IS SLING STIFFNESS ASSOCIATED WITH POSTOPERATIVE VOIDING DYSFUNCTION? A COMPARISION OF TWO POLYPROPYLENE MIDURETHRAL SLINGS

INTRODUCTION AND OBJECTIVES: Recent modifications to midurethral slings (MUS) by some manufacturers have resulted in stiffer slings which are less resistant to deformation in vitro. The performance of these materials after implantation and the incidence of voiding dysfunction have not been fully investigated. We retrospectively report on the postoperative voiding dysfunction after two types of suprapubic (SP) and transobturator (TO) MUS: high-stiffness (Bard) and low-stiffness (AMS). METHODS: Group 1 consisted of 80 consecutive women who underwent high-stiffness MUS (40 TO, 40 SP), under a manufacturerinstitutional agreement. Group 2 consisted of the most recent 80 consecutive women who underwent an established low-stiffness MUS (40 TO, 40 SP). All procedures were performed by one surgeon using standard placement and tensioning technique. All voiding trials were performed per protocol. Postoperative voiding dysfunction was subcategorized by: asymptomatic high post void residual (PVR), positional voiding, urinary retention < 30 days, and retention requiring urethrolysis. Secondary outcomes included validated quality of life (QOL) questionnaires. RESULTS: Of 40 women undergoing high-stiffness SP sling, 17 (42.5%) women had voiding dysfunction: high PVR (5%), retention < 30 days (25%) and urethrolysis (12.5%). In comparison, 3 (7.5%) women undergoing low-stiffness SP sling had voiding dysfunction: high PVR (5%) and retention < 30 days (2.5%) (p<0.001). The incidence of voiding dysfunction was similar between high-stiffness and low-stiffness TO slings (NS). Fifteen percent of women undergoing high-stiffness TO sling had postoperative voiding dysfunction: high PVR (10%), retention <30 days (2.5%), and positional voiding (2.5%). In comparison, 12.5% of women had voiding dysfunction after low-stiffness TO sling: high PVR (5%), positional voiding (2.5%), retention < 30 days (2.5%), and urethrolysis (2.5%). Despite the differences in voiding dysfunction, QOL indices were significantly improved for all groups. CONCLUSIONS: We noted a significantly higher incidence of postoperative voiding dysfunction in women undergoing high-stiffness SP MUS, when compared with low-stiffness SP MUS. These slings may require even looser tensioning techniques than their low-stiffness counterparts. No significant difference was observed in highand lowstiffness TO slings, suggesting that this approach may be less dependent on specific tensioning technique.