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. 2022 Aug;26(36):1–152. doi: 10.3310/TBFZ0277

Synthetic sling or artificial urinary sphincter for men with urodynamic stress incontinence after prostate surgery: the MASTER non-inferiority RCT.

Lynda Constable, Paul Abrams, David Cooper, Mary Kilonzo, Nikki Cotterill, Chris Harding, Marcus J Drake, Megan N Pardoe, Alison McDonald, Rebecca Smith, John Norrie, Kirsty McCormack, Craig Ramsay, Alan Uren, Tony Mundy, Cathryn Glazener, Graeme MacLennan
PMCID: PMC9421661  PMID: 35972773

Abstract

BACKGROUND

Stress urinary incontinence is common in men after prostate surgery and can be difficult to improve. Implantation of an artificial urinary sphincter is the most common surgical procedure for persistent stress urinary incontinence, but it requires specialist surgical skills, and revisions may be necessary. In addition, the sphincter is relatively expensive and its operation requires adequate patient dexterity. New surgical approaches include the male synthetic sling, which is emerging as a possible alternative. However, robust comparable data, derived from randomised controlled trials, on the relative safety and efficacy of the male synthetic sling and the artificial urinary sphincter are lacking.

OBJECTIVE

We aimed to compare the clinical effectiveness and cost-effectiveness of the male synthetic sling with those of the artificial urinary sphincter surgery in men with persistent stress urinary incontinence after prostate surgery.

DESIGN

This was a multicentre, non-inferiority randomised controlled trial, with a parallel non-randomised cohort and embedded qualitative component. Randomised controlled trial allocation was carried out by remote web-based randomisation (1 : 1), minimised on previous prostate surgery (radical prostatectomy or transurethral resection of the prostate), radiotherapy (or not, in relation to prostate surgery) and centre. Surgeons and participants were not blind to the treatment received. Non-randomised cohort allocation was participant and/or surgeon preference.

SETTING

The trial was set in 28 UK urological centres in the NHS.

PARTICIPANTS

Participants were men with urodynamic stress incontinence after prostate surgery for whom surgery was deemed appropriate. Exclusion criteria included previous sling or artificial urinary sphincter surgery, unresolved bladder neck contracture or urethral stricture after prostate surgery, and an inability to give informed consent or complete trial documentation.

INTERVENTIONS

We compared male synthetic sling with artificial urinary sphincter.

MAIN OUTCOME MEASURES

The clinical primary outcome measure was men's reports of continence (assessed from questions 3 and 4 of the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form) at 12 months post randomisation (with a non-inferiority margin of 15%). The primary economic outcome was cost-effectiveness (assessed as the incremental cost per quality-adjusted life-year at 24 months post randomisation).

RESULTS

In total, 380 men were included in the randomised controlled trial (n = 190 in each group), and 99 out of 100 men were included in the non-randomised cohort. In terms of continence, the male sling was non-inferior to the artificial urinary sphincter (intention-to-treat estimated absolute risk difference -0.034, 95% confidence interval -0.117 to 0.048; non-inferiority p = 0.003), indicating a lower success rate in those randomised to receive a sling, but with a confidence interval excluding the non-inferiority margin of -15%. In both groups, treatment resulted in a reduction in incontinence symptoms (as measured by the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form). Between baseline and 12 months' follow-up, the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score fell from 16.1 to 8.7 in the male sling group and from 16.4 to 7.5 in the artificial urinary sphincter group (mean difference for the time point at 12 months 1.30, 95% confidence interval 0.11 to 2.49; p = 0.032). The number of serious adverse events was small (male sling group, n = 8; artificial urinary sphincter group, n = 15; one man in the artificial urinary sphincter group experienced three serious adverse events). Quality-of-life scores improved and satisfaction was high in both groups. Secondary outcomes that showed statistically significant differences favoured the artificial urinary sphincter over the male sling. Outcomes of the non-randomised cohort were similar. The male sling cost less than the artificial sphincter but was associated with a smaller quality-adjusted life-year gain. The incremental cost-effectiveness ratio for male slings compared with an artificial urinary sphincter suggests that there is a cost saving of £425,870 for each quality-adjusted life-year lost. The probability that slings would be cost-effective at a £30,000 willingness-to-pay threshold for a quality-adjusted life-year was 99%.

LIMITATIONS

Follow-up beyond 24 months is not available. More specific surgical/device-related pain outcomes were not included.

CONCLUSIONS

Continence rates improved from baseline, with the male sling non-inferior to the artificial urinary sphincter. Symptoms and quality of life significantly improved in both groups. Men were generally satisfied with both procedures. Overall, secondary and post hoc analyses favoured the artificial urinary sphincter over the male sling.

FUTURE WORK

Participant reports of any further surgery, satisfaction and quality of life at 5-year follow-up will inform longer-term outcomes. Administration of an additional pain questionnaire would provide further information on pain levels after both surgeries.

TRIAL REGISTRATION

This trial is registered as ISRCTN49212975.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 36. See the NIHR Journals Library website for further project information.

Plain language summary

Leakage of urine associated with physical exertion (e.g. sporting activities, sneezing or coughing) is common in men who have undergone prostate surgery, but it is difficult to improve. Many men still leak urine 12 months after their prostate surgery and may continue to wear protective pads or sheaths. The most common operation to improve incontinence is implantation of an artificial urinary sphincter. An artificial urinary sphincter is an inflatable cuff that is placed around the urethra, the tube that drains urine from the bladder. The cuff is inflated and compresses the urethra to prevent leaking. When the man needs to pass urine, he must deflate the cuff by squeezing a pump placed in his scrotum, which releases the compression on the urethra and allows the bladder to empty. Recently, a new device, the male sling (made from non-absorbable plastic mesh), has been developed. The sling, which is surgically inserted under the urethra, supports the bladder, but, in contrast to the artificial sphincter, it does not need to be deactivated by a pump and, therefore, the patient does not need to do anything to operate it. A sling is also easier for the surgeon to insert than a sphincter. However, in some men, the sling does not provide enough improvement in incontinence symptoms and another operation, to place an artificial urinary sphincter, is needed. The aim of this study was to determine if the male sling was as effective as the artificial urinary sphincter in treating men with bothersome incontinence after prostate surgery. The study took the form of a randomised controlled trial (the gold standard and most reliable way to compare treatments) in which men were randomised (allocated at random to one of two groups using a computer) to either a male sling or an artificial urinary sphincter operation. We asked men how they got on in the first 2 years after their operation. Regardless of which operation they had, incontinence and quality of life significantly improved and complications were rare. A small number of men did require another operation to improve their incontinence, and it was more likely that an artificial urinary sphincter was needed, rather than another sling operation, if a male sling was not successful. Satisfaction was high in both groups, but it was significantly higher in the artificial urinary sphincter group than in the male sling group. Those who received a male sling were less likely than those who received an artificial urinary sphincter to say that they would recommend their surgery to a friend.


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