Safety and efficacy of transobturator tension-free midurethral sling for surgical management of stress urinary incontinence in women

Abstract

Dear Editor, The article by Barry et al. [1] is a nicely conducted multicenter randomized study from Australia, which further establishes the efficacy of transobturator approach (TO) of tension-free midurethral slings in the management of stress urinary incontinence (SUI), comparable to suprapubic tension-free vaginal tape (TVT-SP) at least in short term (objective and subjective success rates; 82.8 vs 78%, p= 0.51, and 84.2 vs 85.4%, p=0.66, respectively). It also establishes the safety advantage of this approach over the suprapubic counterpart with regards to bladder perforation (0 vs 8.5%, p<0.05), blood loss (49 vs 64 ml, p<0.05), and operative time (14.6 vs 18.5 min, p<0.001). However, while one can be assured of utilizing this approach with impunity in most of the cases of SUI, there are certain important issues to be addressed in a given individual case before embarking onto any approach for a successful outcome. Since the successful inception of pubovaginal sling more than a century ago, a lot of research has been undertaken towards improving the understanding of continence mechanisms in women. The focus has shifted from the bladder neck to the midurethra; DeLancey’s hammock hypothesis emphasized the importance of pubourethral ligaments in maintaining the continence, and lately Petros and Ulmstein proposed the “midurethra theory” elucidating the role of weakening of pubococcygeus muscle in addition of the former [2]. These theories have led to the development of TVTs placed at midurethral level by suprapubic, transobturator, or prepubic routes. The former has been proven to be highly efficacious over long term (85–92% success rate), which is equivalent to pubovaginal sling and superior to colposuspension, both in primary as well as in recurrent SUI [3]. Various single-armed clinical studies and randomized controlled trials have proven the efficacy, although short term, of transobturator tape procedure as well, with the added advantage of lower incidence of side effects, e.g., bladder perforation, postoperative voiding dysfunction, and early return to work. Despite the shift of the focus from bladder neck to midurethra, intrinsic sphincter deficiency (ISD) remains one of the important pathophysiological mechanisms underlying SUI, and some degree of ISD is present in most of the patients. Significant ISD is found in only a small percentage of patients and is usually associated with highgrade incontinence. There is still no consensus on the urodynamic definition of ISD and measures like maximal urethral closure pressure (MUCP) less than 20–30 cmH2O and Valsalva leak point pressure (VLPP) <60 cmH2O have been used for definition. There is only moderate correlation between the two parameters, and they are described to represent weakness at different levels: MUCP at midurethra and VLPP at bladder neck. Studies on TVT-SP have failed to demonstrate a significant effect of either of the parameters on the surgical results; however, a combination of both, along with absence of a significant hypermobility, has shown to be predictive of poor results [4]. Int Urogynecol J (2008) 19:893–894 DOI 10.1007/s00192-007-0485-7