Urethral Disease Flashcards
How can the penile urethra be divided?
Perineal
Scrotal
Pre Scrotal
Which are of the male urethra is most commonly used for performing permanent urethostomy?
Scrotal region
What is the goal of urethral obstruction/trauna?
Regain urethral continuity and/or ability to redirect urine flow externally.
What uroliths are amenable to dissolution?
Struvite
Urate
Cysteine
Why is dissolution not an option in male dogs?
Risk of life threatening obstruction
What are non surgical cystolith removal option? (4)
- Diet
- Voiding hydorpulsion
- Transurethral cystoscopic retrieval
- Lithotripsy
What is the approach to a proximal urethral lesion?
Midline celiotomy
What is the approach to a intrapelvic urethral lesion?
Pelvic osteotomy
What is the approach to a perineal/penile urethral lesion?
urethrostomy proximal to the lesion
What suture method/material for primary urethral repair?
Simple interrupted - monofilament/absorbable
How can we support primary urethra repair? (2)
Tube cystotomy
Urethral catheter
Is recurrent obstruction from urolith more common in dogs or cats?
Dogs
Which urolith has highest rate of recurrence?
Calcium oxalate
How often does struvite recur in:
A) Dogs?
B) Cats?
A) 21%
B) 2.7%
Why should a urethrotomy be avoided where possible (2)
- Haemorrhage
- Urethral stricture
What is the preferred location of urethrotomy?
Pre scrotal
What muscle is retracted to allow urethrotomy?
Retractor preputial muscle
How is the urethra incised?
Longitudinally
Why is it important to remain on the midline of urethrotomy?
The ischiocavernosus tissue is present on each side of the urethra.
How can urethrotomy be closed?
4-0 or 5-0 monofilament absorbable suture in a simple interrupted or continuous pattern
What anatomy needs to be included when suturing urethrotomy? (2)
Urethra mucosa
Tunica aluginea
Following a urethrotomy; for how long is haematuria expected?
4-5days
When should a urethostomy be considered?
recurrent obstructions or if primary repair of the urethra is not feasible,
What is a urethrostomy?
This procedure involves creating a permanent stoma in a wider part of the urethra to allow stones to pass out during urination or, in case of urethral rupture to anastomose the viable part of the urethra directly to the skin
What urethrostomy is preferred in male dogs?
Scrotal
Why is the scrotal urethrostomy a preferred site in males? (2)
Superficial and wide urethra here
Less haenorrhage
Most common short term urethrostomy complication?
Stricture formation
What urethrostomy is preferred in male cats?
Perineal
How to limit stricture formation?
Correct length and width
Long term urethrostomy complications (3)
- Urinary incontinence
- UTI
- Urine scalding
What muscle is retracted in a scrotal urethosotomy?
Retractor penis
Steps for scrotal urethostomy?
- The dog is positioned in dorsal recumbency and a dog urinary catheter placed in the penile urethra up to the obstruction to facilitate identification of the urethra.
- An elliptical incision is made in the scrotal region, and the subcutaneous tissues are dissected until the penile shaft is identified.
- The retractor penis muscles are retracted laterally to expose the purple-coloured urethra surrounded by corpus
- An incision is made over the urinary catheter (if possible) using a no. 15 blade. Bleeding will occur when the corpus spongiosum is incised, which can be controlled with direct pressure.spongiosum.
The obstructive material is removed (if possible), and the catheter advanced into the urinary bladder to confirm patency.
The urethral mucosa is sutured to the skin. Bites can include the tunica albuginea but not the corpus spongiosum.
How to perform scrotal urethrostomy if entire?
Castrate/scrotal ablation first
What suture/pattern is used to close scrotal urethrostomy?
A simple interrupted or simple continuous pattern can be used (absorbable or nonabsorbable monofilament).
What layers should bites NOT include in scrotal urethrosotomy?
Corpus spongiosum
What layers should bites include in scrotal urethrosotomy?
Tunia albuginea
How is a cat positioned for perineal urethostomy?
Ventral recumbency
How is the incision made in a perineal urethosotomy?
An elliptical incision is made in the scrotal and preputial region (if the cat is entire, castration is needed), and the subcutaneous tissues are dissected until the penis is identified.
How is the penis reflected in a perineal urethostomy?
Dorsally
Perinneal urethostomy:
A) What ligament is cut?
B) What muscle attachements are cut?
A) Ventral penile lig
B) Ischio cavenrous
What glands when exposed reveal with widest portion of the urethra during perineal urethostomy?
Bulbous urethalis glands
How and what is sutured during a perineal urethostomy?
Suture urethral mucosa to skin with 4-0 to 5-0 monofilament absorbable or not, simple interrupted or simple continuous.
What is retrohydropulsion?
Retrohydropulsion is indicated in cases of urethral obstruction, in order to propel obstructive material back into the bladder.
How to perforn retrohydropulsion?
A catheter coated with sterile aqueous lubricant is introduced into the urethra distal to the obstruction.
Sterile saline is injected into the catheter firmly, at the same time compressing the pelvic urethra per rectum. This allows the urethra to distend and frees up stones from the crevices of the collapsed urethral wall.
The digital pressure should then be suddenly released while flushing is still maintained, in order to propel the material into the bladder.
Retropulsion with sterile saline, how much:
A) Dog?
B) Cat/Small dog?
A) 50ml
B) 10/20ml
What should happen if its unable to relieve obstruction via retropulsion?
If it is not possible to relieve the obstruction, cystocentesis may be performed and retrohydropropulsion tried again 12 hours later, or a temporary urethral diversion can be placed i.e. tube cystostomy (surgical or minimally invasive using a pig tail catheter).
When is urethral stenting used?
The relief of malignant (for e.g., transitional cell carcinoma) or benign (proliferative urethritis, urethral strictures) urothelial obstructions in the urethra.
What breeds are predisposed to urethral prolapse?
- English Bulldog
- Boston terrier, Yorkshire terrier
How to surgically correct a urethral prolapse?
The definitive treatment is surgical and consists in either a resection of the protruded part of the urethra or a urethropexy using vertical mattress sutures (2/0 to 3/0) monofilament absorbable.
What pattern for urethral anastomosis following resection?
Simple continuous
Triangulation technique - 3 series 120 degrees apart
How is a urethropexy performed?
A groove director is placed in the urethra. Using a 2/0 to 3/0 monofilament absorbable suture with a long swaged-on needle, pass the suture from the penis to the urethral opening using the groove director as a guide then pass the needle in reverse fashion (vertical mattress suture) exiting only a few millimetres distal to the initial entry site. The sutures are not removed.
Suture patten for urethropexy?
Vertical mattress suture to perform a pexy of the prolapse portion of the urethra. A groove director is used to push and maintain the prolapsed mucosa back in and guide the direction of the needle and suture. Two to three sutures are usually needed.
