Urethral pressure measurement in stress incontinence: does it help?

Transcription

1 Int Urol Nephrol (2009) 41: DOI /s UROLOGY - ORIGINAL PAPER Urethral pressure measurement in stress incontinence: does it help? Bassem S. Wadie Æ Ahmed S. El-Hefnawy Received: 28 October 2008 / Accepted: 10 November 2008 / Published online: 2 December 2008 Ó Springer Science+Business Media, B.V Abstract Introduction and objectives The resting urethral pressure profile (UPP), used for the assessment of women with stress incontinence, is routine in many urodynamic units. It is time- and effort-consuming, and its diagnostic value is controversial, as well as its value in the prediction of outcome of anti-incontinence surgery. Herein, we assessed its value in the prediction of the outcome of surgery. Patients and methods Sixty women were randomized to fascial sling or TVT. Urodynamics were performed preoperatively, 6 months and annually thereafter. After filling and voiding cystometry, resting UPP was performed while sitting. Automated catheter pulling, at a rate of 1 mm/s, was adopted. Averaged readings were obtained. Comparison of maximum urethral closure pressure (MUCP) in success and failure, as well as in sling and TVT, was performed, utilizing ANOVA. Results Preoperative MUCP and functional urethral length (FUL) were 72.9 ± 27.9 cmh2o and 2.4 ± 0.7 cm. At last follow-up, they were 71.1 ± 20.7 cmh2o and 2.7 ± 0.7 cm, respectively. The differences between sling and TVT as regards value of MUCP and FUL were not significant. The relationship of the outcome of surgery and UPP B. S. Wadie A. S. El-Hefnawy (&) Female Urology and Voiding Dysfunction, Urology and Nephrology Center, Mansoura, Egypt a_s_elhefnawy@yahoo.com parameters showed no statistical difference. No significant effect was shown for the success of surgery, duration of follow-up, and interaction of outcome and time over MUCP (P = 0.82, 0.56 and 0.69, respectively) or FUL (P = 0.82, 0.11 and 0.67, respectively). Conclusion The routine use of resting UPP has no added value in terms of the prediction of success of incontinence surgery. It does not help with follow-up and adds to the time and cost of the examination. Keywords Urethral pressure Stress Incontinence Outcome Surgery Abbreviations UPP Urethral pressure profile SUI Stress urinary incontinence ICS International continence Society LPP Leak point pressure MUCP Maximum urethral closure pressure FUL Functional urethral length TVT Tension-free vaginal tape ANOVA Analysis of variance BOO Bladder outlet obstruction Introduction The urethral pressure profile (UPP) has long been utilized in the evaluation of women with urodynamic stress urinary incontinence (SUI) [1]. According to

2 492 Int Urol Nephrol (2009) 41: the ICS, two types of UPP are in common use: resting and stress UPP [2]. Inherent pitfalls of UPP have been drawbacks in its application, and accordingly its use in the assessment of female urinary incontinence has been in dispute [3]. Nevertheless, resting UPP is a routine preoperative test in many urodynamic laboratories, including ours. As a part of a randomized controlled trial, patients were allocated to either pubovaginal sling or TVT. All of them had pre- and postoperative complete urodynamic testing, including UPP. In view of the time needed to have three repetitions for the test, in order to have an averaged reading, and considering the inconvenience the patient feels as a result of multiple catheter insertions, we retrospectively evaluated the value of UPP in the prediction of the outcome of anti-incontinence surgery. 5 cm from the distal one, used for urethral pressure measurement. Rate of catheter pulling, using an automatic puller, was 1 mm/s, and the rate of urethral infusion was 2 ml/min. Curves automatically obtained were manually revised so that the beginning and the end of the pressure profile were accurately located. Surgical treatment for SUI was either TVT (29 patients) or pubovaginal rectus fascia sling (31 patients). The primary outcome measure was cure of SUI and was defined as complete dryness with no usage of pads, anti-incontinence surgery response score of zero and negative stress test, while failure was defined as visible leakage on a stress test and a total score of six. According to this definition, five cases were considered failures at last follow-up (6 48 months, mean: 9.15 months). Patients and methods Sixty women, with a mean age of 45.9 years (range: years), were included in this analysis. All patients had SUI as a leading symptom. All of them had complete physical and limited neuro-urologic examinations (knee jerk, bulbocavernosus reflex and the integrity of anal sphincter tone). Women with high-grade cystocele (grade 3 or more, according to Baden and Walker), associated urethral and/or bladder pathology, or recent surgery for SUI (within the preceding 6 months) were excluded from the study. Urodynamic examination included filling cystometry. Medium fill water cystometry (50 ml/min) using a dual-lumen 8-F catheter was carried out. Compliance was calculated at maximum cystometric capacity/detrusor pressure at maximum capacity. At 200-ml bladder volume, abdominal LPP was tested. In case no leakage was noticed, the test was repeated again at 300-ml bladder volume. At the end of filling phase, the patient was allowed to void in the sitting position in privacy. The technique, definitions and units of the urodynamic measurement conform to the standards proposed by the International Continence Society [4]. UPP was performed at half-full bladder with the patient in a semi-sitting position. An eight dual-lumen waterfilled catheter was utilized, with a terminal hole used for bladder pressure measurement and a side hole, Statistical method Changes in maximum urethral closure pressure (MUCP) and functional urethral length (FUL) were studied pre- as well as postoperative, when urodynamics was performed (at last follow-up), using oneway ANOVA. The changes in the two parameters in patients with success or failure outcome were also studied, using repeated measures ANOVA. The effect of the sling type on the change of the urethral pressure parameters was also studied, using repeated measures ANOVA. Results Overall, mean preoperative MUCP and FUL were 72.9 ± 27.9 cmh2o and 2.4 ± 0.7 cm, respectively. At last follow-up (mean: 9.15 months), MUCP and FUL were 71.1 ± 20.7 cmh2o and 2.7 ± 0.7 cm, respectively. MUCP and FUL at baseline and at last follow-up in those who had a successful outcome and those who were considered failure are depicted in Table 1. It is noted that MUCP was significantly higher in those with successful outcome than in those who failed surgery at last follow-up. The presence of two types of surgery is a potential confounding factor, so a comparison of MUCP and FUL among patients receiving the two types of surgery was made. Table 2 demonstrates the effect of

3 Int Urol Nephrol (2009) 41: Table 1 Difference between success (n = 55) and failure (n = 5) at baseline and last follow-up Preoperative Postoperative Success Failure P value Success Failure P value MUCP (mean ± SD) 72.8 ± ± ± ± * FUL (mean ± SD) 2.33 ± ± ± ± * P is significant, using one-way ANOVA Table 2 Differences between the fascial sling and TVT, as regards MUCP and FUL, at baseline and postoperative Baseline Postoperative TVT Sling P value TVT Sling P value MUCP 67.8 ± ± ± ± FUL 2.3 ± ± ± ± P calculated using one-way ANOVA the type of surgery (fascial sling or TVT) on MUCP and FUL. No significant differences as regards MUCP and FUL were noticed between patients who received sling as compared to those who received TVT. Only postoperative MUCP was found to be higher among the TVT group; however, the difference did not amount to significance (P = 0.05). The outcome of surgery (success versus failure) was not associated with a statistically significant difference of UPP parameters (MUCP and FUL). The same applied to the effect of time, interaction of time and outcome on these parameters. Table 3 displays the effect of outcome (success or failure), time and interaction of time and outcome on MUCP and FUL. There was no significant effect for the success of surgery, the duration of follow-up and the interaction of outcome and time over MUCP (P = 0.82, 0.56 and 0.69, respectively) or FUL (P = 0.82, 0.11 and 0.67, respectively). Table 3 Effect of the outcome, time and interaction of time and outcome on the changes in MUCP and FUL Outcome (success versus failure) Effect of time MUCP FUL Using repeated measures-anova Interaction of outcome and time Discussion The use of UPP in the evaluation of women with SUI has been a time-honored practice. Based on previous reports, MUCP and FUL were found to be useful parameters as regards evaluation of incontinence. Observations of Susset and Plante suggested that measurement of functional urethral length among other parameters allows a more accurate analysis of urethral resistance [5]. It has long been perceived that maximum urethral closure pressure has the highest potential for diagnostic accuracy of sphincteric competence, as suggested by Awad et al. [6]. In another study carried out on 147 women, 85 of them had stress incontinence, and 42 were urologically free. Hendriksson et al. [7] found that both MUCP and FUL decreased significantly in incontinent women, as well as with the advent of older age. However, they could not come up with a cutoff point below which a woman could be considered incontinent for either MUCP of FUL. Many potential shortcomings have been associated with UPP. First is the lack of a standardized nomogram for normal/abnormal values of MUCP and FUL in women. The study of Hendriksson and associates is one of many trials that embarked on this mission. Second, the technique is highly dependent on changeable factors, such as the rate of withdrawal of the catheter during the test, whether this is achieved through an automated puller or manually, and the rate of water infusion (in case of water-filled

4 494 Int Urol Nephrol (2009) 41: catheters): rapid flow is associated with false high and slow flow is associated with false low readings. This, together with automatic calculations, is made by most commercially available software used in urodynamic equipment, making the interpretation of the results of UPP a daunting task. A question remains as to how relevant the results of UPP are to the outcome of surgery in SUI. This question is intuitively important because SUI is a surgically treated condition, and tools that can predict the outcome of surgery are valued most. However, as early as 1979, Abrams [3] disputed the value of UPP in SUI. In another study by Versi [8], he demonstrated that the UPP is not an accurate test for diagnosis of stress incontinence. Another report by Lose [9] showed that UPP parameters are of limited value in the assessment of urethral sphincter function. He concluded that these parameters do not (1) discriminate stress incontinence from other disorders, (2) provide a measure of the severity of the condition and (3) return to normal after successful incontinence. The last point elucidated by Lose in his study was revisited many times thereafter. Hilton [10] randomized 20 women for sling or Stamey s needle suspension and performed UPP before and after surgery. He found no significant changes in the resting urethral pressure profile. Outcome of TVT as a surgical treatment of SUI was associated with a significant increase in these two parameters. Such a finding was further emphasized by the work of Koelle and associates [11]. In their study, 80 women with SUI were treated by TVT. UPP was performed before, 6 and 12 months after surgery. There was a reported 66% cure rate (including both objective and subjective) and 20% objective cure, but still with complaining about incontinence. They found no significant increase in the MUCP at rest. The baseline median was 44 cmh2o, decreasing to 40 cmh2o at 3 months and 38 cmh2o at 6 months. In another study, Lo et al. [12] treated 41 women with recurrent SUI with TVT. There was no significant increase in static and dynamic UPP when comparing pre- to postoperative studies. It is apparent, based on our results, that cure accomplished by surgery and defined in the most strict way (both subjective and objective) was not associated with a significant increase of MUCP and FUL, and those who failed surgery did not have significantly lower values than those who had success. Although Table 1 demonstrates a significant difference between those who were cured and those who failed as regards MUCP only (72.8 ± 18.9 vs ± 33.1, P = 0.03), when the effect of outcome (success versus failure) on MUCP and FUL was considered, the difference was found to be insignificant. This also applied to the effect of time and interaction of outcome/time on MUCP and FUL. This study also shows that technical differences in the incontinence surgery, i.e., using autologous fascial sling or synthetic polypropylene tape, did not translate into changes in resting UPP parameters. The differences between the two techniques as regards MUCP and FUL were insignificant at both baseline and last follow-up. Conclusion The routine use of resting UPP has no benefit in terms of prediction of success of incontinence surgery. It does not help with follow-up and adds to the time and cost of the examination. Different surgical techniques are not associated with difference in terms of MUCP or FUL. In a further trial on SUI, we plan to stop applying UPP as a routine test. References 1. Bates P, Bradley W, Melchior H, Rowan D, Sterling A, Hald T (1976) First report on the standardization of terminology of lower urinary tract function. Br J Urol 48: Abrams P, Blaivas J, Stanton S, Andersen JT (1988) The standardization of terminology of lower urinary tract function. Scand J Urol Nephrol Suppl 114: Abrams P (1979) Perfusion urethral profilometry. Urol Clin North Am 6: Abrams P, Cardozo L, Fall M, Griffiths D, Rosier P, Ulmsten U et al (2002) The standardisation of terminology of lower urinary tract function: report from the Standardisation Subcommittee of the International Continence Society. Neurourol Urodyn 21: Susset J, Plante P (1980) Studies of female urethral pressure profile. Part II. Urethral pressure profile in female incontinence. J Urol (1): Awad SA, Bryniak SR, Lowe PJ, Bruce AW, Twiddy DA (1978) Urethral pressure profile in female stress incontinence. J Urol 120(4): Hendriksson L, Andersson KE, Ulmsten U (1979) The urethral pressure profiles in continent and stress-incontinent women. Scand J Urol Nephrol 13(1):5 10

5 Int Urol Nephrol (2009) 41: Versi E (1990) Discriminant analysis of urethral pressure profilometry data for the diagnosis of genuine stress incontinence. Br J Obstet Gynaecol 97(3): Lose G (1997) Urethral pressure measurement. Acta Obstet Gynecol Scand Suppl 166: Hilton P (1989) A clinical and urodynamic study comparing the Stamey bladder neck suspension and suburethral sling procedures in the treatment of genuine stress incontinence. Br J Obstet Gynaecol 96(2): Koelle D, Windisch J, Doerfler D, Marth C, Kropshofer S (2006) Effect of tension-free vaginal tape operation on urethral closure function. Urology 67(3): doi: /j.urology Lo TS, Horng SG, Chang CL, Huang HJ, Tseng LH, Liang CC (2002) Tension-free vaginal tape procedure after previous failure in incontinence surgery. Urology 60(1): doi: /s (02)