Sequential Assessment of Urodynamic Findings before and aftertension-free Vaginal Tape (TVT) Operation for Female Genuine Stress Incontinence

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1 European Urology European Urology 45 (2004) Sequential Assessment of Urodynamic Findings before and aftertension-free Vaginal Tape (TVT) Operation for Female Genuine Stress Incontinence Long-Yau Lin a, Bor-Ching Sheu b, Ho-Hsiung Lin b,* a Department of Obstetrics and Gynecology, Chung-Shan Medical University, Taichung, Taiwan b Department of Obstetrics and Gynecology, National Taiwan University College of Medicine and National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 100, Taiwan Accepted 6 November 2003 Published online 26 November 2003 Abstract Objectives: To sequentially compare the urodynamic findings in patients with genuine stress incontinence (GSI) before and after tension-free vaginal tape (TVT) operation. Patients and Methods: Between January 2001 and January 2002, 24 consecutive patients with GSI who completed multi-channel urodynamic study and 20-minute pad test before operation and at 3, 6, and 12 months after operation were enrolled. The sequential urodynamic findings of each case were compared and analyzed. Results: The mean age of the 24 patients was 60:6 10:7 years with the parity of 3:5 1:4. No statistical differences in voiding and storage functions before and after TVT operation were noted. In contrast, significant changes of stress urethral pressure profile (supp) including maximal urethral pressure, maximal urethral closure pressure, functional urethral length, urethral closure area and continence area were observed at 6 and 12 months postoperatively ( p < 0:03). The median pad weight test decreased from 72 g (range ) to 0 g 3 months after operation and remained unchanged at 6 and 12 months postoperatively. Conclusions: This prospective study demonstrates that TVT operation, if done properly, does not significantly impair voiding and storage functions. The significantly increased supp parameters may contribute, at least in part, to the high cure rate of TVT operation. # 2003 Elsevier B.V. All rights reserved. Keywords: Tension-free vaginal tape; TVT; Genuine stress incontinence; GSI; Urodynamic findings 1.Introduction The tension-free vaginal tape (TVT) operation for female stress urinary incontinence (SUI) was first introduced by Ulmsten in 1995 [1,2]. Although more than 150 kinds of operation for treating SUI have been reported [3], TVToperation has now become one of the most common operations for SUI due to its easy procedure, high success rate and low complication rate [4 10]. Only several reports, however, have discussed * Corresponding author. Tel. þ ; Fax: þ address: hhlin@ha.mc.ntu.edu.tw (H.-H. Lin). the responsible mechanism for the success of this treatment based on evaluation of urodynamic findings [11 13]. This study investigated the correlation between urodynamic findings and TVT operation by comparison of urodynamic findings in patients with genuine stress incontinence (GSI) before and at 3, 6, and 12 months after TVT operation. 2. Patients and methods Between January 2001 and January 2002, 32 female patients with GSI underwent TVT operation at the Department of Obstetrics and Gynecology of National Taiwan University Hospital. The TVT operation was done under spinal anesthesia in all cases, unlike the /$ see front matter # 2003 Elsevier B.V. All rights reserved. doi: /j.eururo

2 L.-Y. Lin et al. / European Urology 45 (2004) original TVT operation which used local anesthesia [1,2]. Except for the method of anesthesia, all the procedures conformed to those described in two previous reports [1,2]. Intra-operative determination of the tension of TVT was done as follows: (1) Absence of bladder perforation was confirmed by cystoscopy after insertion of two stainless needles through the patient s pubic skin. (2) Distilled water was infused into the patient s bladder until reaching the amount of strong desire, which was determined by the result of filling cystometry performed preoperatively. (3) TVT was then pulled through the two holes in the pubic skin, and the patient s position was changed from the lithotomy to sitting position. (4) Finally the fist of the operator was gently pressed against the full bladder of the patient to determine adjustment to optimal tension of TVT instead of based on patient s cough response, since the patient was under spinal anesthesia. Of the 32 patients, 24 completed urodynamic study and pad test 4 times before TVToperation, and at 3, 6, and 12 months after TVT operation. Of them, 2 (8%) had previously undergone surgery for GSI by Burch s colposuspension. These 24 patients were enrolled in this study and the ethical approval for the study was obtained from our research ethics committee in the hospital. In contrast, the remaining 8 patients who only completed postoperative urodynamic study once (n ¼ 2) and twice (n ¼ 6) were excluded from this study. A detailed patient history was recorded for each patient prior to physical examination and multi-channel urodynamic study. The urodynamic assessment included a 20-minute pad test [14,15], uroflowmetry, both filling (with a rate of 60 ml/min) and voiding cystometry with infusion of 35 8C distilled water, and stress urethral pressure profile with a comfortable and full amount of distilled water in the bladder. A two-way No. 9 flexible Foley catheter and a sidemounted transducer with a rate of 0.5 mm/s were used for stress urethral pressure profile (supp) [16]. The distal part of Foley was fixed at the perineum and inner thigh of the patient with adhesive tape to avoid catheter movement during cough. The 20-minute pad test was used to determine the amount of urine leakage. The average and maximal flow rates, voiding time, voiding amount and postvoid residual urine amount after catheterization were recorded. The presence of idiopathic detrusor overactivity, low bladder compliance, compliance at urgency in the unit of cmh 2 O, or decreased bladder capacity during filling cystometry was determined. Electromyography of the pelvic floor with perineal surface electrodes was also recorded while the presence of disco-ordination between the detrusor and the urethra was simultaneously observed. The presence of GSI, pressure equalization, maximal urethral pressure (MUP), maximal urethral closure pressure (MUCP), pressure transmission ratio (PTR) at MUP, functional urethral length (FUL), urethral closure area and continence area were also recorded. Voiding dysfunction was defined as low average and maximal flow rates (less than 8 and 15 ml/s, respectively), prolonged voiding time (more than 30 s), abnormally large postvoid residual urine amount (more than 50 ml) during uroflowmetry or low detrusor pressure (less than 25 cmh 2 O) at peak flow during voiding cystometry. Bladder storage dysfunction was defined based on the urodynamic findings as a decreased bladder capacity (less than 300 ml) at the point of strong desire, or the presence of idiopathic detrusor overactivity or low bladder compliance or GSI when a urine leak occurred following a cough during filling cystometry or supp [15]. The types of urinary incontinence were classified as idiopathic detrusor overactivity, GSI, or mixed GSI/idiopathic detrusor overactivity according to the definitions recommended by the International Continence Society (ICS) and Urodynamic Society [17 21]. A Life-Tech six-channel urodynamic monitor with computer analysis and urovision Urolab Janus System III (Houston, TX, USA) were used. All terminology used in this paper conforms to the standards recommended by the ICS or Urodynamic Society [17 21]. All procedures were performed by an experienced technician and the data were interpreted by a single observer to avoid bias. All data were expressed as mean 1 standard deviation unless otherwise indicated. The generalized linear estimation of repeated measurement with Bonferroni s multiple comparison test was used for statistical analysis. A p value of <0.05 was considered statistically significant. 3. Results The mean age of the 24 patients was 60:6 10:7 years with a mean parity of 3:5 1:4, and 79% (19/24) of the 24 patients were menopausal. The median pad weight test was 72 g with a range from 10 to 220 g prior to TVT operation, and became 0 g at 3 months after TVT operation, and remained unchanged at 6 and 12 months after TVT operation. The cure rate in these 24 patients after TVT operation was 100% by the dry pad test result. Only one (4%) of the 24 patients had bladder perforation intra-operatively and no complications such as great vessel injury, intestinal injury, retropubic bleeding requiring surgery or wound infection were noted. This patient received postoperative indwelling Foley catheter for 3 days and recovered smoothly thereafter. Data from the assessment of urodynamic parameters of voiding function in the 24 patients with GSI before and after TVT operation are shown in Table 1. The mean preoperative values of average flow rate, maximal flow rate, residual urine amount and the detrusor pressure at peak flow during voiding cystometry (P det;qmax ) showed no significant differences compared with values at 3, 6, and 12 months after TVT operation. The urodynamic parameters of bladder storage function in the 24 patients with GSI before and after TVT operation are shown in Table 2. The mean preoperative values of first sensation, first desire, strong desire, urgency and the compliance at urgency were not significantly different from values at 3, 6, and 12 months after TVT operation. In addition, idiopathic detrusor overactivity was not observed in any of the 24 patients after TVT operation during the follow-up period. These results demonstrated that TVT operation did not cause any impairment of storage function. After TVT operation, the urodynamic parameters of stress urethral pressure profile (supp) in the 24 patients with GSI showed significant improvements compared to preoperative values except for PTR at MUP (Table 3). Further analysis showed significant improvements in the urodynamic parameters of the supp at 6 months after TVT operation and persisting at 12 months after operation. In addition, 12 of the 24 patients with GSI showed positive urethral closure pressure in the

3 364 L.-Y. Lin et al. / European Urology 45 (2004) Table 1 Comparisons of urodynamic study variables of voiding function in the 24 patients with genuine stress incontinence before and after TVT operation Q avr (ml/s) Q max (ml/s) Residual urine (ml) P det;qmax (cmh 2 O) Values are given as mean S:D: Q avr : average flow rate; Q max : maximal flow rate; P det;qmax : maximal detrusor pressure during voiding cystometry. * By generalized linear estimation of repeated measurement with Bonferroni s multiple comparison test. Table 2 Comparisons of urodynamic study variables of storage function in the 24 patients with genuine stress incontinence before and after TVT operation FS (ml) FD (ml) SD (ml) Urg (ml) C urg (cmh 2 O) Values are given as mean S:D: FS: first sensation; FD: first desire; SD strong desire; Urg: urgency; C urg : compliance at urgency. * By generalized linear estimation of repeated measurement with Bonferroni s multiple comparison test. Table 3 Comparisons of urodynamic study variables of stress urethral pressure profile in the 24 patients with genuine stress incontinence before and after TVT operation MUP (cmh 2 O) MUCP (cmh 2 O) PTR at MUP (%) FUL (cm) Urethral closure area (cm 2 H 2 O) Continence area (cm 2 H 2 O) Values are given as mean S:D: MUP: maximal urethral pressure; MUCP: maximal urethral closure pressure; PTR: pressure transmission ratio; FUL: functional urethral length. * By generalized linear estimation of repeated measurement with Bonferroni s multiple compatison test. mid-urethral zone on supp at 6 and at 12 months after TVT operation, whereas the remaining 12 patients showed no such a change after TVT operation during 1-year follow-up. However, all the 24 patients were dry by pad test at 3 months after TVT operation and remained dry thereafter during 1-year follow-up. 4. Discussion In this study, sequential assessment of urodynamic parameters in women with GSI before and after TVT operation revealed dramatic improvement in supp parameters at 6 months after TVT operation, and that persisted at 12 months postoperatively. In contrast, the urodynamic parameters of uroflowmetry and filling and voiding cystometry were not significantly different before and after TVT operation. Although the results were based on relatively small number of patients, it was adequate to detect the difference after correction for multiple comparison at statistical power over 80% supp parameters and 60% for some urodynamic parameters. Lo et al. found that urodynamic parameters including supp showed no significant differences compared with preoperative values at 1 year after TVT operation [12]. In contrast, Wang found that MUP had

4 L.-Y. Lin et al. / European Urology 45 (2004) significantly increased after TVT operation [11]. The results of uroflowmetry, and filling and voiding cystometry in this present study are consistent with previous reports [11 13]. This study further demonstrated that the urodynamic parameters of supp, except for PTR at MUP, were significantly improved at 6 months after TVT operation and this improvement persisted at 12 months postoperatively. These findings are different from those in the previous reports [11,12]. The true reasons remain unclear but might be that all procedures in this study were performed by an experienced technician and the data were interpreted by a single observer to avoid bias. In the present study, sequential assessment of urodynamic parameters at pre-operation and 3, 6, and 12 months postoperatively provided detailed information about the changes of urodynamic findings after TVT operation. The urodynamic parameters of supp assessed in this study included urethral closure area and continence area besides MUP, MUCP and FUL (Table 3). This is the first study of TVT operation in GSI to report significant postoperative improvements of MUP, MUCP, FUL, urethral closure area and continence area. Although a previous study showed that MUP and FUL were not significantly increased at 1 year after TVT operation compared to preoperative values, the postoperative data still showed an increased trend in these parameters compared to preoperative data [12]. In contrast, Wang found that MUP had significantly increased after TVT operation [11]. Our findings showed that the benefit of increased MUP after TVT operation continued at 1-year follow-up. The mechanisms responsible for maintaining continence are complex and the mechanisms responsible for the effectiveness of TVT operation for urinary incontinence remain unclear. This study demonstrated that the urodynamic parameters of supp are significantly increased after TVT operation, indicating that urethral function including MUP, MUCP, FUL, urethral closure area and continence area is significantly improved after TVT operation. These findings suggest that the mechanism by which TVT operation restores continence may be through reinforcing the urethropelvic ligament, which is believed to be one of the most important features of mid-urethral support. This urethropelvic ligament, together with the continuity of the endopelvic fascia, anterior vaginal wall, arc tendineus of pelvic fascia and levator ani, forms the hammocklike structure against which the urethra is compressed to achieve continence [22]. Because the TVT is applied to the mid-urethra of patients with GSI, we investigated the pressure transmission ratio (PTR) at MUP. However, the results showed no significant differences between preoperative and postoperative data. One plausible explanation is that TVT itself provides no elevation of urethra, because this operation uses a tension-free tape. Kaum and Wolff found that more than half of the TVT operation cases had the position of TVT at the proximal third of the urethra instead of at the mid-urethra [23]. Nonetheless, the continence effect after TVT operation still results from the operation regardless of whether the TVT is placed precisely at the mid-urethra or not [23]. In conclusion, this prospective study demonstrated that the cure rate after TVT operation was 100%, and only 1 (4%) out of the 24 patients had bladder perforation. Such a high success rate and low complication rate are consistent with many previous reports [4 10]. TVT operation, if done properly, does not significantly impair the urodynamic parameters of voiding and storage functions. The significantly increased values of stress urethral pressure profile parameters may contribute, at least in part, to the high cure rate after TVT operation. Acknowledgements We thank Dr. Chi-Ling Chen, Ph.D., Institute of Epidemiology, National Taiwan University College of Public Health for her statistical assistance in this study. References [1] Ulmsten U, Petros P. Intravaginal slingplasty (IVS): an ambulatory surgical procedure for treatment of female urinary incontinence. Scand J Urol Nephrol 1995;29: [2] Ulmsten U. TVT tension-free vaginal tape: an ambulatory surgical procedure under local anesthesia for treatment of female stress urinary incontinence. Riv It Biol Med 1997;17(Suppl 4):S40 3. [3] Ostergard DR. The epochs and ethics of incontinence surgery: is the direction forward or backwards? Int Urogynecol J 2002;13: 1 3. [4] Ulmsten U, Falconer C, Johnson P, Jomma M, Lanner L, Nilsson CG, et al. A multicenter study of tension free vaginal tape (TVT) for surgical treatment of stress urinary incontinence. Int Urogynecol J 1998;9: [5] Ulmsten U, Johnson P, Rezapour M. A three-year follw-up of tension free vaginal tape for surgical treatment of female stress urinary incontinence. Brit J Obstet Gynaec 1999;106: [6] Meschia M, Buonaguidi A, Gattei U, Bernasconi F, Magatti F, Guercio E, et al. Tension free vaginal tape (TVT) for the treatment of stress incontinence: An Italian multicentre study. Int Urogynecol J 1999;10(Suppl):S1 9. [7] Nilsson CG, Kuuva N, Falconer C, Rezapour M, Ulmsten U. Long-term results of the tension-free vaginal tape (TVT) procedure

5 366 L.-Y. Lin et al. / European Urology 45 (2004) for surgical treatment of female stress urinary incontinence. Int Urogynecol J 2001;12(Suppl 2):S5 8. [8] Rezapour M, Ulmsten U. Tension-free vaginal tape (TVT) in women with recurrent stress urinary incontinence a long-term follow-up. Int Urogynecol J 2001;12(Suppl 2):S9 S11. [9] Rezapour M, Falconer C, Ulmsten U. Tension-free vaginal tape (TVT) in stress incontinent women with intrinsic sphincteric deficiency (ISD) a long-term follow-up. Int Urogynecol J 2001; 12(Suppl 2):S12 4. [10] Nilsson CG, Kuuva N. The tension-free vaginal tape procedure is successful in the majority of women with indications for surgical treatment of urinary stress incontinence. Br J Obstet Gynaec 2001; 108: [11] Wang AC. An assessment of the early surgical outcome and urodynamic effects of the tension-free vaginal tape (TVT). Int Urogynecol J 2000;11: [12] Lo TS, Wang AC, Horng SG, Liang CC, Soong YK. Ultrasonographic and urodynamic evaluation after tension free vaginal tape procedure (TVT). Acta Obstet Gynecol Scand 2001;80: [13] Ward K, Hilton P. Prospective multicentre randomized trial of tension-free vaginal tape and colposuspension as primary treatment for stress incontinence. Br Med J 2002;325: [14] Sand PK, Ostergard DR. Pad testing. In: Sand PK, Ostergard DR, editors. Urodynamics and the evaluation of female incontinence: a practical guide. London: Springer-Verlag, 1995; p. 2002;20 3. [15] Lin HH, Yu HJ, Sheu BC, Huang SC. Importance of urodynamic study before radical hysterectomy for cervical cancer. Gynecol Oncol 2001;81: [16] Lose G, Griffiths D, Hosker G, Kulseng-Hanssen S, Perucchini D, Schafer W, et al. Standardisation of urethral pressure measurement: report from the Standardization Sub-Committee of the International Continence Society. Neurourol Urodynam 2002;21: [17] Abrams P, Blaivas JG, Stanton SL, Anderson JT, Eowler CJ, Gerstenberg T, et al. Sixth report on the standardization of terminology of lower urinary tract function. Procedures related to neurophysiological investigation: electromyography, nerve conduction studies, reflex latencies, evoked potential and sensory testing. Scand J Urol Nephrol 1986;20: [18] Abrams P, Blaivas JG, Stanton SL, Anderson JT. Standardization of terminology of lower urinary tract function. Neurourol Urodynam 1988;7: [19] Anderson JT, Blaivas JG, Cardozo L, Thuroff J. Seventh report on the standardization of terminology of lower urinary tract function: lower urinary tract rehabilitation techniques. Int Urogynecol J 1992;3:75 7. [20] Blaivas JG, Appell RA, Fantl JA, Leach G, McGuire EJ, Resnick NM, et al. Definition and classification of urinary incontinence: recommendation of the urodynamic society. Neurourol Urodynam 1997;16: [21] Abrams P, Cardozo L, Fall M, Grifiths D, Rosier P, Ulmsten U, et al. The standardization of terminology of lower urinary tract function: report from the Standardization Sub-Committee of the International Continence Society. Neurourol Urodynam 2002;21: [22] DeLancey JOL. Structural support of the urethra as it relates to stress urinary incontinence- the hammock hypothesis. Am J Obstet Gynecol 1994;170: [23] Kaum HJ, Wolff F. TVT: on midurethral tape positioning and its influence on continence. Int Urogynecol J 2002;13: Editorial Comment D. Griffiths, Pittsburgh, PA, USA. There are relatively little hard data concerning the mechanism by which continence is restored by incontinence surgery. Prospective assessment of the urodynamic changes associated with TVT treatment might in principle help to reveal the mechanism. The authors have assessed the changes over a considerable postoperative period, studying both urethral and voiding variables. Because the sample size is small, the absence of significant postoperative changes in voiding variables may reflect inadequate statistical power, and does not prove that voiding is unaffected by TVT treatment. The observation of significant changes in urethral variables, however, is striking. Although urethral pressure measurements made with cathetermounted transducers and especially so-called stress profiles are difficult to understand and interpret, the authors seem to have carried out the measurements as carefully as could be expected. Consequently, in their hands, TVT does indeed appear to alter urethral mechanics in a way that might contribute to operative success. The fact that there are changes in urethral variables after surgery, however, does not necessarily mean that they are the mechanism of improvement. To reveal the mechanism one would have to show not only that the urethral variables changed after successful surgery, but also that they did not do so after unsuccessful surgery. Ironically, this cannot be done with the present data because surgery was too successful there were apparently no failures. Thus this interesting work is a suggestive but not yet a definitive study of the urodynamic effects and mechanism of TVT therapy.