Tensile strength of cadaveric fascia lata compared to small intestinal submucosa using suture pull through analysis

The modified pubovaginal sling has become popular as first line treatment for stress urinary incontinence. With the increasing use of cadaveric fascia as a sling material, widespread shortages are prevalent, hence limiting its availability. The increased morbidity with the use of synthetic sling materials and autologous fascia has stimulated investigation of other sling materials. We evaluated the tensile strength of 4 suture types, and compared tensile strength of cadaveric fascia lata to porcine small intestinal submucosa using suture pull through analysis to assess their efficacy and durability for use in anti-incontinence procedures.

Suture breaking load was determined using 2 and 1-zero polypropylene suture, and 2 and 1-zero polyglactin suture. Freeze dried gamma irradiated human fascia lata and freeze-dried small intestinal submucosa were evaluated. Suture was fixed to sling material using the cross fold technique. Mean suture breakage and suture pull through were determined using a tensionometer by measuring the load applied to the sling/suture system. Statistical analysis was performed.

Mean suture breakage load was greatest with 1-zero polyglactin (8.10 pounds) and least with 2-zero polypropylene (3.68 pounds). Mean suture breakage strength was similar for 1-zero polypropylene and 2-zero polyglactin at 5.26 and 5.40 pounds, respectively. Mean suture pull through load using 1-zero polypropylene suture and the cross fold technique was 5.64 pounds for cadaveric fascia and 2.74 pounds for small intestinal submucosa (p <0.0001). Maximum load was limited by the suture strength when using cadaveric fascia, whereas, maximum load was limited in small intestinal submucosa by its inherent tensile strength. However, using a new technique for suture fixation to the small intestinal submucosa, we were able to increase significantly mean suture pull through load to 3.36 pounds (p = 0.008). Additionally, with this new technique small intestinal submucosa allowed gross stretching before suture pull through that was not seen with cadaveric fascia.

Despite the current standard use of 1-zero polypropylene suture for pubovaginal sling fixation, our data suggest that 1-zero polyglactin suture is the strongest, and its use with pubovaginal sling fixation warrants further investigation. Using the cross fold technique and 1-zero polypropylene suture, tensile strength was greatest with cadaveric fascia compared to small intestinal submucosa. Although small intestinal submucosa was not as strong as cadaveric fascia, our persuasive preliminary data suggest that further investigation is warranted in the use of small intestinal submucosa and other suture fixation techniques, and its observed stretch capacity. Hence, with further studies small intestinal submucosa may remain a viable option for pubovaginal sling material.