26. Surgical diseases of the urinary bladder & urethra. Cystotomy, cystectomy, urethrotomy & urethrostomy in dog & tomcats.

Where is the urinary bladder located?

Within the peritoneal cavity, attached to the abdominal wall by loose, double-layered peritoneal ligaments

What are the names of the ligaments attaching the bladder?

1. Ventral median ligament: very thin structure connecting bladder to linea alba & pelvic symphysis.

2. Lateral ligaments: attach pelvic walls & contain fat along with distal portion of ureter & umbilical artery on each side.

What are examples of surgical diseases of the urinary bladder?

1. Rupture

2. Urolithiasis

3. Neoplasia

4. Cystitis

What are some causes of bladder rupture?

Trauma, severe cystitis, neoplasia, urethral obstruction (FLUTD), calculi, iatrogenic injury

What are the clinical signs of bladder rupture?

Haematuria, anuria, dysuria, abdominal pain, uroabdomen, azotaemia, dehydration, metabolic acidosis, hyperkalemia, death

How is bladder rupture diagnosed?

Ultrasound, abdominocentesis, positive contrast retrograde urethrocystogram

What confirms urine in abdominal fluid?

Higher creatinine in fluid than in serum

What is the treatment for bladder rupture?

Stabilisation (often with other injuries e.g. pelvic fracture), exploratory laparotomy, resection of unviable tissue, omentalisation

What are urinary stones made of?

Precipitated minerals (struvite, calcium oxalate, urate, cystine)

Which type of stone is most common in cats?

Struvite (alkaline)

Which type of stone is most common in dogs?

Calcium oxalate (acidic)

What are the clinical signs of urolithiasis?

Dysuria, haematuria, stranguria, distended/painful abdomen, azotaemia

How is urolithiasis diagnosed?

History, urinalysis, ultrasound, X-ray

What are the treatment options for urolithiasis?

1. Conservative: Diet change, dissolution (struvite, urate, cystine)

2. Surgical removal (cystotomy/urethrotomy), hydropropulsion

What are some types of bladder neoplasia?

Transitional cell carcinoma, lymphoma, adenocarcinoma, squamous cell carcinoma, haemangioma, haemangiosarcoma, fibroma, fibrosarcoma, leiomyoma, leiomyosarcoma

What is the most common malignant bladder tumour in dogs?

Transitional cell carcinoma

Where is transitional cell carcinoma typically located?

Trigonum of the bladder

What are the clinical signs of bladder neoplasia?

Haematuria, pollakiuria, dysuria, incontinence, PU/PD

How is bladder neoplasia diagnosed?

Ultrasound, X-ray, biopsy, double-contrast cystography

What are the treatment options for bladder neoplasia?

Surgical excision (may be impossible due to location), NSAIDs, chemotherapy, cystectomy

What is cystitis?

Inflammation of the urinary bladder

What are some causes of cystitis?

Bacterial infection, urolithiasis, neoplasia, polypoid cystitis

What is polypoid cystitis?

Uncommon, non-neoplastic inflammatory disease of the cranvioventral bladder

What are the clinical signs of cystitis?

Pollakiuria, dysuria, stranguria. Haematuria (haemorrhage from polyp)

How is cystitis diagnosed?

Palpation, X-ray (thickened bladder wall), cystoscopy

What is the treatment for cystitis?

Depends on aetiology; antibiotics, NSAIDs, cystotomy (if unresponsive), resection of polyps

What suture material is preferred for bladder surgery?

Monofilament, absorbable. Less drag in bladder, & less introduction of MO

Which layer of the bladder wall is important for suture placement?

Submucosa

What are some suture patterns used in bladder surgery?

1. Simple continuous, full-thickness provides accurate apposition

2. Simple interrupted appositional for irregularly shaped bladder defects after resection

3. Cushing or Lembert if leaking is a concern. Done after simple continuous

4. Schmieden suture pattern (appositional)

What is a Schmeiden suture pattern?

From inside to outside

What is a cystotomy?

Surgical incision into the bladder

What are some indications for cystotomy?

Calculi removal, trauma repair, biopsy, mass resection, severe cystitis, ectopic ureter repair, ureter catheterisation

What is the procedure for a cystotomy?

Midline laparotomy incision from umbilicus to pubis (curving parapreputially through skin & subQ in male dogs). Identify & isolate bladder. Flip to reveal dorsal side. 4x stay sutures placed: 2 each side of incision site (very close to incision). Cystotomy incision made in midline (stab incision, remove urine & blood by suction) → Further stay sutures on either side of incision. Closure: Lembert/ Connel-Cushing suture (inverting) → double. Routine closure of linea alba.

What is a cystectomy?

Surgical removal of part of the bladder

What are some indications for cystectomy?

Patent urachus, bladder diverticulum, neoplasia, polyp, necrosis, trauma

What is used to maintain decompression after a large cystectomy?

Temporary cystostomy tube or indwelling urethral catheter

What happens if cystectomy includes urethral orifices?

Ureters are transected and reimplanted

Where are the ureter entrances located?

Trigonum of the bladder

How much healthy tissue should be excised with a bladder tumour?

1cm

How is a cystectomy defect closed?

Appositionally, similar to cystotomy

What can be done if tissues of the bladder are friable after a cystotomy?

Create a serosal patch over the incision line

What are the parts of the male dog urethra?

Pelvic (preprostatic and prostatic) and penile

What is distinct about the male cat urethra?

More distinct preprostatic urethra

Where is the external orifice of the female dog urethra located?

Vestibule of the vagina

What are examples of surgical diseases of the urethra?

1. Obstruction

2. Stricture

3. Prolapse

What are some causes of urethral obstruction?

Calculi (Ca oxalate, struvite, cysteine, urate (hepatic encephalopathy – allopurinol))

What are the clinical signs of urethral obstruction?

Straining to urinate, painful abdomen, crying when urinating, dribbling urine, lethargy, vomiting, anorexia, collapse, death

What are some diagnostic tests for urethral obstruction?

1. Haematology: normal (inflammation can lead to stress leukogram)

2. Biochemistry: azotemia, met. acidosis, HyperP/K, hypoCa

3. Imaging: positive contrast urethrography, double contrast cystography or excretory urography

4. Urinalysis & culture (haematuria, proteinuria, crystalluria)

What are some treatment options for urethral obstruction?

1. Medical management (pain relief, medication to relax the urethra, fluids)

2. Dietary change

3. Urohydropropulsion

4. Surgery (perineal urethrostomy)

What may predispose to urate stones?

Hepatic encephalopathy (allopurinol = treatment)

What is urohydropropulsion?

Flushing calculi from the urethra into the bladder

What are some causes of urethral stricture?

Inflammation, neoplasia, trauma, surgical intervention

When is treatment for urethral strictures indicated?

Only when there are signs of obstruction

What are some treatments for urethral stricture?

Balloon dilation, stent placement, resection and anastomosis, urethrostomy

What breeds are predisposed to urethral prolapse?

Bulldogs and Boston Terriers

What are some clinical signs of urethral prolapse?

Congested mucosal mass protrudes from external urethral orifice with varying degrees of haemorrhage. Persistent urethral bleeding, leaking, dysuria, pollakiuria, anaemia

What are some treatments for urethral prolapse?

Castration, urethral resection, urethropexy, antibiotics

What are examples of urethral surgeries?

1. Urethrotomy

2. Urethrosomy

What is a urethrotomy?

Temporary opening of the urethra

What are some indications for urethrotomy?

Calculi removal, neoplasia, recurrent UTI, urethral stricture

Where can a urethrotomy be performed?

Prescrotal or perineal

What is the positioning of the animal for a prescrotal urethrotomy?

Dorsal recumbency → remove calculi from distal penile urethra

How does a prescrotal urethrotomy heal?

Primary or secondary intention

What is the positioning of the animal for a perineal urethrotomy?

Sternal recumbency → remove calculi at the level of the ischial arch

How is a perineal urethrotomy closed?

Sutures

What is a urethrostomy?

Creation of a permanent stoma to bypass the distal urethra

What are the types of urethrostomy?

Prescrotal, scrotal (dogs), perineal (cats), prepubic, subpubic

Which urethrostomy is performed in male dogs?

Scrotal

Which urethrostomy is performed in male cats?

Perineal or subpubic

What is the general procedure for a scrotal urethrostomy?

Dorsal recumbency: place urinary catheter, elliptical incision around or near base of scrotum in intact male dogs or remnants of neutered ones.

Castration performed in routine manner.

Interrupted sutures placed on tunica albuginea to subcutaneous tissue on either side of urethrostomy site.

Incision into lumen of urethra on ventral midline.

Closed by suture to skin on each side in a single layer simple interrupted or continuous pattern, monofilament, absorbable or nonabsorbable.

What is the general procedure for a perineal urethrostomy in cats?

1. Penis and distal urethra are freed from surrounding tissues

2. Transect m. ischiocavernosus and m. ischiourethralis near their origin on the ischium to avoid damaging the n. pudendalis branches

3. Urethra transected proximal to penile portion near bulbourethral glands

4. Pelvic urethra sutured to perineal skin from dorsal aspect

What is the procedure for a subpubic urethrostomy in cats?

Ventral midline incision from umbilicus to pubis → Partially incise prepubic tendon and reflect it laterally to expose pubic rami → (pubic osteotomy) osteotomise pubic rami 1.5 cm laterally to pubic symphysis and transverse incision through body of pubic bone → rotate pubic flap ventrally to visualise intrapelvic urethra → transect urethra cranial to lesion/obstruction and replace pubic flap → urethra exteriorised caudal to the brim of the pubis through stab incision → spatulate urethral end and suture to skin.

What does FLUTD stand for?

Feline Lower Urinary Tract Disease

What are some potential causes of FLUTD?

Congenital, uroliths, trauma, tumours, idiopathic

What are some clinical signs of FLUTD?

Pollakiuria, haematuria, stranguria, dysuria

What are some diagnostic methods for FLUTD?

History, clinical signs, physical exam (thickened wall), rectal palpation, urinalysis, X-ray, ultrasound, biochemistry, haematology

What are some treatment options for FLUTD?

1. Conservative (IV fluids, antibiotics, diet, opioids)

2. Surgical (catheterisation, cystocentesis, urethrotomy, cystotomy)

Where is the trigone of the bladder?

Dorsally

What are the ligaments of the bladder?

1. Ventral median ligament: very thin structure connecting bladder to linea alba & pelvic symphysis.

2. Lateral ligaments: attach pelvic walls & contain fat along w/ distal portion of ureter & umbilical artery on each side.

Where are incisions on the bladder made?

Ventrally as has less blood vessels

What percentage of the bladder can be removed and it still stay functional?

40%

Where are urethrostomies usually carried out?

Base of the penis where the urethra is the most narrow

Which urinary crystals are not visible on USG?

Urate, cysteine

What are the types of cystocentesis?

Blind or USG-guided