TUCSON, ARIZ. — Three studies presented at the annual meeting of the Society of Gynecologic Surgeons have begun to unravel the advantages and disadvantages of tension-free vaginal tape (TVT) and transobturator tape (TOT) procedures in patients with stress or mixed urinary incontinence.
The introduction of TVT sling procedures in the mid-1990s rapidly took hold worldwide as a simple, minimally invasive alternative to open or laparoscopic Burch colposuspension. They are now the most widely performed procedures in the United States for stress urinary incontinence.
The more recent entry into this arena of hammocklike procedures using TOT avoided the retropubic space and therefore offered a theoretical safety advantage over TVT procedures. Bladder perforation has been reported in as many as 6%–9% of TVT cases; bowel and vascular injuries are very rare but do occur, explained Dr. Matthew Barber of the Cleveland Clinic.
Few studies have directly compared the two approaches in terms of safety and efficacy, or to identify the best candidates for each procedure. The SGS meeting featured comparisons of the following:
▸ Perioperative complications and adverse events. Dr. Barber and associates reviewed safety in 205 patients who underwent a TOT and 213 who underwent a TVT procedure at the Cleveland Clinic between January 2003 and August 2005. Concurrent surgical procedures were performed in 72% of all subjects, but neither the number nor type of procedures differed between the two groups.
The most significant difference in perioperative complications was bladder injury, which occurred in 5.1% of women undergoing TVT and no patient undergoing TOT.
Voiding dysfunction was present in 8.9% of women following TVT surgery and 2.9% of women following TOT procedures. Anticholinergic medications were required beyond 6 weeks postsurgery in 14% of women in the TVT group and 6.3% of those in the TOT group.
Dr. Barber disclosed that he has received grant/research support from American Medical Systems and Eli Lilly, and two of his coinvestigators have served as consultants or received support from Gynecare, American Medical Systems, or Organogenesis, makers of products used in stress incontinence surgery.
▸ Efficacy in patients with borderline maximal urethral closure pressure. Dr. Jay-James Miller and associates at Northwestern University in Evanston, Ill., and Michigan State University in Flint noted that most TOT failures occur in patients with low maximal urethral closure pressures.
They therefore undertook a study of 14-week outcomes in 145 patients (85 who underwent TOT and 60 who underwent TVT), analyzing results based on a cutoff point of maximal urethral closure pressure of 42 cm H20 or less. With that threshold, the TOT procedure was six times more likely to fail in patients with a borderline maximal urethral closure pressure at baseline. Specifically, failure occurred in 7 of 37 patients meeting that definition who had TOT vs. 1 of 36 patients who had a TVT procedure.
Among all patients evaluated at 14 weeks, almost three times as many objective failures were seen with TOT: 8 of 77 vs. 2 of 58 with TVT.
Longer-term follow-up and a prospective randomized controlled trial would be helpful in determining whether this preliminary observation proves true, said Dr. Miller, a fellow at the Evanston Continence Center of Evanston Northwestern Healthcare. If so, routine preoperative evaluation of urethral function may be helpful during preoperative planning so that patients receive the most appropriate surgical procedure, said Dr. Miller.
Dr. Peter K. Sand, director of urogynecology at Evanston Northwestern Healthcare and an investigator on the study has been an advisor, investigator, and lecturer for American Medical Systems (AMS), which makes MONARC transobturator tape. AMS did not fund the study.
▸ Detrusor overactivity and urge incontinence following surgery. Dr. Sylvia M. Botros, also a fellow at Northwestern's Evanston Continence Center, presented a poster detailing postsurgical resolution rates of detrusor overactivity and subjective urge urinary incontinence (UUI) in 276 subjects with urodynamic stress or mixed urinary incontinence.
Patients underwent one of three procedures: TVT (n=99), SPARC (suprapubic arch sling, n=52), or TOT (N=125). Preoperatively, subjective UUI was reported by 66%, 61%, and 64%, and detrusor overactivity was present in 59%, 62%, and 66% of patients undergoing TVT, SPARC, or TOT.
“At 1 year, with follow-up ranging from 54% to 90% in the three groups, 85% Monarc [TOT] vs. 55% TVT vs. 60% SPARC subjectively had no UUI,” she said.
Patients in the TOT group had a very low rate of de novo UUI and were three times as likely to have resolution of presurgical UUI as those who underwent retropubic midurethral sling procedures.
“When adjusted for possible confounding factors, the Monarc significantly increased the chance of resolution of UUI over TVT (odds ratio 3.12) or SPARC (odds ratio 3.03) postoperatively.”