Ultrasound Evaluation of Mid-Urethral Sling Position: A Potential Predictor of Outcomes and Adverse Effects

The aim of this study was to evaluate mid-urethral sling (MUS) position and its association with postoperative outcomes and complications.This was a prospective cohort study. Ninety-two women who underwent MUS procedure with a median follow-up period of 11 months (interquartile range 5-24 months) were recruited.Two-dimensional trans-labial ultrasound with an endovaginal probe was used to visualize the urethral length (UL), sling distance to the bladder neck (BN) and to the urethra longitudinal smooth muscle (LSM).Mean sling-LSM, UL, and sling-BN distances were 5.97 ± 2.04 mm, 28.66 ± 3.19 mm, and 18.85 ± 4.46 mm, respectively. Sling position relative to BN (proximal vs. middle vs. distal) was not associated with surgery outcomes and complications; however, mean sling-LSM in patients with exposure (4.3%) was significantly higher compared to those who did not experience exposure (8.80 ± 1.9 mm vs. 5.8 ± 2.0 mm, p = 0.048). Moreover, the mean sling-LSM distance was associated with patient satisfaction (5.87 ± 2.0 mm in satisfied patients with VAS > 6 vs. 6.29 ± 2.1 mm in unsatisfied patients, p value = 0.043). Likewise, patients who had worsened or showed de novo overactive bladder (OAB) symptoms (8.8%) had significantly higher mean sling-LSM distance compared to patients with improved OAB symptoms (6.52 ± 2.0 mm vs. 5.37 ± 1.9 mm, p = 0.007). Mean sling-LSM distance was lower in patients with recurrent urinary tract infection (UTI), voiding dysfunction, and improved stress urinary incontinence, whereas patients with dyspareunia after surgery had higher mean sling-LSM distance; however, these differences were not statistically significant.Both trans-obturator and retropubic procedures with or without concomitant prolapse surgery were assessed. Heterogeneity of the study population and pelvic floor ultrasound being performed by a single urogynecologist were the limitations of the current study.Ultrasound visualization of MUS is feasible and has the potential to predict outcomes and complications. High sling-LSM distance was associated with exposure, and low sling-LSM distance with increased satisfaction rate, probability of voiding dysfunction, and recurrent UTI.