radalis muscle activity of 12 subjects at the last minute of the trial in comparison to the muscle activity at the MVC (time interval = 0.5 sec) for with support (WS) and without support (WS) conditions...... 89 Figure 36 Force with error bars recorded by the force sensors for tube diameters 12.45mm and 13.7mm...... 93 Figure 37 Evaluation of the Splatter shield by ten students...... 95 Figure 38 Evaluation of the CHH by ten students...... 95 Figure 39 Cecal intubation time taken by ten subjects on the ACTM for with developed equipment (WS) and without developed equipment (WOS)...... 97 Figure 40 Total intubation time taken by ten subjects on the ACTM for with developed equipment (WS) and without developed equipment (WOS)...... 98 Figure 41 Shield with angular bends and one actuator...... 104 Figure 42 Isometric BioDex equipment...... 118 Figure 43 Jamar dynamometer...... 118 Fig 44 Front and top view of the CHH...... 119 Fig 45 Front and right view of the Splatter shield...... 119 Fig 46 Front view of the Tube Holder...... 120

CHAPTER 1: INTRODUCTION

Colonoscopy is a procedure that allows the physician to check the inner lining of the colon. The human colon is at risk for diseases like diverticulitis, angiodyplasias, inflammatory bowel diseases, polyps, and cancer which might cause serious health issues

[2]. The diagnosis of these diseases is possible through colonoscopy where an insertion tube tipped with a camera connected to computerized imaging equipment is inserted into the colon through the anus. During the procedure, tissue samples can be obtained for microscopic analysis. The physicians performing the procedures equip themselves with personal protective equipment (PPE) to minimize the infectious risks involved in colonoscopy. There is high probability of infections getting transmitted if the physician comes in direct contact with the bodily fluids [3][4].

As public awareness of colorectal cancer grows, there is a significant increase in the number of people undergoing colonoscopy screening [5]. The awareness has resulted in an increased procedural volume which has led to an increased incidence of occupational injuries amongst the physicians. New trainees receiving endoscopic supervision should be aware of the risks involved in colonoscopy and should be conscious of the preventive measures required. Preventing injuries and hazards is essential to pursue a long and safe career in colonoscopy[3]. Even though there are techniques of virtual colonoscopy available, the physicians recommend conventional colonoscopy because detection of any aberrant growth will eventually lead to a colonoscopy procedure to biopsy and treat abnormalities [6]. The need of biopsy to treat 13 abnormalities makes conventional colonoscopy a suitable screening tool to detect adenomatous polyps which might cause colorectal cancer.

1.1 Literature review

Colorectal cancer is the second major cause of cancer causing deaths in the

United States [7]. It is a malignant growth in the large intestine which causes serious health problems. The earlier the diagnosis, the better the outcome. Ideally, it is better to identify and treat colon polyps, the precursors to cancer. Detection is accomplished through visualization of the inner lining of the colon, the mucosa. Once a polyp is detected, it is partially or totally removed, and destroyed by cautery via an electric current. Felice Consentino states in his research that “A relative 5 - year survival rate for colorectal cancer is around 90%, when detected early.”[8].

1.1.1 Colonoscopy overview

One important requirement of colonoscopy is detection and removal of polyps before it becomes malignant [2]. The insertion tube is inserted and the polyp is removed either by biopsy forceps or polypectomy snares. The difficult part of the procedure is to maneuver the insertion tube through the loops of the colon without causing discomfort or damage to the patient. The procedure requires vigilance and skill which is obtained through practice.

It is widely observed that the risk of developing colon related diseases increases with age. It is recommended for an individual to have screening baseline colonoscopy at age 50, and every ten years thereafter [9]. Even the smallest polyp can turn malignant. It is helpful to detect and eliminate precancerous polyps. Conventional Colonoscopy is the 14

“gold standard” for detection and treatment of colon polyps and early detection of malignancy. The procedure requires an average duration of half an hour to complete. In high volume hospitals, physicians perform ten to twelve colonoscopies at a single stretch in a shift which may produce fatigue.

Figure 1 Colonoscopy clinical support [2].

The colonoscopy insertion tube is comprised of multiple channels for water, air, video and instruments for biopsy and other procedures. There is no automation in advancing or maneuvering the shaft. The movement is achieved through manually pushing the tube into the colon and deflecting the tube right and left through the dials on the control head [4]. Skill and dexterity in conventional colonoscopy is achieved only through repetitive experience. If the physician is ambidextrous, the movement of the scope is smooth and the strain involved is mitigated. The endoscopist also utilizes tactile sensation to gauge the forces on the colon from the insertion tube.

According to ASGE (American Society of Gastrointestinal Endoscopy) a physician practicing endoscopy spends 43% of his time performing colonoscopy[10]. 15

Before a trainee starts practicing colonoscopy, s/he has to perform an ample number of procedures under supervision.

Equipment has been devised for conventional colonoscopy to improve the movement of the scope inside the colon. One, the Variable Rigidity Colonoscope (VRC) applies a variable degree of stiffness to the insertion tube. The scope has minimum rigidity setting only when the insertion tube passes through splenic flexure and is set at maximum rigidity for the rest. In a study conducted, the VRC reached the first portion of the colon, the cecum, 100% of the time. The cecum is the farthest point of examination from the insertion point at the anus. The only danger from this type of colonoscope is that the chances of perforations are high with novice colonoscopists [11].

One important risk of colonoscopy is perforation of the colon wall. Every colon is unique and the force required to rupture the colon varies. But in general, it is observed that the force required to rupture the seromuscular layer of the human colon is around

9.1lbs and the colon is 12lbs. In an observation, it was noted that a human colon can rupture at 6 lbs when the insertion tube tip impinges the colon wall[12]. The rate of perforations with conventional colonoscopy varies from 0.005% to 0.63%. Perforations are found to be higher in patients of age greater than 65, due to weakening of the wall with age [13].

CHAPTER 2: ENDOSCOPIST RISKS INVOLVED IN COLONOSCOPY

Fatigue is defined as restlessness, lethargy or tiredness either physically or mentally. Under physical fatigue, one cannot continue functioning at his/her normal levels of physical activity. Physical strain is also manifested through muscular weakness and lack of strength. Fatigue involved in colonoscopy is due to procedure duration, procedure scheduling, workload, shift duration, circadian disruption, working environmental condition, and individual factors etc. [14][15]. It is observed that the mental performance increases from 8 AM to 2PM and after 2PM, it deteriorates. A physician under fatigue, will be less vigilant and studies have shown that a lesser number of polyps get detected as the day progresses. Hence most of the procedures are set in the morning times when the physician is alert and refreshed. Observations also show that adenoma/polyp detection is higher in morning shifts than in afternoon shifts [16][17]. In another study, 27% more polyps were removed in the morning than in the evening shifts[18]. Sleep experts agree at least 8 hours of sleep is required for most people. After standardized testing, investigators have found that after a night of sleep deprivation, physicians demonstrate bad language, poor numerical skills and bad retention, short term memory, and poor concentration, which increases probability of a medical errors[19].

Almost 98,000 Americans die each year because of medical errors[15].

Performing monotonous physical work continuously for extended periods of time induces fatigue. Increase in insertion times and impaired detection indicate fatigue. It is known that number of polyps detected increase with increase in withdrawal time. Experts state that the minimal withdrawal time should be 6 minutes. Colonoscopy involves 17 complex monitoring tasks and demands high vigilance, which a stressful environment can impair. A physician has to be physiologically active to be vigilant. During the procedure, he has to be highly watchful and must be mentally aware to gather information and make appropriate decisions[15]. If he is sleep deprived, he will not be able to grasp the information. With fatigue, he will have poor ‘hand eye’ co-ordination and will not be able to detect the polyps and will lead to longer withdrawal times [14].

Upper extremity cases are considered to have minimal risk if the strain index is 7.

The colonoscopy procedure has a strain index score of 27, which means that the physicians are at high risk. It is advised to alter the working equipment or the working schedule to alleviate the risk involved [24]. Usage of ergonomic furniture, lifting equipment and anti-fatigue matting for repetitive tasks is advised.

2.1 Forces involved in colonoscopy

The standard posture for colonoscopy is that the control head is held in left hand and the right hand holds the insertion tube. Endoscopy forces comprise of repeated pinching, gripping and involves awkward hand, shoulder, elbow and neck postures which might be a risk factor leading to overuse injuries.

In a study of forces applied by the physicians during colonoscopy, the left forearm muscle demonstrated high muscle load during the procedure. The right thumb pinch force during the right colon and left colon insertion were found to be 10.4±4.1 N and 10.1±4.5

N respectively. For both arms, peak values were found during insertion in the forearms through sEMG. Colon insertion force was measured to be 10.1±4.5N. The peak forces recorded indicate highest force during insertion. It has to be observed that only a part of 18 the force component gets transmitted to the colonoscope tip. The right forearm muscle activity levels demonstrated highest loads during insertion. The left forearm peak forces were close to 50% of the threshold values[20] . In another study, the measuring device was a handle equipped with strain gauges which enclosed the insertion tube. The physician instead of holding the scope, holds the measuring device and the force is measured by the strain gauges on the inner sleeve of the equipment. The equipment recorded the peak pushing force to be 4.4Kg and the pulling force as 1.8Kg. The clockwise and counterclockwise torque was recorded to be 1Nm and 0.8 Nm respectively. The forces were recorded to be maximum for just 5% of the time during the procedure[21].

In an in-vitro evaluation, the maximum forces were recorded to be 12.73N. All the forces recorded were less than 10N. This measured force was found in the outer loop and in the region of the right colon where it generally loops [22]. A similar study recorded the axial force to be in the range from 5N to -5N and torque between 0.2Nm to -

0.2Nm [23].

Repetitive forces of such magnitude can damage the tendons and the muscle tissues. Preventive measures can be taken by exercising regularly, practicing healthy postures while performing procedures, etc. Postures such as left hand shaft grip or pinkie maneuvers have been postulated to mitigate the risks of overuse injuries. Left hand shaft grip is a postulated posture during sharp turns - the control head is held by the left hand index and middle fingers while the shaft is inserted with the fourth and the fifth fingers. 19

The right hand is used to manipulate the dials. Though this posture seems a difficult, adeptness in these postures can be only attained through practice [3].

2.2 Risks involved in colonoscopy

Physicians practicing colonoscopy may be at risk. The risks involve patients’ bodily fluids splashed, fatigue involved in handling the colonoscope, mental stress involved because of high concentration and vigilance, physical pain involved in observing the television screen which is at non ergonomically raised height, bad design of the control head which makes it difficult to manipulate the control dials etc. Repetitive hand, shoulder and wrist movements put endoscopists at risk. These movements lead to serious health issues in the long run. A study of surgeons revealed that at least 47% of the endoscopists perform more than 30 procedures per week. ACGIH (American Conference of Governmental Industrial Hygienists) has classified works that require hand usage from

0-10. The colonoscopy procedure received a score of 4, i.e. the procedure requires slow and steady hand motion [20]. Some of the diseases related to physicians practicing colonoscopy are the DeQuervains tenosynovitis, lateral epicondylitis, bursitis and many more. A colonoscopist uses his left thumb to turn both the dials on the colonoscope head for controlled deflection and steering. This activity can injure the thumb tendon. The overuse injury might just be on a ligament/tendon but, overtime it might lead to declension of the entire part. With increase in the number of physicians who practice colonoscopy and procedural volumes, this occupational injury is a prime concern among the risks faced by the physicians. In a study conducted, three out of ten physicians who perform more than 1000 procedures a year showed pain. A questionnaire administered 20 for the endoscopists in Korea found that 89% reported musculoskeletal pain in at least 1 anatomic location and 73% reported to have severe musculoskeletal pain[10]. Of 300 colonoscopists surveyed, it was recorded that at least 2% of the physicians gave up colonoscopy because of the physical pain involved[24].

In another study regarding the splashes of bodily fluids from the patient’s natural orifice, there were 9.5% splashes on face, forearms and feet. 4.1% of splashes recorded were on physician’s eyes. These infectious splashes put endoscopists at high risk. There have been instances of blood splashes which have led to transmission of HIV in 9 cases and Hepatitis-C in 3 cases. Even though there are no cases of “mucocuteneous transmission of blood borne pathogens” recorded, these may be potential sources of

HIV[4].

Some general problems related to musculoskeletal pain are listed below:

• Ulnar and radial nerve entrapment syndromes – bone spurs might compress the

nerve which might lead to inflammation on repetitive usage.[24]

• Wrist and hand injury – Repetitive swerve motion of the wrist and hand can cause

inflammation of the tissue. “The median traverses the underside of the wrist

through a tunnel surrounded by bone and fibrous tissue”. This inflammation

occurs mainly because of entrapment of tendons of extensor policies brevis and

abductor policies [24]. Bursitis is also one of the overuse hand injuries which is

caused by prolonged friction or pressure. The smooth movement of bursa is

affected, yielding pain in the joint [25] 21

• Metacarpophalangical joint injury of right index finger - The joints enlarge when

repetitive pushing stints are used [24].

Injuries to right hand are caused by torqueing. Torque can be minimized by having an assistant or by using a thin colonosocope [3]. Survey reveals that about 62% of physicians have injuries because of the control head. The regions of complaint is mainly the left thumb finger [13]. Hand injuries are attributed to the control dials and gripping the colonoscope handle. The overuse will harm the ligament, which might lead to degeneration affecting professional careers. Risk factors include high pinch force, repetitive hand postures, vibration and contact [24].

Keeping an arm raised for a long time compresses the blood vessels that flow to the tendons and supraspinous muscle, which hampers circulation of blood in the tendons.

It would be safe if the physician takes the pressure off the left hand and modifies one handed method to a two handed method. Even if the method is not that efficient, with practice, the new trainees can adapt[26].

Fatigue can arise from a combination of innumerable factors and therefore the most effective way is to implement risk control measures. It is advised that “the best way to control the risk is to eliminate it, if not, to reduce it”[27].

2.3 Equipment which aid physicians

A few devices are available in the market today to mitigate the risks on the physicians practicing colonoscopy. The physician must be well equipped with PPE during the procedure. Protective equipment like aprons, medical gloves, caps etc. are 22 mandatory. There are safety masks and eye glasses to protect the physicians from the splashes, but it might be uncomfortable to wear them [28].

Earlier, colonoscopists held the colonoscope control head in left hand and manipulated the dials with the right hand. Another physician controlled the advancement of the insertion tube in the colon. There have been devices in the past, to make physicians more comfortable and independent. The devices aim at easing the strain on the physician and mitigating the pain to the patient. One of them is the colonoscope tube holder. This device helps in eliminating the third hand or the assistance required during the procedure.

The holder is equipped with spring jaws and is made of non-rusting steel. It weighs around two kilograms and is 18 cm high. The holder helps in manual feeding of the insertion tube in to the colon [29]. Another device was a holder, stationed around the physician’s neck which held the control head of the colonoscope. This device gives complete operator independence, thus eliminating the third hand. It promotes manipulation of the control dials through one free hand, thereby reducing the load on the physician’s hand[30].

Another holder made by the doctors themselves, was a 45cm post made of non- rusting steel which was stationed beside the patients’ bed. The holder not only eliminated the requirement of assistance, it also facilitated free use of the hands to maneuver the tube inside the colon with dials. But a major drawback was that the equipment had poor sturdiness during biopsies[31]. It is preferable to have an obstruction free working area for the physician. The procedure demands the holder to be as close as possible, to achieve cecal intubation. But, having a post very close to the hospital bed may constrain the 23 movements of the physician. Holding the control head for prolonged durations also induces fatigue in the biceps and elbows.

Figure 2 Devices that aid colonoscopy – (Right to left, CW) The neck harness, the

colonoscope holder and insertion tube holder [29]–[31]. 24

Other protective equipment includes operation gowns, lead aprons and masks, face shields, thyroid shields, leaded eyeglasses etc. The procedure room is made ergonomically sound so that physicians are more comfortable. Elevation of the video monitor at appropriate height (10 – 15deg), color of the room, lighting in the room, the height of the bed, the chair on which the physician sits etc. are some of the measures taken to improve the comfort of the physician [10]. Colonoscopy requires the physician to be very alert and all the above stated factors contribute to the quality of observation.

2.4 Surface electromyography and muscle fatigue

Electromyography (EMG) is a diagnostic procedure of determining the muscle activity using electrodes. When the muscle cells are stimulated using an electric potential, their response can be mapped, which indicates muscle activity. The equipment uses two electrodes in combination with the ground electrode to determine the muscle activity during contraction and relaxation of the muscle [32]. The potential response recorded helps in distinguishing the voluntary muscle activity and the activity occurring through stimulation. Surface electromyography is used to determine the fatigue involved the sustained activity for this study.

A study conducted by Toshio Moretani et al indicated a significant drop in frequency and amplitude during sustained maximum voluntary contraction (MVC). It was also observed that the force declined linearly with time during sustained maximal voluntary contractions. However, the force was maintained stable during a 50% contraction. This decline in force and muscle activity is due to loss in central motor drive

[32][33]. In a different study by B. Bigland Ritchie, it was observed that during a 60s 25

MVC, the force fell by 30-50%. This study defines muscle fatigue as a fall in the capability of force generation by neuromuscular system during sustained activity[33].

2.5 Thesis objectives

The main objective of this research is to develop equipment that would make colonoscopy safer and comfortable for the physicians. It is tiring to carry the control head of the colonoscope for prolonged procedures. A support to hold the equipment will make the procedure more favorable to the physicians. In a standard posture, the control head is held in the left hand and the dials are manipulated with the left thumb. Tasks like gripping the colonoscope control head, manipulating the dials and holding it for prolonged durations is hectic. A holder to hold the control head would reduce the gripping force and would give the physician better reach to manipulate the dials. The holder also reduces the load on the biceps and forearms.

Even though, some protective equipment has been developed the physicians often feel uncomfortable while wearing them [28]. These fluids are very dangerous and can cause deadly infections. This thesis aims at developing protective equipment, stationed close to the patient’s anus, which helps in preventing the splatters from reaching the physicians.

In conventional colonoscopy, once the physician finds a polyp, a biopsy forceps is passed through the biopsy channel to burn the cancerous polyp. To feed the biopsy forceps through the channel, the physician needs assistance to hold the insertion tube, so that the polyp does not get lost from his vicinity. A supplementary add-on to hold the colonoscope insertion tube is developed which is attached to the splatter shield. 26

The objectives of this thesis are as follows:

i. Develop a holder to grip the control head of the colonoscope as per the physician

requirements.

ii. Test the holder for reduction of fatigue in biceps brachii and flexor carpi radialis

muscle groups due to the sustained activity. Analyze the obtained data by using

statistical tools. iii. Functional evaluation of the holder by recruiting volunteers to perform the procedure

on a simulator with the holder. iv. Conceptual analysis for a development of a Splatter shield to resist infectious splatters

from reaching the physician.

v. Conceptual analysis of a tube holder to facilitate gripping of the insertion tube when

the physician performs a biopsy.

CHAPTER 3: DEVELOPMENT OF THE EQUIPMENT

It is necessary to identify the appropriate requirements before developing a part or a component. Frequent discussions with the physician were held to assess the requirements. A couple of procedures were also observed to understand the procedure and list the equipment requirements. Subsequently, the equipment was developed as per the listed requirements.

3.1 Requirements for the developed proof of concept prototype

The physician holds the control head of the colonoscope throughout the procedure. There is continuous gripping and pinching load on the physician’s arm. This sustained activity of the physician can cause stress overuse injuries to his arm. The main function of the Control Head Holder (CHH) is to hold the control head of the colonoscope, thereby taking off the load from the physician’s arm. The requirements of a

CHH are as follows:

i. The CHH must sustain the loads that occur during the procedure.

The CHH holds the control head of the colonoscopy equipment, which weighs

around 1 kilogram (measured). The weight of the human arm is around 4.790Kg

[34]. Adding up the weight of the human arm and the CHH, the overall weight is

around 6 kilograms. The structure should be able to support at least 4 times the

working load [35], and the CHH should hold around 24 Kilograms.

ii. The CHH should be able to grip all the control heads of different colonoscopes.

There are a number of colonoscopes available in the market. The structure should

be capable of holding all the control heads. 28 iii. The CHH should not hinder the movement of the physicians.

Colonoscopy is a procedure which includes a lot of hand motions. The physician

should be comfortable during the procedure. The developed equipment should not

restrain the physicians from having a comfortable degree of freedom. iv. The CHH should cater to the physicians’ preference.

Some physicians sit to perform the procedure while others prefer to stand. The

CHH should facilitate variation in height of the structure as per the physician’s

preference.

v. The CHH should be easily sterilized using disinfectant wipes.

All hospital equipment should be sterilized. Equipment is usually put in a steam

autoclave, but equipment like saline stands, infusion stands etc. are normally

wiped with disinfectant wipes. vi. The CHH should be easily portable.

The equipment will be required to be moved around the procedure rooms. To

make portability feasible and easier, casters have to be used. In hospitals, nickel-

plated casters with raceway grease seals and zerk grease fitting are used [36].

Casters should support 4 times the working load. Casters should have locking

mechanisms and should be of swivel type. vii. The CHH operational range should adhere to the safe working limits.

The maximum work level height shall not exceed four times the minimum or least

base dimensions, ensuring that the elevation level of the CHH is safe enough for

the procedure to be conducted[35]. 29

Specific requirements cannot be mentioned because the product is new and unique. Instead, other load-bearing equipment, like a ladder or scaffold, is considered for working range specifications. Material and design standards cannot be stated precisely because of the variety of possibilities involved. Still, the component has to safely sustain the specified loads, and the material selected has to meet the sufficient strength of the requirements. Corrosion is another important parameter to be considered. All exposed surface area should be free of burrs and edges [35].

There is continuous water irrigation and air insufflation during colonoscopy to get a clear view of the colon, which lead to spurts of bowel water sporadically bursting out of the patient’s anus. These spurts can be very infectious and can transmit diseases [3][31].

The main purpose of the splatter shield is to prevent the splatters from reaching the physician. The requirements that were considered for splatter shield are as follows:

i. The shield should be able to resist the splashes from the patient’s anus.

The defecation angle is a good measure to determine the range of splashes

generated from the patient’s anus. The shield should be placed very close to the

patient’s anus. It has been observed that the defecation angle from a healthy

human varies from 126 deg to 100 deg (squatting to sitting)[37]. So the shield

should be capable of restraining the splashes for a range up to 126 deg.

ii. The shield should accommodate all patients.

Patients differ in their body mass index (BMI) and the shield should be able to

accommodate all of them. The hole of the splatter shield should be properly

aligned with the patient’s anus, so there is a need of a mechanism to vary the 30

height of the shield depending on the patient’s BMI. The extent of variation in a

patient’s hip height is also important. Considering factor 19 (95 percentile) from

the human data digest, the maximum and minimum height of the human hip is

determined. The maximum is found to be 663 mm, the minimum, 350 mm[38].

Figure 3 Anthropomorphic data (factor 19) of human hip [39].

Table 1 Anthropomorphic data of human hip [39].

Dimension Men Women Max Percentile 5 95 5 95 Hip (mm) 350 430 350 460 663

iii. The shield should be removable from the bed whenever desired by the doctor.

The shield should facilitate easy removal from the bed. There might be times

when the physician may need the patient to change his/her posture from a fetal

position to a supine position. During such times, the equipment should facilitate

easy removal from the bed.

31 iv. The shield should not obscure the vision of the physician.

Once the insertion tube is inserted into the anus, there is no necessity of vision of

the patient’s anus. However, for precautionary care, it is better to have the shield

transparent so that the physician has a clear view of the patient’s anus.

v. The shield should be easily sterilized.

The shield and the colonoscopy equipment are subjected to sterilization in

hospitals through steam autoclave or disinfestation equipment. Preventing the

entry of pathogenic organisms into the body is the main objective of sterilization.

To keep the bio burden below the safe limit is important. The equipment

components should be suitable to be sterilized by putting them into an

autoclave[40]. For this research, the steam autoclave from the Nelsonville hospital

is considered. The autoclave equipment used at the Doctors Hospital in

Nelsonville is Amsco 3000 series. Most modern hospitals have this equipment or

something equivalent. vi. The shield base should have a stable lock to prevent it from falling off the bed,

thus preventing fatal accidents.

During the procedure, the physician is involved in various hand movements to

achieve different activities. This movement can accidently bump the shield and

cause the equipment to fall off the bed causing catastrophic damage that could be

fatal to the patient. Accordingly, there is a need for a clamp that would affix the

shield base firmly to the bed.

vii. The shield should not shatter if dropped.

The shield, when in use, might get dropped. However, from a height of 30 in or

less, this fall should not shatter the shield. Even if the shield breaks, it should not

be brittle such that the impact makes the shield shatter into pieces. Brittle material

should not be used, considering both safety risks and difficulty in cleaning. viii. The shield should be able to handle all loads during the procedure.

Stability is a prominent factor during the procedure. The shield should be stable

and should sustain all the loads, such as the physician pushing the insertion tube,

that act on it during the procedure.

ix. The thickness of the shield should be no less than 1mm (3mm for glass).

American National Standards Institute (ANSI Z87.1-2003) requires that all eye

and face protection devices by 1mm thick (3mm for glass). Thus, the minimum

thickness of the shield should be no less than 1mm [41].

Colonoscopy screening is conducted to check colons for abnormalities or

unwanted carcinogenic growth. During screening, if the physician finds any polyp, the

cancerous growth is burnt using biopsy forceps. Once the physician finds a polyp, the

insertion tube is positioned favorably to have a clear view of the polyp. To keep the polyp

in the scope’s vicinity, the physician needs an assistant to hold the insertion tube. The

physician then inserts the biopsy forceps through the biopsy channel and burns the

cancerous tissue. The Tube Holder (TH) is developed to reduce the need of assistance

from a nurse.

The requirements of the TH is as follows:

i. The TH should firmly hold the insertion tube of the colonoscope.

The function of the TH is to hold the insertion tube while the physician feeds the

biopsy forceps through the biopsy channel after finding the polyp. The insertion

tube should be held firmly in the position such that the polyp does not move out

of the physician’s vicinity.

ii. The TH should be able to hold insertion tubes of all sizes available on the market.

There are a number of available colonoscopes on the market. The insertion tube

diameters vary from 9.5 mm to 13.7 mm. The TH should be able to firmly hold

insertion tubes of all diameters. iii. The TH should be easily affixed to the splatter shield.

The TH needs a firm foundation on which it should be affixed. In this research,

the splatter shield is considered to be an appropriate location to station the TH.

The TH should facilitate an option of being easily attached to the splatter shield. iv. The TH should be appropriately constrained to the splatter shield.

There should not be any relative motion between the TH and the shield that would

hamper the movement of the scope during the procedure. All such relative motion

should be constrained. However, there should be means for facilitating relative

motion only when desired.

v. The TH should facilitate easy removal of the insertion tube whenever desired by

the physician.

The procedure is generally conducted when the patient is in a fetal position. There

might be times when the physician needs the patient to change his/her position in

order to make way for easy movement of the scope. During such times, it is

necessary to remove the shield from the bed. The TH that is affixed to the shield

should also facilitate the easy removal of the tube. vi. The TH should be easily sterilized.

All the equipment used during the procedure should undergo a thorough

sterilization process. The TH should facilitate easy sterilization. The sterilization

process might involve subjecting the TH to a steam autoclave or a disinfestation

process. vii. The TH should be easy to use.

The mechanism introduced to hold the insertion tube in the TH should be simple

and easy to use. The mechanism should not be complex and must be easily

understood by the physicians.

3.2 Development of the proof of concept prototype

The requirements were noted and the equipment was modelled and fabricated.

The equipment was modelled in Unigraphics NX 8.5. Figures 4 and 5 show the model

CHH and the Splatter shield respectively. 35

Figure 4 Modelled CHH in Unigraphics NX and the proof of concept prototype.

Figure 5 Modelled shield in Unigraphics NX and proof of concept prototype.

After considering the listed requirements, the CHH was modelled and developed.

The highlights of the CHH are mentioned below:

i. The CHH is modeled in Working Model 2D to determine the tipping load

(vertical). This tipping load is well within the working conditions. The equipment

is developed with a factor of safety of 5.16. The CHH should hold an overall

weight of 6 kilograms, i.e. 60N. The structure tips at a load of 315N. The

simulation in Working Model 2D is shown in Figure 8.

Figure 6 Working Model 2D simulation of tipping load of the CHH.

ii. The CHH is equipped with a holder to accommodate the control heads of different

scopes in the market. For this research, dimensions of the Olympus PCF 140L and

Olympus CF 100TL scopes are used. The scopes are held in the holder cup. The 37

holder cup tapers from 26mm (major diameter) to 22mm (minor diameter). The

taper would accommodate all the scopes at the rubber pad as shown in Figure 9.

Figure 7 Encircled region indicates the region of gripping by the CHH.

iii. The holder cup is mounted on a column making a step shape. This step keeps the

column away from the physician, thereby keeping the physician free and

unconstrained. The structure has a ball link to facilitate swiveling motion of the

control head around the ball, which would make the activity less sustained. It also

has a revolute joint to allow a degree of motion of almost 180 deg. This

movement gives more freedom of movement around the column. Figure 10 shows

the ball link and the spherical joint. 38

Figure 8 Developed ball joint of the CHH.

iv. The physicians perform the procedure either by standing or sitting, depending on

their preference. The CHH also has a rack link with a gear and lock pin to

facilitate linear motion to adjust the height. The holder can be adjusted from

800mm to 1350mm. Figure 13 shows the rack and gear mechanism used in the

CHH.

As per the Human Data Digest, the factors of 31 and 20 are considered for

sitting. Similarly, for the standing posture, the factors of 24 and 42 are used. 39

Figure 9 Factors 31 and 20 from the Human data digest [39].

Table 2 Anthropomorphic data of factor 31 and 20 [39].

Sitting Factor 31 20 TOTAL Percentile 99 99 Length (mm) 495 329 824

Figure 10 Factors 21 and 42 taken from the Human data digest [39]. 40

Table 3 The anthropomorphic data of factors 24 and 42 [39].

Standing Factor 24 42 TOTAL Percentile 99 99 Length(mm) 1005 297 1302

Figure 11 Rack and pinion arrangement of the CHH.

v. The CHH can be sterilized using disinfectant wipes. If more sterilization is

necessary, the holder cup can be dismantled and can be subjected to sterilization

through a steam autoclave. vi. The CHH is fitted with four casters with a locking mechanism. The prototype is

fitted with hard rubber casters with a wheel diameter of 3.5cm. The maximum

load of each caster is around 353 pounds [42]. The casters also have a locking

mechanism and swivel. vii. The maximum work height of the CHH is around 1350mm, which is less than

four times the base width of 400mm. This height is well within the safe working

range.

The highlights of the developed Splatter shield are as follows: i. Considering the defecation angle of 126 deg in a healthy human while squatting,

the shield is symmetrically bent around the Z axis for 130 deg. This curvature

should prevent splatters from reaching the physician. ii. A linear actuator is developed such that the shield accommodates patients of all

BMI. To facilitate the movement of the shield and to align it with the patient’s

anus, a stepper motor equipped with a belt drive is used. The holding torque of the

stepper motor used is 0.81 Nm. The weight of the shield is around 0.6 kilograms.

Figure 6 shows the developed linear actuator. The travel length of the actuator is

around 100mm. The linear motion is controlled by an Arduino microcontroller

through a slider potentiometer.

Figure 12 Developed linear actuator for the Splatter shield.

42 iii. Whenever the physician desires to change the position of the patient from fetal to

supine, the shield facilitates its easy removal from the bed. The groove at the

center of the shield helps to easily guide the insertion tube out, whenever the

removal is desired. iv. The shield is made from acrylic sheet, which is clear, so vision of the patient is

not obscured. Even though the physician observes the endoscopic monitor after

insertion of the scope, it is safer to have a clear view of the patient’s anus.

v. Most modern hospitals use steam autoclave for sterilization of equipment. The

equipment is generally sterilized at 270F for four minutes. Even though the

prototype in this research is made of acrylic, use of material which is suitable for

autoclaving is recommended[40]. The dimensions of the Amsco 3000 series

steam autoclave is 20” by 30”. The developed shield is well within these

dimensions. vi. Colonoscopy procedures involve various hand activities that sometimes can lead

to accidents such as the shield falling off the bed, which can be catastrophic and

even fatal. The shield is equipped with a locking mechanism that is latched to the

bed, which prevents the shield equipment from falling off the bed. Figure 7 shows

the modelled locking mechanism. The mechanism involves two clevis joints with

a main link to allow translational motion, which helps to align the equipment with

the patient’s anus. There is a wide mouth clamp at the end of the bottom clevis

joint that facilitates locking. The clamp secures the shield to the bed and prevents 43

the shield from falling. The bed dimensions for this research are taken from the

Nelsonville hospital.

Figure 13 Developed lock to hold the shield firmly on the bed.

vii. The developed shield is subjected to drop test and drop ball test. The shield in this

research is thermoformed from an acrylic sheet. The developed shield satisfies the

test requirements. The results are explained in later chapters. viii. The procedure involves various hand gestures by the physician. Any impact from

the physician’s hand should be sustained by the equipment and not cause the

shield to tip over. The shield is supposed to be held rigidly on the bed. Tipping of

the shield against the patient is not favorable. 44 ix. The thickness of the shield is greater than 1mm, which satisfies one of the

requirements in ANSI standards[41].

Similarly, the Tube Holder is developed considering all the requirements mentioned above. The modelled TH is as shown in Figure 14. Some of the important highlights of the TH are as follows:

Figure 14 Modelled and fabricated Tube Holder.

i. The TH holds the insertion tube firmly while the physician inserts the biopsy

forceps into the biopsy channel, keeping the polyp in the scope’s vicinity. A

spring-actuated mechanism is used to achieve this action. The physician actuates

the spring when the polyp is found and the insertion tube is positioned. The

groove on the plunger holds the spring from retracting. Once the biopsy is 45

completed, the button is pressed. When the button is pressed, the button spring is

pushed back, taking the dowel pin off the groove, thus retracting the plunger back

to its earlier position.

ii. The TH has a tube to hold the insertion tube of the colonoscopy equipment. It

should have the capability of holding insertion tubes of all sizes. The tubes

available in the market vary from 12.5mm to 13.7 mm (pediatric scopes not

considered). The tube in the TH has a diameter of 14mm, which should

accommodate all the available sizes on the market. Even the clamp has a diameter

of 14mm to facilitate firm gripping of the colonoscope tube. iii. The TH easily affixes itself to the shield. It is attached to the shield with the help

of a metallic ring supported with 3 setscrews that tightly hold on to the Delrin

material. The metallic ring prevents the TH from falling off the shield. iv. Even though the shield holds the TH, there is relative motion between the shield

and the TH. The TH might rotate in the slot of the shield, which fails to serve the

purpose of holding the insertion tube firmly. Hence, the TH is equipped with a

push pin to lock it in a fixed position. The pin is a ball spring push pin, which is

inserted through a hole in the shield.

v. The TH and the metal ring attached also have a groove at right angles to facilitate

the easy removal of the shield from the bed whenever desired. The TH groove can

be aligned with the groove on the shield to easily guide out the insertion tube. 46

vi. The TH is mainly made of Delrin. Delrin is light and wear resistant. The TH

weighs around 0.4 kilograms, which would induce negligible torque on the

stepper motors. The holding torque of the stepper motors is around 0.81Nm.

vii. The TH is made of parts that can be easily sterilized in a steam autoclave. Delrin

and the metals used are suitable to be subjected to steam autoclave

sterilization[43]. viii. The TH has an easy clamp mechanism to firmly grip the insertion tube. The

mechanism is an easy push-retract spring system. Additionally, the entire

assembly can be easily dismantled and reassembled in case of a maintenance

check.

For a bill of materials generated for the Tube Holder, refer to Appendix A.

3.3 Failure mode effect and analysis

It is necessary to assess the failure modes involved in using equipment before

production. The Shield, the CHH, and TH are used during colonoscopy procedures. Any

minor failure can turn fatal. Hence, care should be taken to make a fault free system. The

Failure Mode Effects and Analysis (FMEA) study is conducted on the equipment to

evaluate the possible failures involved and the corrective action taken to mitigate any

severity. The risk analysis should answer two important questions, 1) what could go

wrong and 2) what is the probability of that thing going wrong in relation with its

consequences. There are three components that define the priority of failure: Severity

(consequences of the failure, S), Occurrence (frequency of failures, O), and Detection

(ability to detect the failure. D). Risk Priority Number (RPN) is the product of 47

Occurrence, Severity, and Detection [44]. This FMEA acts as an input to evaluate future implementations. The failure modes with a severity rating greater than 7 are prioritized.

Effort is made to reduce the severity rating by taking the necessary corrective measures.

Table 5 shows the FMEA of the CHH.

Table 4 Failure mode effect and analysis of the CHH.

Reduction Parts and Failure Cause and Consequences of S O D RPN assemblies Modes Occurrence Occurrence 1. The control head cannot 1. HOLDER be held in Increase CUP 1. The cup rod 1. The cup an in the ASSEMBLY can easily rod can appropriate diameter 1. 3 1. 2->1 1. 1 1. 3 1. Holder cup bend at higher yield and position. of the rod 2. Cup slot loads. fracture. from 3/8`` 3. Cup rod Smaller to 0.5`` diameter of the rod. 1. The stability of 1. The the movement of structure the plate is assembly over hindered 1. a. The the ball might and the Control head lead to two holder PLATE cannot be failures :- a. if doesn’t ASSEMBLY held too smooth, serve the 1. Holder appropriatel the assembly purpose. 1. Proper upper plate y because of 1. 4 1. 6->2 1. 1 1. 8 freely rotates 2. The and adequate 2. Holder the free 2. 2 2. 6->2 2. 1 2. 4 around the motion is maintenance. bottom plate rotation. ball; more 3. Plate bolt b. The b. if it is too constrained. and nut movement is tight, The rough and movement of Improper constrained. the assembly maintenance. around the ball will be Too much difficult. tightening of the bolt.

Table 4 (continued): 1 Failure mode effect and analysis of the CHH

1. It is fatal to the 1. The Rack 1. Introduce patient if link might indentations the control have a free on the Rack head is fall which link to have not held can hurt the a firm by the patient as contact and physician. the have a

RACK LINK 1. Failure of physician marking 2. The ASSEMBLY the push pin to loses the which finger of 1. 10 1. 6->2 1. 1 1. 20 1. Rack link hold the Rack grip of indicates a the 2. 2 2. 4->2 2. 1 2. 4 2. Rack link in control full contact physician 3. Push pin position. head. between the can get male and bruised. 2. The female parts.

finger of the Improper physician 2. Safety mechanism can get cover plate to hold the caught in the for the rack link gear. gear. assembly in position. 1. This can turn fatal to the patient, if the control CLEVIS head is JOINT not held ASSEMBLY 1. Delrin 1. This firmly by 1. Extension 1. The free washers movement the link. rotation enable a can tip off physician. 2. Extension around the controlled the link bolt clevis joint rotation of 1. 10 1. 2 1. 5 1. 100 equipment Lack of 3. Threaded may make the the which can washers steel sleeve movement extension turn out and 4. Base uneasy. link around fatal. retainers column the pin. to restrain 5. Clevis the motion joint of the extension link in the clevis joint.

Table 4 (continued): Failure mode effect and analysis of the CHH

1. Portability will become difficult. 2. Rust is not allowed in the hospital environment. 1. Use of Infections the casters 1. The and septic 1. The casters only in the portability are bound to BASE might wear out hospital of the occur if the 1.Base plate due to the premises equipment is patients or 2.Support movement on where the 1. 2 1. 6->2 1. 1 1. 4 hampered. physician bars rough floors are 2. 5 2. 3->2 2. 2 2. 20 2. Rust is come in 3.Casters surfaces. smooth. dangerous to contact. 4. Caster 2. The parts 2. Paint Job the patients bolts can rust. to curtail and the Abuse the rusting physicians. during the of the steel. movement

of the equipment .

Lack of necessary measures to counter rust. 1. The control head HOLDER cannot be 1. Increase BALL 1. The ball 1. The ball held the ASSEMBLY shaft can bend shaft can appropriately diameter of 1.Ball 1. 4 1. 2->1 1. 1 1. 4 and yield at bend and . the rod 2.Ball link higher loads. rupture. from 3/8`` 3. Extension Smaller to 0.5``. set screw diameter of the rod.

Table 4 (continued): Failure mode effect and analysis of the CHH

1. More force can 1. Delrin destroy Sleeve with 1. More GEAR the gear close 1. Any force has to ASSEMBLY teeth. tolerances can misalignment be applied to 1. Central facilitate easy can make the the gear and support Improper sliding of the gear restrain two hands 1. 2 1. 7->2 1. 1 1. 4 bushing. material Rack link. It the linear are required 2. Gear shaft selection can also motion of the to align the 3. Gear for areas curtail link. rack link 4. Handle of contact. misalignment back. Gulling of of the Rack Al – Al Link. surfaces

Necessary counter measures to mitigate severity factors were taken and the required changes were made. The corrective measures taken are as follows:

i. A delrin sleeve was implemented to make movement of the rack link easier. It

prevents misalignment of the rack link and the gulling between Al surfaces.

ii. Delrin washers were implemented to curtail the free motion of the extension link

around the clevis joint. iii. All of the steel surfaces were painted to prevent corrosion. iv. A safety cover was implemented over the gear wheel to prevent any accidents

because of the open gear and pinion arrangement.

The FMEA of the Shield shown in Table 5.

Table 5 Failure mode effects and analysis of the Splatter shield.

Parts and Failure Cause and Reduction of Consequence S O D RPN assemblies Modes Occurrences Occurrences ACTUATOR 1. Timing 1. Lack of belt power to 2. Extrusion 1. The hold the rod shield position of 3. Idler holder will the motor. pulley 1. The motor move to its 2. 4. Tooth 1. A safety can release lowest Prolonged timing lock, to from its position. It usage. pulley grip the existing can be fatal 1. 10 1. 7->1 1. 5 1. 50 5. Modular holder to position. if it occurs Lacking 2. 2 2. 2->1 2. 1 2. 2 end mounts the column. 2. The belt during the safety 6. Screws 2. Proper may sag. procedure. mechanism 7. Set maintenance 2. It will to lock the Screws make the position of 8. Mini V belt drive the holder. plate inefficient. 9. Wheels Improper 10. Bearings maintenance 11. Stepper motors 1. High surge of current. 2. Misalignment of the shield. 1. The chips 1. Use of 1. Failure It can be fatal L293NE can heat sinks of the also. get to dissipate controller. Arduino overheated. heat. 1. 2 2. The Inefficient 1. 10 1. 8->3 1. 60 controller and 2. The 2. A safety 2. 5 motor control of 2. 10 2. 4->1 2. 50 potentiometer potentiomet lock to hold moves the the current er can be the position of shield to the turned on the down. controller. accidentally. potentiometer.

Inappropriate enclosure of the electrical unit. 1. SHIELD Excessive 1. Use of HOLDER 1. Lock nut 1. The tightening better ASSEMBLY pressure can shield of the lock material 1. 2 1. 4->2 1. 1 1. 4 1. Shield crack the cannot be handle. than holder shield held firmly. acrylic. 2. Lock nut Use of acrylic sheet. 52

Table 5 (continued): Failure mode effects and analysis of the Splatter shield.

POWER 1. SUPPLY Contamination UNIT from splashes 1. An 1. The parts 1. Difficult to 1.9v power from the patientenclosure to left open in sterilize the supply to or the safely protect the contaminated arduino procedure. the electrical 1. 10 1. 10->3 1. 2 1. 60 environment electronic 2. 5V unit from tend to get parts. They external Failure to contamination contaminated. can fail. power isolate the . supply to electrical motors. unit. 1. The shield falls of from 1. Having a 1. The a height. single acrylic 1. The acrylic Shield shield joined shield will Joining three sheet bent 1. 2 1. 6->2 1. 5 1. 20 with acrylic break. different into the cement can thermoformed desired crack. acrylic sheets shape. together.

The corrective measures taken to reduce the safety of the shield are as follows:

i. A safety latch locks the position of the shield once it is elevated to the desired

height.

ii. The ICs on the Arduino microcontroller are equipped with heat sinks to

effectively dissipate heat. iii. The electrical unit is isolated to prevent it from contamination. Use of

Polycarbonate material is recommended, however, temperature requirements in

sterilization process may restrict the use of this material. A thorough material

selection study is recommended for shield.

Similarly, an FMEA analysis of the TH was completed and the failure modes is analyzed to reduce the risks involved.

Table 6 Failure mode effect and analysis of the TH.

Reduction Parts and Failure Cause and Consequences of S O D RPN Assemblies Modes Occurrence Occurrence 1. The insertion tube cannot be guided out of the 1. The assembly metal ring whenever might hold desired. on to the 2. The acrylic 1. 1. The physician shield more Appropriate clamp grip cannot use tightly thus initial setup HOLDER assembly both his preventing before the ASSEMBLY cannot be hands to the grip procedure. 1. Clamp grip rotated. feed the 1. 7 1. 5->2 1. 5 1. 70 from 2. Better 2. Metal ring 2. The tube biopsy 2. 3 2. 7->4 2. 1 2. 12 rotating. traction 3. Set screw cannot be forceps into 2. The between 4. Tube grip positioned the channel. tube may pipe and for biopsy. not be insertion Improper rigidly tube. initial setup. hold the

insertion Improper tube of gripping the scope. between the diameter of the insertion tube and the pipe. 1. Locking the insertion tube. It is a 1. The serious issue Button for patient’s spring safety. 1. Usage of might 1. The 2. The lower resist to plunger insertion BUTTON stiffness compress. cannot be tube cannot ASSEMBLY spring. 2. The retrieved. be 1. 7 1. 3->2 1. 2 1. 28 1. Button 2. Use a dowel pin 2. The positioned 2. 3 2. 5->2 2. 5 2. 30 2. Dowel pin bigger might locking for a biopsy. 3. Spring(1) diameter for rupture mechanism the dowel because of will fail. High pin. high stiffness of loads. the spring.

Smaller diameter of the dowel pin. 54

Table 6 (continued): Failure mode effects and analysis of the TH.

1. The lock 1. Check the 1. The pin will shield for lock pin initiate a proper might 1. The lock crack in the maintenance rupture pin will not 1. 1 1. 3->1 1. 1 1. 1 Lock pin shield. . the acrylic hold the TH 2. 1 2. 1 2. Use of shield firmly. Excessive polycarbonate eventually force to pull shield rather over use. the lock pin. than acrylic.

The failure modes are listed and the corresponding severity, occurrences, and detection ratings are noted. The failure modes whose severity rating is greater than 7 are reconsidered and necessary corrective measures have been implemented. Some of the notable changes are as follows:

i. A 1mm diameter dowel pin was used to replace a 0.5 mm diameter, which gives a

better load bearing capability for the dowel pin and prevents it from getting

ruptured.

ii. The tube is provided with a rubber layer coating to improve the grip quality of the

clamp.

CHAPTER 4: METHODS OF STUDY.

Once the equipment prototype is developed, it is tested and validated. In this research, the equipment is validated by various procedures like mechanical testing, fatigue testing, and testing on a simulator. Mechanical testing involves tests such as drop test and drop ball test conducted on the shield. These tests are conducted to determine the endurance of the equipment during high or impact loads.

4.1 Testing of the CHH

The CHH is also subjected to static analysis through Working Model 2D to determine the toppling load and was tested for fatigue reduction in humans through surface electromyography (sEMG).

4.1.1 Test of fatigue through surface electromyography

The CHH not only makes the physician more dexterous, but also dissipates the load on the physician’s arm. It reduces the fatigue involved in holding the control head of the colonoscope. The fatigue induced varies for each individual. In this research, an effort is made to analyze and asses the fatigue involved in holding the control head of the colonoscope and the extent to which CHH mitigates the load on the physician’s hand.

The fatigue involved in holding the control head of the scope can be calculated by the maximum force the human arm is capable of generating. The load of the control head is shared by the human biceps (brachii) and forearm group (flexor carpi radialis) muscles.

This force is recorded when a maximum voluntary contraction (MVC) is given through an Isometric Biodex equipment for the biceps brachii muscle and through a Jamar

Dynamometer for the flexor carpi radialis muscle. The muscle activity for the MVC can 56 be recorded through surface electromyography. Two different channels (one for biceps and the other for forearm group muscles) of Biopac MP-150 are used to record the muscle activity. AcqKnowledge is the acquisition software used to record the muscle activity. The maximum voluntary contraction is recorded pre- and post-activity. The difference between pre and post determines the fatigue involved in the activity. Muscle activity amplitude recorded at the last minute of the trial when compared with the amplitude recorded at MVC gives the estimate about the number of motor units recruited for that particular action.

For this study, twelve subjects were hired after IRB approval. The subjects were asked to hold the control head of the scope for half an hour and the MVC of biceps and forearm group muscles were recorded. These observations can be compared with the data obtained from the procedure when the control head is held with the CHH [1].

A brief outline of the protocol during the experiment is as follows:

i. Step 1: The subject is clearly informed about the colonoscopy procedure and the

experimentation process. They are allowed to become familiar with the equipment

(Biodex System 4 Dynamometer, Handgrip Dynamometer, and colonoscopy

equipment). The consent form is reviewed and any question regarding the form

are addressed before the subject signs. The procedure is scheduled. During

scheduling, the subjects are again asked about their dominant hand and usage of

pacemakers (the exclusion criterion) for safety purposes.

ii. Step 2: A part of the subject’s left hand forearm and biceps is cleanly shaved to

ensure a good signal and avoid artifacts. The electrode terminals are attached to 57

the biceps and forearm muscles. A ground electrode is also connected. The

subject is asked to give three Maximum Voluntary Contractions (MVC) for the

biceps muscles of the left hand on the Biodex System 4 Dynamometer and then

three readings of Maximum grip strength for forearm muscles of the left hand on

the Hand Dynamometer. iii. Step 3: The subject is then asked to hold the control head for half an hour. The

subject holds the control head in the left hand. The subject will also be asked to

give 20 rotations of each dial on the control head to mimic the procedure done by

the physician. The muscle activity is recorded for the entire duration. At the

completion of the task, the subject is asked to give another set of three MVCs for

both muscle groups. iv. Step 4: After a span of two days, the same procedure is repeated utilizing the

holder.

To eliminate the effect of learning curve, the testing is randomized by dividing the students into two study groups. While one group performs the experimentation without the support and later with the support, the other group perform the experimentation initially with the support and later without the support.

The RMS EMG amplitude over the last minute of the trial is expressed in terms of the RMS EMG amplitude recorded at the baseline (Pre) EMG. It is generally observed that the amplitude of the muscle activity signal increases characteristically if fatigue is induced as additional motor units are recruited[1]. 58

4.2 Testing of the Splatter shield.

The shield might be subjected to various heavy and impact loads. Mechanical tests like drop test, high mass impact test, high velocity impact test, and drop ball test help in simulating such conditions to determine the strength of the component in bearing such loads. The shield in this study is subjected to drop test and drop ball test.

4.2.1 Drop test

The shield is stationed on the bed close to the patient’s anus. During shield sterilization, setup, or transit, there are chances that the shield might fall on to the ground causing the shield to break. The developed shield is expected to sustain such impacts. To validate the impact resistance of the shield, the drop test is conducted. This test helps in determining the impact strength of the shield when dropped from a bed height of 760mm

(30”). Additionally, this height is the prescribed in MIL standards, MIL-STD-810 [45].

The test is conducted such that the shield lands on the floor with the apex of the shield facing the ground.

Figure 15 Pictorial depiction of the drop test.

It is highly recommended that the test is conducted on a shield that is made of a single acrylic sheet and is bent into the desired shape. Because the prototype shield is made of three different acrylic parts and are fastened together with the help of acrylic cement, the shield is weak at these seams. Hence, the testing is conducted for a worst case scenario where the parts are fastened together with a thread to keep the weight same as the assembled prototype. The fastened shield is shown in Figure 16. The Shield is dropped from a height of 760mm (30”) by hand. The drop test is conducted over ten trials and the shield is checked for cracks after each trial.

Figure 16 Shield which is fastened together for drop test.

4.2.2 Drop ball test

There might be times when the shield faces an impact from a falling object. The developed shield is expected to sustain such impacts. To validate the impact resistance of the shield, the drop ball test is conducted. These tests are conducted to ensure that the shield possesses levels of impact resistance when tested with a traditional ball impactor[41]. 61

Figure 17 (a) Drop test apparatus (b) The ball impactor.

The drop ball test helps in determining the impact resistance of the shield. This test is conducted with reference to American National standards Z87.1-2003. The test standards are derived from considering the standards for removable face shields, which are in the same category as the developed shield. The test procedure states that a steel ball of 1in diameter (68 grams) is supposed to be dropped on the equipment from the height of 50in or 127cm. The shield is to be supported by 50 percentile Anderson head form.

Because the developed shield is not exactly a face shield, no head form is used. The ball is aligned such that it impacts the apex of the shield. Ten trials are conducted to assess the impact resistance of the shield [41]. 62

4.3 Testing of the TH

The force required to initiate slipping in the clamp of the TH is determined using a force sensor. The methods of the testing are explained below in detail. Because the TH is in direct interaction with the insertion tube, the stiffness of the insertion tube was also measured.

4.3.1 Compliance of a colonoscope insertion tube

In the process of development of a TH, it was necessary to know the stiffness of the insertion tube. This test is one of the preliminary tests conducted to determine the compliance of the insertion tube. When the insertion tube is subjected to bending load, the tube offers resistance to the bending motion. Hence the bending radius suitable for the working range can be determined. To analyze the forces exerted by the insertion tube, the tube is bent and the resistance offered is recorded. The tube is constrained at one end and then resistance offered is recorded at the other end through a force sensor. The force sensor is connected to the computer through a Data acquisition system “LabPro”. The interface software used is “Logger Pro”. The recorded values are the forces exerted by the insertion tube. The distance between the force sensor and the fixed end is the diameter of the bend. The product of the recorded force and the radius is the moment. The moment is plotted against the radius of curvature.

The apparatus is setup as shown in the Figure 25. Proper care should be taken to maintain the bars in parellel. The force sensor used here is the Vernier dual range force sensor. The range of the sensor is set from +50 N to -50 N. Necessary graduations with a step of 0.5 inch are marked on the link. 63

Figure 18 Experimental setup to determine the Compliance of the insertion tube of

CF140L.

The colonoscope used is CF-140L. The readings are taken for four positions along the circumference of the insertion tube. The positions are denoted as A, B, C and D.

Figure 19 Cross section with markings of positions on the colonoscope insertion tube.

The force was noted for ten seconds duration at the rate of one reading per second. Zero error should be ensured prior to recording. Values are recorded for all four positions for different diameters of the curvature of the bend. The test is repeated at three different locations on the insertion tube. The values are noted and the corresponding moment values are calculated after considering the average of the recorded force values. 64

Moment, Mean, and Standard deviations are calculated for corresponding lengths and the moment with respect to the radius of bend is plotted. The range of values obtained for a corresponding radius is marked with the help of error bars. The resulting plots are as shown:

i. Plot 1 – Moment vs. Radius of curvature

When plot 1 is examined, it is found that the error bars are larger for the bend

radius of 2 inches. This steep bend is a hypothetical case and will not be

encountered during the procedure. Moreover, the values fluctuate because an

extra force is necessary to give the steep bend to the insertion tube and then it is

fit into the experimental apparatus. Secondly, whenever there is such a steep bend

induced in the tube, the tube tends to move into the plastic limit and the reaction

force offered by the tube is dampened.

120

100

cm) 80 - 60

40 Moment(N 20

0 0 2 4 6 8 10 Radius of curvature(cm)

Figure 20 Moment vs. Radius of curvature of the insertion tube.

65 ii. Plot 2 – Moment vs. Radius of curvature (for different positions)

To find similarity of the position points (A, B, C and D), moment is plotted

against the radius of curvature again. Through the mean values of the moment,

position A and B share a similar behavior while the position C and D are also

similar. Hence, the colonoscope is not symmetrical and the channels of water, air

and camera with the dial strings contribute to the stiffness of the colonoscope with

the steel meshing.

Figure 21 Moment vs radius of curvature for positions A, B, C and D (clockwise). 66

From the above graphs, the force applied by the insertion tube when it is subjected to bending can be determined. This data is an important input to decide the diameter of contours which interact with the insertion tube in the TH.

4.3.2 Force test of the TH

The main function of the TH is to hold the insertion tube of the colonoscopy equipment. While screening, the physician checks the colon for polyps or any abnormal growth. Once the physician finds the polyp, he needs assistance in holding the insertion tube so that the polyp does not move out of the vicinity. This assistance can provided by the TH, which holds the insertion tube. The insertion tube generally is smeared with lubricant, which facilitates easy movement through the colon. The lubricant causes the slipping of the insertion tube due to self-weight. This test helps in determining the force required to initiate slipping action when the insertion tube is help by the TH. The weight of the insertion tube is 0.5kg. The force generated by its self-weight is around 5N.

The insertion tubes available on the market vary from 12.5mm to 13.7mm.

Pediatric colonoscopies are not considered in this research. Two different diameter tubes were considered for testing. One diameter is the smallest, 12.45mm and the other is the largest, 13.7mm. The force required to initiate slipping is recorded with a force sensor.

The insertion tube is smeared with the lubricant, and small serrated grooves are made on the insertion tube. Through these serrations, an inelastic thread is tied and the other end of the thread is attached to the hook of the force sensor. The force sensor is set at a range of +50N to -50N. The force sensor is mounted rigidly on a wooden plank through a mount pole. The insertion tube is then held by the TH grip. The tension force 67 is recorded by the force sensor. The force sensor arrangement with the TH is shown in

Figure 29. Then the TH is slowly pulled away from the sensor until the tube starts to slide from the clamp. The force sensor readings are recorded through LabPro. A zero reading is ensured prior to each trial. The experimental values are recorded for 10 seconds. The experiment is repeated for three trials at three different locations of the scope. The same procedure is conducted for tube diameters of 12.45mm and 13.7mm.

Figure 22 Force sensor arrangement for the force impart test of TH.

4.4 Equipment evaluation through survey

After the equipment is developed, the equipment is evaluated from a user point of view. Ten students participated in this evaluation after getting the IRB consent. The students are asked to perform the colonoscopy procedure on a simulator ACTM (Active

Colonoscopy Training Model). The colonoscope procedure is conducted in two environments: once with the developed equipment and then again without the equipment. 68

To eliminate the effect of a learning curve, the hired students are divided into two groups, one group that performs the procedure with the equipment first and later without the equipment. The other group first performs the procedure without the equipment and then later with the developed equipment. Three trials are conducted for both the scenarios. The cecal intubation time and the total time of the procedure are recorded for all the trails.

The instruments consist of a training model that has a silicone colon. The operator will be using the Olympus CF-140 L colonoscope to perform the test. There is a video imaging unit consisting of a monitor (Olympus OEV 201), image recorder (Olympus CV 100), and a colonoscope power source (Olympus CLV – U20).

Figure 23 ACTM - Active Colonoscopy Training Model.

A brief program of study is mentioned below:

i. Step 1: The students will be given a short orientation about the colonoscopy

procedure and the steps necessary to perform the procedure on the simulator

(ACTM).

ii. Step 2: The students will be recruited as per their availability. Then, the student

will perform the procedure on the simulator. They will also be educated about the

dangers of occupational injuries and the infectious diseases that can be

transmitted through colonoscopy. All the students will be numbered sequentially.

The data recorded will be identified by a number and not by their name. The data

will be anonymous. The subject will be performing three trials and the intubation

time is clocked. iii. Step 3: The student will be asked to perform the procedure again with the

equipment fo r three trials. iv. Step 4: The students will then be administered a questionnaire. The questionnaire

asks the student to rate the equipment based on different variables. This data

helps to evaluate the effectiveness of the equipment.

The survey questions are attached in Appendix C.

CHAPTER 5: RESULTS AND DISCUSSIONS.

The CHH, the Shield, and the TH were fabricated as per the physician’s requirements and the observing the colonoscopy procedure. The equipment was subjected to various testing and validation. The testing involved subjecting the developed shield to drop ball test and drop test. The force required by the insertion tube to slip from the TH is also determined using a force sensor. The results are explained in detail in this chapter.

5.1 Validation of the CHH

The CHH aims at improving the comfort of the physician while performing colonoscopy. Many new medical students who aspire to have a career in colonoscopy find it difficult to manipulate the control head dials while simultaneously gripping it. The procedure involves the physical task of gripping the colonoscope, pushing the insertion tube through the colon, pinching the dials to bend the distal tip, pushing the tube and holding the control head. The physician also has to observe the video monitor stationed at an elevated height. He has to be vigilant and has to look out for any aberrant growth and polyps. These activities performed simultaneously, can be very strenuous and can lead to stress overuse injuries like Carpal tunnel syndrome, lateral epicondylitis etc. The lubricant smeared over the scope can also lead to the slipping of the colonoscope from the physician’s hand. The inclusion of the CHH in the procedure not only enhances the grip and the control of the colonoscope, it also reduces the fatigue load on the physician’s arm. 71

5.1.1 Test for fatigue reduction using surface electromyography

In general, the colonoscope procedure takes place for half an hour. The amount of fatigue reduced by the implementation of the CHH into the procedure can be evaluated by surface electromyography. Twelve healthy medical students were recruited for the study. They were asked to hold and manipulate the dials of the control head of the scope for 20 rotations for half an hour. The muscle activity of the biceps brachii and flexor carpi radialis muscles were recorded throughout the duration. The procedure was conducted for both cases: one with the control head being supported by the CHH and the other in absence of the CHH.

The study in which results are dependent on the performance of the participant is always subjected to learning effect. Learning effect is defined as the improvement in the measurements demanding co-operation from the subjects taken at small intervals. The

Biodex equipment has negligible learning effect on the performance of the student [46].

However, the subjects were randomly divided into two groups to avoid the learning effect. While Group 1 first held the control head without the CHH and then held it with the CHH, Group 2 first held the control head with the CHH and then later without the

CHH. The classification of the subjects are shown in the Table 13 below.

Table 7 Classification of groups for the surface electromyography test.

Group 1 Group 2 S2 S1 S5 S3 S6 S4 S8 S7 S10 S9 S11 S12

The MVC for the biceps brachii and flexor carpi radialis was recorded on a

Biodex isometric dynamometer and Jamar dynamometer respectively with help of Biopac

MP-150 channel through the Acqnowledge software. Three trials of MVC for both muscle groups were recorded pre- and post-procedure. The difference in MVC values gives us an appropriate estimate of the fatigue induced in that muscle group. The Table

15 shows the recorded MVC values at baseline and post procedure of biceps brachii for with CHH and without CHH conditions.

Table 8 MVC values recorded for biceps brachii at pre and post procedure for with

support (WS) and without support (WOS) conditions.

Bicep MVC Subject No Pre_WS (ft-lbs) Post_WS (ft-lbs) Pre_WOS (ft-lbs) Post_WOS (ft-lbs) 31.93 23.53 26.73 22.01 S1 29.39 22.28 25.57 19.87 32.04 22.88 23.66 21.01 23.61 31.45 20.06 19.72 S2 21.80 31.28 18.32 19.02 20.35 31.16 18.01 19.81 35.23 34.25 34.70 32.95 S3 30.79 30.10 32.57 30.76 30.04 30.65 30.71 28.90 28.03 25.93 31.76 31.90 S4 28.36 24.44 35.33 34.19 27.45 25.27 35.39 32.82 5.86 6.26 14.34 13.92 S5 6.13 6.08 13.41 14.06 6.01 7.29 15.12 12.19 32.52 41.79 39.70 31.29 S6 35.51 42.38 35.40 27.65 39.25 42.84 32.60 33.88 14.04 16.02 15.41 15.42 S7 13.52 16.22 14.75 13.91 13.88 17.43 14.86 14.23 32.87 29.92 28.73 30.15 S8 31.04 29.33 27.39 29.51 30.26 31.19 27.58 28.99 45.66 48.46 35.82 35.77 S9 43.41 41.54 38.95 33.31 40.82 40.86 36.35 30.45 16.89 15.42 19.70 17.55 S10 16.39 15.51 18.95 17.79 15.52 15.43 19.30 17.87 33.42 31.20 31.97 31.75 S11 30.03 30.08 33.37 31.36 29.97 32.02 30.97 29.97 45.51 51.00 44.47 40.19 S12 46.79 45.58 45.87 39.45 46.49 47.18 44.19 40.25 Mean 28.08 28.73 28.11 26.22 Standard 11.56 12.01 9.48 8.40 deviation Percentage -1.49% 6.7% difference 74

MVC of the Biceps Brachii for with and without CHH 40

lbs) 35 -

30 With support 25 Without support 20 Force recorded(ft

15 PRE POST Time

Figure 24 Plot of fatigue induced in biceps brachii for both events - with support (WS)

and without support (WOS).

Figure 34 shows the comparison between MVC values of biceps brachii at conditions when the control head is supported and when it is not. There is 6.7% induction of overall fatigue when the control head is held by the subject and there is no fatigue when the control head is held by the CHH. A difference of 8.7% was found between post- procedure states for with and without support conditions. The obtained results are subjected to two way repeated measures ANOVA analysis. The data is checked for homogeneity through SPSS, which compares the condition main effect, the time main effect and the interaction between the two main effects. The values of time main effect

(pre and post) and condition main effect (with support and without support) are compared. The probability values are found to be lesser than 0.05 for the interaction between the time and the condition main effect (p = 0.005). The p values of the 75 interaction of the sphericity assumption test is found to be insignificant for the time and the condition main effects when considered individually (p = 0.184 and p = 0.16).

Because of this significant difference in values, the data is subjected to one way repeated measures ANOVA.

One way repeated measures ANOVA is conducted on the data for comparison between all the four possibilities shown in the graph – pre (WS) and pre (WOS), post

(WS) and post (WOS), pre(WS) and post (WS), post (WOS) and post (WOS). The significance p, between the conditions through a one way repeated measures is as shown in the Table below. The significance values for each comparison are highlighted in bold.

The comparison between the post states (WS and WOS) and pre (WOS) and post (WOS) clearly indicates significant difference between the conditions through the obtained p values.

Table 9 Sphericity tests for the one way repeated measures ANOVA.

Comparison Test F Sig. Sphericity pre (WS) - pre (WOS) 0.002 0.96 Assumed Sphericity post (WS) - post (WOS) 5.18 0.029 Assumed Sphericity pre (WS) - post (WS) 0.73 0.39 Assumed Sphericity pre (WOS) - post (WOS) 17.36 0.00 Assumed

The MVC readings for biceps brachii muscles of the 12 subjects for with support and without support condition are plotted in Figure 35. The fatigue induced because of the sustained activity varied for each person. There were subjects where the fatigue 76 induced was around 17%. The percentage of fatigue induced in biceps brachii muscles for all 12 subjects is shown in the Figure 36. Some results showed an increase in strength with the use of the CHH. The increase in strength could be due to the learning effect and the warm up of the muscles due to the activity.

MVC Biceps Brachii - without support 50 45 40 35 lbs) - 30 25 MVC_BICEPS_PRE_WOS 20 MVC_BICEPS_POST_WOS Torque (ft Torque 15 10 5 0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 Subjects (12)

Figure 25 MVC of biceps pre and post procedure for without support condition.

MVC Biceps Brachii - with support 60 50 lbs)

- 40 30 MVC_Biceps_PRE_WS 20 MVC_Biceps_POST_WS Torque(ft 10 0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 Subjects (12)

Figure 26 MVC of biceps pre and post procedure for with support condition.

Similarly, there were two cases of exceptions were observed – S4 and S8 where there was fatigue induced because of the CHH. No proper explanation could be made to understand this observation[46].

MVC Bicep Brachii percentage difference 20 15 10 5 0 MVC BICEPS_WOS S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 -5 MVC BICEPS_WS -10 Percentage (%) Percentage -15 -20 -25 Subjects (12)

Figure 27 Percentage of fatigue induced in the twelve subjects for without support

(WOS) and with support (WS) conditions for biceps brachii. 78

The flexor carpi radialis or the forearm muscle group MVC values are listed in the

Table below. The forearm muscles are equally stressed during the procedure due to the simultaneous gripping and pinching load. The tabulation also shows the mean and standard deviations for with support and without support conditions.

MVC of Flexor Carpi Radialis for with and without CHH 55

50 lbs) - 45

Force induced (ft 30

25 PRE POST Time

Figure 28 Plot of fatigue induced in flexor carpi radialis for both events - with support

(WS) and without support (WOS).

Table 10 MVC values recorded for flexor carpi radialis at pre and post procedure for with

support (WS) and without support (WOS) conditions.

Forearm MVC Subject No Pre_WS (ft-lbs) Post_WS(ft-lbs) Pre_WOS (ft-lbs) Post_WOS (ft-lbs) 32 32 36 30 S1 32 34 32 27 30 34 30 28 38 38 36 38 S2 37 36 38 34 32 32 36 32 46 52 53 52 S3 42 46 46 49 46 42 49 45 40 42 40 42 S4 40 38 38 40 39 36 39 38 30 31 26 22 S5 30 27 26 20 26 26 24 22 57 55 57 52 S6 48 50 55 47 45 52 53 47 20 22 22 20 S7 24 25 22 23 23 26 24 21 49 49 46 46 S8 48 46 46 44 45 44 43 38 42 43 38 37 S9 39 43 38 30 37 41 37 28 31 30 31 29 S10 31 29 29 26 31 30 28 27 49 55 50 49 S11 52 52 52 48 50 49 46 49 62 58 60 56 S12 55 51 55 58 60 62 56 52 Mean 39.94 40.5 39.91 37.38 Standard 10.63 10.59 11.14 11.48 deviation Percentage difference -1.39% 6.33% (%)

Figure 28 shows the comparison between MVC values of flexor carpi radialis at conditions when the control head is supported and when it is not. There is a 6.33% induction of overall fatigue when the control head is held by the subject and there is no fatigue when the control head is held by the CHH. There was a difference of 7.68% between the post-procedure states for with and without CHH conditions. Similar to biceps brachii muscles, the data is subjected to two way repeated measures ANOVA. The data is checked for homogeneity and normality through SPSS, which compares the condition main effect, the time main effect and the interaction between the main effects.

The values of the time main effect (pre and post) and the values of the condition main effect (with support and without support) are compared separately. The probability values are found to be greater than 0.05, for the interaction between the time and the condition main effects. For the forearms, the p values of the sphericity assumption test is found to be significant for time and condition main effects when considered individually (p = 0.05 and p = 0.03) and significant for the interaction factor (p = 0.00). Because of this significant difference in values, the data can be subjected to one way repeated measures

ANOVA for pairwise comparisons.

One way repeated measures ANOVA is conducted on the flexor carpi radialis data for comparison between all the four possibilities shown in the graph – pre (WS) and pre (WOS), post (WS) and post (WOS), pre(WS) and post (WS), post (WOS) and post

(WOS). The significance factor between the conditions through a one way repeated measures is as shown in the Table below. The significance values of p < 0.05 are 81 highlighted in bold. The comparison between the post states (WS and WOS) and pre and post (WOS) states indicates significant difference through the obtained p values.

Table 11 Sphericity tests for the one way repeated measures ANOVA.

Comparison Test F Sig. Sphericity pre (WS) - pre (WOS) 0.003 0.95 Assumed Sphericity post (WS) - post (WOS) 19.069 0.00 Assumed Sphericity pre (WS) - post (WS) 1.32 0.25 Assumed Sphericity pre (WOS) - post (WOS) 22.55 0.00 Assumed

The MVC readings for flexor carpi radialis muscles of the 12 subjects for with support and without support condition are plotted in Figure 39. The fatigue induced because of the sustained activity varied for each person. There were some subjects where the fatigue induced was around 17%. The percentage of fatigue induced in flexor carpi radialis muscles is shown in the Figure 41. Some results showed an increase in strength with the use of the CHH. The increase in strength could be due to the learning effect and the warm up of the muscles.

MVC Flexor Carpi Radialis - without support

70 60 50 40 30 MVC_Forearms_PRE_WOS

Force (lbs) 20 MVC_forearms_POST_WOS 10 0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 Subjects (12)

Figure 29 MVC of forearms pre and post procedure for without support condition.

MVC Flexor Carpi Radialis- with support 70 60 50 40 30 MVC_Forearms_PRE_WS

Force (lbs) 20 MVC_Forearm_POST_WS 10 0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 Subjects (12)

Figure 30 MVC of forearms pre and post procedure for with support condition.

Similar to the biceps, there was only one case of exception observed – S4 where there was fatigue induced because of the CHH. No proper explanation or appropriate conclusion has been made till now regarding these exceptions [47].

MVC Flexor Carpi Radialis - percentage difference in 20 MVC 15

5 MVC FOREARMS_WOS 0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 MVC FORARMS_WS Percentage (%) -5

-10

-15 Subjects (12)

Figure 31 Percentage of fatigue induced in the twelve subjects for without support

(WOS) and with support (WS) conditions for flexor carpi radialis.

The above results were subjected to two way repeated measures ANOVA analysis through SPSS. The two main effects in the analysis are time and condition. The muscle activity of the biceps brachii muscles and flexor group muscles was recorded throughout the procedure duration. The RMS EMG signal recorded at the last minute of the trial can be expressed in terms of the RMS EMG recorded at the MVC (0.5s time interval), which gives an estimate of the global muscle activity (e.g., motor units recruited) to perform the activity. The higher the amplitude of the signal recorded at the last minute, the greater the muscle activity required, which could be argued to indicate that more fatigue was induced. This increase in amplitude is largely driven by additional motor units being recruited in order to maintain the sustained activity.

Table 12 Percentage RMS EMG activity of biceps brachii recorded at the last minute of

the trial to the MVC recorded with support (WS) and without support (WOS).

Subjects Biceps_WS (mV) Percentage (%) Biceps_WOS (mV) Percentage (%) S1 0.0151 1.138 1.32 0.11 1.3754 7.99 S2 0.0443 0.3446 12.85 0.0720 0.8818 8.16 S3 0.0165 1.1547 1.42 0.0242 1.4573 1.66 S4 0.0138 0.555 2.48 0.0635 1.0597 5.99 S5 0.0048 0.7394 0.64 0.0584 0.9292 6.28 S6 0.0092 0.5805 1.58 0.0361 1.1168 3.23 S7 0.0101 0.281 3.59 0.0646 0.5623 11.48 S8 0.0052 0.8494 0.62 0.0779 1.3322 5.84 S9 0.01 0.8504 1.17 0.1421 0.8091 17.56 S10 0.0225 1.4882 1.51 0.0898 1.5679 5.73 S11 0.0047 1.0492 0.44 0.0606 1.6093 3.76 S12 0.0093 2.4611 0.37 0.0403 2.5899 1.55

The percentage of muscle activity of RMS EMG recorded at the last minute in comparison with the RMS EMG recorded at the MVC is tabulated as shown in Table 18.

The RMS EMG values recorded at the last minute in comparison with the MVC RMS

EMG values (0.5 time interval) clearly indicate that the muscles get more fatigued when the control head of the scope is unsupported. The mean value of the biceps brachii muscle activity recorded for the last minute was 5.50% of the MVC recorded. It can be observed that the RMS EMG value of muscle activity drops with the implementation of CHH in the procedure. However, there were exceptions like with subject S2, there was more muscle activity observed at the last minute with CHH when compared to the muscle activity of the last minute without CHH. No appropriate conclusions could be made to explain this behavior[46]. The data was subjected to two way repeated measures, the main effects being time and condition. The sphericity test indicated a significance value 85 is less than 0.05 for the interaction (time * condition, p = 0.002). The time and condition main effects had significance factor of 0.00 and 0.00 respectively. The graph in Figure 41 shows the difference in muscle activity for the two conditions at pre and post events.

RMS EMG values at the last minute Vs. RMS EMG values at MVC - Biceps Brachii 2 1.8 1.6 1.4 1.2 1 WITH SUPPORT 0.8 WITHOUT SUPPORT 0.6

Muscle activity Muscle activity (mV) 0.4 0.2 0 LAST MINUTE OF MVC THE TRIAL

Figure 32 RMS EMG values at the last minute of the trial in comparison with the RMS

EMG values recorded at MVC for with CHH (WS) and without CHH (WOS) conditions -

biceps brachii.

One way repeated measures were conducted to compare conditions like pre (WS) and pre (WOS), post (WS) and post (WOS), pre (WS) and post (WS), post (WOS) and post (WOS). The significance values are shown in Table 20.

Table 13 Sphericity tests for the one way repeated measures ANOVA for muscle activity

of biceps brachii

Comparison Test F Sig. pre (WS) - pre (WOS Sphericity Assumed 33.713 0.00 post (WOS) - post (WOS) Sphericity Assumed 28.61 0.00 pre (WS) - post (WS) Sphericity Assumed 30.475 0.00 pre (WOS) - post (WOS) Sphericity Assumed 30.475 0.00

Bicep Brachii muscle activity 20

12 BICEP BRACHII MUSCLE 10 ACTIVITY_WOS BICEP BRACHII MUSCLE 8 ACTIVITY_WS Percentage (%) 6

0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12

Figure 33 Biceps muscle activity of 12 subjects at the last minute of the trial in

comparison to the muscle activity at the MVC (time interval = 0.5 sec) for with support

(WS) and without support (WS) conditions.

Similar to the muscle activity of the biceps brachii, the flexor carpi radialis muscle activity is also recorded for a period of 30 minutes. 87

Table 14 Percentage RMS EMG activity of flexor carpi radialis recorded at the last minute of the trial to the MVC recorded with support (WS) and without support (WOS) –

flexor carpi radialis.

Percentage Forearms_WOS Percentage Subjects Forearms_WS (mV) (%) (mV) (%) S1 0.00842 0.81184 1.03 0.03651 0.8643 4.22 S2 0.0386 0.3848 10.03 0.0229 0.3222 7.10 S3 0.0126 1.1862 1.06 0.00928 0.967 0.95 S4 0.0199 0.4709 4.22 0.0159 0.8707 1.82 S5 0.0178 0.314 5.66 0.0341 0.2873 11.86 S6 0.0091 1.3941 0.65 0.0128 1.4467 0.88 S7 0.0027 0.4761 0.56 0.0307 0.4274 7.18 S8 0.00726 0.8554 0.84 0.0371 0.5333 6.95 S9 0.00861 0.3815 2.25 0.0103 0.5879 1.75 S10 0.01694 0.5731 2.95 0.0582 0.6805 8.55 S11 0.02422 0.854 2.83 0.0309 0.8332 3.70 S12 0.01921 0.9916 1.93 0.0071 1.2644 0.56

The data was subjected to two way repeated measures, the main effects being time and condition. The sphericity test indicated a non - significant value which was greater than 0.05 (p = 0.712) for the interaction (time * condition). The time and condition main effects had significance factor of 0.000 and 0.465. The graph in Figure 44 shows the difference in muscle activity for the two conditions at pre and post events.

RMS EMG values at the last minute Vs. RMS EMG values at MVC - Flexor Carpi Radialis

1.2

0.8

0.6 WITH SUPPORT 0.4 WITHOUT SUPPORT

Muscle activity Muscle activity (mV) 0.2

0 LAST MINUTE OF MVC THE TRIAL

Figure 34 RMS EMG values at the last minute of the trial in comparison with the RMS

EMG values recorded at MVC for with CHH (WS) and without CHH (WOS) conditions

– flexor carpi radialis.

The two way repeated measures ANOVA clearly indicate that the values do not vary from each other significantly. Thus, the muscle activity of the flexor carpi radialis muscle group was influenced very little by the implementation of CHH.

Flexor carpi radialis muscle activity 14

8 FLEXOR CARPI RADIALIS 6 MUSCLE ACTIVITY_WOS FLEXOR CARPI RADIALIS Percentage (%) 4 MUSCLE ACTIVITY_WS

0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 Subjects (12)

Figure 35 Flexor carpi radalis muscle activity of 12 subjects at the last minute of the trial

in comparison to the muscle activity at the MVC (time interval = 0.5 sec) for with

support (WS) and without support (WS) conditions.

5.2 Validation of Splatter shield

In order to use the shield, it has to satisfy the requirements like drop test and drop ball test. The results of the tests conducted on the shield are mentioned below.

5.2.1 Drop test

The shield is subjected to a drop test where it is dropped from a height of

30in[45]. The thermoformed shield is made from three different sheets of acrylic and is tied together. The drop test is conducted for ten trials. The impact was negligible and there were small scratches observed on the surface of the shield after the fourth trial.

Table 7 below explains the results of the drop test. 90

Table 15 Drop test results conducted on the prototype shield

Impact Mass of Trial Height Energy the Shield Observations on the prototype No (m) (J) (Kg)

1 0.6 0.76 4.47 No cracks or scratches observed. 2 0.6 0.76 4.47 No cracks or scratches observed. 3 0.6 0.76 4.47 No cracks or scratches observed. 4 0.6 0.76 4.47 Negligible scratches observed. 5 0.6 0.76 4.47 Negligible scratches observed. 6 0.6 0.76 4.47 Negligible scratches observed. 7 0.6 0.76 4.47 Negligible scratches observed. 8 0.6 0.76 4.47 Negligible scratches observed. 9 0.6 0.76 4.47 Negligible scratches observed. 10 0.6 0.76 4.47 Negligible scratches observed. * The testing is conducted tying the parts of the shield together for worst case scenario.

5.2.2 Drop ball test

The shield is subjected to drop ball test. The ball impactor is made of steel and weighs 78gms. A ball impactor is dropped on to the apex of the shield from a height of

0.127m to test the impact resistance of the shield. Ten trials were conducted and the position of the shield was not changed for any trial. The proof of concept prototype is made of three different acrylic sheets, thermoformed, then joined together using acrylic cement. Developing a shield using a single sheet of acrylic will improve the endurance of the shield.

Table 16 Results of the drop ball test on the shield

Trial Mass of the Height Observations on the prototype No Ball (Kg) (m) 1 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 2 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 3 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 4 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 5 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 6 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 7 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 8 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 9 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield. 10 0.076 1.27 Small Indentation marks (<<1 mm) were recorded on the shield.

The shield is observed for indentations or cracks. There were no cracks observed after of the impact. However, there were very small indentations observed on the shield.

These indentations were of negligible (<<1mm) depth. The shield was able to sustain impact loads induced from the ball impactor.

5.3 Validation of the TH

The TH is implemented to assist the physician in holding the insertion tube while he performs the biopsy by feeding the biopsy forceps through the biopsy channel. He needs assistance from a nurse to hold the tube to keep the polyp in the vicinity. The TH 92 holds the tube rigidly, preventing the scope from sliding and losing the polyp from the vicinity. The TH is subjected to a force test and tube diameter test to evaluate the performance of the equipment.

5.3.1 Force test of the TH

The colonoscopes available in market vary from 12.5mm to 13.7mm (data obtained from Olympus and Pentex websites). The TH should be capable of holding all scopes. While in procedure, the insertion tube is smeared with lubricant. The self-weight causes the insertion tube to slide down due to self-weight. The weight of the scope is around 0.5kgs, which renders a force of 5N. The grip of the TH should be capable of holding the tube to avoid sliding. Once the tube slides, the polyp is lost from the vicinity.

The physician has to find the polyp all over again, which is tiresome. Hence the force imparted by the TH to grip the insertion tube should be much greater than the self-weight of the colonoscope. This experiment determines the force required to initiate slipping of the tube from the TH. Table 23 gives the values of the forces recorded for tube diameters

12.45mm and 13.7mm.

The force sensor recorded average forces of 44.0028N and 45.4370N for tube diameters of 12.45mm and 13.7mm respectively. This force is greater than the self- weight of the insertion tube.

Table 17 Forces recorded at 3 positions for 3 trials on colonoscope of sizes 12.45mm

diameter and 13.7 diameter

12.45mm diameter 13.7mm diameter

Sl No Maximum force recorded Maximum force recorded 1 44.73 41.35 2 44.55 42.71 3 36.49 47.94 4 45.25 51.69 5 34.10 54.18 6 40.16 63.93 7 41.99 38.05 8 49.81 32.98 9 58.92 36.05 Average 44.00 45.43 Standard Deviation 7.34 9.91

Force imparted by the plunger of the TH 60

Force (N) 20

0 12.45mm 13.7mm Diameter of the insertion tube (mm)

Figure 36 Force with error bars recorded by the force sensors for tube diameters

12.45mm and 13.7mm.

Table 18 Factor of Safety for the force grip imparted by the TH for tube diameters

12.5mm and 13.7mm respectively.

Tube Sl Average force Force induced by the Factor Of Diameter No recorded (N) insertion tube(N) Safety (FOS) (mm) 1 12.45 44.0028 5 8.8006 2 13.7 45.4370 5 9.0874

5.4 Equipment evaluation through survey

Both the CHH and the shield with the TH was evaluated by students to determine the effectiveness and amicability of the equipment usage. The equipment was evaluated by expert physicians also. It helps to note a neutral point of view from the participating subjects. The variables tested include usability, the space occupied, the effectiveness and the safety ensured by the equipment. The experiment was conducted by ten subjects on a simulator, ACTM (Active Colonoscopy Training Model) with and without the developed equipment for three trials. The cecal intubation time and the total time was noted for each trial. The subjects’ feedback was collected through an administered survey at the end of the trial. The results of the equipment evaluation survey is as follows. 95

Splatter shield evaluation 6

5 How much do you feel, the 4 shield improves endoscopist's safety?

3 Does the equipment take too much bed space? Rating

2 Rate the overall value of the shield 1

0 Subjects (10)

Figure 37 Evaluation of the Splatter shield by ten students.

CHH evaluation 6

5 How heavy is the contol head of the colonoscope? How much the holder decrease 4 the stress? How much space does the 3 control head holder utilize?

Rating How much does the holder hinder your movement? 2 Does dexterity improve with the use of CHH? 1 Rate the overall value of the CHH from 1 to 5 0 Subjects (10)

Figure 38 Evaluation of the CHH by ten students.

Eight out of ten students felt that the control head of the colonoscope was heavy and the simultaneous movement of the dials and gripping the control head was a difficult task. The use of the lubricant makes the task more difficult because it makes the control head slippery. The subjects expressed better control over the procedure as they had more command over the manipulation of the dials, because the CHH relieves the gripping load off the subject’s arm. The subjects indicated pain in thumb, wrist and biceps due to the sustained activity. All the subjects agreed that a stand to hold the control head was necessary. 60% of the subjects indicated that the implementation of the CHH relieves the stress entirely. All the subjects expressed content over the improvement of dexterity through the use of CHH. The subjects rated the CHH to be a valuable addition into the procedure (mean = 4.5; standard deviation = 0.5270).

All the subjects indicated that the implementation of the shield improves the safety of the physician. The shield is found not to interfere with the subjects hand movements during the procedure. The clear acrylic shield does not obscure the physician’s vision of the patient. Seven out of ten students mentioned that the shield did not occupy much bed space. They rated the shield to have a value of 4.6 out of 5

(standard deviation = 0.5163). However, a few subjects as well as the physicians complained about the additional length of the insertion tube taken up by the shield curvature.

Most of the subjects were unaware of the dangers of the splashes and the need of the protective equipment during colonoscopy procedure. The study helped them realize the importance of PPE in any surgical procedure. The subjects also expressed their 97 ignorance about the mechanical risks to the physician during colonoscopy. The study helped them realize the importance of following a right posture and the need of support equipment during any strenuous activity.

The cecal intubation time and the total time was measured for all subjects for each trial. Figure 50 shows the cecal intubation time by the subjects to perform the procedure on the ACTM with and without the equipment. The students were able to exercise better control of the procedure through the CHH and were able to maneuver better through the simulator. The students took 32% less time to reach cecum with the help of the equipment. The total time was also 25% less than the time taken by the student without the equipment. Figure 51 shows the total time taken by the students for three trials with and without the developed equipment.

Intubation time 900 800 700 600 500 400 intubation time_WOS Time Time (s) 300 intubation time_WS 200 100 0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 Subjects (10)

Figure 39 Cecal intubation time taken by ten subjects on the ACTM for with developed

equipment (WS) and without developed equipment (WOS). 98

Total Time 1200

1000

800

600 Total Time_WOS Time Time (s) 400 Total time_WS

200

0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 Subjects (10)

Figure 40 Total intubation time taken by ten subjects on the ACTM for with developed

equipment (WS) and without developed equipment (WOS).

However, there was one case where the subject took more time to reach the cecum with the developed equipment. The delay was mainly because of the poor clarity of the video monitor during the trials with support.

CHAPTER 6: CONCLUSIONS

The Splatter shield, the CHH and the TH were fabricated as per the requirements derived from the discussions with the physician. The colonoscopy procedure was also observed to understand and address the problem better.

6.1 Evaluation of thesis objectives

The thesis objectives mentioned in section 2.5 are as follows:

i. Develop a holder to grip the control head of the colonoscope as per the physician

requirements.

ii. Test the holder for reduction of fatigue in biceps brachii and flexor carpi radialis

muscle groups due to the sustained activity of holding the control head. Analyze

the obtained data by using statistical tools. iii. Functional evaluation of the holder by recruiting volunteers to perform the

procedure on a simulator with the holder. iv. Conceptual analysis of a Splatter shield to resist infectious splatters from reaching

the physician.

v. Conceptual analysis of a tube holder to facilitate gripping of the insertion tube

when the physician performs a biopsy.

The thesis objectives were achieved as follows:

i. The CHH was developed as per the requirements derived from observing the

colonoscopy procedure coupled with discussions with the physician. The

equipment was fabricated conforming to these requirements. 100 ii. The CHH was tested for reduction of fatigue through comparison in MVC and

electromyography. The results clearly indicate that there was significant decline

of MVC by 6.7% in biceps brachii and 6.3% in flexor carpi radialis muscle groups

due to the sustained activity. The implementation of CHH into the procedure, not

only reduced the fatigue, but also showed a trend of increase in strength. There

was increase in strength in biceps brachii by 2.3% and in the flexor carpi radialis

by 1.4%. However, the increase in strength can be justified by the learning effect.

There was also a drop in bicep brachii and flexor carpi radialis muscle activity

with the implementation of CHH, which was indicated by a drop in percentage of

RMS EMG value at the last minute of the trial when compared to the RMS EMG

value at the MVC. The data obtained for MVC for both muscle group were found

to be homogeneous and significant (p < 0.05). But the muscle activity recorded

for the flexor carpi radialis was found to be insignificant (p > 0.05).

The CHH not only enables the physician to have better control of the

procedure but also reduces the amount of fatigue involved with manipulation of

dials and gripping the insertion tube. Colonoscopy procedure also involves tasks

like pushing the insertion tube observing the video monitor, and looking out for

polyps. It has to be noted that the students who participated in this study were not

subjected to such conditions. They only held the scope in their left hand and

manipulated the dials. Secondly, an expert physician performs eight to ten

colonoscopies in a single shift in renowned hospitals, which is four to five hours

of procedural observation. The experiment conducted in this research is for 30 101

min, considering the average duration for one colonoscopy procedure. Taking

these factors into consideration, 7% drop in MVC imposes a serious problem to

the physician that can lead to occupational injuries. iii. The CHH was evaluated by ten students by performing the procedure on a

simulator, ACTM. The students rated the CHH to be helpful and stated that it

would give them better control of the colonoscope. They also stated that the CHH

alleviated the pain in their arms and they were able to maneuver the scope through

the colon easily. Additionally, the results also showed a drop in time taken for

cecal intubation by the subjects with the CHH. The improvement is because of the

better control environment set up by the CHH. When the subjects conducted the

procedure without the CHH, most time was spent in holding the control head

firmly in hand. However, experts rated the CHH to be bulky and reduction in its

size would lead to preservation of space. iv. A Splatter shield was also developed conforming to the requirements derived

from observing the procedure coupled with discussions with the physician. A

prototype was built for conceptual analysis. The shield was able to sustain the

impact loads when it was subjected to drop test and drop ball test. The proof of

concept prototype did not address critical issues like sterilization of the

equipment, stability, isolation from contamination, type of interaction between the

patient and shield etc. There was no testing conducted to validate the use of

shield, but the proof of concept prototype and the data considered for developing

the it, can be referred for future research. 102 v. The TH was fabricated as per the specifications that were derived after

discussions with the physician. The TH can grip the scope till a force of 45N is

imparted on the insertion tube to initiate slipping. The experiment is conducted on

both 12.45mm and 13.7mm diameter tubes which satisfies the requirement of

gripping various tubes available in the market. One important limitation in this

objective is the interaction between the clamp grip and the insertion tube is not

studied in this research. Similar to the Splatter shield, the proof of concept

prototype can only exhibit the idea involved. There was no testing conducted to

validate the use of the tube holder. However, this data obtained to develop the TH

can be used for future research.

103

CHAPTER 7: FUTURE WORK

The developed equipment satisfies all the prescribed requirements by the physician. However, the prototype was made as a proof of concept, not a final product.

More research is necessary to enhance the usability of the equipment. There is more study required to make the equipment hospital friendly so that it can be taken ahead to the implementation stage for a procedure. A few areas of improvement which can improve the assistance provided by the equipment are mentioned below.

i. Making of the shield using one single polycarbonate sheet.

The prototype in this study is made of three different thermoformed acrylic

sheets. They are joined with the help of acrylic cement. Use of polycarbonate

material is recommended. However, temperature requirements in sterilization

process may restrict the use of this material. A thorough material selection study

is recommended for shield [48].

ii. Fabrication of the prototype with the suggested changes.

The experts who evaluated the developed shield mentioned that the curvature of

the shield would lead to wastage in insertion tube length. To eliminate the

wastage, the shield can be redeveloped by using angular bends. Use of a single

actuator and provision of a slider to affix the shield to the bed may make the

shield perform better. Figure 41 shows the shield with angular bends and one

actuator 104

Figure 41 Shield with angular bends and one actuator.

iii. Making the shield disposable.

Disinfestation of the shield in the steam autoclave increases the operating costs

and time. It also increases the setup time before the procedure. The costs can be

reduced by the use of the disposable shields. iv. Measuring the muscle activity and MVC while the participating subjects perform

the procedure on the simulator.

The test for fatigue with the CHH revealed that the sustained activity of holding

the scope leads to a drop of 7% in MVC. The testing never considered the

physical stress due to multiple activities like pushing the tube with the right hand,

having a constant eye on the video monitor, holding of the control head, and

manipulating the dials. This test would give a more realistic idea of the fatigue

induced when the control head is not supported by the CHH. Future study should 105

be concentrated on collecting the EMG and the MVC values of the subject when

the procedure is performed on the simulator.

v. Age group of 31-40 years should be targeted.

The present study targeted a study group of medical students who varied in the

age group of 23 – 27 years. The age group of the physicians performing

colonoscopies is generally around 40 – 55 years [49]. The fatigue induced by the

sustained activity for individuals in this age group is suspected to be more and the

future research should consider testing this age group. vi. Improvement in the mechanism of the CHH to mitigate the pain in the thumb.

Though the CHH tries to make the procedure more comfortable to the physician,

the major problems related to overuse injuries concentrate more on the thumb.

The CHH reduces the stress on the thumb, by gripping the control head. A more

flexible mechanism to reduce the stress on the thumb will lead to fewer

complaints of occupational injuries.

106

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APPENDIX A – BILL OF MATERIALS OF THE DEVELOPED EQUIPMENT

Table 19 Bill of materials of the CHH.

Item Part Finished Assembly Material Details Quantity No Name part No A B C D E F G 1018 Base plate 400mm*400mm, 1 * carbon 1 1 6.35mm thick steel 1018 Support 10mm*10mm, 2 * carbon 3 bars 1ft long steel 1005 OD = 100mm, Base 3 * carbon 5mm thick 1 Column steel hallow. 1018 Threaded 4 * carbon 3/6 - 16 thread 1 steel sleeve steel 1018 5mm thick 5 * Clevis carbon 100mm*150mm, 1 steel welded 91286A495 Grade 9 3/4 - 16 thread, 6 * Bolt Mcmaster 1 steel length = 50mm Carr 25mm thick, Extension 6061 350mm long, 7 * 1 link aluminum hole of 25mm diameter Aluminum 6061 40mm thick, 520 8 * 1 Rod aluminum mm long Pressure angle 6295K14 - 1018C 9 * Rack =14.5, pitch = Mcmaster 1 steel 16, teeth = 14 Carr ID = 40mm, Holder thickness = 10 * Steel Sleeve 5mm, setscrew to tighten 1018 Diameter = 11 * Ball link carbon 10mm, 150mm 1

steel long 304 Diameter = 12 * Ball stainless 25mm, welded 1

steel to Holder link

111

Table 20 (continued) Bill of materials of the CHH.

L plate: Longer link = 90mm, Upper Shorter link = 13 * 1 Plate 25mm, groove 304 of 15mm, stainless welded steel L plate: Longer Lower link = 90mm, 14 * 1 plate Shorter link = 25mm, welded Diameter = Holder cup 15 * 10mm, 30mm 1 link long thickness= Holder cup 25mm, 15mm 16 * Slot diameter through hole 6061 Tapered hole: aluminum Major diameter = 26mm, Minor 17 * Holder cup 1 Diameter = 22mm, groove:17mm SAE 840 Self lubricating Central 5912K3 bronze bronze bearing, 18 * support Mcmaster 2 and shaft diameter = bushing Carr aluminum 9.525mm, 304 Diameter=10mm, 19 * Gear shaft stainless 1 20mm long steel pressure angle - 14.5, pitch = 16, 6325K12 1018C teeth = 14, pitch 20 * gear wheel Mcmaster 1 steel diameter = Carr 22.22mm, bore = 9.525mm safety 21 * Aluminum 1 cover

112

Table 20 (continued) Bill of materials of the CHH.

61515K241 6061 22 * Handle Mcmaster 1 aluminum Carr 6061 T6 1/4-20 thread for 23 * Tight Pin 1 aluminum 20mm long A CHH B Clevis joint C Rack link D Holder link E Holder plate F Holder cup G Gear

Table 20 Bill of materials of the Splatter Shield.

Item Finished Assembly Part Name Material Details Quantity No Part No A B C D E F Inner most Diameter = 240mm, Cast Outer most 1 * Shield 1 acrylic Diameter = 270mm, thickness = 5mm, thermoformed Extrusion 6061 20mm*20mm V 2 * 2 rod aluminum slot, 210mm long Modular end 3 * Steel 2 mounts Mini V 4 * Rubber wheel Openbuilds Ball Website 5 * Steel DGBB bearings recognizes Precision component 6 * Steel 5mm long by part shim 4 Aluminum names 7 * Aluminum 5mm long spacer 8 * Screw Steel M5,25mm long Lock nut Steel/ 9 * M5 with insert Nylon

113

Table 20 (continued) Bill of materials of the Splatter shield.

10 * Idler pulley Plastic 2

Ball 11 * Steel DGBB 2 bearings 12 * Shim Steel 5mm long 2

13 * Spacer Aluminum 5mm long 2

14 * Screw Steel M5,25mm long 2

Lock nut Steel/ 15 * 1 with insert Nylon Eccentric 16 * Steel 4 spacers 17 * Tee nuts Steel 10

Low profile 18 * Steel M5, 6mm long 8 screws 19 * Spacer Aluminum 3.2mm long 4

Tooth 30 tooth, 2mm 20 * timing Aluminum 2 pitch pulley 2mm pitch, 21 * Timing belt Rubber 2 500mm long 22 * Cable ties Plastic 4

Motor 23 * Aluminum 2 mount plate Stepper 24 * Steel 2 motor

114

Table 20 (continued) Bill of materials of the Splatter shield.

V-slot gantry 25 * Aluminum 2 plate

Arduino RB- 26 * Plastic Arduino Uno, R3 1 board Ard34

Slidepot - Xlarge- 27 * Potentiometer Plastic 0 - 60mm, slider. 1 Sparkfun electronics Power 28 * 5v, 1A limit 2 supply 80/20 6850 OTP 29 * L handle Plastic industrial 2 solutions 1/4-20, 25mm 30 * Bolt Steel long 1018 140mm*180mm, 31 * Base carbon 2 5mm thick steel 6061 32 * L clamps 2 aluminum curved slot of 6061 33 * Holder 270mm, 5mm 2 aluminum thick 34 * Screws Steel M5, 10mm long 35 1/4-20 female 6071K41 35 * Clevis joint Steel thread, 50mm McMaster 2 long - Carr 6061 T6 1/4-20 thread, 36 * Thread rod 2 aluminum 25mm long 1018 10mm*10mm, 37 * Main link 1 steel 250mm long Wide Mouth width 38 * mouthed steel 1 >35mm clamp 1/4-20 thread, 39 * Lock screw steel 2 10mm long Cast bent and 40 * Base cover colored 4 thermoformed acrylic A Shield B Linear actuator C Safety lock D Bed clamp E Mini wheel kit F Idler pulley kit 115

Table 21 Bill of materials of TH.

Item Finished Assembly Part Material Details Quantity No Part No A B C Clamp 1 * Delrin 1 Grip Diameter = 12.7mm, length 6061 2 * Button 25mm, groove width = 10mm, 1 aluminum groove length = 10mm Zinc 9657K333 plated length =15mm, OD = 9.144mm, 3 * Spring Mcmaster 1 music Wire diameter = 1.0414 mm Carr wire Metal 6061 Ring with 3 setscrews, Groove 4 * 1 Ring aluminum of 20mm 90293A10 Ball Diameter = 4.5mm, length = 6 - 5 * Spring Steel 1 50mm McMaster Pushpin Carr 1018 Plunger Diameter = 8mm, taper groove 6 * carbon 1 rod of 2mm deep Steel Zinc 9657K312 Plunger plated length = 60mm, OD = 12.7mm, - 7 * 1 spring music Wire diameter = 1.0414mm McMaster wire Carr Plunger 6061 8 * Diameter = 14mm 1 grip aluminum Rubber 9 * Rubber 1 grip Plunger 1018 Diameter =10 mm, 20mm 10 * 1 Head steel length Plunger 6061 11 * 1 cover aluminum PVC 12 * Tube grip Diameter = 17mm. 1 Plastic A Tube Holder Assembly B Retract button C Plunger

116

APPENDIX B - SURVEY QUESTIONS FOR EQUIPMENT EVALUATION SURVEY i. Survey Questions for Splatter Shield

Before the procedure

 How harmful do you think the splashes from a patient would be to you?

Not at all      Very Harmful

 Are you aware of the diseases that may get transmitted because of the splashes

and the spurts?

Yes No

 Would you be more comfortable, if a shield is utilized to protect you from

splashes?

Yes No  How safe do you think you would be, while conducting a colonoscopy?

Not very safe      Very safe

After the procedure

 Does the shield obscure your view of the patient?

Yes No  How much do you feel, the shield improves endoscopist’s safety?

Not at all      Very much

 Does the equipment take too much of the bed space?

Not at all      Interferes with the procedure

 Rate the overall value of the shield?

Not very      Very Valuable

117 ii. Survey Questions for the Control Head Holder

Before the procedure

 How heavy do you feel the control head is? Rate from 1 to 5.

Not heavy      Very heavy

 Where do you most feel the stress after using the equipment without the Control

Head Holder?

 Do you think a stand to hold the colonoscope control head would be useful?

Yes No  Do you know about the mechanical risks to the endoscopist?

Yes No After the procedure

 How much does the holder decrease the stress on your biceps and forearm?

No change      Greatly decreased

 How much space does the control head holder utilize?

Very little      Too much

 How much does the holder hinder your movement?

Not at all      Significantly

 Does dexterity improve with the use of Control Head Holder?

Not at all      Very much improved

 Rate the overall value of the Control Head Holder from 1 to 5?

Poor      Excellent 118

APPENDIX C – EQUIPMENT USED FOR THE RESEARCH

Figure 42 Isometric BioDex equipment.

Figure 43 Jamar dynamometer.

119

APPENDIX D - PARTS AND ASSEMBLIES OF THE DEVELOPED EQUIPMENT

Fig 44 Front and top view of the CHH.

Fig 45 Front and right view of the Splatter shield. 120

Fig 46 Front view of the Tube Holder.

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