ARTIFICIAL URINARY SPHINCTER
Category: Urology
Abstract : incontinence the artificial urinary sphincter The artificial urinary sphincter (AUS; AMS800â„¢) consists of an inflatable cuff placed, via a lower abdominal incision (midline or Pfannenstiel), around the bladder neck in both men or women or the bulbar urethra in men, a pressure-regulating balloon placed extraperitoneally, and an activating pump placed in the scrotum or labia majora. The c
incontinence the artificial urinary sphincter
The artificial urinary sphincter (AUS; AMS800â„¢) consists of an inflatable cuff placed, via a lower abdominal incision (midline or Pfannenstiel), around the bladder neck in both men or women or the bulbar urethra in men, a pressure-regulating balloon placed extraperitoneally, and an activating pump placed in the scrotum or labia majora.
The cuff provides a constant pressure to compress the urethra. To void, the pump is squeezed, which transfers fluid to the reservoir balloon, thereby deflating the cuff. The cuff then automatically refills within 3 minutes. Voiding takes place in the interval taken for the cuff to refill.
Indications and patient selection
Incontinence secondary to urethral sphincter deficiency in patients with normal bladder capacity and compliance. In men, it is used for sphincter damage due to prostatectomy (radical prostatectomy for prostate cancer or TURP), pelvic radiotherapy, pelvic fracture, and following urethral reconstruction. In women it is used after other treatments for incontinence have failed. It can be used for neuropathic sphincter weakness (e.g. spinal cord injury, spina bifida) if the incontinence is not due to bladder overactivity. If there is combined bladder overactivity and sphincter weakness, treat the bladder first (i.e. lower bladder pressures with anticholinergics, intravesical botulinum injections, augmentation) in some cases this will be enough to achieve continence. If incontinence persists, proceed with AUS at a later date.
Patient evaluation
Patients should undergo urodynamics, cystoscopy, and upper tract imaging to evaluate voiding function and identify anatomical abnormalities that might affect the efficacy of the sphincter. Good manual dexterity is required to manipulate the pump and perform ISC if needed. The patient must also have sufficient cognitive function to operate the sphincter themselves, several times daily.
Results
AUS can function well for many years. Overall long-term success (continued continence, no device malfunction) is 80%. Revision rates are about 20%.
Complications and long-term outcomes
- Recurrent incontinence: secondary to urethral atrophy underneath the cuff (10% over the first 5 years post implantation); mechanical failure (of the pump or slow leak of fluid from the system); urethral erosion (essentially a pressure sore in the urethra due to chronic pressure from the cuff, and leading to poor apposition of the urethra under the cuff); bladder overactivity or reduced compliance causing reflux, hydronephrosis, and renal failure. Investigate recurrent incontinence by cystoscopy (to
exclude erosion), X-ray to determine leaks from the system (the balloon loses its round shape), and urodynamics (to detect high bladder pressures).
- Erosion: most common at 3 - 4 months, with 75% occurring in the first year. Presents with pain and swelling of scrotum, labia, or perineum; UI; and bloody discharge.
- Infection: primary implant infection rates are 1 - 3%. With infection or erosion, remove entire device and wait 3 - 6 months before reinsertion.
- Other: haematoma (scrotum or labia); late urinary retention may signify obstruction from urethral stricture or bladder neck contracture.
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