Reptile and Fish surgery Flashcards
What considerations with reptiles?
- Some species have bladders or not?
- Spectacle or not?
- Autotomy ?
Surgeon & patient considerations?
- PAtient must have optimum ventilation -> extend neck, IPPV, body positioned to minimise coelomic contents impinging on lungs/ air was
- Surgeon must have optimum motor control
- Magnification if needed
What equipment considerations?
○ Fine tipped microsurgical equipment ideal for
smaller patients.
○ Can use normal surgical equipment for most
patients.
○ Dremel oscillating, thin blade.
What haemostasis ocnsiderations?
● Minimise blood loss 0.5-0.8ml/100g max amount.
● Sterile cotton tip applicators
● Artery forceps
● Suture material
● Haemoclips
● Haemostatic sponge.
How do we stabilise reptiles?
- Warmth
- Analgesia
- Fluids
- Nutritional support
What baselines do we want pre-GA?
Bloods ; RR; HR
Assessing pain?
- Absence of normal bhvr
- Hunched?
- Hiding ?
- Rubing at affected area?
- Change to HR, RR, depth
What fluid infusion rate recommendation for reptiles?
- 3ml/kg /hr
(differences in metabolism)
What post-op considerations reptiles?
- Monitor (recovery times in reptiles are prolonged compared with birds and mammals)
- Analgesia essential
- Fluid and nutritional support
- Therapeutic laser therapy
- Phovia
Describe surgical skin prep - reptiles
● Wash off any mud/substrate prior to anaesthesia
● Povidone iodine & appropriate contact time.
● Clean tooth brush to scrub between scales
● Avoid excessive use of alcohol due to evaporative losses
What different scales to consider?
normal vs letherback vs silkback bearded dragons
-> silkbacks very thin, small scales tears easily
Where to incise with regards to scales?
between them to reduce risk of dysecdysis
Reasons for skin surgery ?
- Lump removal -> often neoplasia
- Abscess surgery -> thick, caseous material within a thick capsule
- Wound management
What wound closure?
- Monofilament suture repair
- Everting pattern (horizontal mattress)
- Wound healing longer - sutures left in approx -8 wks
Who are aural abscesses common in ?
semi-aquatic and aquatic species
Vit A role in aural abscesses
role in vision and production and
maintenance of epithelial surfaces.
C/S
conjunctivitis, aural asbcesses, dysecdysis, respiratory signs
TX for aural abscesses?
Vit supplementation / address husabandry (caution)
Surgery for aural abscess?
Sternal recumbency -> semi-circular incision -> curette out purulent material -> ensure clear eustachian tube -> flush -> leave surgical site open -> AMs
describe subspectacular dx
- Distention of the subspectacular space and neovascularization of the spectacle as a result of blockage of the NL duct in snakes an dlizard species, which possess spectacles
- Fluid builds up and often becomes infected and insipissated
Step 1 - Subspectacular dx surgery
make 30-90° resection from the ventral aspect, in the most dependent part of the spectacle
Step 2 - Subspectacular dx surgery
Remove the caseous material (send off for cytology and culture)
- Flush until infected material removed
Step 3 Subspectacular dx surgery
- Cornea should now be visible and exposed
- Open mouth; it is easier to catherise the buccal opening of the NL duct. This is found close to cranial margin of the palatine teeth
Step 4 Subspectacular dx surgery ?
Flush retrograde to remove material
Leave the spectacle wedge incision open - apply topical ophthalmic medication
Healing of spectacle?
- Germinal epithelium of the spectacle is repaired in approx 3 weeks
- Complete spectacle healing often takes 3 months
Approaches to celiotomy
- Paramedian (black of the picture)
- Midline
What to avoid with coeliotomy?
large abdominal vein branching into the paired pelvic veins
Describe paramedian approach to coeliotomy
Make a craniocaudal incision, parralel but lateral to the midline. This si to avoid the ventral abdo vein
use reversed guarded scalpel blade to avoid iatrogenic damage
Describe right lateral recumbency approach to coeliotomy (in chameleons)
Dissection along the ventral border of the ribcage
use sterile cotton tipped applicators to dissect through the thin abdo musculature and coelomic membrane to enter coelemic cavity
(CARE do not rupture distended bladder if operating a species with a bladder
Describe ovaries in reptiles
- Reproductively inacitve lizzard ovaries small
- Located adjacent top dorsal renal veins and adrenal glands in mid caudal coelom
- Ative ovaries enlarged and mesovarian vessels are larger
Describe ovariectomy
- Gently exteriorise ovary and place vascular clips along the mesovarium to ligate vessels
- Dissect ovary
- Oviduts often small and involuted and do not need to be removed unless there is pathology
Describe coelomic closure in town layers
- Coelomic membrane and muscle simple continuous or simple interrupted
- Skin- horizontal mattress, monofilament absorbable suture (PDS)
(in small lizards not always possible to suture coelomic membrane or thin abdo muscles)
Describe the midline approach? step 1
- Incision between pubis and umbilical scar as ventral abdo bein devices into the pelvic veins
Describe the midline approach? step 2
Incision extended cranially using blunt dissection to reveal abdominal vein must be avoided and gently retracted laterally
Describe the midline approach? step 3
closure is routine - using everting skin pattern
What approach to coeliotomy in snakes?
Multiple incisions may need to be made; it is impossible to make a single coeliotomy incision to visualise all organs
Describe Snake Coeliotomy
Make the incision between the second and third rows (or first and second rows) of lateral scales (surgeons’ preference)
Incise between scales
Dissect through the subcutaneous layer
Dissect through the muscle layer, just ventral to the ribs
Enter the coelom
Describe snake coeliotomy closure
A two-layer closure
o Coelomic membrane and muscle
o Skin (position knots on the dorsal side of the incision)
o Skin closure: everting horizontal mattress pattern
What is salpingotomy? Why may we need to do it ?
Opening into the fallopian tube but tube itself is not removed in procedure
Bc often multiple coeliotomy incisions to access all of the oviduct
How do we do salpingotomy in the snake?
Incise oviduct in a healthy appearing section (when inflamed the wall is thicker but more friable)
Gently manipulate the egg along and into the incision site for removal.
If adhered to oviduct wall, insert an IV cannula between the egg and oviduct wall and inject sterile saline
(or sterile water-soluble lubricant 1:10 lubricant to sterile saline) to separate the wall from the egg
Approximately, 3-5 eggs can be manipulated through a single incision.
Once eggs removed - clsoure fo slapingotomy?
Close oviduct with fine monoF synthetic absorbable on atraumatic needle in a two-layer inverting pattern or a simple continuous oversewn with an inverting pattern
Describe an Ovariosalpingectomy
Ovariectomy or ovariosalpingectomy where there is severe pathology to the reproductive tract.
Will prevent further episodes of dystocia/breeding.
Ovaries are cranial to the oviduct and must be approached through separate incisions or by extending the
coeliotomy craniad until ovaries are identified.
Indications for Chelonian coeliotomy
- Prefemoral approach better but transplastron approach -> longe rop time, more painful postop but extensive surgical access
What chelonion coeliotomy LAndmarks?
- HEART -> RED CICLE : IN THE MIDLINE INTERSECTION OF THE PECTORAL AND ABDOMINAL SCUTES
- PLASTRON HINGE: PURPLE LINE; OFTEN BETWEEN ABDO AND femoral scutes
- Abdo veins: red lines: parallel , running in a craniocaudal direction below the plastron
- BLACK RECTANGLE -> plastronotomy site
Plastronoomy - practical things to remmeber?
- Oscillating saggital saw OR high speed dremel
- Wear eye protection
- Avoid overheating o blade by irrigating with saline
Step 1 - of chelonian coeliotomy ?
o Cutting at an angle (45 degrees) makes the inner aspect of the flap smaller than the outer.
o Once replaced, the flap will not fall into the tortoise.
o Make 2 lateral cuts first, then the caudal cut and finally the cranial cut.
Step 2 of chelonian coeliotomy?
o Make full shell thickness cuts for the lateral and caudal cuts
o Check depth with 25-gauge needle
Step 3 of chelonian coeliotomy?
o Remove all powdered debris, aseptically prep plastron again and re-drape
o The cranial site is not cut to full shell thickness so this will act as a potential hinge.
Step 4 -of chelonian coeliotomy?
A sterile instrument (osteotome) is used to lever the
osteotomy flap to free the three incised sides.
Blunt dissection on soft tissue attachments, staying as
close to the plastron segment as possible
Step 5 - chelonian coeliotomy?
Further blunt dissection is used on the soft tissue to
further elevate the flap. The flap of bone remains
attached to the underlying musculature on one side
and is then reflected to gain access to the coelom.
Visualise the coelomic membrane and the two large
vessels (abdominal veins).
STEP 6 CHELOMNIAN COELIOTOMY?
Incise the coelomic membrane in the midline
avoiding the abdominal veins.
If it is not possible to incise between the abdominal
veins, an incision through the coelomic membrane
can be made lateral to the abdominal veins.
If there is a very large structure intra coelom one
abdominal vein may be ligated and transected to
allow an L-shaped flap (e.g., large bladder stone to be
removed).
Is ligation of both abdominal veins advised?
NO!
Where are chelonian ovaries?
- Originate close to ventrolateral aspect of te kidneys -> in mature females large and extend into coeom
How to do ovariectomy in chelonians?
● Gently exteriorise the whole ovary – the mesovarium is extensive
● In pre-ovulatory stasis, the ovaries resemble a cluster of yellow grapes and are very delicate and
friable. The left ovary is attached to a branch of the renal vein. The adrenal gland is located
between the ovary and the renal vein. The right ovary is adjacent to the vena cava.
● Elevate the ovary and ligate the ovarian vessels
T/F in many cases plastron becomes a sequestrum after closure @
True
Healing time of plastron?
12-18 weeks but covering in place for 12 months
How to suture coelemic membrane in chelonians?
- MonoF absorbable
- PDS
How do we reposition plastron flap?
○ Some authors will drill 3 to 4 holes in the plastron flap and shell to anchor the plastron
flap by placing absorbable suture through.
○ Apply IntraSite around the site. Important that the sealing material does not fill the
fissures as this may result in a non-union
○ Seal with fibre glass, epoxy resin or low temperature polymethyl methacrylate.
Kooliner (dental acrylic recommended). Apply epoxy or resin at four points of the
osteotomy site if secure OR apply around the entire bony incision line.
What is the prefemoral approach?
soft tissue approach that involves a skin incision in the
prefemoral fossa and avoids invading the plastron.
Considerations for prefemoral coeliotomy?
Preferred method to enter the coelomic cavity of a tortoise.
Technically easier to perform.
Standard surgical kit needed
Shorter op time
Likely to be less painful post-op.
Shorter healing time of 4-8 weeks.
However, surgical access varied. Provides limited lateral access to the coelom. Better in
species with large prefemoral fossae, especially aquatic species.
Bilateral surgery may be required,
Prefemoral ceoliotomy prep?
- Dorsal or lateral with cranial part of body slightly elevated
- Secure pelvic limb caudal to expose the prefemoral fossa
- Aseptic skin prep
Prefemoral coeliotomy step 1
A craniocaudal incision is made in the skin, halfway between the carapace and the plastron.
The underlying abdominal muscles are bluntly dissected. Blunt dissect cranial to the
sartorius and ventral to the iliacus muscles.
PRefemoral coeliotomy sep 2
The coelomic aponeurosis of the transverse and oblique abdominal muscles are seen.
The coelomic membrane is dissected to gain entry into the coelomic cavity. Placing stay
sutures in the incision layers may aid in closure after the surgery.
Prefemoral coeliotomy step 3
To close, either a continuous pattern or a simple interrupted pattern is used with
absorbable monofilament suture material for the coelomic membrane, muscles and fat.
The skin is closed using an everting pattern such as a horizontal mattress suture pattern.
How do we identify tissue of prolapse?
o Colon/cloaca – shiny pink colour with a lumen.
o Bladder – often thin walled and no lumen.
o Oviduct – thin walled, plicated with lumen.
o Phallus – distal end is pointed with a groove running down the
dorsal midline
What are some possibel underlying causes of cloacal prolapses?
o Gastrointestinal impactions
o Dystocia
o Parasitism
o Hypocalcaemia
o Space occupying lesion
Where should you not place purse string sutures?
Around vent - instead place single interrupted suture either side of vent aperture
What to do for transcutaneous cloaco or colopexy ?
- Aseptic skin prep
- Replaced viable prolapsed tissue
- Insert large, lubricated cotton tipped applicator in coaca
- Tent against ventrolateral body wall
- Place 2 to 3 simple interrupted PDS sutures through skin and cotton tip & leave long
- Still holding onto suture end, gently remove cotton tipped applicator from cloaca
- Tease away cotton tip from sutures
- Pull sutures back into cloaca with haemostats -> tie and suture
healing of cloaco- or colopexy ?
The cloacocolonic wall is now sutured to the body wall and a fibrous adhesion takes
approximately 4-8 weeks to develop.
When should we do hemipene amputation?
When the penis/hemipenis becomes prolapsed
outside of its normal inverted position in the tail
of lizards or snakes, OR is not retracted back
inside the cloaca of chelonians
If tissue desiccation, traumatised and necrotic,
hemipene amputation is warranted
If there is no strength in the penile retractor
muscle, amputation is often warranted
The reptile penis or hemipenes only function as a
copulatory organ; the ureters and urethra empty
into the cloaca.
if recent prolapse tissue healthy what can we use to reduce swelling?
hypertonic dextrose or saline solutions
how to replace hemipene prolapse?
Lubricate with an antibiotic topical ointment (e.g., isathal) and manipulate back
under a GA.
A temporary simple interrupted suture may be placed either side of the vent
aperture in tortoises OR directly over the hemipenis opening in snakes and lizards.
Remove suture after 14 days (tortoises) and after 14-21 days (snakes and lizards).
If re-prolapse or necrotic -> amputation - how do we do this?
Multimodal analgesia, local anaesthesia (infused at base) and GA
Gently retract the hemipene
Place a clamp across the base to crush the tissue.
Place 1-2 transfixing ligatures through the crushed tissue
Transect distal to the ligatures.
Replace the stump back in the cloaca (tortoise) or into the hemipenal opening
(snakes & lizard)
When would we place an O tube in chelonians and lizards?
- Longer term nutritional support and/ or oral medication admin for the anorexic patient
- Post surgery management if patient unlikely to eat
what scutes of the plastron are there?
1 = Gular
2 = humeral
3 = pectoral
4 = abdominal
5= femoral
6 = anal
HOW TO MEASURE for chelonian O tube?
Measure out the tube from the cranial rim of the plastron to
the junction of the pectoral and abdominal scutes (between 3
and 4 on picture).
What to do after O tube measured?
- Mark length -> fill tube with sterile saline and measure volume of. tube -> this is volume needed to flush tube after each feed
What 1st step in O tube placement?
- Prep skin with providone-iodine or F10
- Insert forceps through mouth avoid jugular vein and carotid (want it more caudo-dorsal placed)
Step 2 O tube?
Incise skin over forceps
- Advance hameostats grab tube & pull out mouth
Step 3 O tube?
Pass tube back down oesophagus
Suture in place with Chinese finger trap suture. Tape free end of capped tube to carapace
Step 4 O tube?
Radiorgaphs to heck tube placement (can use small amount of contrast)
What tube care to be mindful of?
- Always flush with water after use to prevent blockage
Flush at least once daily to maintain patency - CLean skin around tube
- Once they are eating O tube can be removed - site will contract and heal 2nd intention
How do we deal with GI FBs?
- SImilar to smallies
- Reptile tissues very delicate -> careful tissue handling essential
- Use saline soaked swabs to protect coelemic cavity
- Standard closure of stomach or intestines
Which reptiles have a bladder?
- Present in chelonians and some lizzards such as iguana
why would we do cystotomy?
- Cystotomy to remove bladder stones or eggs that go into the bladder by retropulsion
What approach for cystotomy in chelonians ?
- Transplastron or prefemoral approach in chelonians or midline or paramedian approach in lizards
Other details about cystotomy?
- Stay sutures in bladder help!
- Bladder closure -> single layer
- Flush coelomic cavity
why is INTERNAL fixation not always possible as fracture repair?
Fracture repair As fractures are commonly a result of NSHP, internal
fixation is often not possible because the bones are
demineralised, soft and will not hold implants.
Extremity fractures are rarely comminuted as most
fractures are a result of low impact forces. Most
fractures can be stabilised with external coaptation.
What factors in fracture management?
- Proper alignement
- Rigid stabilisation
- careful tissue handling
- Preserve blood supply
- Prevent bending, rotation, compression and shearing forces
What to do on top of fracture stabilization?
establish calcium homeostasis, provide analgesia and address husbandry discrpancies
What common complication in lizards/ chelonians?
stump trauma and infection
What is recommended ?
disarticulation of scapulohumeral or coxofemoral joint
Describe disarticulation of the scapulohumeral joint?
Initial skin incision to create a large dorsolateral skin flap that is reflected to reveal the triceps and brachialis muscles.
Transect the muscles
Ligate major vessels and nerves.
Disarticulate the humerus and remove the limb.
Suture the transected muscle bellies of the triceps, biceps and coracobrachialis over the exposed glenoid fossa.
Close routinely, using horizontal mattress sutures. For chelonians a prosthesis (furniture roller or lego wheel) can be
glued to the plastron to aid in ambulation.
How to manage shell repair?
- usually dog bite -> primary closure not an option -> DO NOT want to trap dirt/ infection
- FLUSH wounds, analgesia
- Bacterial & fungal C & S
- Xray / CT
What is the point of Xray / CT shell damage?
essential to determine if the underlying
bony plates of the shell have been
damaged, rather than solely the
keratinised scutes above.
What are the repair options for shell?
- Adhesives and epoxy
- Screws and wire
- Cable tie and hook fixation
- Epoxy and metal
Describe Ahesive and epoxy option
Not recommended now for shell fractures; abscessation and osteomyelitis may develop underneath the fibreglass
patch. Historically, was the standard treatment for shell fractures. Occasionally used now in combination with
bone plates and cable
Long term effects on shell growth not understood – advise removal once healed.
Describe Screws and wire option
Use of stainless-steel screws - All fixation devices must be sterilised. Do not use galvanised zinc screws as these
may release zinc systemically.
GA and aseptic shell/skin prep
Reconstruct the shell
Screws drilled into shell fragments (preferably staying back at least 0.5cm from the edge of the fracture site).
Use stainless steel wire (20-gauge) around two opposing screw heads in a figure-of-eight pattern.
Place the knot between the two screw caps.
If the knot cannot be flattened against the shell cover the sharp tip with epoxy.
Describe cable tie and hook fixation?
For non-displaced fractures.
Not as strong as screws and wires, but less invasive.
Wire hooks or grommets adhered to shell using epoxy or cyanoacrylate glue.
Secure with wire or cable ties
Describe Epoxy and metal fixation ?
To stabilise plastron fractures
Glue or epoxy used to adhere a bone plate across a fracture site
Indications for tail amp?
Ischaemic necrosis or trauma to tail. esp in species that undergo autonomy
How do we do a tail amputation?
Brief GA
Analgesia
Amputate (twist and snap) through a fracture
plane. The site of amputation must be proximal
to all abnormal tissue.
Trim muscle strands
Apply local
Surgical site left open
What do we do before a tail amp?
radiography to assess for osteolysis
If osteolysis present?
Culture and sensitivity often indicated ● General anaesthesia ● Multimodal analgesia ● Aseptic skin prep ● Incise the dorsal skin of the tail ● Continue surgical dissection through
the tail musculature and vertebra,
ensuring that a large ventral flap is
preserved.
● Lift over ventral flap and suture to the
dorsal skin margin using single
interrupted sutures.
What must be maintained during fish surgery?
thermoregulation, osmoregulation, and other water quality parameters
What might we do post op fish surgery?
depending on species and procedure,
may want to add salt to the water concentration of 3-
5ppt for freshwater species reduces osmotic stress.
sutures in fish?
absorbable suture will remain
for a longer period of time lower environmental
temperatures.
surgical prep in fish?
Surgical prep must not disrupt the natural mucus layer
critical for protection and innate immunity.
Describe Gill Clip as diagnostic procedure?
● Lift operculum and take a small sample of gill
filaments.
● Examine under microscope immediately.
○ Assess for parasites
○ Assess structure and cellularity of gills
Mass removals - fish
● Indication for surgery should ideally be
confirmed, before the procedure as
some masses will regress
spontaneously (cyprinid herpesvirus 1
infection)
● External mass incisional or excisional
biopsies are similar to that in mammals.
Skin scrapes & wound management - fish?
● Debride necrotic tissues, remove detached
scales
● Lavage wound
● Apply thin layer of gel
● Skin scrape
microscopy slide
scrape in
direction of scales to collect mucus
apply
coverslip
examine immediately.
● Collect from several areas to include under
fins and the underside of the fish
● Non invasive procedure
Indications for enucleation of fish?
ocular injury or to alleviate pain associated with unsolvable ocular lesions
How do we do enucleation (fish) ?
● Anaesthetise lidocaine block dissect and
transect periorbital tissue, conjunctiva and
oculomotor muscles off the globe.
● Minimise traction on the optic nerve to prevent
damage to the optic chiasm.
● Transect and remove the globe.
● Ligate retro-orbital vessels, apply digital
pressure and a haemostatic gel if available.
● Leave the orbit open to heal by secondary
intention.
● I apply a waterproof paste into the orbit over
the next 24-72 hours.
describe Dentals in fish?
● Oral surgery and incisive plate adjustments to
aid in food prehension if there has been
insufficient wearing of the dental plates or an
oral mass.
● Pufferfish continuously growing incisor
plates (normal!). If overgrown, under a GA trim
with a dental burr or rotary tool.
● Care not to overheat the incisor plates
● Address diet to prevent this reoccurring
