Dynamic maximum urethral closure pressures measured by high-resolution manometry increase markedly after sling surgery.

Abstract

The premise of midurethral sling (MUS) surgery is to apply a tension-free vaginal tape in the midurethra that does not constrict the urethra at rest but stabilizes the urethra and prevents downward descent and opening of the urethra during stress maneuvers, but current technology has limitations in measuring urethral pressures during dynamic conditions. Our objective was to describe the change in maximum urethral closure pressures (MUCPs) after MUS surgery using an 8F high-resolution manometry (HRM) system that can measure urethral pressures during cough and strain maneuvers (ManoScan® ESO; Covidien) without migration or withdrawal limitations. We measured rest, cough, and strain MUCPs in 26 women before and after retropubic or transobturator MUS for stress urinary incontinence using the HRM system. The objective success rate after MUS was 92.3 % based on postoperative cough stress testing. Mean resting MUCPs measured by HRM did not change after surgery (59.3 before vs. 59.7 cm H2O after surgery; p = 1.0). Mean cough MUCPs measured by HRM increased from 36.9 to 100.7 cm H2O (p < 0.001), and strain MUCPs increased from 35.0 to 92.7 cm H2O (p < 0.001). Advanced HRM technology to measure MUCPs under cough and strain conditions without withdrawal techniques provides new insights into the continence mechanism after tension-free MUS: MUCPs do not change at rest but do increase significantly during cough and strain maneuvers.