A multicentre prospective randomised study of single-incision mini-sling (Ajust^®) versus tension-free vaginal tape-obturator (TVT-O™) in the management of female stress urinary incontinence: pain profile and short-term outcomes

Abstract

Objectives

To compare the postoperative pain profile, peri-operative details, and short-term patient-reported and objective success rates of single-incision mini-slings (SIMS) versus standard mid-urethral slings (SMUS).

Study design

In a multicentre prospective randomised trial in six UK centres in the period between October 2009 and October 2010, 137 women were randomised to either adjustable SIMS (Ajust^®, C. R. Bard Inc., NJ, USA), performed under local anaesthesia as an opt-out policy (n = 69), or SMUS (TVT-O™, Ethicon Inc., Somerville, USA) performed under general anaesthesia (n = 68). Randomisation was done through number-allocation software and using telephone randomisation. Postoperative pain profile (primary outcome) was assessed on a ten-point visual analogue scale at fixed time-points. Pre- and post operatively (4–6 months) women completed symptom severity, urgency perception scale (UPS), quality of life and sexual function questionnaires. In addition, women completed a Patient Global Impression of Improvement Questionnaire and underwent a cough stress test at 4–6 months follow up. Sample size calculation was performed and data were analysed using SPSS 18. Descriptive analyses are given and between-group comparisons were performed using chi-square, Fischer exact test and Mann–Whitney test as appropriate. Significance level was set at 5%.

Results

Women in the SIMS Ajust^® group had a significantly lower postoperative pain profile up to 4 weeks (p = <0.001, 95% CI 1.151, 2.480). There was no significant difference in peri-operative complications between groups. All 137 women completed the 4–6 months follow-up. Patient-reported and objective cure rates were not significantly different: 85.5% versus 91.2% (p = 0.443) and 90% versus 97% (p = 0.165) between the SIMS Ajust^® and TVT-O™ groups respectively. There was a trend towards higher rates of de novo urgency or worsening of pre-existing urgency in the SIMS Ajust^® group (21.7% versus 8.8%) but this did not reach statistical significance (p = 0.063). Women in the SIMS Ajust^® group had shorter hospital stay (median (IQR) 3.65 (2.49, 4.96)) compared to (4.42 (3.16, 5.56)) the TVT-O™ group 95% CI (−0.026, 1.326), with significantly earlier return to normal activities (p = 0.025) and to work (p = 0.006).

Conclusion

The adjustable single-incision mini-sling (Ajust^®) is associated with a significantly improved postoperative pain profile and earlier return to work when compared to standard mid-urethral slings (TVT-O™), with encouraging results in patient-reported and objective success rates at short-term follow-up.

Introduction

Stress urinary incontinence (SUI) is the most common type of urinary incontinence (UI) in premenopausal women, accounting for almost 50% of cases [1]. Initial management of SUI includes conservative therapy such as pelvic floor muscle training (PFMT), biofeedback, and electrical stimulation with or without pharmacotherapy. Surgical procedures have been continuously evolving over the last four decades with the ultimate aim of providing an effective and truly ambulatory surgical procedure. Reduction of peri-operative morbidity, shorter hospital stay, less postoperative pain and a quicker recovery period have been the principal driving forces for this continued innovation.

Of the surgical treatments available, standard mid-urethral slings (SMUS), both retropubic tension-free vaginal tapes (RP-TVT) [2] and transobturator tension-free vaginal tapes (TO-TVT) [3], [4], are the most commonly performed procedures for SUI, resulting in 11,000 finished consultant episodes in England in 2009–10, with estimated costs of £22.5 million/year [5]. A Cochrane review of SMUS and more recently a robust systematic review and meta-analysis concluded that there was no evidence of significant differences in patient-reported success rates between TO-TVT and RP-TVT in the management of SUI [6], [7]. RP-TVT, however, were associated with a higher risk of bladder injuries and postoperative voiding dysfunction (VD) while a significantly higher incidence of post-operative groin/thigh pain occurred with TO-TVT. SMUS were initially described under local anaesthesia (LA) and sedation, but the British Society of Urogynaecologists’ surgical database showed that SMUS are predominantly done under general anaesthesia (GA) [8]. Similarly, the Hospital Episode Statistics (HES) showed that >50% of SMUS performed in England in 2010–2011 required one or more overnight hospital stay (HES 2010–2011; as checked on 28th September 2011).

Single-incision mini-sling (SIMS) utilises a single vaginal insertion approach and aims to avoid the blind passage of the trochars through the retropubic area and the groin/adductor muscles, consequently reducing the incidence of peri-operative morbidity compared to SMUS. The main advantages of SIMS are attributed to their higher tolerability to be done under LA and lower incidence of postoperative pain; shorter hospital stay, quicker recovery, early resumption of day-to-day activities and earlier return to work [9]. A recent systematic review and meta-analysis [10] have shown that earlier types of SIMS were associated with inferior objective and patient-reported cure rates when compared to SMUS. None of the RCTs included, however, assessed the new adjustable SIMS which, unlike earlier SIMS, are reported to have a robust anchoring mechanism to the obturator complex with superior pull-out force [11], [12] and the possibility of post-insertion adjustability to the appropriate tension.

SIMS-Ajust^® (C. R. Bard, Inc., NJ, USA) is a novel “adjustable SIMS” procedure that has been recently introduced into clinical practice with the potential of being a truly ambulatory surgical treatment for SUI under LA [9], [13] and has gained popularity due to its relatively short learning curve. An RCT is urgently needed to robustly evaluate this new intervention and compare it with SMUS before it can be widely adopted in clinical practice.