DEMINERALISED BONE MATRIX (DBM) AS AN EFFECTIVE ADJUVANT TO AUTOGRAFT IN SPINAL FUSION–RESULTS OF PROSPECTIVE RANDOMISED TRAIL.

Abstract

Background: A common problem achieving lumbar spinal fusion is developing a pseudarthrosis. The current gold standard in achieving fusion is the use of autograft from pelvis or posterior elements of the spine. However the potential limitations of insufficient quantity and donor site morbidity have led to the use of bone graft alternatives such as DBM which contains osteoinductive BMPs.

Aims & Methods: A prospective randomized control trial comparing the effectiveness of Demineralised Bone Matrix (DBM Putty)/autograft composite with autograft in lumbar postero-lateral or 270 degree spinal fusion.

35 patients were required for the study. They were randomized to have DBM and autograft on one side of the posterior approach and autograft alone on other side of the same approach. Patients were followed up with interval radiographs for total of 24mons. To date 32 patients have been recruited and with an average follow up a15.3 months. The mineralization of fusion mass lateral to the instrumentation on each side was graded as Absent, Mild (< 50%), Moderate (> 50%) or Complete fusion (100%). The assessment was made by independent orthopaedic consultant and a musculoskeletal radiologist who were blinded to graft assignment.

Results: The sex distribution was 17:15 male to females with a mean age of 55.2 (21–87years) and an average follow up of 15.3mons (3–24mons). 50% of patients had single level fusion and the remainder had more than one level fusion. At 12months, on the side of DBM 28% had complete fusion, 65% had moderate fusion, and 7% had no fusion mass. During the same period on the other side (non DBM side) approx 25% did not show any sign of fusion. There was no correlation with number of levels, age or sex.

Conclusions: Osteoinductive properties of DBM would appear to enhance the consolidation of the lumbar spinal fusion. DBM reduces the amount of harvested autograft graft and also minimises the morbidity of donor site complications.