Effect of tension-free vaginal tape operation on urethral closure function

Objectives. To evaluate whether the tension-free vaginal tape operation changes urethral hypermobility, funneling, and urethral urodynamic parameters in different parts of the urethra. Methods. We conducted a cohort study of our first 80 unselected female patients (age 36 to 78 years, median 53) undergoing a tension-free vaginal tape procedure. Urethral pressure profile measurements were done before and 6 and 12 months after the operation. Lateral cystography was performed before and after surgery in 50 patients. Of the 80 women, 29 had previously undergone prolapse or incontinence surgery. Parameter-free techniques were used for statistical evaluation. Results. Five patients were lost to follow-up. On an intention-to-treat basis, 66% of the patients were objectively and subjectively cured, 20% were objectively dry but subjectively occasionally incontinent, and 14% had treatment failure. The maximal urethral closure pressure at rest showed no significant changes (median baseline and 6 and 12 months postoperatively, 44, 40, and 38 cm H2O, respectively). The pressure transmission ratio increased in the proximal urethra (median 107.5%, 122.5%, and 123.5% at baseline and 6 and 12 months postoperatively, respectively, P <0.05) and distal urethra (median 80%, 112%, 107.5% at baseline and 6 and 12 months postoperatively, respectively, P <0.01). The downward movement of the bladder neck during the Valsalva maneuver decreased (median 2.3 cm preoperatively versus 1.7 cm postoperatively, P <0.001). Urethral rotation was diminished (median 35.5 degrees versus 23 degrees, P <0.01). Funneling was seen postoperatively in only 5 of 25 preoperative cases. Conclusions. The tension-free vaginal tape procedure stabilizes the urethra anatomically and improves funneling and pressure transmission ratios all along the urethra. The maximal urethral closure pressure at rest decreased without statistical significance.