Surgery of the Bladder Notes

Surgery of the Bladder

Course Information

  • Course Title: VMS 5649 Small Animal Surgery

Anatomy of the Bladder

  • Attachments: The bladder is attached by ligaments.

    • Ventral Ligament: Connects the bladder to the abdominal wall.

    • Urachus in Fetus: A conduit that connects the bladder to the allantoic sac during fetal development.

    • Cut during Cystotomy: Surgical procedure that involves these ligaments.

    • Lateral Ligaments: Contain the distal ureters; care must be taken to avoid during surgery.

  • Trigone: The triangular region between the urethra and the ureteral openings.

Surgical Diseases

  • Common Conditions:

    • Urachal Abnormalities: Congenital defects related to the urachus.

    • Ruptured Bladder: Often due to trauma or other medical conditions.

    • Cystic Calculi: Bladder stones associated with urinary obstruction.

    • Neoplasia: Tumors affecting the bladder.

    • Urinary Incontinence: Loss of bladder control.

  • Key Surgical Procedures:

    • Cystotomy: Surgical incision into the bladder.

    • Cystectomy: Complete surgical removal of the bladder.

    • Cystostomy: Creation of an opening into the bladder.

    • Cystopexy: Attachment of the bladder to the abdominal wall to prevent displacement.

Urachal Abnormalities

  • Definition: An embryonic conduit that provides communication between the bladder and the allantoic sac, which typically atrophies at birth.

  • Types of Urachal Abnormalities:

    • Persistent Urachus: Failure of the urachus to close after birth.

    • Vesicourachal Diverticulum: A closed external opening with a patent bladder attachment.

    • Urachal Cyst: A secretion-producing urachal epithelium that persists, typically asymptomatic unless complications arise.

    • Urachal Sinus: A condition where the distal urachus remains open, often leading to omphalitis.

Persistent Urachus

  • Characteristics: Patent urachal canal that can lead to several clinical signs.

  • Clinical Signs:

    • Urine Dribbling from Umbilicus: Discharges due to the open urachus.

    • Omphalitis: Inflammation of the umbilical region.

    • Ventral Abdominal Dermatitis: Skin irritation in the abdomen.

    • Urinary Tract Infection (UTI): Due to constant urine exposure.

  • Diagnosis:

    • Contrast Study: Placing contrast material in the umbilicus to visualize the urachus.

  • Treatment: Surgical removal of the urachal tube, involving dissection from the umbilicus and excision at the apex of the bladder.

Vesicourachal Diverticulum

  • Description: The external opening is closed; however, the attachment to the bladder is patent. It is the most common congenital abnormality of the bladder.

  • Consequences: Increases the likelihood of forming uroliths and developing urinary tract infections (UTIs).

  • Diagnosis: Utilization of positive contrast cystography.

  • Surgical Intervention: Options include partial cystectomy and diverticulectomy.

Urachal Cyst

  • Characteristics: The urachal epithelium continues to secrete; usually only an isolated segment remains.

  • Symptoms: Typically asymptomatic unless clinical signs develop.

  • Management: Surgical excision if symptoms are present.

Urachal Sinus

  • Description: A condition where the distal urachus remains open.

  • Symptoms: Similar to those of a persisting urachus, particularly omphalitis.

  • Treatment: Surgical excision.

Bladder Rupture

  • Etiology: Causes include trauma, severe cystitis, neoplasia, urethral obstruction, and iatrogenic factors such as cystocentesis and catheterization.

  • Clinical Signs:

    • Can vary from being asymptomatic to signs like hematuria, anuria, and abdominal pain.

    • As the condition progresses, may lead to dehydration, acidosis, azotemia, hyperkalemia, and ultimately death within 47-90 hours.

  • Key Points: Always consider bladder rupture in trauma cases; a palpable bladder or normal urination does not rule out rupture.

Diagnosis of Bladder Rupture

  • Diagnostic Techniques:

    • Plain Radiographs: Can identify free abdominal fluid, absence of bladder, and decreased serosal detail.

    • Ultrasound: Can show free fluid and concurrent injuries; aids in guiding abdominocentesis and determining the source of injury.

    • Positive Contrast Urethrocystogram: Considered the most reliable method; contrast leakage in the abdomen confirms rupture, highlighting intestinal loops.

Additional Diagnostics

  • Abdominocentesis: Used to gather fluid for analysis; presence of urea in peritoneal fluid indicates bladder plane rupture.

    • Urea molecule comparison:

    • Urea equilibrates across peritoneum but creatinine does not; elevated creatinine in peritoneal fluid signifies rupture.

    • Potassium levels are also typically higher in peritoneal fluid.

Treatment of Bladder Rupture

  • Initial Management:

    • Stabilization of the patient if medically unstable; involves fluids and abdominocentesis.

    • Urinary Diversion: Implementing urethral catheters, tube cystostomy, to minimize urine accumulation in the abdomen.

  • Surgical Management: To be performed when stable, typically via exploratory laparotomy.

    • Debridement of Torn Tissue: Removing necrotic areas, closing the bladder wall, and omentalizing to improve healing.

    • Techniques: Careful catheterization of the urethra to keep the bladder empty.

Tube Cystostomy

  • Indications:

    • For urinary diversion when the patient cannot be catheterized due to LUT obstruction, trauma, or neurologic conditions. It may also be conducted long-term, necessitating cystopexy.

  • Technique:

    • Ventral Midline Approach: Involves purse-string suture and a stab incision; often a 6-16 fr Foley or mushroom tip catheter is utilized, followed by cystopexy to stabilize the position.

Cystopexy

  • Indications:

    • Tube cystostomy, perineal hernia, and urinary incontinence associated with pelvic bladder.

  • Technique: Attachment involves cranial traction and securing the bladder wall to the abdominal wall using two line sutures.

  • Complications: High risk of inadvertent tube removal by the pet, chewing on the tube, breakage, bladder fistula formation post removal, and urine leakage around the tube.

Cystic Calculi

  • Prevalence: Commonest disease; bladder is the most frequent site, with struvite (50%) and calcium oxalate (40%) being the most common types, alongside urate, calcium phosphate, silica, xanthine, and cystine.

  • Clinical Signs:

    • Present similarly to other lower urinary tract disease (LUTD) syndromes, often leading to infection in 76% of cases; may indicate obstruction if more severe symptoms occur.

  • Diagnosis Methods:

    • Plain Radiographs: Diagnose specific types; cystine and urate calculi are radiolucent.

    • Pneumocystography: Involves air to enhance visualization on imaging studies.

    • Double Contrast Cystography: Provides additional detail.

    • Ultrasound: Offers non-invasive assessment of the bladder.

Non-Surgical Treatment of Cystic Calculi

  • Voiding Hydropropulsion: A non-invasive method under sedation or anesthesia for small stones; multiple attempts may be necessary with monitoring radiographs.

  • Transurethral Cystoscopy: Though non-invasive with potentially high costs, it handles one stone at a time and may cause urethral trauma.

  • Dietary Modification:

    • Special diets for struvites/urates, generally not for obstructed patients, which take time and necessitate monitoring for potential blockage.

  • Electrohydraulic Lithotripsy: Involves expensive equipment and can be time-consuming; may lead to urinary tract obstruction.

Cystotomy

  • Overview: Most common bladder surgery for urolith removal, known for its efficiency and effectiveness due to indications such as urinary tract obstruction or failure of other retrieval methods.

  • Techniques:

    • Dorsal vs. Ventral Cystotomy:

    • Dorsal was previously favored due to reduced urine leakage and adhesion formation.

    • Ventral approach currently preferred for better visualization of bladder neck and ureteral orifices.

    • Surgical Approach:

    • Caudal ventral midline incision is made; caregivers use moistened lap sponges, empty the bladder through compression, and male patients receive proper draping.

  • Considerations:

    • Avoid handling tissue directly with stay sutures; select an avascular area and make a stab incision at the apex to extend for thorough evaluation.

    • Evert walls for full inspection and ensure calculi are removed with appropriate instruments.

    • Pass a urethral catheter for patency checks and submit samples for culture and sensitivity.

Principles of Closure

  • Objective: Achieve a watertight closure wherein sutures do not penetrate the bladder lumen.

  • Important Considerations:

    • Avoiding ureteral impingement is crucial; ensure serosa-to-serosa contact encourages a fibrin seal.

    • The submucosa provides the layer of strength; various suture patterns are acceptable.

Suture Materials

  • Options: Either absorbable or non-absorbable, considering factors like delayed healing and exposure to lumen.

    • Choices include PDS, Monocryl, Vicryl, Dexon, Prolene, and Nylon; familiarity with materials is essential.

  • Patterns:

    • Inversions and appositional techniques can secure closure without affecting bursting strength, utilizing combinations like Cushing and Lembert sutures.

Post-Operative Considerations

  • Leak Testing: Post-surgery involves compressing the bladder neck to ensure closure integrity.

  • Post-operative Radiographs: Effective in assessing healing; bladder regains its strength by the 14-21 day mark after surgery.

Polypoid Cystitis

  • Description: Uncommon condition affecting the mucosa without neoplasm; more frequently noted in females, leading to intermittent hematuria.

  • Diagnostics: Identified via ultrasound and cystoscopy, confirmed via biopsy.

  • Treatment: Surgical removal is indicated.

Bladder Tumors

  • Canine Characteristics:

    • Bladder tumors are uncommon; most cases are malignant, with transitional cell carcinoma (TCC) being the most prevalent. Commonly observed in older female dogs, particularly Scottish terriers, Shelties, and Beagles.

  • Feline Characteristics:

    • Bladder is the second most common tumor site in cats; TCC is also the predominant tumor type.

  • Risk Factors: Obesity and exposure to various chemical agents increase the risk.

Transitional Cell Carcinoma (TCC)

  • Invasiveness: Very aggressive with significant rates of urethral and prostate involvement.

  • Clinical Signs: Mimic those of LUTD; may witness metastatic diseases affecting lungs and lymph nodes.

Diagnosis of Bladder Tumors

  • Approaches:

    • Physical exams emphasizing abdominal palpation and signs like lameness/coughing; cytology and ultrasound are integral for diagnosis.

  • Diagnostic Tests: Consider urine cytology, radiographs for positive contrast, and transurethral biopsy for tumors.

Treatment Options for TCC

  • Surgical Intervention: Partial cystectomy should ensure appropriate margins to prevent tumor seeding.

  • Adjuvant Treatments: Chemotherapy (e.g., using Piroxicam, Cisplatin, Mitoxantrone), optimizing treatment strategies with single or multiple modalities.

  • Expected Outcomes: Mean survival time (MST) for treated patients typically spans 4-6 months.