Equine Male Urogenital Surgery Flashcards
Testicle anatomy:
What are the 3 layers that cover the testicle?
- vaginal tunic - continuation of the abdominal peritoneum that passes through the inguinal canal and covers the testis and spermatic cord
- visceral tunic - covers testis and associated duct
- parietal tunic - continuous with the parietal peritoneum, which forms the sac lining of the scrotum
When is castration most commonly performed in horses? What are the 3 major indications?
1-2 years old –> small enough to handle
- behavioral
- management
- medical - orchitis, epididymitis, testicular neoplasia, hydrocele, trauma, testicular torsion, inguinal herniation
What are the 3 techniques when performing a castration on a horse?
- CLOSED - does not incise the parietal tunic
- SEMI-CLOSED - incise the parietal tunic, but emasculate cord is still covered by the parietal tunic
- OPEN - incise parietal tunic and leave insitu when done, allows for direct visualization of the testis and epididymis
What field anesthesia is recommended during castration?
- PREMED - Xylazine, NSAID
- INDUCTION - Ketamine +/- Benzodiazepine
- INTRA-TESTICULAR BLOCK - 10 mL Lidocaine per testicle
What are the 2 major positions used for equine castration?
- dorsal recumbency
- lateral recumbency - tie or hold leg out of the surgical field, best to situate surgeon along the back or between the hindlimbs
How is castration performed in horses?
- incise skin and SQ tissue - use flat part of a #10 scalpel blade
- break gubernaculum and strip cord using a 4x4 gause and a towel clamp for stabilization
- ligate one spermatic cord - especially important in older (transfixing, Miller’s, Roeder) horses, donkeys, and mules
- apply emasculator to reduce the risk of evisceration and provide reliable hemostasis
- start onto the second testicle while the emasculator is on the other cord
- perform another scrotal incision and follow the same directions
What are 4 types of emasculators used for equine castraction? What action do they provide?
- Reimer - crushes and cuts with separate handles
- Serra - crushes and cuts with same handles, self-retaining
- Sand - crushing only
- Henderson - attached to a drill, spins testicle off
How are emasculators placed on the spermatic cord correctly?
nut to nut –> crushes toward the abdomen and cuts away from it
What 3 things should be done once both testicles are removed?
- keep an Allis tissue forceps or hemostat on cord until hemorrhage stops
- trim SQ that could hang down when horse stands up
- stretch incision to allow proper drainage
What are 3 options if hemostasis is not achieved during a castration?
- clamp vessels and wake horse up with hemostats - will fall off or can remove the next day
- find cord again and re-ligate - keep clamped until there is no blood
- pack incisions - Kerlix tied together, can suture in place, tie in a bow
How are horses recovered post-op after a castration?
- keep horse recumbent as long as they have nystagmus
- cover head
- sit on head and neck
- stay quiet!
What is a major pro and con of standing castrations?
PRO - safer for horse
CON - more dangerous for surgeon
(commonly done in Europe)
What 4 peri-operative medications are given to horses getting castrated?
- antibiotics - 1 dose pre-op
- Phenylbutazone - cheap, PO, 3 days post-op
- Flunixin meglumine - more expensive, better for soft tissue injuries, 3 days post-op
- tetanus vaccine toxoid - if not administered in last 6 months; give anti-toxin if never vaccinated
What are 4 important aspects to castration aftercare?
- after 24 hours, the horse must move around to prevent swelling - forced exercise, NOT pasture or arena turnout
- monitor for complications - swelling, hemorrhage, SQ tissue hanging out, post-op pain, septic funiculitis, penile trauma, septic peritonitis, evisceration
- careful placing with mares - can still impregnate up to 2 days after
- be aware that 5% of horses will still exhibit stallion-like behavior - learned
How is excessive edema following castration treated?
- hydrotherapy - cold hose (NOT in incision)
- exercise the horse
(may affect penile function)
Excessive edema following castration:
How are omental hernias following a castration treated?
refer if possible –> pack and close incision
- surgery to replace tissue
- close external inguinal ring
Evisceration following a castration:
What is septic funiculitis? What are 5 parts to treatment?
inflammation/infection of spermatic cord –> chronic = schirrous cord
- establish drainage
- exercise
- antibiotics
- hydrotherapy or lavage
- may need to debride under general anesthesia - remove abnormal cord through original incision, exteriorize the cord, ligate, emasculate
What 3 approaches are used for cryptorchidectomies?
- inguinal
- parainguinal
- laparoscopy - dorsal recumbency or standing
Cryptorchidectomy, inguinal:
find testicle and apply pressure on gubernaculum to exteriorize it –> will typically be small
Cryptorchidectomy, parainguinal:
next to inguinal ring –> reach in, pick up tunic, and exteriorize testicle
Cryptorchidectomy, laparoscopic:
What are 3 surgical options available for penile SCC?
- segmental posthectomy (reefing) - removal of epidermis in lesions only involving the superficial layers
- partial phallectomy - deeper invasion past the epidermis
- partial phallectomy + en block resection + retroversion - lesions involving penis and prepuce or evidence of metastasis
Partial phallectomy:
What parasite can cause penile masses in horses? What treatment is recommended?
Habronemiasis
- Ivermectin or Moxidectin
- debulk large lesions
