(CR-071) A Prospective Study of 400 Soft Tissue Reconstructions: Interim Analysis of the Ovine Forestomach Matrix MASTRR Registry

Moshe Barnajian, MD; Brandon Bosque, DPM; Christopher Butts, DO; John Choi, MD; Michael Cormican, MD; Claire Dillingham, DO; Jessica Felton, MD; Pranat Kumar, MD; Lung Lau, MD; John Lawlor, DPM; Kyle Leneweaver, DO; John Loftus, MD; Patrick Martyka, DPM; Barnaby May, PhD; Yosef Nasseri, MD; Tracee Short, MD; Jessica Simon, PA-C; Alison Smith, MD; W. Matthew Vassy, MD; Joshua Wolf, MD

Introduction: Clinical literature describing the in-patient use of bioscaffolds across surgical specialties is typically limited to case series and retrospective analyses. This prospective multi-center study provides insights into the safety and efficacy of ovine forestomach matrix (OFM) grafts across a range of surgical procedures.

Methods: The prospective study was approved by a central IRB (Advarra, PA; NCT05243966). The primary endpoint is proportion of treatment emergent adverse events (AEs). Each AE was investigated for severity and causality according to ISO14155. Patients were monitored at weeks 1, 4, and 12, with follow up until healed or lost to follow up. This interim analysis includes the first 432 patients enrolled across 10 US sites between May 2022 and June 2025.

Results:

A total of 432 patients were enrolled, with n=7 screen failures. Of the n=425 Safety population (SP), n=14 were lost to follow-up (LTFU) immediately after index procedure, leaving n=411 in the Intent to Treat (ITT) population; n=400 completed ≥ 14 days of follow-up (Per Protocol population).  Fifty-three SP patients reported ≥1 AEs (12.5%), and there were a total of 63 unique AEs reported. The most common AEs were dehiscence (~3.1%), superficial infection (~2.8%), infection (~2.4%) or death (~2.4%). Most AEs were concluded to be unrelated (80.6%) or unlikely (17.7%) to be related to the OFM graft. A single (~0.2%) AE, ‘allergic reaction’ was concluded to ‘probably’ be related to the OFM graft, though this could not be confirmed via pathology. There were no reported incidents of graft loss.

PP patients (n=400) had a median of one defect per patient (range; 1, 5) giving a total of n=464 defects. This included many defect types including burns (8.6%), DFU (22.1%), fistulae (9.5%), NSTI (2.9%), ostomy takedowns (10.9%), pilonidal sinus (10.7%), pressure injury (9.1%), surgical dehiscence (4.0%) and defects resulting from trauma (16.4%). Sub-group analysis of efficacy outcomes has shown the time to tissue coverage or fill of 2-4 weeks, depending on the extent of the defect and patient factors, and is consistent with prior published studies.

Discussion: This interim analysis demonstrates that OFM grafts have a low complication rate and are clinically effective.