Department of Obstetrics and Gynecology, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile

Transcription

1 Efficacy and Safety of Tension-Free Vaginal Tape Compared With Transobturator Tape Among Obese Women With Stress Urinary Incontinence: A Retrospective Cohort Study Victor Miranda, MD, MSc, 1,2 Rodrigo Pineda, MD, 2 Danny Lovatsis, MD, MSc, 1 May Alarab, MD, 1 Harold Drutz, MD 1 1 Mount Sinai Hospital, Department of Obstetrics and Gynecology, University of Toronto, Toronto ON 2 Department of Obstetrics and Gynecology, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile Abstract Objective: To determine the efficacy and safety of tension-free vaginal tape (TVT) compared with transobturator tape (TOT) in obese women with stress urinary incontinence (SUI). Methods: We performed a retrospective chart review of patients who underwent insertion of TVT or TOT for stress urinary incontinence between January 2003 and October Women were excluded if they had had previous surgery for SUI or had a diagnosis of intrinsic sphincter deficiency. Results: One hundred eighty obese women (BMI > 30 kg/m 2 ) with SUI and with follow-up for at least one year were identified (90 had TVT and 90 had TOT). The rates of success on the objective criteria were 91% for the TVT group and 88% for the TOT group (P = 0.46) and 87% versus 80% (P = 0.23) on subjective assessment. Conclusion: Our retrospective cohort study demonstrated similar rates of cure for obese women with SUI who underwent insertion of TVT and TOT. Résumé Objectif : Déterminer l efficacité et l innocuité de la bandelette vaginale sans tension (TVT), par comparaison avec la bandelette transobturatrice (TOT), chez les femmes obèses qui présentent une incontinence urinaire à l effort (IUE). Méthodes : Nous avons mené une analyse rétrospective des dossiers de patientes ayant subi l insertion d une TVT ou d une TOT en vue de contrer une incontinence urinaire à l effort entre janvier 2003 et octobre Les femmes qui avaient déjà Key Words: Midurethral slings, obesity, stress urinary incontinence Competing Interests: None declared. Received on January 31, 2012 Accepted on March 16, 2012 subi une chirurgie visant l IUE ou qui ont reçu un diagnostic d insuffisance sphinctérienne intrinsèque ont été exclues. Résultats : Cent quatre-vingt femmes obèses (IMC > 30 kg/m 2 ) présentant une IUE et ayant fait l objet d un suivi pendant au moins un an ont été identifiées (90 d entre elles ont subi une intervention par TVT et les 90 autres ont subi une intervention par TOT). Les taux de réussite en fonction des critères objectifs ont été de 91 % au sein du groupe TVT et de 88 % au sein du groupe TOT (P = 0,46), tandis que ces taux ont été de 87 % et de 80 %, respectivement (P = 0,23), à la suite de l évaluation subjective. Conclusion : Notre étude de cohorte rétrospective a démontré des taux semblables de guérison chez les femmes obèses présentant une IUE, qu elles aient subi l insertion d une TVT ou d une TOT. J Obstet Gynaecol Can 2012;34(8): INTRODUCTION Obesity has become an epidemic problem worldwide. In Canada the proportion of obese women has been estimated as approximately 23.3% of the adult population. 1 Stress urinary incontinence affects from 10% to 40% of women and is associated with multiple risk factors and contributing variables; obesity has been strongly associated with an increased risk of developing urinary incontinence, as well as a higher grade of severity. 2,3 A strong association between intra-abdominal pressure and body mass index has been demonstrated. 4 Theoretically, increased intra-abdominal pressure results in increased intravesical pressure, which may contribute to the development of SUI. 4 6 Although weight loss reduces the frequency of episodes of self-reported urinary incontinence among overweight AUGUST JOGC AOÛT

2 and obese women, 7 definitive treatment may be best obtained through surgical intervention. Surgical insertion of tension-free vaginal tape and transobturator tape are the most common procedures used to treat SUI, and these two procedures have been shown to have an equivalent rate of cure (> 77%) and low rates of complication in a general population. 8 Some studies have assessed cure and complications among obese women who had undergone TVT, and have shown results similar to those in a non-obese population There are no studies comparing the results of TOT between an obese and a non-obese population. One prospective study compared TVT and TOT in obese women, but it was underpowered to detect a difference between the treatments; furthermore, there was no information about risk adjustment for potential confounders such as intrinsic sphincter deficiency and mixed urinary incontinence. 13 The objective of this retrospective cohort study was to compare the efficacy and safety of TVT and TOT among obese patients with the diagnosis of SUI. METHODS We performed a retrospective chart review of patients who underwent insertion of TVT or TOT for stress urinary incontinence between January 2003 and October Patients were identified from the surgical case list at the Urogynaecology Unit, Mount Sinai Hospital, Toronto. For purposes of this study, obesity was defined as a body mass index 30 kg/m 2. Data on menopausal status, use of postmenopausal hormone therapy, use of anticholinergic medications, intraoperative complications, diagnosis and quantification of pelvic organ prolapse (using the Baden Walker system 14 ), concomitant surgery for prolapse, previous surgical procedures for SUI and/or prolapse, duration of follow-up, and preoperative and postoperative urodynamic parameters were collected. Cure, defined as having no postoperative stress urinary incontinence, was assessed subjectively and objectively. Objective cure was determined by a cough stress test with a comfortable full bladder during follow-up pelvic examination in our out-patient clinic (with spontaneous ABBREVIATIONS SUI stress urinary incontinence TOT transobturator tape TVT tension-free vaginal tape filling of the bladder rather than retrograde bladder filling). Subjective cure was recorded during the postoperative follow-up as the absence of any leaking with coughing, laughing, sneezing, or exertion. Postoperative urodynamic studies were not routinely performed. Symptoms of overactive bladder (urgency, frequency, nocturia, and urge incontinence) were determined by subjective report. Every patient was asked to rank her grade of satisfaction after surgery using the following descriptors: worse than before the surgery, same as before the surgery, or better than before the surgery. Subjects were excluded if there was less than a one-year period of follow-up, if they had had previous surgery for SUI, or if there was a low-pressure urethra (maximum urethral closure pressure of 20 mm H 2 O). In this obese population who underwent TVT and TOT insertion, the primary outcome measure was cure of stress urinary incontinence. Secondary outcome measures included intraoperative and postoperative complications. Chi-square was used for discrete variables and t test for continuous variables. An a priori power calculation demonstrated that a total of 178 women would be required to detect a difference of 20% in cure of stress urinary incontinence, with a power of 80% using a 2-tailed test and with an alpha error of Ethics approval was obtained from the Mount Sinai Hospital research ethics board. RESULTS A total of 732 midurethral sling operations were performed between January 1, 2003, and October 31, From this total, 231 women had a BMI > 30 kg/m 2 (30%), and 180 patients met our inclusion criteria. Baseline data for age, parity, menopausal status, urodynamic characteristics, use of postmenopausal hormone therapy, and previous surgery for pelvic organ prolapse are summarized in Table 1. There was a statistically significant difference in BMI and use of postmenopausal hormone therapy between groups. Women in the TVT group had a higher BMI (33.7 kg/m 2 ) than women in the TOT group (32.7 kg/m 2 ). There was no statistically significant difference between slings in the subgroup of women with a BMI over 35 kg/m 2. There were no statistically significant differences in the severity of anterior and posterior vaginal wall prolapse between groups. More women had a vaginal central defect in the TOT group (33) than in the TVT group (29) (P = 0.035). 756 AUGUST JOGC AOÛT 2012

3 Efficacy and Safety of Tension-Free Vaginal Tape Compared With Transobturator Tape Among Obese Women Table 1. Baseline characteristics of study participants Patient characteristics TVT (n = 90) TOT (n = 90) P Mean age (SD), years 57.8 (11.8) 58.6 (12.9) 0.59 Mean BMI (SD), kg/m (3.7) 32.7 (3.2) 0.04 BMI > 35 kg/m 2, 28 (31) 19 (21) 0.12 Mean number of vaginal deliveries (SD) 2.3 (1.4) 2 (1.3) 0.20 Postmenopausal, 59 (66) 63 (70) 0.45 Use of postmenopausal hormone therapy, 26 (29) 38 (42) 0.04 Mixed incontinence, 64 (71) 52 (58) 0.80 Use of anticholinergic agents, 7 (8) 7 (8) 0.41 Previous surgery for prolapse, 24 (27) 27 (30) 0.62 Mean maximum urethral closure pressure (SD), cm H 2 O 49.5 (23.9) 50.9 (25.9) 0.72 Mean post-void residual (SD), ml 39.7 (56.4) 51.4 (62.8) 0.19 Mean maximum cystometric capacity (SD), ml (144.6) (134.8) 0.39 Detrusor instability, 8 (9) 5 (6) 0.38 Table 2. Intraoperative and postoperative complications Intra/postoperative complications TVT (n = 90) TOT (n = 90) P Bladder perforation, 4 (4.4) Postoperative urge incontinence, 11 (12) 9 (10) 0.82 Mean post-void residual (SD), ml 45.7 (77.3) 62.6 (87.2) 0.21 Surgical data are summarized in Table 2. Similar numbers of women had concomitant surgery for pelvic organ prolapse, 55 women (61%) in the TVT group and 60 women (67%) in the TOT group (P = 0.43). The rates of high uterosacral vault suspension (TVT: 8 and TOT: 0, P = 0.003) and sacrospinous vault suspension (TVT: 5 and TOT: 19, P = 0.002) were statistically significantly different between groups. On the other hand, the rates of hysterectomy, cystocele repair and rectocele repair, sacrocolpopexy, and vaginal mesh procedure were similar between groups. Four bladder perforations occurred in the TVT group (4.4%) and none in the TOT group. No cases of mesh erosion were identified. The rate of postoperative voiding dysfunction (defined as post-void residual 200 ml) was similar between the groups at one-year follow-up. None of the women in this cohort experienced a major complication. The objective and subjective outcomes in each group are summarized in Table 3. Even though fewer obese women were objectively and subjectively cured in the TOT group than in the TVT group, this difference was not statistically significant. The rates of success for the objective criteria were 91% for the TVT group and 88% for the TOT group; the rates of success for subjective assessment were 87% in the TVT group and 80% in the TOT group. When asked about improvement in SUI symptoms since surgery, the great majority of women (TVT = 89% and TOT = 81%) thought that they were better, and this result was similar between the two groups. The results in women with a BMI over 35 kg/m 2 (n = 48; 27%) are summarized in Table 4. When they were compared with the results of women who had a BMI of 30 to 35, there were no statistically significant differences in objective (P = 0.59) and subjective (P = 0.58) failure. A greater number of women in the TOT group than in the TVT group who were morbidly obese (BMI > 35 kg/m 2 ) met the criteria of objective and subjective failure, but the difference was not statistically significant. Four morbidly obese women in the TOT group and two in the TVT group felt that surgery for SUI did not help them at all; this difference also was not significant. We performed risk adjustment for other possible confounders such as previous surgery for SUI and intrinsic sphincter deficiency; other potential confounding variables AUGUST JOGC AOÛT

4 Table 3. Outcomes in obese patients Outcome TVT (n = 90) TOT (n = 90) P Objective failure 8 (9) 11 (12) 0.46 Subjective failure 12 (13) 18 (20) 0.23 No change 9 (10) 17 (19) 0.08 Subjective improvement 81 (90) 73 (81) 0.09 Table 4. Outcomes in morbidly obese patients (subgroup BMI > 35 kg/m 2 ) Outcome TVT (n = 28) TOT (n = 19) P Objective failure 1 (3.6) 3 (15) 0.28 Subjective failure 4 (14) 5 (26) 0.45 No change 2 (7.2) 4 (21) 0.20 Subjective improvement 26 (93) 15 (79) 0.21 such as age over 60 years (P = 0.09), mixed urinary incontinence (P = 0.8), and concomitant surgery for pelvic organ prolapse (P = 0.43) were similar between groups. The low number of positive outcomes (objective SUI) prevented the use of a logistic regression approach to deal with potential confounders. DISCUSSION This retrospective cohort study demonstrated similar rates of objective and subjective cure between two of the most commonly performed midurethral sling procedures in obese women with stress urinary incontinence. In addition, patients satisfaction with the result of both procedures was similar between groups. The rates of complication differed between groups: the number of bladder perforations was higher among women who underwent TVT than among those who underwent TOT, but otherwise there were no differences between the groups in postoperative voiding dysfunction and mesh erosion. In addition, TVT and TOT demonstrated similar rates of cure, both objectively and subjectively, among morbidly obese women. The rates of cure for morbidly obese women (BMI > 35 kg/m 2 ) were similar to those in obese women (BMI 30 kg/m 2 to 35 kg/m 2 ). Our rates of treatment success in obese women according to the objective and subjective criteria were similar to the rates reported for the general population. 15 However, our subjective rate of success was lower than our objective rate. This finding correlated with previous studies that have shown a similar tendency. 8,16,17 Since the subjective outcome may be a more important measure for women, having this information as an outcome is a strength of our study. Of note, we did not use a validated scale to measure quality of life or patient satisfaction. The higher number of bladder perforations found among women who underwent TVT is not surprising and has been described elsewhere. 8 The rate of postoperative voiding dysfunction was similar between groups. This finding is not consistent with previous studies, which report higher rates of postoperative voiding dysfunction after a TVT procedure than after a TOT procedure. 8,18 The reason for this could be that the study was underpowered to detect any difference in postoperative voiding dysfunction between the two slings. Few studies have explored the results of midurethral sling procedures in morbidly obese women. 9,12 Lovatsis et al. 9 did not demonstrate a difference in rate of cure with use of TVT in women with BMI > 35 kg/m 2 and in non-obese women. However, Hellberg et al. 12 found a statistically significant difference in the rate of cure between patients with BMI < 25 kg/m 2 and those with BMI > 35 kg/m 2. Our study supports the findings of Lovatsis et al., because our rate of cure was similar in morbidly obese women and in women with a BMI between 30 kg/m 2 and 35 kg/m 2. Each midurethral sling procedure had a similar rate of cure in this subgroup of patients. However, we did not observe a difference in the rate of cure for morbidly obese women; our study was not powered to detect a difference in this population. This study gives additional evidence that midurethral sling procedures are effective in this specific group of patients. 758 AUGUST JOGC AOÛT 2012

5 Efficacy and Safety of Tension-Free Vaginal Tape Compared With Transobturator Tape Among Obese Women The limitations of this study are its retrospective design and possible confounders such as the differences between groups in BMI and use of postmenopausal hormone therapy. In order to avoid these differences, a prospective, randomized trial should be considered. The strengths of this study include the adequate sample size and the complete data collection at one-year post surgery. CONCLUSION Obesity is associated with stress urinary incontinence. Our retrospective cohort study demonstrated similar rates of cure for obese women with SUI who underwent a TVT procedure and those who underwent a TOT procedure. The rates of success in this obese population are similar to the rates in the general population. Therefore, TVT and TOT procedures are equally effective in obese women with stress urinary incontinence who have not had a previous surgical procedure for SUI and who do not have intrinsic sphincter deficiency. A prospective randomized controlled study is needed to determine whether one surgical technique is superior to the other in this challenging population. REFERENCES 1. Tjepkema M. Adult obesity. Health Rep 2006;17(3): Melville JL, Katon W, Delaney K, Newton K. Urinary incontinence in US women: a population-based study. Arch Intern Med 2005;165: Waetjen LE, Liao S, Johnson WO, Sampselle CM, Sternfield B, Harlow SD, Factors associated with prevalent and incident urinary incontinence in a cohort of midlife women: a longitudinal analysis of data: study of women s health across the nation. Am J Epidemiol 2007;165: Noblett KL, Jensen JK, Ostergard DR. The relationship of body mass index to intra-abdominal pressure as measured by multichannel cystometry. Int Urogynecol J 1997;8: Cummings JM, Rodning CB. Urinary stress incontinence among obese women: review of pathophysiology therapy. Int Urogynecol J 2000;11: Dwyer PL, Lee ET, Hay DM. Obesity and urinary incontinence in women. Br J Obstet Gynaecol 1988;95: Subak LL, Wing R, Smith West D, Frankling F, Vittinghoff E, Creasman JM. Weight loss to treat urinary incontinence in overweight and obese women. N Engl J Med 2009;360: Richter HE, Albo M, Zyczynski H, Kenton K, Norton PA, Sirls LT. Retropubic versus transobturator midurethral slings for stress incontinence. N Engl J Med 2010;362: Lovatsis D, Gupta C, Dean E, Lee F. Tension-free vaginal tape procedure is an ideal treatment for obese patients. Am J Obstet Gynecol 2003;189:1601 4; discussion Rogers RG, Lebkuchner U, Kammerer-Doak DN, Thompson PK, Walters MD, Nygaard IE. Obesity and retropubic surgery for stress incontinence: is there really an increased risk of intraoperative complications? Am J Obstet Gynecol 2006;195: Killingsworth LB, Wheeler TL 2nd, Burgio KL, Martirosian TE, Redden DT, Richter HE. One-year outcomes of tension-free vaginal tape (TVT) mid-urethral slings in overweight and obese women. Int Urogynecol J 2009;20: Hellberg D, Holmgren C, Lanner L, Nilsson S. The very obese woman and the very old woman: tension-free vaginal tape for the treatment of stress urinary incontinence. Int Urogynecol J 2007;18: Rechberger T, Futyma K, Jankiewicz K, Adamiak A, Bogusiewicz M, Skorupski P. Body mass index does not influence the outcome of antiincontinence surgery among women whereas menopausal status and ageing do: a randomised trial. Int Urogynecol J Pelvic Floor Dysfunct 2010;21: Baden WF, Walker TA. Genesis of the vaginal profile: a correlated classification of vaginal relaxation. Clin Obstet Gynecol 1972;15: Ogah J, Cody JD, Rogerson L. Minimally invasive synthetic suburethral sling operations for stress urinary incontinence in women. Cochrane Database Syst Rev 2009;(4):CD Barber MD, Kleeman S, Karram MM, Paraiso MF, Walters MD, Vasavada S. Transobturator tape compared with tension-free vaginal tape for the treatment of stress urinary incontinence: a randomized controlled trial. Obstet Gynecol 2008;111: Albo ME, Richter H, Brubaker L, Norton P, Kraus S, Zimmern P. Burch colposuspension versus fascial sling to reduce urinary stress incontinence. N Engl J Med 2007;356: Novara G, Boscolo-Berto R, Secco S, Cavalleri S, Ficarra V, Artibani W. Complication rates of tension-free midurethral slings in the treatment of female stress urinary incontinence: a systematic review and meta-analysis of randomized controlled trials comparing tension-free midurethral tapes to other surgical procedures and different devices. Eur Urol 2008;53: AUGUST JOGC AOÛT