Fundamentals of Microsurgery
David A. Wilkie, DVM, MS, Diplomate ACVO Professor Department Chair The Ohio State University [email protected] Microsurgery
Ophthalmic Vascular Urogenital Neurologic Microsurgery
Definition Surgery utilizing magnification and small, handheld instruments and suture to correct defects in small &/or delicate tissues 16th CENTURY
Ouch! To do a job….you need the right tools Microsurgery Differs from traditional surgery in: Surgeon position Magnification Specialized instrumentation Suture and needle size
Dr. Dyce Surgeon Position
Surgical Position Seated Specialized chairs with armrests Arms resting on armrest Essential for fine motor control Microsurgery
Surgical Position Seated Specialized chairs with armrests Arms resting on table or armrest Essential for fine motor control Able to adjust height Height is adjustable Elbows and wrists are locked Magnification - There are choices… Fundamentals of Microsurgery
Magnification – purpose: provide an improved view of the tissues of concern Will vary by tissue of interest allow a comfortable working distance for the surgeon Back straight, arms at 90 degrees facilitate adjustment of the interpupillary distance to suit the surgeon permit a wide field of view Microsurgery
Differs from traditional surgery in: Specialized instrumentation Surgeon position Magnification Type & size of suture Human Hair
9-0 MonofilamentVicryl Fundamentals of Microsurgery
Rules of microsurgery are meant as a foundation to guide the beginning ophthalmic surgeon Once understood, rules can occasionally be molded and adapted to suit the surgeon and the individual patient The surgeon must however always re-visit the basic microsurgical rules and principles when a new or unfamiliar technique or procedure is to be performed Fundamentals of Microsurgery
Surgeons must have a goal and a plan to achieve the goal, but must also be adaptable and familiar with more than one technique so that obstacles encountered during the surgical procedure may be overcome. Fundamentals of Microsurgery
Not all surgeries proceed according to the plan. All eyes are different and the surgeon who says “I always do it this way” is destined to encounter situations where their technique does not meet the patients needs. Fundamentals of Microsurgery
Think of surgery like your commute to work We may all travel a different a route and method We get there in various ways, BUT…..we all get to the same destination Fundamentals of Microsurgery
Think of surgery like your drive to work You have a route that you usually take Do you know other routes? What if there is an accident or detour, how would you respond? Fundamentals of Microsurgery
Regardless of our individual variations, we must all follow the basic rules: to use appropriate magnification and instrumentation to be efficient and precise to ensure minimal tissue trauma to minimize surgical time to maintain the anterior chamber using small incisions and viscoelastic materials to obtain excellent tissue wound apposition with the smallest and most appropriate suture materials to achieve a successful, comfortable, cosmetic and whenever possible, visual outcome Fundamentals of Microsurgery
The surgeon must at all times keep several ophthalmic microsurgical principles and rules in mind: time is trauma tissues should be handled as little and as efficiently as possible ophthalmic microsurgery procedures are comprised of a series of steps in sequence, each one designed to move the surgery forward towards the goal. The surgeon must be familiar with these steps, perform them economically, efficiently and atraumatically, making no wasted movements and moving steadily forward towards the surgical goal. Fundamentals of Microsurgery
Magnification Began in 1876 using simple head loupes First microscope for human ophthalmic surgery described in 1950 and in veterinary ophthalmology in the 1970’s Fundamentals of Microsurgery
Magnification – purpose: provide an improved view of the tissues of concern Will vary by tissue of interest allow a comfortable working distance for the surgeon Back straight, arms at 90 degrees facilitate adjustment of the interpupillary distance to suit the surgeon permit a wide field of view Fundamentals of Microsurgery
Magnification Beginning surgeons should start with magnification early as part of their basic training Will improve their tissue handling and appreciation for tissue trauma and wound apposition Microsurgery
Magnification Eyelids, conjunctiva 2-5X Cornea, urogenital 5-10X Intraocular, vascular, neurologic 8-15X 2.5X 10X
5X 15X Fundamentals of Microsurgery
Magnification Essential to select the appropriate magnification. If we consider ourselves ophthalmic microsurgeons then we must use the appropriate magnification at all times. Fundamentals of Microsurgery
Magnification Head Loupes used for microsurgery when operating microscopes are not available such as in the field or a large animal barn setting and for orbital and eyelid surgeries Operating Microscope Better choice, especially for ≥ 5X Fundamentals of Microsurgery
Magnification Head Loupes Simple loupes Galilean-type loupes Prismatic loupes (Keplerian) Fundamentals of Microsurgery
Magnification Simple Loupes one pair of positive meniscus lenses limited by spherical aberration and color fringing plastic construction fixed interpupillary distance very short working distance poor surgeon body and arm position strain on the surgeon’s neck and back. POOR CHOICE Fundamentals of Microsurgery
Magnification Galilean Loupes up to 2.5x magnification multiple lenses to offer magnification and are generally lightweight and less expensive adjustable interpupillary distance working distance varies Fundamentals of Microsurgery
Magnification Prismatic Loupes up to 8.0x magnification ≥5.0x a microscope is preferred highest optical quality series of lenses and prisms to magnify the subject similar in principle to low-power telescopes greater magnification sharp resolution greater depth of field heavier and more expensive Fundamentals of Microsurgery
Magnification Prismatic Loupes As magnification increases they become long and heavy Shallow depth of field Head movements make use difficult (>5X) Fundamentals of Microsurgery
Magnification Loupes Surgeons should have their own loupes Surgeons should have both a Galilean and a Prismatic set with lower and higher magnification Can add light source if desired Fundamentals of Microsurgery
Magnification Loupes - styles Fundamentals of Microsurgery
Magnification Loupes - light Fundamentals of Microsurgery
Magnification Operating Microscope magnification from 5-40x For ophthalmic microsurgery, magnification of 5-20x is generally sufficient. Increased cost and maintenance longer surgical setup time less intraoperative positioning flexibility less portability Fundamentals of Microsurgery
Magnification Operating Microscope Coaxial illumination Projected through viewing objective variable magnification motorized continuous zoom motorized focus motorized X-Y axis Foot controls adjust light, magnification, zoom, focus and X-Y axis Allow multiple surgeons Floor, table or ceiling mount Additional attachments Fundamentals of Microsurgery
Magnification Operating Microscope Floor mounted Ceiling Mounted Table Mounted Portable 2.0-9.0X Fundamentals of Microsurgery
Magnification Operating Microscope Attachments Video/camera laser – need a filter Fundamentals of Microsurgery
Magnification Operating Microscope While portable - movement over distance is discouraged Articulating arms with tension adjustment Gross focus done manually prior to start of surgery Fundamentals of Microsurgery
Magnification Operating Microscope Optical head has Primary surgeon Beam splitter Assistant surgeon Video attachment Fundamentals of Microsurgery
Magnification Operating Microscope Objective lens 150-400mm 175 mm most common in ophthalmology Magnification:
Magnification = Focal length of binocular tubes x magnifying power of Focal length of the objective the eye pieces x magnifying power of magnification changer Fundamentals of Microsurgery
Magnification Prior to surgery Center the X-Y axis Lowest magnification Zero the fine focus Adjust the gross focus manually Fundamentals of Microsurgery
Magnification Prior to surgery Adjust the interpupillary distance Fundamentals of Microsurgery
Magnification Prior to surgery Adjust the chair and table height Fundamentals of Microsurgery
Magnification Prior to surgery Ensure the surgeons view and the video view are both in focus Verify at the highest magnification to be used Fundamentals of Microsurgery
Magnification Prior to surgery Position all foot pedals where they can be reached With multiple foot pedals the microscope pedal goes to the non- dominant foot Fundamentals of Microsurgery
Magnification Prior to surgery KNOW WHERE ALL THE FOOT PEDAL CONTROLS ARE BEFORE STARTING SURGERY Fundamentals of Microsurgery
Magnification Use your magnification Adjust during surgery – cornea vs lens Fundamentals of Microsurgery
Magnification As magnification increases The field of view and depth of field decrease At 3.5X - field of view is 50mm and depth of field is 2.6mm At 20X - field of view is 10mm and depth of field is 0.4mm Fundamentals of Microsurgery
Magnification As magnification increases The field of view and depth of field decrease At 3.5X - field of view is 50mm and depth of field is 2.6mm At 20X - field of view is 10mm and depth of field is 0.4mm 3.5X 20X Fundamentals of Microsurgery
Prior to surgery Position the patient Lateral vs dorsal recumbency Sand bags, vacuum pillows Eye looks up into microscope Fundamentals of Microsurgery
Prior to surgery Position the patient Anesthesiologist at opposite end of the patient To avoid tube obstruction use a 90 degree connector or a guarded endotracheal tube Fundamentals of Microsurgery
Prior to surgery When seated, adjust gross focus by hand, not foot pedal Microsurgery
Surgical Position Seated Specialized chairs with armrests Arms resting on table or armrest Essential for fine motor control
Fundamentals of Microsurgery
At the start of surgery Turn on microscope lights Turn off room lights Fundamentals of Microsurgery Fundamentals of Microsurgery
At the start of surgery Surgeon is seated comfortably Feet reach the pedals Back is straight Arms at 90 degrees Lean slightly forward Arms on armrests Hands positioned and supported Fundamentals of Microsurgery
Hands must be supported Rest on the ball of the hand or extend 5th finger for support Fundamentals of Microsurgery Adjust chair height Pre-op Check Adjust chair armrest position List Adjust table height Adjust microscope height Set microscope fine focus to neutral Center X-Y axis Adjust microscope tilt Adjust interpupillary distance Set microscope to highest magnification to be used Adjust focus of oculars Ensure video and assistant images are also in focus Return microscope to low magnification Place foot pedals to be comfortably accessible Fundamentals of Microsurgery
Pre and peri-operative medications Antibiotics Antiinflammatories Mydriatics Surgeon preference on when to initiate Fundamentals of Microsurgery
Prior to surgery Administer intravenous anti- inflammatory and antimicrobial drugs Despite our best efforts we will create tissue trauma and contaminate the field
Taylor MM, Kern TJ, Riis RC, McDonough PL, Erb HN: Intraocular bacterial contamination during canine cataract surgery. J Am Vet Med Assoc. 1995; 206(11): 1716-1720.
Pre-Operative Prep
Clip hair 0.5% povidone iodine (1:20 to 1:50 dilution) Final prep - povidone iodine 10% Paint the adnexa Avoid chlorhexidine Protective ointment for non-surgical eye
Fundamentals of Microsurgery
Anesthesia General anesthesia is required for microsurgery Non-depolarizing neuromuscular blocking agents may be required Microsurgery
Patient position critical No movement under anesthesia Sand bags Vacuum pillows Paralysis
Patient Position paralysis Atracurium Neuromuscular blockade
Most common is Atracurium 0.2 mg/kg dog and cat; 0.02-0.06 mg/kg horse If needed a 2nd injection 0.1 mg/kg dog and cat; 0.025mg/kg horse “low dose” – still ventilate to avoid respiratory acidosis provides excellent globe exposure and will minimize globe compression as a result of extraocular muscle tension Reversal - edrophonium 0.5 mg/kg or neostigmine 0.02mg/kg anticholinergic (glycopyrrolate 0.02mg/kg IV or atropine 0.04mg/kg IV in small animals; glycopyrrolate 0.005 mg/kg IV in horses) should be administered concurrently with neostigmine
Fundamentals of Microsurgery
Equine considerations Induction Patient Position unilateral vs bilateral Equine Microsurgery
Patient position critical No movement under anesthesia Sand bags Inner tube Vacuum pillows Paralysis Retrobulbar Block
Patient Position
Courtesy – Dr. Brian Gilger Patient Position
Unilateral lateral recumbency Bilateral dorsal recumbency Equipment Position
Opposite to the surgeon phaco, microscope Difficult to get comfortable foot position awkward Do not expect to be comfortable Equine Recovery Fundamentals of Microsurgery Patient Drapes Water repellant Adhesive Fundamentals of Microsurgery Patient Speculum Avoid external pressure on the globe Globe collapse Iris prolapse Vitreous prolapse Extrusion of visco Fundamentals of Microsurgery
Patient Epinephrine 1:10,000 for Vasoconstriction Hemostasis Decrease fibrin Mydriasis
Preservative vs preservative-free Tools to manage small pupil and lens stability issues
Epinephrine Viscoelastic Lidocaine
Miosis
Lidocaine Intracameral Preservative-free 1-2% 0.1 – 0.3ml Onset: 1-10 minutes Duration: 72-142 minutes No systemic effects Miosis Intracameral lidocaine Dose-dependant onset & duration
Park SA, et al: The mydriatic effect of intracameral lidocaine in clinically normal dogs. Am J Vet Res 70:1521-5, 2009 Personally - I feel this helps with ECP patients Small Pupil – Epi, Lido, Visco
Jack Russell 5yr Lens instability IOP controlled with latanoprost
<15kg 1ml lidocaine + 1ml bupivacaine
>15kg 1.5ml lidocaine + 1.5ml bupivacaine Miochol® post phaco/IOL
Corneal/Lens laceration – corneal repair, phaco, suture IOL Perfect Pupil® Perfect Pupil® Malyugin Ring MST Technologies Malyugin Ring - cadaver Small Pupil – Sphincterotomy Fundamentals of Microsurgery
Patient Stay suture Include the episclera Fundamentals of Microsurgery
Patient Lateral canthotomy? More common for beginning surgeons Terriers, ICLE Fundamentals of Microsurgery
Patient Cornea irrigated to keep moist Assistant surgeon Every 20-30 seconds Fundamentals of Microsurgery
Patient Recovery Calm Operated eye up – lateral or sternal recumbency +/-Temporary Tarsorraphy, cold compress Elizabethan collar +/-SPL in horses Fundamentals of Microsurgery
Instrumentation Microsurgical instruments are typically 1/3 smaller than traditional instruments – 100mm vs 150mm Jaws and teeth made delicate Finish does not reflect light Should have several packs Basic/Minor – eyelids, orbit, adnexa Microsurgical – cornea, intraocular Phaco pack Posterior segment pack ECP pack Fundamentals of Microsurgery
Instrumentation Instrument choices length of the instrument size of the teeth and jaws angle of the jaws length of the jaws sharp vs. blunt tips straight vs. curved flat vs. rounded handles serrated, six sided or knurled handle grips locking vs. non-locking with or without a tying platform with or without a pin stop dull vs. polished finish stainless steel vs. titanium Fundamentals of Microsurgery
Instrumentation Instrument choices Instruments to be rotated have rounded handle Instruments not rotated have flat handle To prevent slippage during manipulation instrument handles are serrated, knurled or six-sided Hinged using an X or box hinge design and spring handles as seen with Wescott tenotomy scissors or Barraquer needle holders Pin stop to prevent over closure Bar hinge design is used for most microsurgical forceps Fundamentals of Microsurgery
Instrumentation Finger pressure goes here
Pin Stop Fundamentals of Microsurgery
Instrumentation Bar hinge Fundamentals of Microsurgery
Instrumentation X or box hinge spring handles Fundamentals of Microsurgery
Instrumentation Fundamentals of Microsurgery
Instrumentation Round and knurled handle Fundamentals of Microsurgery
Instrumentation Flat handle Fundamentals of Microsurgery Instrumentation Steel vs Titanium Titanium stronger, more corrosion resistant, sharper longer Germany vs Pakistan vs China Quality of steel varies Fundamentals of Microsurgery
Instrumentation X Instrument handling Finger movement Pencil-like grip Hands stabilized Microsurgery
Hold instruments in a pencil-like grip Finger movements
X Microsurgery
Hold instruments like a pencil Finger movements Wrists and elbows fixed Microsurgery
Tissue handling Make no wasted movement Handle tissues as little as possible
IF YOU TOUCH IT….DO SOMETHING, DO NOT RELEASE UNTIL YOU HAVE DONE ALL THAT YOU CAN! Fundamentals of Microsurgery
Instrument Handling Delicate, precise movements Finger movements only Pencil grip Arms on armrests Elbows and wrists locked Fundamentals of Microsurgery
Instrumentation Instrument handling “microsurgical instruments held in a pencil-like grip are supported by resting against the first metacarpophalangeal joint of the first finger with the fingertips of the thumb and first finger used to control and rotate the instrument” Fundamentals of Microsurgery
Instrumentation Instrument handling “Hand stability is provided by resting the outside of the 5th finger on the vacuum pillow or patients periorbital tissues” Fundamentals of Microsurgery
Instrumentation Instrument handling Resist the tendency to grasp the instruments tightly as this will decrease flexibility, fatigue the hand and forearm, traumatize tissues and damage instruments and needles Fundamentals of Microsurgery Fundamentals of Microsurgery
Instrumentation Instrument handling Palm or tripod grip acceptable for Steven’s tenotomy scissors Fundamentals of Microsurgery
Instrumentation Basic pack Basic Pack
Eyelid speculum – Barraquer wire in several sizes Forceps- Brown-Adson Colibri utility 0.3mm and 0.5mm Bishop-Harmon fine teeth Castroviejo scleral fixation Tying forceps Scissors- Stevens tenotomy – blunt, curved Westcott tenotomy – blunt, curved Needle holders - Barraquer type medium and heavy curved, non-locking, rounded and knurled handle -Derf or Alabama-Green Desmarres chalazion clamp Jaeger eyelid plate Calipers- Jameson, Castroviejo Carter sphere introducer Muscle hooks Irrigating cannulas – 21, 23, 27, 30 gauge Beaver and Bard Parker blade handles Mosquito hemostats Martinez corneal dissector Serrefine clamps Cyclodialysis spatula 1 2
3 5 4 9 7 6
10 8
11 13
12 Corneal/Intraocular Pack
Eyelid speculum – Barraquer wire in several sizes Forceps- Colibri utility .12mm and 0.3mm Bishop-Harmon delicate teeth Castroviejo scleral fixation Utrata capsulorhexis IOL folding McPherson tying – straight and angled Scissors- Stevens tenotomy – blunt, curved Westcott tenotomy – blunt, curved Vannas – curved with a sharp tip Right and Left Corneal section scissors Intraocular Needle holders- Barraquer type delicate and fine curved, non-locking, rounded and knurled handle Lens dialer/manipulator Phaco chopper Calipers- Jameson, Castroviejo Lens loop Irrigating cannulas – 21, 23, 25, 30 gauge Beaver blade handles Martinez corneal dissector Serrefine clamps Cyclodialysis spatual or iris spatula 1 3
5
2 4 6
9 7
8 Fundamentals of Microsurgery
Instrumentation Incisions Incisions must be precise, accurate and atraumatic Avoid “crush” techniques Blade vs scissors In general blades initiate corneal/adnexal incisions and scissors may complete the incision Scissors often used alone for conjunctival incisions Fundamentals of Microsurgery
Instrumentation Incisions Eyelid May use a chalzion clamp or eyelid plate for stability and hemostatsis Fundamentals of Microsurgery Instrumentation Incisions Cornea Position forceps as close to incision as possible Cut towards or away from forceps Re-position the forceps as little as possible If entering the anterior chamber incision depth ≥75% Uni vs multi plane incisions We use a 3.2mm biplanar incision for phaco Superficial Keratectomy
Cadaver surgery
What is the mistake? Lamellar Dissection Equine Corneal FB Corneal Entry
What is the mistake? Corneal Entry
Two-step incision Fundamentals of Microsurgery Instrumentation Incisions Knives Disposable vs re-useable Bard Parker, Beaver, sapphire, diamond Fundamentals of Microsurgery Why does this incision not work well in our patients?
Fundamentals of Microsurgery Instrumentation Incisions Scissors Fundamentals of Microsurgery Instrumentation Incisions Scissors Sharp vs blunt tip Straight vs curved Ringed, hinged, spring handled Left and right directional With or without a stop Fundamentals of Microsurgery Instrumentation Incisions Scissors
Comments? Fundamentals of Microsurgery Instrumentation Incisions Scissors
What is this and what is it for? Fundamentals of Microsurgery “when using scissors to cut tissue, avoid producing a serrated edge. Scissors are closed partially, reopened and carefully advanced in the original direction. Without removing the scissors, the blades are reapplied to the tissue” Fundamentals of Microsurgery Instrumentation Suture Choices absorbable vs. non-absorbable braided vs. monofilament size of the suture size and type of needle In general monofilament, non-absorbable is less reactive Can remove absorbable in cornea to decrease reaction Choose the smallest suture to achieve success Avoid closure of instruments on suture whenever possible
Microsurgery
Suture Absorbable vs non-absorbable Microsurgery
Suture Absorbable vs non-absorbable Monofilament vs braided Swaged on needle essential Suture size 6-0 to 11-0
Microsurgery
Suture pattern Interrupted vs continuous Microsurgery
Suture Absorbable vs non-absorbable Monofilament vs braided Swaged on needle essential Fundamentals of Microsurgery Instrumentation Suture Size typically 6-0 to 10-0 volume of suture material left in the tissue increases logarithmically with increasing diameter volume of material in 7-0 and 8-0 suture is 5x and 3x greater than in 9-0 respectively Increased tissue reaction and knot size Suture material size based as defined by the United States Pharmacopoeia code
USP designation Collagen Absorbable Non-absorbable diameter (mm) diameter (mm) diameter (mm)
10-0 0.03 0.02 0.02 9-0 0.03 0.03 0.03 8-0 0.05 0.04 0.04 7-0 0.07 0.05 0.05 6-0 0.1 0.07 0.07 5-0 0.15 0.1 0.1 4-0 0.2 0.15 0.15
Suture gauge affects knot size more than # throws. Adding 2 additional knot throws increases mass by 1.5X while doubling suture gauge increases know volume by 4-6X. Fundamentals of Microsurgery Instrumentation Suture pattern Surgeon preference Astigmatism Water tight seal Interrupted, interlocking, continuous, double- continuous Fundamentals of Microsurgery Instrumentation Suture pattern Interrupted take longer to place leave more knots provide unidirectional tension vectors more likely to tear out Compressive or appositional effect of a simple interrupted suture is maximal only in the plane of the suture tract Lateral to the suture tract the compressive effect diminishes Lateral extent of the compression effect may be increased by increasing the size of the suture loop within the cornea Fundamentals of Microsurgery Instrumentation Suture pattern Zones of compression seen with simple interrupted sutures. Note how the different length of the suture bites alters the zones of compression. Failure to achieve overlap of the compression zones will result in wound leakage. Fundamentals of Microsurgery Instrumentation Suture pattern Simple continuous Less time to place Less knots Results in lateral shifting of the wound Suture break = dehiscence
Fundamentals of Microsurgery Instrumentation Suture pattern Double continuous or counter suture pattern takes slightly longer to place leaves more suture material advantages of even vector forces in all directions better water-tight seal less astigmatism better wound integrity should a suture break occur Fundamentals of Microsurgery Instrumentation Suture pattern A. A simple sawtooth suture pattern B. A symmetrical sawtooth suture pattern C. A double sawtooth suture pattern D. A symmetrical double sawtooth suture pattern
Cat Claw Cat Claw
Seidel Test Seidel Test Positive Seidel Test - Canine Magnification Epinephrine Viscoelastic 8-0 to 9-0 suture Microsurgical instruments http://youtu.be/ex8EZVaP2aI Cat Claw Perforating with Lens capsule tear Cat Claw Perforating with Iris prolapse
Phacoanaphylaxis
Fundamentals of Microsurgery Instrumentation Suture pattern Tied using instruments, preferably two tying forceps Can use the tying platform on the colibri forceps for efficiency Fundamentals of Microsurgery Instrumentation Suture pattern McPherson straight and angled Right handed surgeon holds the straight forceps in their left hand Left forceps wrap suture around the right Microsurgery
Instrumentation Suture forceps Over compression or poor instrument care may result is a failure to grasp the suture The first knotting loop is the “approximation loop” Additional loops secure the approximation loop Direction of tension applied will affect the type of knot created Microsurgery
Instrumentation Tissue forceps Tying platform Tying platform Microsurgery
Instrumentation Specialized forceps
Colibri Utrata Microsurgery
Instrumentation Specialized forceps
2-4 um 50-70 um
Vannas Scissors
Utrata Forceps
Diathermy Shearing -safer, less radial tears, more control
Ripping -dangerous, more radial tears, less control The “Q” Sign
CCC – Vannas, Utrata The “Q” Sign Avoiding The “Q” Sign Avoiding The “Q” Sign Enlarge CCC post phaco Posterior capsulorhexis Fundamentals of Microsurgery Instrumentation Needles Swaged on Described by curve of the needle wire diameter length of the needle chord length, radius shape of the needle in cross-section or point geometry curve of microsurgical ophthalmic needle can be straight, 1/8, ¼, 3/8 and 1/2 circles Fundamentals of Microsurgery Instrumentation Needles Corneal surgery needles with a 3/8 to 1/2 curve and a short 5-6mm length are most common 3/8 needle will result in a larger shallower bite while the ½ needle results in a short, deep bite Microsurgery
Swaged on needle essential Fundamentals of Microsurgery Instrumentation Needles point geometry is described as taper (round needle with a taper point) cutting (cuts on the inside curve) reverse-cutting (cuts on the outside curve) tapercut (round needle ending in a triangular cutting tip) side cutting or spatula (flat top and bottom, cuts on the side)
Fundamentals of Microsurgery Instrumentation Needles Cutting needles used for eyelid and adnexa Spatula needles for cornea Microsurgery
Needle Swaged on Curved Taper Cutting Reverse cutting Spatula
Fundamentals of Microsurgery Instrumentation Needle holder Microneedle holders vary by Size of the jaw (delicate, fine, medium, heavy) Straight or curved jaw Smooth or serrated jaw Locking or non-locking Style of the handle Curved, non-locking, round handled Castroveijo or Barraquer most common Fundamentals of Microsurgery Instrumentation Needle holder Must match the size of needle used Grasp anterior to the midpoint Fundamentals of Microsurgery
I disagree with this, the needle will bend midshaft Microsurgery
Instrumentation Needle holders
Hold curved needle holders with the jaws curving upwards Fundamentals of Microsurgery Instrumentation Needle holder When passing a needle, the curve of the needle holder is upwards Tissue must be stabilized at the point of needle insertion Use toothed forceps and if possible drive the needle towards the side with the most teeth – others disagree with this Needle encounters the cornea perpendicular Needle holder is rotated in the surgeon’s fingers allowing the needle to follow its natural curve while the forceps elevate and open or evert the wound slightly Forceps are used to stabilize, provide counter pressure and rotate the tissue as required to allow the needle to follow its path Needle is grasped and re-grasped as it is advanced Fundamentals of Microsurgery Instrumentation Forceps Basic functions of forceps are to manipulate and stabilize ocular tissues tying of sutures removal of foreign bodies or distichia performing a capsulorrhexis IOL manipulation With or without teeth May or may not interdigitate Teeth angle varies - ≥90 degrees Size of teeth varies +/- tying platform Fundamentals of Microsurgery Instrumentation Forceps Size of teeth Colibri 0.12 mm (cornea) or 0.3 mm and 0.5mm teeth (conjunctiva) Bishop Harmon eyelid (fine teeth) and conjunctiva (delicate teeth) Fundamentals of Microsurgery Instrumentation Forceps Fundamentals of Microsurgery Instrumentation Forceps Tools to help with capsulorhexis and sutured IOL
Duet® microsurgical tying forceps Microsurgical Technologies http://www.microsurgical.com/
Two-handed CTCC
4yr old terrier 2-handed CTCC
5yr old JRT other eye lost Modified ab-externo IOL
Wilkie DA, et al: A modified ab-externo approach for suture fixation of an intraocular IOL in the dog. Veterinary Ophthalmology 11:43-48, 2008 Dorsal suture placement - Duet® Forceps
Hemostasis
Chemical Epinephrine Mechanical Chalazion clamp Wet field cautery CO2 Laser Corneal Transplant
Corneal transplant Corneal transplant Corneal transplant Corneal transplant Penetrating Keratoplasty Penetrating Keratoplasty Penetrating Keratoplasty Penetrating Keratoplasty Penetrating Keratoplasty Pre-op
2yr Post-op 1 Days Postop
12 Days Postop 14 Days Postop
21 Days Postop
Viscoelastics
Tools for spacial tactics protect tissue and cells from mechanical trauma create and preserve space for surgical manipulation lubricate separate tissues prevent adhesions tamponade hemorrhage move or relocate tissue Visco over inflation –Iris Prolapse Viscoelastics Viscoelastics
Viscoelastic substances must be sterile, nontoxic, nonpyrogenic, noninflammatory, and nonimmunogenic Viscoelastics have properties of both fluids and solids Described based on their rheologic properties of: viscosity pseudoplasticity viscoelasticity surface tension Viscoelastics
Viscosity Solutions resistance to flow Concentration, molecular weight, size of the flexible random coils Described in units of centipoise (cp) Pseudoplasticity With movement, viscosity decreases Makes it easier to inject through a small cannula Ideally a high viscosity at rest and this decreases as shear forces are applied Viscoelastics
Viscoelasticity Tendency to return to original shape Surface tension Lower surface tension = better ability to adhere or coat tissues Viscoelastics Dispersive vs. Cohesive Viscoelastics Dispersive Consistency of molasses Coat tissues well Harder to remove Cohesive More solid than liquid Do not coat or flow well Maintain space better Move tissues better Easier to remove Can use both – put dispersive in first Viscoelastics
Na Hyaluronate Rooster combs, umbilical cords, bacterial fermentation
Chondroition sulfate Shark fin cartilage
Hydroxypropylmethylcellulose (HPMC) Made from wood pulp and may contain particulate material Vitrectomy
Oscillating Single vs double cut Guillotine Pneumatic Best for veterinary ophthalmology Disposable best
Manual Vitrectomy Guillotine
Oscillating Single port - bad design Two port - best design What parameters can you control/adjust? Single port
X Bimanual Oscillating Guillotine Vitrectomy Posterior segment vitrectomy more complicated
Rabbit Fundamentals of Microsurgery
Instrumentation Arrange instruments in order of use Replace in the same order Fundamentals of Microsurgery
Instrumentation Instrument cleaning and storage Fundamentals of Microsurgery
Instrumentation Instrument cleaning and storage Distilled water Delicate tooth brush/microwipes Avoid direct instrument to instrument contact Spray with instrument milk Place in tray with lid ALL SURGEONS ARE RESPONSIBLE FOR INSTRUMENT CARE Fundamentals of Microsurgery
Instrumentation Instrument cleaning and storage Instruments with a lumen can be air blown and must be autoclaved NOT gassed Should you re-use your materials? Sterilization
Do Not gas your tubing or handpieces Gas does not sterilize areas that are wet or have trapped liquid Clean after each use Distilled water Steam autoclave Routine Flash Fundamentals of Microsurgery
Additional instruments Corneal trephines Cryosurgical unit Phaco unit Vitrectomy unit Wet field cautery Diode laser Indirect Transscleral Intraocular Microscope ECP Fluid-gas exchange pump CO2 laser As we seek to improve we must all follow the basic rules: to use appropriate magnification and instrumentation, to be efficient and precise, to ensure minimal tissue trauma, to minimize surgical time, to maintain the anterior chamber using small incisions and viscoelastic materials, to obtain excellent tissue wound apposition with the smallest and most appropriate suture materials and finally, to achieve a successful, comfortable, cosmetic and whenever possible, visual outcome We must remember that microsurgery is both a technique and an art and as such we must constantly work to refine and improve ourselves as microsurgeons. We must also remain open to new ideas and respect the opinions of others who may have a different method to achieve success. Intraocular Surgery
“The enemy of GOOD is BETTER” Questions?