Equine Male Urogenital Surgery Flashcards

1
Q

Testicle anatomy:

A
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2
Q

What are the 3 layers that cover the testicle?

A
  1. vaginal tunic - continuation of the abdominal peritoneum that passes through the inguinal canal and covers the testis and spermatic cord
  2. visceral tunic - covers testis and associated duct
  3. parietal tunic - continuous with the parietal peritoneum, which forms the sac lining of the scrotum
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3
Q

When is castration most commonly performed in horses? What are the 3 major indications?

A

1-2 years old –> small enough to handle

  1. behavioral
  2. management
  3. medical - orchitis, epididymitis, testicular neoplasia, hydrocele, trauma, testicular torsion, inguinal herniation
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4
Q

What are the 3 techniques when performing a castration on a horse?

A
  1. CLOSED - does not incise the parietal tunic
  2. SEMI-CLOSED - incise the parietal tunic, but emasculate cord is still covered by the parietal tunic
  3. OPEN - incise parietal tunic and leave insitu when done, allows for direct visualization of the testis and epididymis
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5
Q

What field anesthesia is recommended during castration?

A
  • PREMED - Xylazine, NSAID
  • INDUCTION - Ketamine +/- Benzodiazepine
  • INTRA-TESTICULAR BLOCK - 10 mL Lidocaine per testicle
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6
Q

What are the 2 major positions used for equine castration?

A
  1. dorsal recumbency
  2. lateral recumbency - tie or hold leg out of the surgical field, best to situate surgeon along the back or between the hindlimbs
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7
Q

How is castration performed in horses?

A
  • 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
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8
Q

What are 4 types of emasculators used for equine castraction? What action do they provide?

A
  1. Reimer - crushes and cuts with separate handles
  2. Serra - crushes and cuts with same handles, self-retaining
  3. Sand - crushing only
  4. Henderson - attached to a drill, spins testicle off
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9
Q

How are emasculators placed on the spermatic cord correctly?

A

nut to nut –> crushes toward the abdomen and cuts away from it

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10
Q

What 3 things should be done once both testicles are removed?

A
  1. keep an Allis tissue forceps or hemostat on cord until hemorrhage stops
  2. trim SQ that could hang down when horse stands up
  3. stretch incision to allow proper drainage
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11
Q

What are 3 options if hemostasis is not achieved during a castration?

A
  1. clamp vessels and wake horse up with hemostats - will fall off or can remove the next day
  2. find cord again and re-ligate - keep clamped until there is no blood
  3. pack incisions - Kerlix tied together, can suture in place, tie in a bow
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12
Q

How are horses recovered post-op after a castration?

A
  • keep horse recumbent as long as they have nystagmus
  • cover head
  • sit on head and neck
  • stay quiet!
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13
Q

What is a major pro and con of standing castrations?

A

PRO - safer for horse

CON - more dangerous for surgeon

(commonly done in Europe)

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14
Q

What 4 peri-operative medications are given to horses getting castrated?

A
  1. antibiotics - 1 dose pre-op
  2. Phenylbutazone - cheap, PO, 3 days post-op
  3. Flunixin meglumine - more expensive, better for soft tissue injuries, 3 days post-op
  4. tetanus vaccine toxoid - if not administered in last 6 months; give anti-toxin if never vaccinated
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15
Q

What are 4 important aspects to castration aftercare?

A
  1. after 24 hours, the horse must move around to prevent swelling - forced exercise, NOT pasture or arena turnout
  2. monitor for complications - swelling, hemorrhage, SQ tissue hanging out, post-op pain, septic funiculitis, penile trauma, septic peritonitis, evisceration
  3. careful placing with mares - can still impregnate up to 2 days after
  4. be aware that 5% of horses will still exhibit stallion-like behavior - learned
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16
Q

How is excessive edema following castration treated?

A
  • hydrotherapy - cold hose (NOT in incision)
  • exercise the horse

(may affect penile function)

17
Q

Excessive edema following castration:

A
18
Q

How is excessive hemorrhage following a castration treated?

A

EMERGENCY

  • pack surgical site
  • lay horse down to find the bleeder
  • administer aminocaproic acid, formalin, and yunnan baiyao
  • monitor PCV/TS - transfuse if <18%
19
Q

How are omental hernias following a castration treated?

A

refer if possible –> pack and close incision

  • surgery to replace tissue
  • close external inguinal ring
20
Q

Evisceration following a castration:

A
21
Q

What is septic funiculitis? What are 5 parts to treatment?

A

inflammation/infection of spermatic cord –> chronic = schirrous cord

  1. establish drainage
  2. exercise
  3. antibiotics
  4. hydrotherapy or lavage
  5. may need to debride under general anesthesia - remove abnormal cord through original incision, exteriorize the cord, ligate, emasculate
22
Q

In what horses is cryptorchidism most commonly seen? What are the 2 types?

A
  • Percherons
  • QH
  • Americal Saddlerbed
  • ponies
    HERITABLE - do NOT breed
  1. abdominal - left most common
  2. inguinal (high flanker) - right
23
Q

How should a horse with cryptorchidism be castrated?

A

do NOT castrate normal testicle if not prepared to go after the retained one

24
Q

What are 2 options for diagnosing cryptorchidism in horses?

A
  1. hCG stimulation test - will have a high testosterone level
  2. quantification of free estrogen - not widely used
25
Q

What 3 things should be done if a testicle cannot be palpated in the scrotum of a horse?

A
  1. sedate - may drop due to muscle relaxation
  2. AUS - can differentiate abdominal vs. inguinal
  3. anesthetize - try to palpate outside of external inguinal ring (high flankers)
26
Q

What 3 approaches are used for cryptorchidectomies?

A
  1. inguinal
  2. parainguinal
  3. laparoscopy - dorsal recumbency or standing
27
Q

Cryptorchidectomy, inguinal:

A

find testicle and apply pressure on gubernaculum to exteriorize it –> will typically be small

28
Q

Cryptorchidectomy, parainguinal:

A

next to inguinal ring –> reach in, pick up tunic, and exteriorize testicle

29
Q

Cryptorchidectomy, laparoscopic:

A
30
Q

What is the most common neoplasia of the male external genitalia? How is metastasis determined? When is treatment recommended?

A

SCC

palpation of inguinal LNs per rectum

prompt treatment - topicals work best on small plaques

31
Q

What 3 types of treatments are recommended for penile SCC?

A
  1. plaques - topical 5-fluorouracil
  2. masses - debulk, topical 5-fluorouracil
  3. non-responders, extensive lesions - surgery
32
Q

What are 3 surgical options available for penile SCC?

A
  1. segmental posthectomy (reefing) - removal of epidermis in lesions only involving the superficial layers
  2. partial phallectomy - deeper invasion past the epidermis
  3. partial phallectomy + en block resection + retroversion - lesions involving penis and prepuce or evidence of metastasis
33
Q

Partial phallectomy:

A
34
Q

What parasite can cause penile masses in horses? What treatment is recommended?

A

Habronemiasis

  • Ivermectin or Moxidectin
  • debulk large lesions
35
Q

Other than SCC, what is another common neoplastic lesion found on the penis of horses? What treatment is recommended?

A

sarcoid

  • partial phallectomy
  • cryotherapy
  • Aldera
  • debulking