Equine urogenital surgery and castration Flashcards
Pros and cons of standing castration
Quicker and don’t have risks of general anaesthetic
But can only do an open castration
When might we choose to do a castration under GA
Mature stallions over 4 years due to increased risk of haemorrhage/herniation
History of inguinal hernia as foal
Cryptorchid
If very fractious
Donkeys
How do we castrate a foal with a hernia
closed castration and twist tunic to milk any intestines back into abdo cavity then ligate as low as possible
Pre-op preparation and analgesia for a standing castrate
Detomidine, butorphanol
Buprenorphine
Tetanus prophylaxis if needed
Antibiotics if very dirty
Prep surgical site including inner thighs
Where do we inject local anaesthetic for standing castrate and how much
5-10 mls total in the testss
Line of LA in the skin, a couple cm lateral to the midline raphe
[end up with 10-15ml per side]
Where to make incision for standing castrate
1-2 cm lateral to the midline raphe (thin dark line)
Need to keep it quite ventral to ensure good drainage and avoid seroma formation
How to place an emasculator
Nut to nut
Want wing close to testicle; this allows it to crush then cut the cord
When should we place ligatures in castration
Only if dealing with haemorrhage because this will predispoe to infection (and this is a contaminated procedure)
How much haemorrhage do we expect after a standing castrate
Dripping for 30-60 mins (such that we can count the drops i.e not a steady stream)
What are some causes of excessive haemorrhage in a standing castrate
Placing emasculator the wrong way round
Using the wrong size emasculator
NOt holding emasculator on long enough
How to deal with a bleeder in a standing castrate
Re-sedate the horse
Try and find the stump of the cord using artery forceps
Place forceps on transversely, leave for 24hrs and re-sedate to remove
(or use ligature if you can’t come back to the yard to remove forceps)
What to do with a bleeder from standing castrate if we can’t find the cord
Pack scrotal wound with long sterile bandage
IF this isn’t enough then go a quick GA, find the cord and then clamp/ligate
What are some advantages of castration under GA
CAn do a closed castration which minimises risk of evisceration, haemorrhage and better asepsis
How to perform a close castration under GA
Incise scrotum, pull out testis, strip off the tissue from the tunic
Place two transfixing ligatures around the cord using thick metric vicryl
Emasculate distal to the ligatures, nut to nut
Probably don’t worry about closing the skin
Post-op care after castrate
NSAIDs for a few days
Antibiotics if very dirty or break in sterility
Box rest for 24 hours and check regularly for haemorrhage
THEN do forced walking out to reduce the oedema
How long can stallions be fertile for after castration
1-2 months
What would we see with a surgical site infection post-castrate
Excessive oedema, purulent discharge, lameness/stiff gait, pyrexia
What are some predisposing factors for surgical site infection with castration
contamination during surgery
using ligatures in non-sterile procedure
dirty environment
too small scrotal incisions since gives poor drainage and too rapid closure to haematoma retained
Too lateral incisions as get poor drainage
Treatment for surgical site infection post-castrate
Sedate, re-establish drainage by opening the incision, clean out clots/pus, lavage using physiological saline or dilute iodine
Systemic antibiotics
What is funiculitis and how do we treat
Infection of the cord stump
Get unresolving acute infection so thickened cord stump
Rare and generally related to sutures being left in
Dissect out bluntly and transect on a clear piece of spermatic cord; avoid ligature placement
What is schirrous cord
Chronic funiculitis with granulomas on scortum and small drainage tracts
Again, related to non-absorbable suture material
What would a lace-like protrusion from a castration wound be
Omentum prolapse
Why are we not likely to get evisceration where there has been omental prolapse
Because the omenum plugs the inguinal canal
Treatment for dartos prolapse post-castration
Sedate, clean, inject LA, clamp and trim
Treatment for omentum prolapse post-castration
Sedate, pull out a bit more healthy omentum and resect using emasculators while stnading or under GA
Which individuals might be more likely to get evisceration post-castration
Draft breeds
Mature stallion
How to deal with large evisceration post-castrate in short term
Sedate horse, place damp nappy to support guts while referring to nearest emergency centre
What is a hydrocoele post-castration and when might we get it
= filling up of the scrotal sac with peritoneal fluid
= Generally after an open castrate where excess vaginal tunic has bene left in place
= non-painful and can be manually reduced bu may open and resect out tunic to solve cosmetic issue
Why might we still get stallion like behaviour post-castrate
Because this behaviour is learned not just hormonal
More common to get this in older stallions
Which breed is prone to cryptorchidism
Welsh ponies
How to tell if a ‘castrated horse’ has a retained testicle
Anti-mullerian hormone bblood test is most accurate marker of testicular tissue
Options other than anti-mullerian hormone for telling if a castrated horse has a retained testicle
Testosterone concentration pre and post-HCG stimulation
Oestrogen sulphate assay (if>3y/o)
Which retained testicle location may resolve at puberty when the testicle enlarges
Inguinal canal (NOT abdo cavity because the vaginal ring will have closed already)
In castration of a rig which testicle do we removed first
Always the retained one
Which area of the penis cannot we not do local excision on and why
Glans
Because it bleeds too much
Which lesions might we do local excision for on the penis
Non-invasive lesions on the skin e.g penile melanoma, some sarcoids
What is a reefing procedure and when might we do it
Removing a ring oc skin around the penis and sewing edges together
Used when there are multiple superficial tumours or certain injuries
When might we do a phallectomy
To remove an invasive tumour e.g squamous cell carcinoma
What is an en-bloc penile resection
Removing the penis, sheath and local lymph nodes
Done for tumours which have invaded prox sheath/tunica or spread to LNs already
Either remove most of penis and leave hole ventrally or do perineal urethrostomy to pull penis through here
Expensive and very invasive
What is the most common penile tumour and which individuals are esp prone
Squamous cell carcinoma
Esp in old geldings
How could we treat pre-cancerous SCC plaques on the penis
With topical 5-FU cream
Or could do reefing operation
What is the recurrence rate like with SCC removal from the penis
Quite low; only 15% after 2 years
(worse prognosis if invasion of tunica, lymphatics or unclear margins)
Should we remove penile melanomas on grey horses
No probably don’t bother
More will just come up
How could we remove sarcoids on the penis
Laser, local excision, local treatments
What must we remember to do if we find sarcoids
Check for more lesions in other sites
What are some potential sequelae of penile trauma
Paraphimosis
Loss of function
Strictures/adhesions
Treating penile trauma
Massage from distal to proximal to push swelling back/use vet wrap for this
Put emolients on
Support penis using bandage strapped to body wanll to prevent dependent oedema
NSAIDs
Forced walking out
What is the perineal body in females
fibromuscular area that separates vestibule/vagina from rectum/anus
Causes of pneumovagina
- Tearing of stretching of labial seal or vulvovaginal sphincter
- Poor conformation: sunken perineal body; cranial displacement of anus, cranial inclination of vulva over brim of pelvis
= common in underweight, old, multiparous mares
Which animals is it more common to see pneumovagina in
Underweight, old, multiparous mares
How to do a caslick’s vulvoplasty
Sedate and restrain
Clear perinum and inject LA in two lines along labial margins
Use mezembaum scissors to incise very thing strip of muco-cutaneous junctions and appose using simple interrupted or continuous suture (non-absorbable)
Remove at 2 weeks
Leave bottom part of cleft open to allow urination and copulation
What is a breeding stitch
Heavier suture placed at the bottom of a caslick’s which can help protect the repair during natural survice my allows some more stretching
When might we go for a vestibuloplasty rather than caslick’s vulvuloplasty
in where there is damage to perineal body so caslick’s not enough to correct pneumovagina
How to do a vestibuloplasty
Sedate and epiturate
Disect the mucosa and submucosa from dorsal aspect of vesticle
Then appose two sites of perineal body musculature which had been torn apart using absorbably sutures in horizontal mattress pattern
Then do Caslick;s
What is a perineal body trasection/pouret
Old fasioned procedure to incise between anus and vulva to free the vulva from rectal attachmetns
When do we get urine pooling/urovagina in mares
Where the external urethral orifice is dorsal to the vaginal fornix due to cranioventral deviation of the vagina
Generally in old pluriparous mares because they have poor muscular tone of the vagina and elongated broad ligaments
What are the treatments like for urovagina
All prone to failure
Which individuals is perineal injury during parturition more common in and why
Primiparous mares because the annular fold (hymen remnant) is more prominent
What are the degrees of perineal tear
Grade 1 = only skin and MMs of dorsal aspect of vestibule affected
Grade 2 = disruption of perineal body (constritor culcae muscle)
Grade 3 = complete disruption of tissue between rectum and vestibule
Lacteration vs fistula 3rd degree perineal tear and what do we see with both
Laceration = complete disruption of perineal body
Fistula = where there is a perforation of vestibule/rectum but some of perineal body remains intact; generally because the malposture was corrected before delivery
See faecal contamination of the vaginaH
How to repair first degree perineal injurt
Just do a Caslick’s
How to deal with second degree perineal injurt
Vestibuloplasty to reconstruct perineal body
How to deal with 3rd degree perineal injury
Need to create new shelf of tissue to separate rectum from vagina
If fistula, freshen up edges and repair in multiple layer closure
Need stool softened to prevent post-op straining
How long to wait to breed after 3rd degree perineal tear repair; what about for AI
2 months for natural service
2 weeks fo AI
What neoplasias are common on vulva/clitoris and how do we treat
SCC or melanoma
Use local excision +/- adjunctive chemo
What direction are most cervical lacerations
Longitudinal
Why do we get cervical laceration
During parturition where the cervix is insufficiently dilated
How do we diagnose a cervical laceration
Palpate per vagina during dioestrus; should not be able to get 1 finger into lumen of the cervix
How are cervical lacerations repairs
Standing with epidural; use long forceps to pull cervix as far caudally as possible
Treatment of uterine cysts
Rupture, then laser the base
How do we diagnose uterine torsion
Rectal exam feel very taut broad ligament
Prognosis for uterine torsion after surgery
for mare 80-90%
Fetus is 50-80%
Indications for ovariectomy
Granulosa cell tumours
Severe behavioural problems associated with oestrus
What is the most common ovarian tumour
Granulosa cell tumour
What do we try before doing a caesarian section
Controlled vaginal delivery
But if don’t get good progress within 15-20 mins then should switch to C secion
How to try controlled delivery attempted
Mare knocked out, hoist up hind limbs to allow vet to push foal back into abdomen using gravity, rearrange and place ropes
Then lower into lateral and deliver
What is the risk with too long controlled vaginal delivery intervention
Cervical adhesions
After starting a c section, we want a live foal within how long?
20 mins
Which horses are more liekly to get urolithiasis (still rare)
GEldings
What neoplasia might we see in the urethra
SCC
