The effects of the tension-free vaginal tape on proximal urethral position: a prospective, longitudinal evaluation.

This study was designed to determine the anatomic effects of the tension-free vaginal tape (TVT). A cohort of 94 patients was followed for 1 year. Urethral position was quantified using the Q-tip angle. Statistical analysis employed the ANOVA and paired t tests. A total of 54 (57%) patients met the criteria for analysis. In these 54 patients the success rate was 81%. Straining Q-tip angles decreased from a mean preoperative value of 52 degrees to 28 degrees before 1 month, 34 degrees at 1-6 months, 41 degrees at 6-12 months, and 45 degrees at 1 year ( P <0.05). The postoperative resting angles remained essentially unchanged. The sling initially provides support to the proximal urethra which diminishes over time. Unchanged resting Q-tip angles confirm the tension-free concept and there appears to be no shrinkage or tightening of the sling. We concluded that the success of the TVT is not due to proximal urethral support.