AB289. SPR-16 A preliminary evaluation of vaginal alignment following a transvaginal procedure using MatriStem™ pelvic floor matrix in the rhesus macaque

OBJECTIVE: Implantation of biological or synthetic mesh is the most common method of surgical intervention for pelvic organ prolapse, however, complications ensuing from these surgical repairs occur in 15.5% of cases. Matristem(TM) (ACell, Inc., USA) Pelvic Floor Matrix is a urinary bladder matrix (UBM) device indicated for transvaginal repair. This device is remodeled and replaced by host tissue following implantation, which raises the concern that the process may result in a loss of support to the vagina. Thus, the goal of this study was to quantify measurable changes in vaginal alignment via magnetic resonance imaging (MRI) before (pre) and after (10 days and 3 months) a transvaginal procedure with this device in a rhesus macaque model. METHODS: Two rhesus macaques underwent a transvaginal procedure in accordance with the IACUC at the University of Pittsburgh (protocol #13081928). Level 1 & 2 support to the vagina was transected to simulate compromised support. Two sheets of 6-ply MatriStem(TM) were implanted to support the anterior and posterior vagina. Vaginal alignment was derived from MRIs taken pre, 10 days, and 3 months after surgery. The border of the vagina was manually traced, and used to calculate the centroid of each tracing. These centroids represent the path of the vagina through the pelvis. Further, a 3D coordinate system was mapped to the pelvis, and lines fit to the proximal and distal vagina were used to measure the angle of each line with respect to a cephalic oriented axis in the mid-sagittal plane, which is referred to as the angle of elevation. RESULTS: At 10 days, the angle of elevation became more acute by 8.6% and 17%, respectively. These changes reflect expectations of a tensioned transvaginal fixation of the vagina. At 3 months post-surgery, angles of elevation approached pre surgery conditions, indicating that MatriStem(TM) was providing a comparable level of support to native tissue, even following remodeling. CONCLUSIONS: This preliminary study shows that MatriStem™ repair appears to be re-establishing vaginal support. Future work will aim to increase sample size and compare data to non-repaired controls and those repaired using synthetic mesh. FUNDING SOURCE(S): ACell Inc. for funding these preliminary findings