Twisting of transobturator midurethral slings: does it matter?

Introduction and hypothesis We assessed rotation/twisting of transobturator midurethral slings (TOTs) and tested for associations with de novo chronic pain and voiding dysfunction. Methods A retrospective pilot study including patients seen after Monarc (TM) TOT surgery at a single tertiary hospital in 2005-2016. Patients underwent an interview, clinical examination, uroflowmetry and 4D pelvic floor ultrasound. Volume datasets were analyzed blinded against all other data. Sling rotation/twisting was evaluated in volumes obtained at rest. The sling axis was measured relative to the vertical in the midline and in the most lateral parasagittal slice. Total sling rotation was calculated by summation of absolute angle differences between midline and lateral angles. "Corkscrew" rotation was noted when direction of rotation was opposite on the contra-lateral side. Results The study included 215 patients. Fifty-two (24%) were excluded, leaving 163. Mean age was 57 years (28-87; SD 12), mean BMI 29.4 kg/m(2) (18.3-47.4, SD 6). Follow-up was at a median of 17 months (IQR 11-27). Chronic de novo pain was reported by 15 women (9%; dyspareunia by 11 and pelvic/vaginal pain by 4). On imaging, mean total sling rotation was 144 degrees (12-335, SD 56). In the majority (n = 103, 63%) it rotated counter-clockwise from its midline position and in 30 (18%) it rotated clockwise. "Corkscrew" rotation was noted in 30 (18%). De novo chronic pain was associated with lower BMI and vaginal sling exposure but not with sling rotation. The latter was not found to be associated with voiding dysfunction either. Conclusions Monarc (TM) TOTs rotate considerably throughout their course. The degree of twisting or rotation and its direction was not found to be associated with de novo postoperative chronic pain or voiding dysfunction.