Biologic Materials for Pelvic Floor Reconstruction

Efficacy and safety of pelvic organ prolapse surgery with porcine small intestinal submucosa graft implantation

OBJECTIVE

The ideal implant material for the surgical repair of pelvic organ prolapse in women is yet to be found. This retrospective study aims to evaluate a porcine small intestinal submucosa (SIS) graft (Surgisis™).

STUDY DESIGN

We reviewed the medical records of women that were operated upon for pelvic organ prolapse using implantation of SIS graft and we examined the short-term complications and recurrence rates.

RESULTS

A total of 155 surgical procedures were reviewed. SIS graft was placed in the anterior, posterior and middle compartments in 93 (60%), 71 (45.8%) and 13 (8.4%) cases, respectively. At three-month follow-up, 22.6% of anterior graft repairs displayed anatomical recurrence (POP-Q stage ≥ 2), compared to 4.8% of posterior and none of the middle compartment graft repairs. During the three postoperative months, 56% of the women were recorded with complications, mostly urinary retention (19%) and pain (12%). The incidence of grade III complications was 5.3%. Persistent complications at three months were observed in 28% of all cases. Logistic regression analysis showed that previous prolapse surgery at the same compartment was a significant predictor for recurrence of prolapse after SIS graft application, whereas lower age, smoking and longer duration of surgery were significant predictors for the development of complications. Younger women had higher risk of developing pain postoperatively.

CONCLUSION

Pain and urinary tract symptoms hold a central position in the complications profile of SIS graft-augmented prolapse surgery. The relatively high recurrence rates do not suggest a clear benefit from SIS graft use.

Extracellular matrix regenerative graft attenuates the negative impact of polypropylene prolapse mesh on vagina in rhesus macaque

BACKGROUND

The use of wide pore lightweight polypropylene mesh to improve anatomical outcomes in the surgical repair of prolapse has been hampered by mesh complications. One of the prototype prolapse meshes has been found to negatively impact the vagina by inducing a decrease in smooth muscle volume and contractility and the degradation of key structural proteins (collagen and elastin), resulting in vaginal degeneration. Recently, bioscaffolds derived from extracellular matrix have been used to mediate tissue regeneration and have been widely adopted in tissue engineering applications.

OBJECTIVE

Here we aimed to: (1) define whether augmentation of a polypropylene prolapse mesh with an extracellular matrix regenerative graft in a primate sacrocolpopexy model could mitigate the degenerative changes; and (2) determine the impact of the extracellular matrix graft on vagina when implanted alone.

STUDY DESIGN

A polypropylene-extracellular matrix composite graft (n = 9) and a 6-layered extracellular matrix graft alone (n = 8) were implanted in 17 middle-aged parous rhesus macaques via sacrocolpopexy and compared to historical data obtained from sham (n = 12) and the polypropylene mesh (n = 12) implanted by the same method. Vaginal function was measured in passive (ball-burst test) and active (smooth muscle contractility) mechanical tests. Vaginal histomorphologic/biochemical assessments included hematoxylin-eosin and trichrome staining, immunofluorescent labeling of α-smooth muscle actin and apoptotic cells, measurement of total collagen, collagen subtypes (ratio III/I), mature elastin, and sulfated glycosaminoglycans. Statistical analyses included 1-way analysis of variance, Kruskal-Wallis, and appropriate post-hoc tests.

RESULTS

The host inflammatory response in the composite mesh-implanted vagina was reduced compared to that following implantation with the polypropylene mesh alone. The increase in apoptotic cells observed with the polypropylene mesh was blunted in the composite (overall P < .001). Passive mechanical testing showed inferior parameters for both polypropylene mesh alone and the composite compared to sham whereas the contractility and thickness of smooth muscle layer in the composite were improved with a value similar to sham, which was distinct from the decreases observed with polypropylene mesh alone. Biochemically, the composite had similar mature elastin content, sulfated glycosaminoglycan content, and collagen subtype III/I ratio but lower total collagen content when compared to sham (P = .011). Multilayered extracellular matrix graft alone showed overall comparable values to sham in aspects of the biomechanical, histomorphologic, or biochemical endpoints of the vagina. The increased collagen subtype ratio III/I with the extracellular matrix graft alone (P = .033 compared to sham) is consistent with an ongoing active remodeling response.

CONCLUSION

Mesh augmentation with a regenerative extracellular matrix graft attenuated the negative impact of polypropylene mesh on the vagina. Application of the extracellular matrix graft alone had no measurable negative effects suggesting that the benefits of this extracellular matrix graft occur when used without a permanent material. Future studies will focus on understanding mechanisms.