OP 14.11: Transperineal 3D pelvic ultrasound in the assessment of voiding dysfunction following suburethral sling surgery

Abstract

Introduction & Objectives: The midurethral synthetic sling (MUS) is the most commonly performed surgical procedure in the treatment of female stress urinary incontinence. However, a small proportion of patients (1-9%) may develop voiding dysfunction/urinary retention due to urethral obstruction which is often treated by sling division. We aimed to evaluate the utility of transperineal 3D pelvic ultrasound in the assessment of patients with persisting voiding dysfunction following MUS surgery. Methods: 15 patients with voiding dysfunction post retropubic MUS were studied. All patients had bladder outlet obstruction based on urodynamic evaluation. Transperineal pelvic ultrasound examinations were performed using Philips IU22 and EPIQ ultrasound machines with X6-1 MHz Matrix transducer. Dynamic 2D imaging was performed in the sagittal plane at rest and on Valsalva to assess sling position and urethral mobility. 3D volume datasets were obtained and off -line analysis performed on Qlab soft ware to evaluate sling position relative to the urethra. Results: Of 15 patients with obstructive slings, 7 had undergone previous transvaginal surgery to relieve obstruction (5 had division of sling and 2 had excision of a suburethral sling segment). All synthetic suburethral slings were easily visualised on 2D transperineal imaging. Dynamic compression of the urethra by sling was observed on 2D imaging in all patients. 12 of 15 patients had overangulation or distortion of axis of the urethra due to the obstructive sling. 3D volume analysis in patients who had persistent voiding dysfunction despite previous sling division showed there was little separation of the ends of the divided sling (< 3 mm). In 2 patients who had undergone excision of a suburethral sling segment, 3D volume analysis showed there was incomplete excision with a small amount of sling continuity. 10 patients subsequently underwent urethrolysis with excision of a suburethal sling segment with resolution of voiding dysfunction. Conclusions: Transperineal 3D Ultrasound has a useful role in the assessment of patients with persistent voiding dysfunction post sling division. Our findings suggest that incision of an obstructive sling may not result in adequate relief of obstruction and excision of a sub-urethral portion of sling may be preferable.