“UPDATE ON PELVIC SURGERY,” BY NAZEMA Y. SIDDIQUI, MD, AND CINDY L. AMUNDSEN, MD (OCTOBER)
Two serious concerns are implicit, but left unexplored in the Update on suburethral sling procedures:
- If the transobturator tape (TOT) sling is less effective than the retropubic tension-free vaginal tape (TVT) for intrinsic sphincter deficiency (ISD), and ISD increases with age, will we see increasing failure rates for TOT among women who have already undergone the procedure?
- If bladder perforation rates for TVT vary from zero in one study to 7% in another, is bladder perforation an intrinsic risk of the retropubic sling—or a preventable problem?
The study that compares the pubovaginal sling, TVT, and TOT for stress urinary incontinence with ISD is not the first to show that the transobturator approach is much less effective (35% cure at 2 years) than either TVT or the pubovaginal sling (87% each).1 Another retrospective cohort study showed that failure was six times as common with TOT, compared with TVT, in patients who had borderline or low urethral closure pressure.2 A study stratifying TOT outcomes by preoperative urethral function showed that TOT failed to cure incontinence in 67% of patients who had maximum urethral closure pressure 2O and Valsalva leak-point pressure 2O.3 In contrast, several observational studies have showed cure rates from 73% to 86% for retropubic TVT in women who have ISD.4-6
Why the wide range of perforation rates?
As for bladder perforation, in the study comparing the pubovaginal sling, TVT, and TOT for stress urinary incontinence with ISD,1 no perforation was reported in a total of 92 TVT procedures. In contrast, Barber and associates reported a 7% perforation rate with TVT, compared with 0% for TOT.7 Other studies report TVT-related bladder-perforation rates ranging from 15% in a multicenter study8 to 0.8% in a series by a single, experienced surgeon.9 Why do bladder perforation rates differ so radically?
In my opinion, the study-to-study variability in the rate of perforation derives from three factors: technique, training, and experience. It is critical that surgeons learn to keep the TVT needle in immediate contact with the posterior surface of the pubic bone until the needle reaches the suprapubic skin incision at the superior edge of the bone, 2 cm lateral to the midline. If the bladder perforation rate for TVT can be minimized by correct technique, this would undermine one of the main arguments in favor of the transobturator approach.
George Flesh, MD
Dr. Flesh has no financial relationships relevant to his letter.
- Jeon MJ, Jung HJ, Chung SM, Kim SK, Bai SW. Comparison of the treatment outcome of pubovaginal sling, tension-free vaginal tape, and transobturator tape for stress urinary incontinence with intrinsic sphincter deficiency. Am J Obstet Gynecol. 2008;199:76.e1-76.e4.
- Miller JJ, Botros SM, Akl MN, et al. Is transobturator tape as effective as tension-free vaginal tape in patients with borderline maximum urethral closure pressure? Am J Obstet Gynecol. 2006;195:1799-1804.
- Guerette NL, Biller DH, Bena JF, Davila GW. Development of a mathematical model to predict antiincontinence surgery outcomes. Int Urogynecol J Pelvic Floor Dysfunct. 2005;16:S120.-
- Liapis A, Bakas P, Salamalekis E, Botsis D, Creatsas G. Tension-free vaginal tape (TVT) in women with low urethral closure pressure. Eur J Obstet Gynecol Reprod Biol. 2004;116:67-70.
- Meschia M, Pifarotti P, Buonaguidi A, Gattei U, Spennachio M. Tension-free vaginal tape (TVT) for treatment of stress urinary incontinence in women with low-pressure urethra. Eur J Obstet Gynecol Reprod Biol. 2005;122:118-121.
- Mutone N, Brizendine E, Hale D. Clinical outcome of tension-free vaginal tape procedure for stress urinary incontinence without preoperative urethral hypermobility. J Pelvic Med Surg. 2003;9:75.-
- Bodelsson G, Henriksson L, Osser S, Stjernquist M. Short term complications of the tension free vaginal tape operation for stress urinary incontinence in women. BJOG. 2002;109:566-569.
- Wang AC. The techniques of trocar insertion and intraoperative urethrocystoscopy in tension-free vaginal taping: an experience of 600 cases. Acta Obstet Gynecol Scand. 2004;83:293-298.
- LaSala CA, Schimpf MO, Udoh E, O’Sullivan DM, Tulikangas P. Outcome of tension-free vaginal tape procedure when complicated by intraoperative cystotomy. Am J Obstet Gynecol. 2006;195:1857-1861.
Drs. Siddiqui and Amundsen respond: How long will a sling hold?
We agree with Dr. Flesh. In a study by Barber and colleagues that compared TOT and TVT,1 mean length of follow-up was 18 months; only time will tell if these results are maintained as the women age. TVT has now been studied for longer than a decade, but there is limited published data about its long-term efficacy—and that is true for any of the sling kits, including TOT.