Research On The Morphology And Efficacy Of Mid-urethral Suspension Surgery With Slings Of Different Materials Via Transperineal Two-dimensional Ultrasound

Objective Mid-urethral sling surgery has become the gold standard surgery for stress urinary incontinence, the purpose of this study was to find a way to study slings’morphology via transperineal two-dimensional ultrasound. And compare the slings made of polypropylene(PP) and polyvinylidene fluoride (PVDF)for their in vitro and in vivo biological and mechanical properties.Methods A retrospective study by transperineal ultrasound on 83 patients who were conducted a mid-urethral sling surgery, comparing these two different materials slings in the cross-sectional width, distance between urethral and sling and displacement of the slings when patients do valsalva procedure.We analysis the connection between these parameters and postoperative efficacy and complications. These two kinds of slings were also conducted mechanics experiments in order to understand their me-chanical properties. We implanted these two kinds of slings beneath the abdominal and anterior vaginal wall of rats,the surrounding tissue is removed and assess the in-flammatory response in 15,30,60 days.Results Operation efficiency was 91.6%, with no serious complications such as vagi-nal erosio, the cross-sectional width of the PP sling group was 8.22±1.84mm, and the PVDF group is 9.49±1.60mm, there is a significant difference (P<0.001) be-tween the two groups.The PVDF slings got less shrinkage than the PP slings(P<0.05).There is no meaningful linear relationship between the cross-sectional width and the postoperative time(P> 0.05). The distance between urethral and sling of PP group is 5.93±1.50mm, and that of PVDF group is 5.62±1.84mm, there is no significant difference (P>0.05) between them.There is also no meaningful linear re-lationship between this parameter and postoperative time (P> 0.05). PP and PVDF slings have similar performance in terms of local inflammatory cell response (P> 0.05). PP slings are superior to PVDF slings on Plastic deformation rate and Elastic recovery rate, but made a low-level performance on Initial modulus and Elongation after the last pre-tension.Conclusions It is feasible to study slings’morphology via transperineal two-dimensional ultrasound. PP slings got more shrinkage than PVDF slings, the ma- jority shrinkage existed intraoperatively or in a very short time postoperative, the shringkage procedure after that is slow and not obvious.the relationship between the shrinkage of slings and the postoperative complications still need further studies. PP and PVDF sling played a similar performance in the urinary tract/reproductive tract erosion,surgery efficiency and inflammatory cell response. PVDF slings may be a good alternative one of PP slings.