P21. Safety and reoperation rates, ABM/P-15 vs allograft with minimum 6 years follow-up

Abstract

BACKGROUND CONTEXT There continues to be a search for an ideal bone graft substitute that leads to improved fusion rates compared to autograft that has little to no known adverse effects. One of the latest bone graft substitutes is ABM/P-15. The RCT showed that there was a fusion rate of 50% in the ABM/P-15 group and 20% in the Allograft group. PURPOSE The purpose of this study is to report on the complications and reoperations in patients enrolled in a randomized controlled trial comparing ABM/P-15 to Allograft in un-instrumented fusion due to lumbar degenerative spondylolisthesis. STUDY DESIGN/SETTING Randomized controlled trial with 6 years follow-up. PATIENT SAMPLE Of 101 patients enrolled in a randomized controlled trial comparing ABM/P-15 to Allograft, 59 patients were available at 6 years postoperative, 30 in the ABM/P-15 group and 29 in the Allograft groups. OUTCOME MEASURES Any complication reported by the patient or identified during the patient s postoperative visit, including changes seen on radiographic imaging; and reoperations. METHODS Randomized controlled trial comparing ABM/P-15 vs allograft with a minimum of 6 years follow-up. RESULTS Of the 101 patients who were included in the RCT, 9 patients had wound complications during admission, 3 in the AMB/P15 group and 6 in the allograft group (p=0.254). One patient in each group had a superficial wound infection which required antibiotic treatment. Twenty-one patients had a reoperation during the 6 years follow-up, 12 in the Allograft group and 9 in the ABM/P15 group (p=0.331). Of the 59 patients available for 6-year follow-up, no osteolysis in the vertebrae was seen in any CT scan at 6 years after surgery. One patient in the ABM/P15 had a calcified hematoma, and one patient had bone migrating ventral from the transverse process into the psoas muscle. Both patients were asymptomatic. CONCLUSIONS Complication and reoperation rates were similar in patients treated with ABM/P15 compared to allograft. FDA DEVICE/DRUG STATUS ABM/P-15 (Not approved for this indication)