SEARCH

SEARCH BY CITATION

Abbreviations
AUS

artificial urinary sphincter

PPI

incontinence after prostatectomy

RP

radical prostatectomy.

INTRODUCTION

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

The artificial urinary sphincter (AUS) is the current ‘gold standard’ for the surgical treatment of incontinence after prostatectomy (PPI). PPI is a recognized complication after open and transurethral surgery for benign disease, and after radical prostatectomy (RP). It carries significant psychosocial morbidity for the patient and reduces the quality of life. More conservative treatment, with lower success and durability, includes non-surgical measures, e.g. Kegel exercises, absorbent appliances, pharmacotherapy and electrostimulation; and less invasive surgical options, e.g. bio-injectable urethral bulking agents and the bulbourethral sling. This review highlights the development of the AUS and its effects on the current management of PPI, with an emphasis on incontinence after RP.

INCIDENCE

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

The reported incidence of stress incontinence after open prostatectomy for benign disease is 1.9% (retropubic and transvesical prostatectomy), 1.8% after transurethral incision and 2.2% after TURP [1]. A more recent report from the International Consultation on Incontinence stated a prevalence of < 2% for benign disease, regardless of surgical approach [2].

After RP the overall incidence of permanent incontinence is 5–25%, with 70–90% of patients dry with no pads at 1 year after surgery, and 80–95% free of nocturnal leakage. The reason for the wide range in incidence is the use of different definitions of continence and methods of assessment. The incidence of PPI is very similar whether the surgical approach is retropubic or perineal [3,4] but no randomized trials have compared the two approaches.

DEVELOPMENT OF THE AUS

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

As PPI is mostly caused by sphincteric weakness, many urologists had worked on the idea of an artificial device to improve urethral resistance. In 1947, Foley was the first to describe an AUS which resembled a sphygmomanometer, consisting of a periurethral inflatable cuff which was connected to a detachable pump carried in the patient's pocket [5]. As it was an external device and not made of inert material, success was minimal and its popularity quickly dwindled. In June 1972, Scott implanted his new device in a 36-year-old woman with myelodysplasia and started the modern era of AUS implantation [6]. This sparked innovators to design other types of AUS, e.g. the Kaufman passive silicone gel prosthesis (1973) and the Rosen sphincter (1975), comprising a three-pronged rubber clamp fitted across the urethra, thus sandwiching it when the middle arm is inflated [7]. Their success rates were low, as they were volume-dependent systems. Craggs [8] presented the first pressure-regulated sphincter, claiming better success than the volume-dependent systems.

However, it was the initial series of 34 patients reported by Scott et al.[9] in 1974, with an overall success rate of 79% and with the greatest durability in patients after prostatectomy, which caught the attention of manufacturers. American Medical Systems (AMS, Minnetonka, Minnesota) was the first to patent this sphincter, the model AS 721. It was associated with a high mechanical failure rate and was cumbersome to implant. Over the next decade, the AS 721 was modified and simplified, which improved its reliability and reduced the rates of urethral erosion, infection, tube kinks, valve failure and device leakage [10].

The first step of this process was the development of the AMS 742, which had a single pump, cuff and a balloon pressure reservoir. It was the first automatic cuff closure prosthesis, so that active pressure in the balloon would fill the cuff automatically and a delay-fill resistor would slow cuff refilling [7]. This was superseded by the AMS 791 (bulb) and 792 (bladder neck) in 1979. In these models, the Dacron-reinforced cuff was replaced by the dip-coated all-silicone rubber cuff. This device could be implanted with or without the cuff being activated at the end of the procedure. The former would increase the risk of urethral erosion, the latter would reduce the risk of erosion, but at the expense of requiring a second operation to activate the device. To overcome this, a deactivation mechanism for delayed cuff activation was developed [7]. In 1983, the AMS 800 was launched, in which the deactivation button is incorporated into the control assembly. Since then, further refinement of the AMS 800 included a fluorosilicone coating to the cuff to diminish potential weakening at cuff folds, a narrow-backed cuff design to improve transmission of cuff pressure to underlying tissue [11], and kink-resistant colour-coded tubing. Currently, the AMS 800 device is the most widely studied and most commonly used AUS for patients with PPI.

THE AUS IN PPI FOR BENIGN DISEASE

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

Publications on this use are scarce; candidates for treatment with the AUS are those with incontinence caused by intrinsic sphincter deficiency, with normal bladder compliance. Those with detrusor overactivity should have this treated first to minimize the risk of storage symptoms, persistent incontinence and upper tract damage after implantation. The AUS has been placed around the bulbar urethra, bladder neck and the membranous urethra at the prostatic apex via a retropubic approach. The cuff placed at the bladder neck afforded slightly better continence than periurethrally. The social continence rates are 75–95% with up to 3 years of follow-up [2].

THE AUS FOR INCONTINENCE AFTER RP

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

AUS implantation is often delayed for at least 6–12 months after RP, to allow time for the spontaneous resolution of incontinence. The AUS was originally described to work best around the bladder neck, but in these patients a bulbar approach is much simpler and avoids the significant postoperative changes at the bladder neck anastomotic area. More recently a transcrotal approach was described, claiming reduced operative duration and similar success rates, at 1 year, to the bulbar approach [12].

OUTCOMES

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

After implanting an AUS for incontinence after RP the reported rates of ‘total continence’ are 27–75%[13–15]. The ‘significantly improved’ rate (0–1 pads/day) was 75–87%, with > 3 years of follow-up [16,17]. Recent studies which included all patients with PPI in whom more than half had RP quoted ‘dry’ rates of 44–86%, and a ‘significantly improved’ rate of 90–96%[18,19]. The wide range of some of these values can be explained by different definitions of continence and methods of assessment. Strict criteria and objective assessments tend to be associated with lower rates of continence [3].

In the largest study to date, Elliott and Barrett [20] reported 245 of 271 (90%) patients having a functioning AUS at mean follow-up of 5 years, and 72% required no revision. Another study with 61 patients and a 10-year follow-up reported a 75% continence rate, with 80% of patients having had at least one revision procedure by 10 years [21].

COMPLICATIONS

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

Although the best results for incontinence after RP are seen with the AUS, it comes at the expense of complications and revisions. Complications of AUS implantation can be classified into mechanical or not. The latter include infection, erosion and pressure atrophy, and the former may be secondary to fluid leakage from tubing or reservoir, pump malfunction, or inadequate compression pressure. A recent large series found a persistently decreasing rate of mechanical failure since the introduction of the narrow-backed cuff in 1988 [19]. With the currently available AMS 800, the revision rate is ≈ 9% for other than mechanical and 7–8% for mechanical failure, yielding a total reoperation rate of ≈ 17%. The expected 5-year survival of the narrow-backed AUS is 75%.

The infection rate can be expected to be 1.8–10% (mean 3.4%) [2,15], with the higher values being in irradiated patients. Infection is often caused by Staphylococcus epidermidis. Infection soon after surgery is thought to be a result of ‘seeding’ of the prosthesis at time of surgery. Late infection may be caused by haematogenous spread from another source. Most infected prostheses will not be salvageable by parenteral antibiotic therapy and thus require explantation. Reimplantation can be planned within a 3–6-month period after complete resolution of the infection.

Since the introduction of delayed activation the current erosion rate is 1–3%[18,20]. Erosion can be precipitated by infection, decreased vascularity from previous irradiation, excessive cuff pressure, undersized cuff, and traumatic injury from catheterization through an activated cuff. Prevention includes careful cuff and balloon sizing, especially in irradiated patients, where a 51–60 cmH2O balloon may be more desirable. It should be routine to deactivate the cuff for 6 weeks after surgery, to reduce the risk of erosion. Remembering to deflate the cuff if the urethra is to be instrumented also lowers the chance of traumatic erosion.

Urethral atrophy is a relatively common cause of recurrent incontinence, with an incidence of 3–9%[18]. Current management options available include placing a new cuff more proximally [22], placing an additional cuff which doubles the surface area compressed without reducing tissue perfusion [23], or the cuff size may be reduced within the existing false capsule [24].

Device leakage is not uncommon and may be the result of microfractures in tubing, cuff or reservoir. Pump malfunction is most often caused by obstruction of fluid flow by tube kinks, debris, airlock, blood or crystals from the contrast solution or antibiotics [11]. It is a rare complication and can be prevented by ensuring that the tubing is devoid of air, blood or debris, by trimming excessive tubing to prevent kinking, and educating the patient about the operation of the pump.

Persistent stress incontinence may occur in up to 15% of patients after AUS insertion. Once the above causes have been excluded, it may be a result of inserting too large a cuff or using a reservoir with too low a pressure. Management includes changing the above to a more appropriate gradation. It may also be managed by proximal repositioning of the cuff or placing a double cuff [25]. Reservoir pressure may only be increased if the lowest pressure reservoir (51–60 cmH2O) had been used previously; the 71–80 cmH2O reservoir should be avoided with bulbar cuff placement.

QUALITY OF LIFE

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

As PPI is largely an issue of quality of life the personal perception of improvement in continence and satisfaction by the patient after implanting an AUS is crucial in determining its success. Recent studies have shown that patient satisfaction with the AUS in PPI is 85–95%, even in the face of the significant revision and complication rates [12,16,18,26,27].

Litwiller et al.[18] specifically explored the issue of long-term patient satisfaction in PPI treated with the AUS. In that study, continence was defined as complete absence of leakage. There was a median (range) follow-up of 23.4 (3–114) months in 50 patients. The authors concluded that patient satisfaction was uniformly high (90%) and was not dependent on perfect continence but rather on the magnitude of improvement and preoperative expectations; 90% of patients who needed an AUS revision did not alter their satisfaction or attitude toward it. The authors noted that even in patients with persistent leakage, 23 of 25 (92%) patients would recommend the AUS to a friend with a similar incontinence problem. It was also apparent that detrusor instability and reduced detrusor compliance have no bearing on the perception of success.

Previous external beam radiotherapy or brachytherapy, although associated with a higher incidence of revision, did not affect patient satisfaction and quality of life, and had a similar outcome when compared with patients who had not been irradiated [18,28,29].

In a recent retrospective study, previous collagen injection therapy neither adversely influenced the surgical complication rate nor compromised AUS efficacy or quality of life in patients with PPI [30]. In patients with a Valsalva leak-point pressure of < 60 cmH2O, the study showed that it was more cost-effective to manage PPI directly with an AUS than with collagen, as the success with the latter was relatively low and associated with prolonged patient dissatisfaction.

COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

Some patients may wish to consider a less involved procedure to manage their PPI, opting for either a bio-injectable bulking agent or a bulbourethral sling. The most commonly studied bio-injectable agent is collagen. Studies on collagen injection in men with PPI have given at best a 35–70% improvement rate, often at the price of many injections (mean 2.6–3.5) [2]. Macroplastique showed unsatisfactory durability, with a 40% deterioration in success after only 3 months [31].

Because of the associated revisions and cost of the AUS, less involved procedures, e.g. the bulbourethral sling to suspend the bulbar urethra to either the abdominal wall or the inferior pubic rami, have recently been introduced. There have been no randomized trials comparing slings and AUS, but recent series with < 2 years of follow-up have claimed satisfactory improvement rates, with results comparable with the AUS, with a similar revision and erosion rate [32,33]. However, the cure rates were inferior to the AUS, at 40–55%, and about half the patients had perineal discomfort. Currently, it is the recommendation by the International Consultation on Incontinence that for PPI the AUS remains the ‘most successful surgical option’[2].

THE FUTURE

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

GRACILIS MYOPLASTY

The dynamic urethral graciloplasty was developed by Janknegt et al.[34], who earlier described the perianal dynamic graciloplasty for fecal incontinence. The principle is to wrap the bladder neck or bulbar urethra with the gracilis and render it in a tonic fatigue-resistant state with an implantable electrostimulator which can be turned off during voiding. Chancellor et al.[35] reported early results in seven patients, with three successes.

NEW SPHINCTER DESIGNS

Mundy et al.[36] developed a new design of AUS, with conditional occlusion; this consists of an adjustable pressure regulator, stress balloon, pump with built-in self-scaling port, and a cuff. The balloon transmits additional pressure to the cuff during periods of increased abdominal pressure, thus allowing lower resting pressures. The pump is activated by injecting saline through a port in the scrotum. An initial pilot study on a few patients with PPI gave promising results, with uncomplicated implantation and device activation.

TISSUE ENGINEERING

Recent research on stress incontinence has involved the use of stem cells. Periurethral injection of skeletal muscle-derived stem cells increased the leak-point pressure in a rat model [37]. In the future, the deficient rhabdosphincter in patients with PPI may be able to be augmented in this manner.

CONCLUSION

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES

Amongst all the treatments available for PPI the AUS still has the best durability and offers the best quality of life. It has a complication profile which necessitates management by urologists experienced with its use. Until another method can be developed to further improve the complication profile and success, the AUS will remain the standard of care in this group of patients.

REFERENCES

  1. Top of page
  2. INTRODUCTION
  3. INCIDENCE
  4. DEVELOPMENT OF THE AUS
  5. THE AUS IN PPI FOR BENIGN DISEASE
  6. THE AUS FOR INCONTINENCE AFTER RP
  7. OUTCOMES
  8. COMPLICATIONS
  9. QUALITY OF LIFE
  10. COLLAGEN AND THE BULBOURETHRAL SLING VS THE AUS
  11. THE FUTURE
  12. CONCLUSION
  13. REFERENCES
  • 1
    McConnell JD, Barry MJ, Bruskewitz RC et al. Benign prostatic hyperplasia. diagnosis and treatment. Clinical practice guidelines, no. 8. AHCPR Publication No. 94–0582. Rockville. Maryland: Agency for Health Care Policy and Research. Public Health Service, US Department of Health and Human Services, 1994
  • 2
    Committee 17. Surgical treatment of urinary incontinence in men. In AbramsP, KhouryS, WeinA eds Incontinence. First International Consultation on Incontinence. Health Publication Ltd., 1999: 691–729
  • 3
    Catalona WJ, Basler JW. Return of erections and urinary incontinence following nerve sparing radical retropubic prostatectomy. J Urol 1993; 150: 9057
  • 4
    Weldon VE, Tavel FR, Neuwirth H. Continence, potency and morbidity after radical perineal prostatectomy. J Urol 1997; 158: 14705
  • 5
    Foley FEB. Artificial sphincter. new device and operation for control of enuresis and urinary incontinence. J Urol 1947; 58: 2509
  • 6
    Scott FB, Bradley WE, Timm GW, Kothari D. Treatment of incontinence secondary to myelodysplasia by an implantable prosthetic urinary sphincter. South Med J 1973; 66: 98790
  • 7
    Hajivassiliou CA. The development and evolution of artificial urethral sphincters. J Med Eng Technol 1998; 22: 1548
  • 8
    Craggs MD. An adjustable pressure regulated artificial urinary sphincter. J Physiol, 1986; 377: 6
  • 9
    Scott FB, Bradley WE, Timm GW. Treatment of urinary incontinence by an implantable prosthetic urinary sphincter. J Urol 1974; 112: 7580
  • 10
    Diokno AC, Peters KM. Artificial urinary sphincter for treatment of male urinary incontinence. In Carson, CCIII, ed. Urologic Prostheses. Totowa: Humana Press, 2002: 26384
  • 11
    Leo ME, Barrett DM. Success of the narrow-backed cuff design of the AMS 800 artificial urinary sphincter: analysis of 144 patients. J Urol 1993; 150: 14124
  • 12
    Wilson SK, Delk JR, Henry GD, Siegel AL. New surgical technique for sphincter urinary control system using upper transverse scrotal incision. J Urol 2003; 169: 21664
  • 13
    Gousse AE, Madjar S, Lambert MM, Fishman IJ. Artificial urinary sphincter for post-radical prostatectomy urinary incontinence: long-term subjective results. J Urol 2001; 166: 17558
  • 14
    Gundian JC, Barrett DM, Parulkar BG. Mayo Clinic experience with the use of the AMS 800 artificial urinary sphincter for urinary incontinence following radical prostatectomy. J Urol 1989; 142: 145961
  • 15
    Montague DK. The artificial urinary sphincter (AMS 800): experience in 166 consecutive patients. J Urol 1992; 147: 3802
  • 16
    Perez LM, Webster GD. Successful outcome of artificial urinary sphincters in men with post-prostatectomy urinary incontinence despite adverse implantation features. J Urol 1992; 148: 116670
  • 17
    Fleshner N, Herschorn S. The artificial urinary sphincter for post-radical prostatectomy incontinence. Impact on urinary symptoms and quality of life. J Urol 1996; 155: 12604
  • 18
    Litwiller SE, Kim KB, Fone PD, White RW, Stone AR. Post-prostatectomy incontinence and the artificial urinary sphincter: along-term study of patient satisfaction and criteria for success. J Urol 1996; 156: 197580
  • 19
    Petrou SP, Elliott DS, Barrett DM. Artificial urethral sphincter for incontinence. Urology 2000; 56: 3539
  • 20
    Elliott DS, Barrett DM. Mayo Clinic long-term analysis of the functional durability of the AMS 800 artificial urinary sphincter: a review of 323 cases. J Urol 1998; 159: 12068
  • 21
    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; 79: 7136
  • 22
    Couillard DR, Vapnek JM, Stone AR. Proximal artificial sphincter cuff repositioning for urethral atrophy. Urology 1994; 45: 6536
  • 23
    Brito CG, Mulcahy JJ, Mitchell ME, Adams MC. Use of a double cuff AMS 800 urinary sphincter for severe stress incontinence. J Urol 1993; 149: 2835
  • 24
    Saffarian A, Walsh K, Walsh IK, Stone AR. Urethral atrophy after artificial urinary sphincter placement: is cuff downsizing effective? J Urol 2003; 169: 5679
  • 25
    Kabalin JN. Addition of a second urethral cuff to enhance performance of the artificial urinary sphincter. J Urol 1996; 156: 13024
  • 26
    Fishman IJ, Shabsingh R, Scott FB. Experience with the artificial urinary sphincter model AMS 800 in 148 patients. J Urol 1989; 141: 30710
  • 27
    Light JK, Reynolds JC. Impact of the new cuff design on reliability of the AS800 artificial urinary sphincter. J Urol 1992; 147: 60911
  • 28
    Gomha MA, Boone TB. Artificial urinary sphincter for post-prostatectomy incontinence in men who had prior radiotherapy. a risk and outcome analysis. J Urol 2002; 167: 5916
  • 29
    Walsh IK, Williams SG, Mahendra V, Nambirajan T, Stone AR. Artificial urinary sphincter implantation in the irradiated patient: safety, efficacy and satisfaction. BJU Int 2002; 89: 3648
  • 30
    Gomes CM, Broderick GA, Sanchez-Ortiz RF, Preate D Jr, Rovner ES, Wein AJ. Artificial urinary sphincter for post-prostatectomy incontinence: impact of prior collagen injection on cost and clinical outcome. J Urol 2000; 163: 8790
  • 31
    Bugel H, Pfister C, Sibert L, Cappele O, Khalaf A, Grise P. Intraurethral Macroplastique injections in the treatment of urinary incontinence after prostatic surgery. Prog Urol 1999; 9: 106876
  • 32
    Schaeffer AJ, Clemens JQ, Ferrari M, Stamey TA. The male bulbourethral sling procedure for post-radical prostatectomy incontinence. J Urol 1998; 159: 15105
  • 33
    Clemens JQ, Bushman W, Schaeffer AJ. Questionnaire based results of the bulbourethral sling procedure. J Urol 1999; 162: 19726
  • 34
    Janknegt RA, Heesakkers JPFA, Weil EHJ, Baeten CG. Electrically stimulated gracilis sphincter (dynamic graciloplasty) for treatment of intrinsic sphincter deficiency: a pilot study on feasibility and side-effects. J Urol 1995; 154: 18303
  • 35
    Chancellor MB, Heesakers JFPA, Janknegt RA. Gracilis muscle transposition with electrical stimulation for urinary incontinence: a new approach. World J Urol 1997; 15: 3208
  • 36
    Mundy AR, Knight SL, Dunglison N, Craggs MD. A new artificial urinary sphincter with conditional occlusion for genuine stress incontinence. J Urol 2001; 165 (Suppl.): 158
  • 37
    Lee JY, Cannon TW, Pruchnic R, Fraser MO, Huard J, Chancellor MB. The effects of periurethral muscle-derived stem cell injection on leak point pressure in a rat model of stress urinary incontinence. Int Urogynecol J Pelvic Floor Dysfunct 2003; 14: 317