Can we place tension-free vaginal tape where it should be? The one-third rule

The tension-free vaginal tape (TVT) insertion technique generally does not take into account individual urethral length. In this study we investigated whether preoperative sonographic measurement of individual urethral length allows for reliable TVT positioning under the midurethra, which is a critical segment for the continence mechanism.

Urethral length was measured by preoperative introital ultrasonography in 102 consecutive female patients with stress urinary incontinence. TVT procedures were performed as recommended by the manufacturer. The suburethral incisions were initiated at one-third of the sonographically measured urethral length. TVT position and tape-urethra distance were followed up 6 months postoperatively.

At 6-month examination of the 102 study participants, 93.1% were cured and 6.9% showed improved continence. TVTs were found in the target range of 50-70% of the urethral length in 88.2% of the cohort. Women with the TVT in the 50-70% urethral length range and a 3-5-mm tape-longitudinal smooth muscle distance had a greater likelihood of being cured without complications (P < 0.001).

Preoperative sonographic measurement of urethral length, combined with the one-third rule, may aid in reliable midurethral TVT positioning.