117. Urethra Flashcards
3 parts of the male urethra
—preprostatic (not distinct in dogs, BUT VERY DISTINCT with 3 muscle layers in cats)–prostatic–cavernous/membranous
smooth muscular layer of the urethra
smooth muscle of urethral blends distally with striated urethralis muscle
histological difference in female spayed vs intact dogs
PROXIMAL urethraspayed–decreases smooth muscle mass, higher collagenoverall females have less muscle and more collagen than males
ECG abN of hyperkalemia
urinary obstructed patient–prolong PR–dropped P waves–wide prolonged QRS width–tented, tall, spiked T waves–bradycardia
imaging of the urethra
–PE, RECTAL–Survey rads—rarely diagnostic–positive contrast retrocystourethrogram, vaginocystourethrogram (rads, fluoro)–ultrasound (extrapelvic urethra)–cystoscopy/vaginoscopy
how much would the urethra need to stricture prior to seeing clinical signs
60%
goal of urethral healing
mucosa can regenerate quickly goal is minimal fibrosis in order to minimize occurrence and severity of urethral strictureavoid tension!
T/Fthe type of urinary diversion used does NOT influence urethral function or healing
TRUEbut it is unclear if prolonged (weeks) maintenance of an intraurethral catheter decreases stricture formation
urethral procedures
—urethrotomy–temporary (prescrotal)—urethrostomy–permanent (scrotal–dog, perineal–cat, prepubic)–urethral R&A
most common complication after urethrotomy
hemorrhage–suturing the urethrotomy decreases amt(urethral stricture is an uncommon complication)
preferences of urethrostomy locations
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
length recommendation for scrotal urethrostomy
5-8x diameter of urethra (3-4 cm)bc the stoma will reduce to one half to two third the initial size
most common complication following urethrostomy
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)
anatomy of dissection for perineal urethrostomy
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)
complications following perineal urethrostomy in cats
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
outcome in cats with prepubic urethrostomy
–40% urinary incontinent–peristomal skin irritation common–persistent lower urinary tract disease–40% euthanized within 1-2 yearsBaines Vet Sx 2001 16 cats
hypospadias
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
tx hypospadias
–primary closure may be complicated–urethrostomy proximal to abN area +/- penile amputation and preputioplasty
epispadias
failure of fusion of the DORSAL urethra
types of urethral fistulas
—urethrorectal –urethrocutaneous
urethral obstruction common location male dog vs male cat
male dog—ischial arch, proximal os penismale cat –distal third of urethra
percentage of cats that have urethral trauma from previous urinary catheterization
80%the most common cause of urethral trauma in dogs is HBC (70%)
treatment options for urethral strictures
- balloon dilation2. urethral stenting3. urethral resection and anastomosis4. proximal urethrostomy
urethral prolapse
young male brachycephalic dogsexcitement, labored breathing, masturbation, dysuria from underlying stoneshemorrhage
surgical recommendations for urethral prolapse
–CASTRATION–tx BCAS– resection and anastomosis–urethropexy(also treat any underlying UTI, cystitis)conservative mgmt: lube, urinary catheter, purse string 5 d, recurrence common
