Bladder Neck Contracture

Bladder neck contracture (BNC) is a fibrotic narrowing of the bladder neck (or vesicourethral anastomosis) causing obstruction of urine outflow. It is a complication of prostate surgery and radiation.

Causes and rates:

• After radical prostatectomy (1 to 10 percent, depending on technique). The rate is higher with prior transurethral resection of the prostate, urinary extravasation, anastomotic leak, and postoperative infection.
• After transurethral resection of the prostate and laser enucleation (0.3 to 9 percent).
• After radiotherapy and brachytherapy for prostate cancer (up to 5 to 10 percent).
• With combined therapy the rate is higher, up to 20 to 30 percent when radiotherapy follows prostatectomy, or when salvage prostatectomy is performed after radiotherapy.
• After high intensity focused ultrasound and cryotherapy.

Rarely it is congenital in children (bladder neck hypertrophy), or occurs after female bladder neck surgery (anti-incontinence procedures) or urethral instrumentation.

The mechanism is ischaemia, poor mucosal apposition, extravasation of urine and scar formation (hypertrophic scarring).

Risk factors: smoking, diabetes, vascular disease, obesity, previous prostatic surgery, large prostate, high blood loss, and anastomotic tension. Radiated contractures are more difficult to treat and carry a higher recurrence and incontinence risk.

• Progressive weak urinary stream, hesitancy, straining, incomplete emptying, intermittent stream, and frequency (typically 2 to 6 months after surgery, but may be delayed by years), after an initial good result.
• Urinary retention (acute or chronic), recurrent infection, and urinary leakage (overflow) as overflow incontinence.
• Loss of previously achieved continence in some.
• Dysuria, haematuria, and bladder stones.
• Examination: palpable bladder in retention.
• Complications: hydronephrosis, renal impairment with chronic retention.

• Uroflowmetry: a flat or low peak flow rate (below 10 mL/second) and a post-void residual above 100 mL.
• Cystoscopy (flexible, then rigid): a narrowed or pinpoint bladder neck, with a scar plate, often with the inability to pass the scope; check the extent, length and whether there is overlying vesicourethral fistula.
• Retrograde urethrogram with simultaneous antegrade cystogram (voiding or via suprapubic catheter) to show the length of the narrowing.
• Urodynamics if bladder dysfunction or incontinence are involved; useful in differentiating from detrusor underactivity, which can present similarly.
• Renal ultrasound for hydronephrosis, creatinine, urine culture.
• Exclude recurrent cancer (prostate specific antigen and imaging) in prostatectomy patients.

Treatment is endoscopic in the first instance, and reconstructive surgery in refractory or radiated cases.

• Acute retention: urethral catheter if it can be passed, or a suprapubic catheter.
• Urethral dilation (sequential metal sounds, or balloon dilation): can be tried first for a new, soft contracture within 3 months of surgery. Success is about 40 to 60 percent, with high recurrence.
• Self-dilation with a catheter (intermittent self-dilation) after treatment reduces recurrence. Avoid repeated dilations that cause scar progression.
• Transurethral incision (bladder neck incision) or resection: a cold knife (Otis or Sachse), holmium laser or electrode incision at 3 and 9 o'clock, or at 12 o'clock, through the scar down to perivesical fat.
• Then optionally inject mitomycin C 0.3 to 1 mg/mL (a concentration of 1 mg/mL, 4 mL injected in 4 quadrants), or triamcinolone 10 to 40 mg into the scar, to reduce recurrence. Leave a catheter for 3 to 7 days.
• Success is about 70 to 80 percent, but about 20 to 40 percent need more than one procedure. Intermittent self-dilation for 3 to 6 months can lower recurrence.
• Warning: aggressive incision or resection may cause stress incontinence in men after prostatectomy. Limit the incision, and counsel the patient.
• Refractory or recurrent contracture (after 2 to 3 attempts), or radiated contracture: open or robotic reconstruction. This is vesicourethral anastomotic reconstruction, with excision of the scar, mobilisation of the bladder and urethra, and a tension free mucosa-to-mucosa anastomosis.
• Use a muscle flap interposition (gracilis or omentum) if necessary. Success is 80 to 90 percent.
• Artificial urinary sphincter: for incontinence, placed 3 to 6 months after a successful reconstruction.
• Last resort: suprapubic catheter, continent catheterisable channel, or urinary diversion.
• In radiated cases, hyperbaric oxygen and prolonged use of intermittent catheterisation may help.
• Prevention: meticulous anastomotic technique (mucosa-to-mucosa, watertight, tension free), adequate drainage, treatment of urine leak, and early diagnosis; avoid prolonged catheterisation and repeated instrumentation.
• Follow up: flow rate and residual at 3 months, 6 months and annually.