117. Urethra

Question 1

3 parts of the male urethra

Answer 1

—preprostatic (not distinct in dogs, BUT VERY DISTINCT with 3 muscle layers in cats)–prostatic–cavernous/membranous

Question 2

smooth muscular layer of the urethra

Answer 2

smooth muscle of urethral blends distally with striated urethralis muscle

Question 3

histological difference in female spayed vs intact dogs

Answer 3

PROXIMAL urethraspayed–decreases smooth muscle mass, higher collagenoverall females have less muscle and more collagen than males

Question 4

ECG abN of hyperkalemia

Answer 4

urinary obstructed patient–prolong PR–dropped P waves–wide prolonged QRS width–tented, tall, spiked T waves–bradycardia

Question 5

imaging of the urethra

Answer 5

–PE, RECTAL–Survey rads—rarely diagnostic–positive contrast retrocystourethrogram, vaginocystourethrogram (rads, fluoro)–ultrasound (extrapelvic urethra)–cystoscopy/vaginoscopy

Question 6

how much would the urethra need to stricture prior to seeing clinical signs

Answer 6

60%

Question 7

goal of urethral healing

Answer 7

mucosa can regenerate quickly goal is minimal fibrosis in order to minimize occurrence and severity of urethral strictureavoid tension!

Question 8

T/Fthe type of urinary diversion used does NOT influence urethral function or healing

Answer 8

TRUEbut it is unclear if prolonged (weeks) maintenance of an intraurethral catheter decreases stricture formation

Question 9

urethral procedures

Answer 9

—urethrotomy–temporary (prescrotal)—urethrostomy–permanent (scrotal–dog, perineal–cat, prepubic)–urethral R&A

Question 10

most common complication after urethrotomy

Answer 10

hemorrhage–suturing the urethrotomy decreases amt(urethral stricture is an uncommon complication)

Question 11

preferences of urethrostomy locations

Answer 11

OPTIONS: prescrotal, scrotal, perineal, prepubicmale dogs: scrotal bc others have high incidence of urine scald and dermatitismale cats: perineal** but prepubic can also be performedfemale dogs/cats: limited to prepubic

Question 12

length recommendation for scrotal urethrostomy

Answer 12

5-8x diameter of urethra (3-4 cm)bc the stoma will reduce to one half to two third the initial size

Question 13

most common complication following urethrostomy

Answer 13

persistent hemorrhage several dayssimple cont (vs simple interrupt) decr days bleeding from 4 days to 0.2 days other complications: urine scald, UTI, recurrent obstruction (ea. 20%), stricture (RARE)

Question 14

anatomy of dissection for perineal urethrostomy

Answer 14

performed in dorsal or ventral recumbency–penile ligament incised (ventral)—ischiocavernosus muscles incised–retractor penile muscle incised (dorsal)–continue dissection until bulbourethral glands noted (urethral diameter 4-5 mm)–incise urethra on dorsal midline to bulbourethral glands–appose mucosa to epidermis/dermis (stoma simple interrupted and then simp or cont, abs vs nonabs—no diff)

Question 15

complications following perineal urethrostomy in cats

Answer 15

short term 25%—hemorrhage, stricture, wound dehisce, urine extravasatelong term—-30% UTI, recurrence of lower urinary tract disease in one study but up to 50% guarded prognosis in another study from lower urinary tract diseasestricture is most commonly from poor technique

Question 16

outcome in cats with prepubic urethrostomy

Answer 16

–40% urinary incontinent–peristomal skin irritation common–persistent lower urinary tract disease–40% euthanized within 1-2 yearsBaines Vet Sx 2001 16 cats

Question 17

hypospadias

Answer 17

ventral failure of fusion of urogenital folds—incomplete urethramales>females (BOSTON TERRIERS)glandular, penile, scrotal, perineal, analcheck for cryptorchidism and/or hypoplasia of penis, prepuce, scrotum, testes

Question 18

tx hypospadias

Answer 18

–primary closure may be complicated–urethrostomy proximal to abN area +/- penile amputation and preputioplasty

Question 19

epispadias

Answer 19

failure of fusion of the DORSAL urethra

Question 20

types of urethral fistulas

Answer 20

—urethrorectal –urethrocutaneous

Question 21

urethral obstruction common location male dog vs male cat

Answer 21

male dog—ischial arch, proximal os penismale cat –distal third of urethra

Question 22

percentage of cats that have urethral trauma from previous urinary catheterization

Answer 22

80%the most common cause of urethral trauma in dogs is HBC (70%)

Question 23

treatment options for urethral strictures

Answer 23

1. balloon dilation2. urethral stenting3. urethral resection and anastomosis4. proximal urethrostomy

Question 24

urethral prolapse

Answer 24

young male brachycephalic dogsexcitement, labored breathing, masturbation, dysuria from underlying stoneshemorrhage

Question 25

surgical recommendations for urethral prolapse

Answer 25

–CASTRATION–tx BCAS– resection and anastomosis–urethropexy(also treat any underlying UTI, cystitis)conservative mgmt: lube, urinary catheter, purse string 5 d, recurrence common