Correlations between sonographic and urodynamic findings after mid-urethral sling surgery

Purpose: We studied correlations between sonographic and urodynamic findings after suburethral sling surgery. Materials and Methods: This retrospective study was done in 141 women who underwent multichannel urodynamic testing and translabial 4-dimensional ultrasound after suburethral sling surgery between 2006 and 2016. We determined the sling-pubis gap, ie the distance between the sling and the inferior posterior margin of the pubic symphysis, during the Valsalva maneuver and the urethral motion profile. The latter was assessed by calculating the mobility vectors of 6 equidistant points along the length of the urethra from the bladder neck to the external urethral meatus against the dorsocaudal margin of the pubic symphysis during the Valsalva maneuver. Correlations were determined between the sling-pubis gap and the mobility vectors, and between these measures and urodynamic data. Results: Median followup in the 126 women with complete data was 36 months. Significant correlations were found between the sling-pubis gap and the mid urethral mobility vectors (all p <0.02). The sling-pubis gap and the mid urethral mobility vectors negatively correlated with detrusor pressure at maximum flow (p = 0.037 and 0.004, respectively). Urodynamic stress incontinence was more likely in women with a greater sling-pubis gap (p = 0.003). Conclusions: The tighter the sling on ultrasound, the less likely is urodynamic stress incontinence and the higher the detrusor pressure during voiding.