VETERINARY CLINICAL SCIENCE Journal homepage: www.jakraya.com/journal/vcs MINI-REVIEW Applications of Endoscopy in Canine Medicine P. Preena 1*, S. Vineetha 1, V.A. Aneesha 1, Divya Mohan 1 and V. Vibin 2 1Indian Veterinary Research Institute, Izatnagar, Bareilly (UP), India. 2Veterinary Officer, PFA-Mysore, Bagodi, Karnataka, India. Abstract Endoscopy is a minimally invasive technique that permits visual inspection of the internal organs, cavities and joints in living colour with *Corresponding Author: enhanced visualisation. Endoscopes work on the principle of total internal P. Preena reflection and relay lens system employing flexible and rigid models for distinct anatomic sites. Endoscopic technique is getting importance in Email: [email protected] veterinary medicine, aiming at the differentiation of inflammation, foreign bodies, neoplasia and anatomic anomalies. It also allows sample collection for histopathological, cytological and microbiological evaluation to support Received: 11/04/2016 treatment decisions, assess prognosis and outcome. Moreover, it paves a way for approaching internal organs for endoscopic surgeries enabling Revised: 07/05/2016 minimal scarring, post-operative pain, faster recovery and less surgical Accepted: 09/05/2016 morbidity. This article reviews basics of endoscopy, various techniques and its indication in dogs. Keywords: Endoscopy, Flexible, Rigid, Relay Lens, Total Internal Reflection, Dogs. 1. Introduction examines the non-tubular structures like abdominal Endoscopy is the examination and inspection of cavity, thoracic cavity, joint spaces etc. There are two the interior of body organs i.e. lumen (mucosa) of basic types of flexible endoscopes based on the method hollow organs, serosal surface of organs in body of sensing and transmitting images viz., fiberoscope cavities, structures in joint cavities; through an utilizing bundles of optical glass fibers and video endoscope to allow physician to peer through the endoscope utilizing CCD chips (Tams and Rawlings, body's passages. An endoscope is an optical instrument 2010). designed to allow visual inspection of the interior of body through small entrances or natural orifices. The 2. History word, endoscopy is derived from the Greek words: First description of the use of endoscopy dates Endo (meaning within) and Skopein (meaning to view to Hippocrates of Greece in 460-375 BC (Arregui et or observe), hence the word endoscopy means to view al., 2012). Detecting faults in gun barrels was one of within (Majumdar, 1993). The advantages of the earliest application for which an endoscope type endoscopy in veterinary practice is that being a instrument (boroscopes) was used (Cook, 1970). minimally invasive method, induces less post-operative Endoscopes for use in people and animals were pain, faster recovery than traditional surgery, creates developed from the first cystoscopes. One of the first minimal scarring and tissue disruption (lesser trauma), reports of performing endoscopy in a domestic animal enables unmatched image resolution and enhanced was by Navratil in 1871 for assessing the laryngeal visualization, improved cosmetic results and less function in dogs (Navratil, 1871). In the early 1900s, surgical morbidity (Tams and Rawlings, 2010). fully rigid lighted telescopes came into the limelight; The components of an endoscope are rigid or later in 1930s, semiflexible gastroscopes was flexible tube, light delivery system (Tungsten-halogen introduced and widespread use of endoscope started or xenon light source), objective, image guide, eye after 1960s (Cappell et al., 2000). piece and additional channels (Slovis, 2004). Basically, The first real endoscope was developed by there are two different types of endoscopes, flexible Phillip Bozzini (Father of endoscopy) in 1805 to endoscopes examines the depth of tubular structures examine the urethra, bladder and vagina. Adolf that turn corners like stomach, intestine, bronchial tree, Kussmaul used a straight rigid metal tube over a male canine urethra etc., and rigid endoscopes flexible obturator to perform the first gastroscopy in Veterinary Clinical Science | April-June, 2016 | Vol 4 | Issue 2 | Pages 19-22 © 2016 Jakraya Publications (P) Ltd Preena et al… Applications of Endoscopy in Canine Medicine 1868. The first practical gastroscope was constructed in body in dogs, biopsy collection in tumours and 1932 by Rudolph Schindler (Father of gastroscopy). In inflammatory conditions (Lecoindre, 1999). 1957, Basil Hirschowitz (Father of modern endoscopy) developed his prototype fiberscope (Cappell et al., 4.2 Lower Gastrointestinal Tract Endoscopy 2000). It is used for examination of GIT lumen from ileum to rectum. The major indications are dyschezia, 3. Priniciple tenesmus, unexplained scooting, constipation, and There are 2 different principles for flexible and chronic diarrhoea containing fresh blood and/or mucus rigid endoscopes based on the science of optics. (Tams and Rawlings, 2010). It can be used for diagnosis of inflammatory conditions, tumours, ileal 3.1 Total Internal Reflection (TIR) stricture in Crohns disease, diverticulitis in sigmoid TIR in flexible endoscope systems: The light colon, colonic tuberculosis, ulcerative colitis, parasitic entering the solid glass rod gets transmitted through the load etc (Twedt, 2003). rod and when it strikes the side of the rod at an angle 0, exceeding the critical angle, then total internal 4.3 Laryngoscopy and Tracheobronchoscopy reflection occurs. Along the whole length of the rod, It involves visual examination of laryngeal the light continues to be internally reflected back and anatomy and movement for evaluating laryngeal forth in its passage, and it emerges from the other end function, lesions in trachea and bronchus. The various with very little loss of intensity (Cheng et al. , 2014). indications are abnormal breathing pattern, acute and chronic cough, airway collapse, inflammatory 3.2 Relay Lens System conditions, neoplasia, unexplained radiographic In rigid endoscope systems: Optical lenses infiltrates etc (Tams and Rawlings, 2010; Courouce- (relay Lenses) are used to manipulate the light Malblanc, 2013). returning from the site of examination in order to produce an enhanced and clearly focused image of the 4.4 Laparoscopy object . The principle in glass fibre optics is that long Otherwise called Celioscopy/ pelvioscopy, glass optical fibres of very small cross-sectional area involves the visual examination, surgical procedures transmit light from one end to other, even when bent, and biopsy of the peritoneal cavity and its organs. without much loss of light through their side walls Diagnostic indications include exploration and biopsy (Cheng et al. , 2014). collection of liver, kidney, prostate, lymphnodes, spleen, intestine, urinary-reproductive tract, 4. Applications cholecystocentesis, cancer staging, laparoscopic Depending on the various site of examination, surgeries for gastropexy, ovariectomy etc. (Tams and there are different types of endoscopy methods using Rawlings, 2010). different types of endoscopes varying in working length and diameter as shown in Table 1. 4.5 Thoracoscopy It provides the opportunity for exploratory and 4.1 Upper Gastrointestinal Tract Endoscopy interventional procedures within the chest through It is used for examination of gastrointestinal multiple 5-10 mm incisions for obtaining a diagnosis (GIT) lumen from mouth till jejunum. Major and treatment of intra-thoracic conditions like pleural indications are anorexia, abdominal pain, regurgitation, and pericardial effusions, pulmonary diseases, retching, vomiting, dysphagia, odynophagia, excessive mediastinal lesions, lymphadenopathy, and affections salivation, haematemesis, diarrhoea, protein losing of thorax (McCarthy and McDermaid, 1990; McCarthy enteropathies and melena (Tams and Rawlings, 2010). and Monnet, 2005). This endoscopy helps to reach a definitive diagnosis for oesophagitis, gastritis, duodenitis, inflammatory bowel 4.5 Cystoscopy disease (IBD), ulcers, neoplasia, gastro-oesophagial It is a minimally invasive diagnostic and intussusception, perforations, strictures, vascular treatment tool for the urogenital system. Indications anomalies, small intestinal bacterial overgrowth include chronic or recurrent UTI, hematuria, dysuria, (SIBO), endoparasites etc., and tentative diagnosis for stranguria, pollakiuria, trauma, calculi, incontinence, megaoesophagus, diverticulam, hiatal hernia (Twedt, neoplastic cells in urine sediments, abnormal findings 2003 and Simpson, 2008). In addition, this is in urine analysis, radiographs and ultrasound etc. frequently used for evaluation and removal of foreign (Morgan and Forman, 2015). Veterinary Clinical Science | April-June, 2016 | Vol 4 | Issue 2 | Pages 19-22 © 2016 Jakraya Publications (P) Ltd 20 Preena et al… Applications of Endoscopy in Canine Medicine Table 1: Different endoscopic methods and endoscopes used for various examination sites Features of endoscope Site of examination Methods Type of Working length Diameter and angle endoscope Oesophagoscopy, Gastroscopy, 100 cm Upper GIT Enteroscopy Flexible 7.8-9.8 mm (Duodenoscopy, (latest – 140 cm) Jejenunoscopy), Rigid: 25 cm 9-18 mm Lower GIT Colonoscopy Flexible and rigid Flexible: 100 cm < 10 mm Upper and Lower Laryngoscopy, Rigid: 55-60 cm 4.8-5.2 mm Flexible and rigid airways Tracheobronchoschopy Flexible: 40-60 cm 3.5-3.7 mm Both flexible and Rigid: 18 cm 2.7 -4mm Urogenital tracts Cystoscopy rigid Flexible: 70-100 cm 2.5 mm 5 mm and 0º Abdominal