Artificial Urinary Sphincter

The artificial urinary sphincter (AUS, AMS 800) is the gold-standard surgical treatment for moderate-to-severe male stress urinary incontinence, most often post-prostatectomy incontinence. The device has three connected components — a urethral cuff, a pressure-regulating balloon (PRB), and a scrotal control pump — that give a 2-cm zone of circumferential urethral compression. Success depends on meticulous urethral dissection, strict antimicrobial discipline, and careful counseling about device handling — above all, deactivating the cuff before any catheterization. Male SUI more broadly (causes, slings, and the treatment algorithm) is covered in the Reconstruction topic.

Indications and Outcomes

• Post-prostatectomy incontinence (PPI) after radical prostatectomy is the commonest indication (8–12% of men seek treatment); others include SUI after TURP or sphincterotomy, sphincteric trauma, and neurogenic bladder, with rare use in women. The AUS is the gold standard across moderate-to-severe loss and is preferred over slings after radiation, urethral reconstruction, or anastomotic stenosis.
• Developed in 1973 and refined to the AMS 800, it has long-term data: patient satisfaction 72–90%, social continence (0–1 pads/day) 97% at ~2 years and 54–77% long-term, with roughly 76% of patients dry (0–1 pad/day).

Preoperative Evaluation and Patient Selection

• Timing — continence keeps improving for up to ~2 years after prostatectomy (92% → 98.5% at 12 and 24 months), though most recovery is by ~12 months, so delay surgery ≥ 12 months; consider earlier surgery only for bothersome, severe SUI with no improvement by 6 months.
• Work-up — history/exam, demonstrate stress incontinence, urinalysis with culture, and PVR (± voiding diary/pad test). Assess manual dexterity and mental status — the patient must be able to operate the pump.
• Cystoscopy to exclude a urethral stricture or bladder-neck contracture — treat these before implantation. Urodynamics if the etiology is unclear (detrusor function, compliance, overactivity); up to 35% of men with PPI will not leak with a catheter in place, so remove the catheter to retest.
• Absolute contraindications — inability to operate the pump, recurrent UTIs, a urethral diverticulum/poor tissue at the site, a complex/recurrent stricture, a small-capacity or non-compliant bladder, and active infection. Relative — high-grade reflux, intravesical disease needing repeat instrumentation, bladder-neck contracture, and detrusor overactivity. Radiation is a risk factor, not a contraindication.
• Antibiotics — AUA recommends an aminoglycoside plus a first-/second-generation cephalosporin or vancomycin (alternatives: ampicillin–sulbactam, ticarcillin–clavulanate, piperacillin–tazobactam); vancomycin + gentamicin is the common combination. InhibiZone (rifampin–minocycline) coats parts of the device but — unlike penile prostheses — has not reduced AUS infection. Use DVT prophylaxis per AUA.

Positioning and Preparation

The cuff site dictates positioning: a bulbar cuff (commonest) is placed in dorsal lithotomy via a perineal (or transscrotal) approach, while a bladder-neck cuff (mostly pediatric/neurogenic) uses a supine abdominal retropubic approach. Under general anaesthesia, shave the infraumbilical abdomen/genitalia/perineum, scrub with povidone-iodine for 10 minutes (chlorhexidine if iodine-allergic — it cuts perineal colonization up to four-fold), place a 14-Fr Foley, and exclude the anus from the field with secure drapes.

Device Preparation

Shod the hemostat jaws with silicone tubing to protect the device.

• Pump — submerge in saline/contrast at 45° (button up) and squeeze to displace all air, then clamp 4–5 cm from the end. Do not soak the InhibiZone-coated pump in saline (it dilutes the antibiotic); lock and unlock it several times so it opens easily at activation.
• PRB — available in pressures of 61–70 cm H₂O (standard) and 51–60 cm H₂O (after radiation); deflate, aspirate residual air, and fill with 20 mL before clamping (the balloon has no antibiotic coating).
• Cuff — fill with 1–5 mL by size (do not overfill while removing air), then clamp (InhibiZone-coated).

Cuff Placement

1. Expose — a midline perineal incision onto the bulbospongiosus; preserve the muscle to reapproximate later as a covering layer; use minimal cautery and sharp Metzenbaum dissection on the thin dorsal urethra.
2. Urethral injury — close it with 4-0 absorbable suture and abort the procedure (or repair, move the cuff away from the injury, and delay activation, weighing the erosion risk).
3. Dissect and size — encircle the urethra, pass a right-angle clamp with a vessel loop/Penrose, and enlarge the space to the cuff width, placing the cuff as proximal as possible (near the crura) without leaving it mobile. Size with the cuff sizer (remove any catheter > 14 Fr first) so it fits snugly, not constricting — typically 3.5–4.5 cm in the bulbar urethra (most often 4 or 4.5 cm; up to 11 cm exists). Seat the tab (mesh out, pillow toward the urethra) and rotate the cuff laterally off the midline.

• Transcorporal cuff — for difficult or revision cases (trauma, radiation, urethral atrophy, prior erosion): incise the corpora cavernosa parallel to the urethra rather than dissecting between spongiosum and cavernosum — less reoperative urethral injury and more urethral bulk for a better fit. It is reserved for these high-erosion-risk urethras (so it appears among erosion risk factors), but the added corporal bulk is protective in that setting, with erectile function usually preserved.
• Bladder-neck cuff — an abdominal-approach option in young patients/children (exstrophy/epispadias, spina bifida, neurogenic bladder): lower erosion/atrophy risk but needs a larger cuff (> 8 cm) and a higher-pressure PRB, and is contraindicated after radical prostatectomy.
• Tandem cuff — historical; a cadaver study (Wright) found no leak-point-pressure benefit from the second cuff, so its apparent benefit is really the more-proximal placement, and it carries a higher explant rate (17% vs 4%) — a single proximal cuff is preferred.

Pressure-Regulating Balloon Placement

Place the PRB via a scrotal, perineal, or abdominal route — commonly a transverse inguinal incision ipsilateral to the pump (or a midline suprapubic incision). Drain the bladder first, open the rectus/external-oblique fascia, bluntly create a preperitoneal/retropubic pocket, preplace the fascial-closure sutures, seat the balloon, fill it to 23 mL, and clamp. Passing through the external ring is contraindicated after inguinal mesh hernia repair or extensive abdominal surgery; in the morbidly obese, an ectopic supra-fascial location may be needed.

Scrotal Pump and Connections

• Pump — a dependent subdartos pocket, away from the testis, with minimal overlying tissue so the patient can feel it; orient the deactivation button toward the skin.
• Connections — pass the cuff tubing to the inguinal incision close to the pubic bone, trim the excess, flush air with a 22-gauge needle, and join the tubing with quick-connectors (a right-angle connector for the cuff–pump junction) secured by collet rings (suture-tie connectors with 3-0 polypropylene for revisions). Cycle the device 2–3 times to confirm function, then deactivate it (cycle once, push the button, feel the indentation).

Closure and Postoperative Care

Irrigate copiously, close the perineum in multiple absorbable layers to obliterate dead space, and close skin subcuticularly — no drains; apply a scrotal support. Keep the patient overnight with the catheter removed the next morning; antibiotics are not recommended beyond 24 hours (AUA), though some implanters add 1–2 weeks of oral antibiotics. Leave the device deactivated for 4–6 weeks (longer after radiation), then activate it in the office. Counsel the patient to avoid sitting on hard objects and cycling for 6 weeks, to consider night-time deactivation for urethral rest, and to always deactivate the cuff before any catheterization (and carry a medical-alert card/bracelet). Device life is 7–10 years; replace the entire device if any component fails after 3 years.

Complications

• Hematoma — the most common immediate complication.
• Infection — about 1–5% (up to ~10% after radiation), usually within ~2 months, from skin flora (Staphylococcus epidermidis, then S. aureus); it presents with scrotal pain ± erythema/edema/purulence and mandates urgent explant (salvage as for penile prostheses, contraindicated with sepsis, ketoacidosis, necrotising infection, immunosuppression, or gross purulence/erosion), with no reimplant for ≥ 3 months. Give antibiotics before any later urinary-tract instrumentation.
• Urethral erosion — up to 5% (reduced by delayed activation; higher with radiation, prior erosion/infection/urethroplasty, repeat endoscopy, prolonged catheterization, and a smaller cuff — transcorporal cuffs appear here because they are used in already high-risk urethras); assumed infected → explant with a urethral catheter ± SPT, reimplant ≥ 3 months proximal or distal to the prior site after confirming healing by urethrography.
• Urethral atrophy — chronic compression of the spongy tissue; the commonest cause of gradually recurrent incontinence and revision — manage by downsizing or relocating the cuff (do not raise the PRB pressure — erosion risk).
• Mechanical failure / revision — device life 7–10 years; failure approaches ~24% at 5 years and ~50% at 10 years (revision ~16% at 2 years, ~28% at 5 years; in a 1082-patient cohort, malfunction 12.1%, atrophy 8.2%, infection/erosion 8.2%, with 31.2% needing secondary surgery).
• Urinary retention — confirm the cuff is deactivated; manage with a 12-Fr catheter, and if a voiding trial fails at 48 hours place an SPT (avoiding the PRB). Long-term retention suggests too small a cuff; late-onset retention suggests erosion.

Urgency After AUS

Post-prostatectomy men may have urgency with or without urge incontinence. First-line is behavioural therapy ± an anticholinergic (watch for dry mouth, constipation, and confusion in the elderly); mirabegron (a β3-agonist, 25–50 mg) is better tolerated; refractory urgency is treated with neuromodulation or intravesical onabotulinumtoxinA.