Introduction

Top Abstract Introduction Methods Results Discussion References

Urinary incontinence is reported by 14% of women, and about half have urodynamic stress incontinencethe involuntary leakage of urine during increased abdominal pressure in the absence of detrusor contraction.^1-3 Cure rates of around 50% are reported with physiotherapy,⁴ and surgery is recommended for those women who fail to respond. Systematic reviews have shown that colposuspension has cure rates of up to 90%, although there are only limited data from randomised trials. ^{5 6} Previous studies have been criticised for insufficient numbers of participants and statistical power as well as lack of standardised criteria for entry to the study and outcome measures.⁶ Some authors, however, have reported less than half of patients remaining dry and free of complications long term.^7-9 Complications include haemorrhage, haematoma, bladder injury, and urinary tract infection. Up to 20% of women may develop de novo detrusor overactivity ^{5 9} ; voiding dysfunction has been reported in 3% to 32% of women, and surgery for vaginal prolapse may be required in 2.5% to 26.7% after the procedure.⁵

The tension-free vaginal tape procedure is a relatively recent treatment for stress incontinence.¹⁰ A polypropylene tape is inserted suburethrally under local anaesthesia with sedation. The procedure is thought to work by providing a pubourethral "neoligament." Increased intra-abdominal pressure results in a kink at the point of fixation, which prevents urine loss. Data from three early case series suggest objective cure rates of 84-100%, with few complications.^10-12 We compared the tension-free vaginal tape procedure with colposuspension in a prospective randomised manner.

	Methods

Top Abstract Introduction Methods Results Discussion References

Women with stress incontinence, who had completed their family, were invited to take part. Exclusion criteria were detrusor overactivity, vaginal prolapse requiring treatment, previous surgery for prolapse or incontinence, a major degree of voiding dysfunction, neurological disease, and allergy to local anaesthetic.

The trial was conducted at gynaecology or urology departments in 14 centres in the United Kingdom and Eire. Women were recruited from outpatient clinics once surgery had been selected for their stress incontinence.

The sample size calculation was performed assuming a 90% cure rate with colposuspension, and that a 10% difference in cure rate between procedures would be clinically important.⁵ To detect this level of difference with 80% power would require 197 patients in each arm of the trial. Recruitment was limited to the period May 1998 to August 1999 owing to logistic and financial constraints.

Researchers randomised participants via a telephone system, which allocated trial identification number and treatment group. It was not possible to blind investigators or participants to the treatment allocation. The tension-free vaginal tape procedure was performed as described by Ulmsten, under local anaesthesia and sedation.¹⁰

At initial assessment, urodynamic evaluation was performed by medium fill dual channel subtracted cystometry with simultaneous pressure and flow voiding studies or videocystourethrography; in some centres urethral pressure profilometry at rest and at stress was also carried out.¹³ Patients were asked to complete a urinary diary for one week, and a one hour perineal pad test was performed.³

Patients' perceptions of changes in their symptoms and treatment outcome were measured with the SF-36 and the Bristol female lower urinary tract symptoms questionnaire. ^{14 15} Six weeks after surgery a postal questionnaire was sent out comprising the SF-36 and questions about recovery. Six months after surgery reassessment was undertaken with symptom review, clinical examination, the one hour pad test, and urodynamic studies. The SF-36 and Bristol female lower urinary tract symptoms questionnaires were completed by the patient in the clinic, and they were given a urinary diary to complete over one week and return by post.

Outcome measures
The primary outcome measure was objective cure of stress incontinence based on a negative stress test on urodynamic testing, combined with a negative one hour pad test (<1 g change in weight). Secondary outcome measures included subjective cure of incontinence and the development of voiding problems, urge symptoms, and vaginal prolapse. Analysis of results was by intention to treat.

	Results

Top Abstract Introduction Methods Results Discussion References

Overall, 344 women were randomised over 15 months (figure). The baseline characteristics of the two groups were comparable.

View larger version (46K): [in this window] [in a new window]   Flow of participants through trial

Operative complications were more common after the vaginal tape procedure (table 1), largely injury to the bladder and vagina. Operation times, blood loss, analgesic requirements, postoperative complications, and catheterisation were greater in the colposuspension group than the vaginal tape group.

Primary outcome measure
A negative one hour pad test was recorded in 128 (73%) patients in the vaginal tape group and 109 (64%) in the colposuspension group. The change in pad weight decreased significantly in both groups, but there was no significant difference between the groups. Stress testing for urodynamic stress incontinence was negative at cystometry in 142 (81%) patients after the vaginal tape procedure and 114 (67%) after colposuspension. Objective cure, defined as a negative pad test and negative cystometry, was found in 115 (66%) patients in the vaginal tape group and 97 (57%) in the colposuspension group (P=0.099, 95% confidence interval for difference in cure 4.7% to 21.3%). More detailed results are given on bmj.com

Secondary outcome measures
Both groups showed significant changes in most urinary symptoms at six months, although there was no significant difference between the vaginal tape procedure and colposuspension for any of these items. Only 63 (36%) patients in the vaginal tape arm and 48 (28%) in the colposuspension arm reported no leakage under any circumstance after surgery; the number of women reporting cure of stress leakage was 103 (59%) and 90 (53%), respectively.

The responses for the SF-36 were combined and transformed to generate eight health dimensions, with a potential score of 0 to 100 (table 2).¹⁶ Higher scores indicate better perceived health. Significant differences were seen at six weeks in emotional, social, and physical function and vitality, with the colposuspension group having lower scores than the vaginal tape group. By six months, scores in the colposuspension group had shown significantly less improvement in emotional and social functioning, vitality, and mental health than those in the tape group.

	Discussion

Top Abstract Introduction Methods Results Discussion References

Blinding may be possible in a trial of surgery for stress incontinence, as shown in a trial of laparoscopic versus open colposuspension.¹⁷ We believed that patients in our trial would be aware of their allocated treatment owing to differences between the procedures in incision, anaesthesia, and catheterisation. Staff undertaking postoperative assessments were not blinded to the procedure for logistical reasons, and will have been vulnerable to observer bias.

Surgery and anaesthesia for the vaginal tape procedure was standardised and was performed as described by Ulmsten.¹⁰ Although colposuspension was performed according to that used by the units it was standardised for numbers of suspensory sutures, suture material, and postoperative catheterisation. The investigators all had expertise in continence surgery, but were from a mixed background including gynaecologists, urogynaecologists, and urologists and represented both general hospitals and university teaching hospitals. All surgeons had undergone similar training in the vaginal tape procedure, although they had variable experience before recruitment. The group therefore reflects the current practice in the United Kingdom and Eire and as such increases the external validity of the study.

The number of patients recruited fell short of the target determined by a sample size calculation owing to limitations of resources and time. Although differences between the procedures for cure of stress incontinence were not shown, the numbers were not sufficient to achieve the power required to assume equivalence. Given that the objective cure for colposuspension was lower than expected from previous literature, the numbers recruited would give only 50% power to detect a 10% difference or 80% power to detect a 15% difference in cure rates.

No differences were shown between the vaginal tape procedure and colposuspension for objective cure of urodynamic stress incontinence, as measured by the pad test and urodynamic testing. Objective cure rates are lower than those previously reported. This may be due to the stricter definition of cure in this study. There has been little consistency in the objective outcome measures used in previous studies, and cure rates are often quoted for single tests. The cure rates for both procedures as measured by single urodynamic tests range from 74% to 84% and are comparable to those reported in previous series. Most reports of incontinence surgery give no information on non-attenders or the handling of missing data. They have by default assumed that non-attenders are equivalent to attenders. We have considered non-attenders or patients with missing data as treatment failures.

Long term follow up is needed to assess the continuing success of the two procedures and to provide further data on the development of prolapse and tape erosion; follow up to five years is planned.

	Acknowledgments

We thank the patients and technical, secretarial, nursing, and medical staff of the participating hospitals, the monitoring staff of Ethicon, James Browning as the sponsor medical advisor to June 2000, Marjory Willins (trial manager), Jane Gibson (trial administration), Ailie Smith (quality assurance), and Peter Wilkinson (statistical advice and analysis).

Contributors: See bmj.com

	Footnotes

Competing interests: KW was supported by a grant from Ethicon, which also provided materials and additional support to collaborating centres. PH and KW have been reimbursed by Ethicon for expenses associated with attending conferences where this, and related work, has been presented.

The full version of this article appears on bmj.com

	References

Top Abstract Introduction Methods Results Discussion References

1.	Brocklehurst JC. Urinary incontinence in the communityanalysis of a MORI poll. BMJ 1993; 306: 832-834.
2.	Keane DP, Eckford SD, Shepherd AM, Abrams P. Referral patterns and diagnoses in women attending a urodynamic unit. BMJ 1992; 305: 808.
3.	Abrams P, Cardozo L, Fall M, Griffiths D, Rosier P, Ulmsten U, et al. The standardisation of terminology of lower urinary tract function. Neurourol Urodynamics 2002; 21: 167-178[CrossRef][ISI][Medline].
4.	Bo K, Talseth T, Holme I. Single blind, randomised controlled trial of pelvic floor exercises, electrical stimulation, vaginal cones, and no treatment in management of genuine stress incontinence in women. BMJ 1999; 318: 487-493[Abstract/Free Full Text].
5.	Jarvis GJ. Surgery for genuine stress incontinence. Brit J Obstet Gynaecol 1994; 101: 371-374[ISI][Medline].
6.	Black NA, Downs SH. The effectiveness of surgery for stress incontinence in women: a systematic review. Brit J Urol 1996; 78: 497-510[ISI][Medline].
7.	Black N, Griffiths J, Pope C, Bowling A, Abel P. Impact of surgery for stress incontinence on morbidity: cohort study. BMJ 1997; 315: 1493-1502[Abstract/Free Full Text].
8.	Galloway N, Davies N, Stephenson T. The complications of colposuspension. Brit J Urol 1987; 60: 122-124[Medline].
9.	Eriksen B, Hagen B, Eik-Nes S, Molne K, Mjolnerod D, Romslo I. Long-term effectiveness of the Burch colposuspension in female urinary stress incontinence. Acta Obstet Gynecol Scand 1990; 69: 45-50[Medline].
10.	Ulmsten U, Henriksson L, Johnson P, Varhos G. An ambulatory surgical procedure under local anesthesia for treatment of female urinary incontinence. Int Urogynecol J Pelvic Floor Dysfunc 1996; 7: 81-86.
11.	Nilsson CG. The tension free vaginal tape procedure (TVT) for treatment of female urinary incontinence. A minimal invasive surgical procedure. Acta Obstet Gynecol Scand Suppl 1998; 168: 34-37[Medline].
12.	Ulmsten U, Falconer C, Johnson P, Jomaa M, Lanner L, Nilsson CG, et al. A multicenter study of tension-free vaginal tape (TVT) for surgical treatment of stress urinary incontinence. Int Urogynec J Pelvic Floor Dysfunc 1998; 9: 210-213.
13.	Hilton P, Stanton SL. Urethral pressure measurement by microtransducer: the results in symptom-free women and in those with genuine stress incontinence. Brit J Obstet Gynaecol 1983; 90: 919-933[ISI][Medline].
14.	Jenkinson C, Coulter A, Wright L. Short form 36 (SF36) health survey questionnaire: normative data for adults of working age. BMJ 1993; 306: 1437-1440.
15.	Jackson S, Donovan J, Brookes S, Eckford S, Swithinbank L, Abrams P. The Bristol female lower urinary tract symptoms questionnaire: development and psychometric testing. Brit J Urol 1996; 77: 805-812[ISI][Medline].
16.	Jenkinson C, Layte R, Wright L, Coulter A. The UK SF-36: an analysis and interpretation manual. Oxford: Health Services Research Unit, University of Oxford, 1996.
17.	Carey M, Rosamilia A, Maher C, Cornish A, Murray C, Ugoni A. Laparoscopic versus open colposuspension: a prospective multicentre randomised single-blind comparison. Neurourol Urodynamics 2000; 19: 389-390.

(Accepted 15 May 2002)