Artificial Urinary Sphincter

1. Concept

  • Artificially increasing the urethral resistance using an implantable device

2. History

  • In 1961, acrylic prostheses to increase urethral resistance by compressing the urethra against the urogenital diaphragm [Berry 1961]
  • In 1973, a gel-filled disc-shaped prosthesis attempted to augment urethral resistance by passive compression of the urethra [Kaufman 1973]
  • In 1973, a 4-piece silicone prosthesis (AS 721) including an inflatable cuff for placement around the urethra or bladder neck [Scott 1973]
  • Since then, multiple improvements in design, structure and function has been made. In the current AMS 800 model is composed of a seamless reservoir, a scrotal-labial pump, non-kink tubing, and narrow back and surface treated cuffs.

3. Terminology

4. Purpose of the Procedure

  • Artificially increasing the urethral resistance

5. Indications

  • Incontinence after prostatectomy: the most common indication
  • Neurogenic bladder in conjunction with intrinsic sphincteric dysfunction For more information, please refer to this.
    • SCI with thoracolumbar symphathetic outflow disorder
    • congenital disorders, including myelomeningocele
    • sacral agenesis and extrophy/epispadias
    • previous pelvic trauma
    • history of pelvic radiation
    • women with failed anti-incontinence procedures
  • Essential prerequisite:
    • highly motivated personality
    • good manual dexterity
    • normal detrusor (after anticholinergic drugs or augmentation cystoplasty)
    • no anatomical or functional outflow obstruction (DSD treated with sphincterotomy)
    • absence of UTI
  • Indication for the SCI/D is relatively narrow because the thoracolumbar SCI resulting in the sphincter deficiency is relatively rare. Most experiences of applying artificial sphincter in SCD are from pediatric SCD (myelodysplasia). Urinary incontinence secondary to neurogenic sphincteric dysfunction most commonly develops in patients with myelomeningocele.
  • Since the pubovaginal sling is popular, the role of an AUS for female patients has diminished.

6. Contraindications

  • Absolute contraindication:
  • Bladder conditions
    • Poor bladder compliance: can lead to upper tract changes
    • Small bladder capacity
    • detrusor hyperreflexia: can lead to upper tract changes
    • foreign body, stone
  • Urethral conditions
    • DSD: can lead to upper tract changes
    • unstable recurrent urethral stricture
    • false passage, diverticulum, bladder neck contracture

7. Procedure

  • Preoperative urodynamic and endoscopic examination to evaluate voiding function and identify any anatomic abnormality that would preclude the efficacy of the implanted sphincter is necessary. [VIDEO]
  • An artificial urinary sphincter may be placed at the same time as augmentation cystoplasty, or placement can be performed as a staged procedure.
  • Once the patient is in the operating room, the abdomen and genitalia are shaved. Following the shave, the area is scrubbed with povidone-iodine soap for 10 minutes.
  • The surgical setup should include a broad-spectrum antibiotic solution for irrigation.
  • Male:
    • lithotomy position for bulbous urethra cuff placement
    • draped for the simultameous perineal and an abdominal approach
    • Reservoir:
      • placed in the prevesical space
      • 61– to 70–cm H2O
    • Pump: placed in the dependent ipsilateral side in a lateral hemiscrotal pocket
    • Cuff:
      • bulbous urethra- most common site of implantation (4.5-cm cuff)
      • bladder neck- retropubic space is developed and exposure of the endopelvic fascia
  • Female
    • Can be approached from an abdominal or transvaginal route
    • Cuff: The bladder neck is the only location
  • After the connections, the sphincter is cycled. Then the cuff is locked deactivated.
  • A small Foley catheter is placed intraoperatively and is removed the day after the surgery.
  • A 6-week deactivation period for healing is needed.
  • Catheterization or any other instrumentation through the urethra without deactivating the device first may result in device failure.

8. Commercial Product Available

  • Artificial urinary sphincter (AMS 800)
    • is composed of pressure-balloon reservoir, inflate-deflate cuff, and control pump
    • over 15,000 devices in men and women
    • is an reliable prosthesis and is easy to place

9. Clinical Outcomes

  • Most experiences of the placement of the artificial urinary sphincter in SCI/D neurogenic bladder are from pediatric subpopulation due to relative few indications for the adult SCI/D patients.

Continence:

  • 83- 84% patients with > 5 year followup [Levesque 1995]
  • 80-95% patients with > 10 year followup [Levesque 1999]

Complication (erosion)

  • The erosion rate reported in contemporary studies is 5% to 15%. [Barrett 1993; O'Flynn 1991]

Revision rate

  • Contemporary series indicate a revision rate of 19% to 28% in those placed after 1987 [Kryger  1999; Singh 1996; Simeoni 1996]
  • Most frequently for fluid leakage, mechanical failure and tissue atrophy beneath the cuff. [Levesque 1996; Kryger 1999]

Authors (Year)

Methods

Results

Comments

Singh G, Thomas DG. [Br J Urol. 1996]

90 patients (75 male and 15 female, mean age 26 years) with neurogenic bladder dysfunction (71 with congenital and 19 with acquired cord lesions)

AUS

mean followup 4 years

52 underwent cystoplasty

92% were continent both night and day

79% required a cystoplasty to achieve continence

21% were controlled with anti-cholinergic therapy.

28% re-operation rate
6 infections,
7 erosions,
8 system failures,
2 pump failures,
1 sheered tube
1 rectal and one bladder perforation.

78% currently perform CIC to treat high post-voiding residual urine volumes.

A rate of continence > 90% was achieved in neurogenic patients after implantation of an AUS

a simultaneous cystoplasty is recommend in patients with detrusor overactivity.

Fulford SC, Sutton C, Bales G, Hickling M, Stephenson TP. [Br J Urol. 1997] 

long-term outcome analysis of AUS implanted more than 10 years ago

61 patients (mean age: 26 years) who had an AUS implanted (incl. 34 with a neuropathic bladder with sphincter dysfunction)

 

95.1% patients experienced major complications 

80.3% have required at least one revision.

 

75% achieved long-term continence with the AUS.

Despite the high complication and revision rate, acceptable continence rates can be achieved in the long-term, particularly in the male neuropathic bladder

Many of the complications encountered may be less common with the current redesigned models of the AUS.

Simeoni J, Guys JM, Mollard P, Buzelin JM, Moscovici J, Bondonny JM, Melin Y, Lortat-Jacob S, Aubert D, Costa F, Galifer B, Debeugny P. [Br J Urol. 1996] 

Retrospective review

107 children (74 boys and 33 girls) treated for neurogenic urinary incontinence (92 spina bifida)

AMS 800 artificial sphincter

mean followup 61 months

revision 58.9%

21 mechanical failures,
40 surgical complication
39 changes in the dynamics of bladder function

81% in whom the device is still in place

83% completely continent

overall success rate 77%

For successful implantation of an artificial urinary sphincter in children, the pre-operative bladder capacity must be sufficient.

Children and parents should be informed of the high complication rate and the need for long-term follow-up.

 

10. Advantages

  • Preservation of spontaneous volitional voiding in some patients, which is not achieved with other techniques
  • High success rate of achieving continence: 90% socially dry
  • Relatively low complication rate in general but somewhat higher incidence of infection and erosion in patients with a neurogenic bladder
  • Patient satisfaction rate is high after successful implantation

11. Disadvantages

  • Operative complications
    • Pump migration, improper cuff size
    • Intraoperative urethral injuries
    • Infection:
      • Staphylococcus epidermidis is the most common organism
      • quite low in recent series though initially high
  • Mechanical complications of the device: Cuff erosion
      • the most common causes of sphincter failure
      • Infection is a major risk factor for erosion.
      • Delayed activation may decrease the risk of erosion and this approach has become a routine [Sidi  1984; Furlow 1981]

12. Current Significance

  • The current trend for increasing bladder outlet resistance in female patients is to create a suburethral sling. For males, the male sling technique has recently been resurrected with most experiences from the treatment for the radical prostatectomy incontinence.
  • In pediatric population with SCI/D, long-term published data favor artificial urinary sphincter for surgically managing neurogenic sphincteric incontinence [Kryger 2000]

Summary

Effectiveness

Very effective but may incite a detrusor response, difficult to use with CIC

Safety

Not very safe in SCI patients without bladder augmentation and bladder neck placement

Ease of application

Difficult to place and keep operating in SCI patients

Patient Comfort

Good when they work

Cost

Relatively high up front cost with a high rarte of required revision

13. Other Comments

  • Close postoperative followup surveillance must be instituted in SCI/D patients because potential adverse phenomena may occur even if uninhibited detrusor contractions or decreased compliance were not identified preoperatively.
  • If VUR is discovered preoperatively, it should be corrected before or at the time of implantation.
  • Previous collagen injection is not a contraindication to placement of the AUS in male or female patients.
  • Bladder augmentation was necessary in only 33% to 58% of patients who received an artificial urinary sphincter in pediatric population with neurogenic bladder [Levesque 1996; González 1995; Kryger 1999]
  • Insertion of the artificial urinary sphincter before puberty does not necessarily require postpubertal revision and children do not outgrow the artificial urinary sphincter. [Levesque 1996]
  • An artificial urinary sphincter placed around the bladder neck does not alter sexual development, function, or prostatic growth or morphology. [Jumper 1990]
  • The artificial urinary sphincter does not preclude normal pregnancy or birth, whether by vaginal delivery or cesarean section. [Creagh 1995]
  • CIC is not a contraindication since it has not led to increased complications in patients with an AUS as long as the cuff remains deflated [Barrett 1984].
  • Most studies confirm that simultaneous artificial urinary sphincter placement and enterocystoplasty are safe. [Aliabadi 1990]
  • Long-term studies have shown new development of hydronephrosis and/or renal failure in 2% to 15% of patients. [Churchill 1987]

Key Points of This Section

  • The artificial sphincter has a very limited place in the treatment of SCI related incontinence. If intermittent catheterization is required bladder neck placement is mandatory.
  • The increased resistance associated with the sphincter can result in a dramatic deterioration in bladder compliance and capacity and upper tract damage.

References

  • Aliabadi H, Gonzalez R. Success of the artificial urinary sphincter after failed surgery for incontinence. J Urol. 1990 May;143(5):987-90.
  • Barrett DM, Furlow WL. Incontinence, intermittent self-catheterization and the artificial genitourinary sphincter. J Urol. 1984 Aug;132(2):268-9. 
  • Barrett DM, Parulkar BG, Kramer SA. Experience with AS 800 artificial sphincter in pediatric and young adult patients. Urology. 1993 Oct;42(4):431-6.
  • Berry JL. A new procedure for correction of urinary incontinence: preliminary report. J Urol, 1961; 85: 771.
  • Churchill BM, Gilmour RF, Khoury AE, McLorie GA. Biological response of bladders rendered continent by insertion of artificial sphincter. J Urol. 1987 Oct;138(4 Pt 2):1116-9.
  • Creagh TA, McInerney PD, Thomas PJ, Mundy AR. Pregnancy after lower urinary tract reconstruction in women. J Urol. 1995 Oct;154(4):1323-4.
  • Fulford SC, Sutton C, Bales G, Hickling M, Stephenson TP. The fate of the 'modern' artificial urinary sphincter with a follow-up of more than 10 years. Br J Urol. 1997 May;79(5):713-6. 
  • Furlow WL. Implantation of a new semiautomatic artificial genitourinary sphincter: experience with primary activation and deactivation in 47 patients. J Urol. 1981 Dec;126(6):741-4.
  • Gonzalez R, Merino FG, Vaughn M. Long-term results of the artificial urinary sphincter in male patients with neurogenic bladder. J Urol. 1995 Aug;154(2 Pt 2):769-70.
  • Jumper BM, McLorie GA, Churchill BM, Khoury AE, Toi A. Effects of the artificial urinary sphincter on prostatic development and sexual function in pubertal boys with meningomyelocele. J Urol. 1990 Aug;144(2 Pt 2):438-42.
  • Kaufman JJ. Treatment of post-prostatectomy urinary incontinence using a silicone gel prosthesis. Br J Urol. 1973 Dec;45(6):646-53.
  • Kryger JV, Gonzalez R, Barthold JS. Surgical management of urinary incontinence in children with neurogenic sphincteric incompetence. J Urol. 2000 Jan;163(1):256-63.
  • Kryger JV, Spencer Barthold J, Fleming P, Gonzalez R. The outcome of artificial urinary sphincter placement after a mean 15-year follow-up in a paediatric population. BJU Int. 1999 Jun;83(9):1026-31.
  • Kryger JV, Spencer Barthold J, Fleming P, Gonzalez R. The outcome of artificial urinary sphincter placement after a mean 15-year follow-up in a paediatric population. BJU Int. 1999 Jun;83(9):1026-31.
  • Levesque PE, Bauer SB, Atala A, Zurakowski D, Colodny A, Peters C, Retik AB. Ten-year experience with the artificial urinary sphincter in children. J Urol. 1996 Aug;156(2 Pt 2):625-8.
  • O'Flynn KJ, Thomas DG. Artificial urinary sphincter insertion in congenital neuropathic bladder. Br J Urol. 1991 Feb;67(2):155-7.
  • Scott FB, Bradley WE, Timm GW. Treatment of urinary incontinence by implantable prosthetic sphincter. Urology. 1973 Mar;1(3):252-9.
  • Sidi AA, Sinha B, Gonzalez R. Treatment of urinary incontinence with an artificial sphincter: further experience with the AS791/792 device. J Urol. 1984 May;131(5):891-3.
  • Simeoni J, Guys JM, Mollard P, Buzelin JM, Moscovici J, Bondonny JM, Melin Y, Lortat-Jacob S, Aubert D, Costa F, Galifer B, Debeugny P. Artificial urinary sphincter implantation for neurogenic bladder: a multi-institutional study in 107 children. Br J Urol. 1996 Aug;78(2):287-93.
  • Singh G, Thomas DG. Artificial urinary sphincter in patients with neurogenic bladder dysfunction. Br J Urol. 1996 Feb;77(2):252-5.

 

 

 

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