Efficacy of calcium sulfate plus decompression bone in lumbar and lumbosacral spinal fusion: preliminary results in 40 patients

To compare the efficacy of calcium sulfate pellets plus bone obtained from decompression with fresh autologous iliac crest bone in lumbar and lumbosacral spinal fusion with decompression. A prospective randomized clinical trial. Four tertiary care centres in Halifax, NS. All were consenting, skeletally mature and suffering from degenerative disc disease or spondylolisthesis. The first 40 patients from a single test centre are reported; 32 of these had completed 1-year follow-up. Posterolateral lumbar or lumbosacral spinal fusion with spinal canal decompression and randomized placement of test material (decompression bone plus an equal volume of calcium sulfate pellets) on one side and control material (autologous posterior iliac crest bone of equal volume to the test material) on the contralateral side, which allowed subjects to act as their own control. Assessment of bone formation by radiographic evaluation at 6 and 12 months after fusion by an independent musculoskeletal radiologist blinded to the placement of test material. At 6 and 12 months after fusion, 78% and 88% of patients, respectively, showed bone formation at the test site that was 75% to 100% of, equal to or more than that at the control site. Increases in bone formation at 6 and 12 months were almost identical at both sites. Smoking status, patient gender or age, instrumentation used and volume of graft used were not predictive of outcome. Calcium sulfate pellets plus decompression bone provided bone formation equivalent to autologous iliac crest bone in a majority of patients. Calcium sulfate pellets plus decompression bone may provide a viable alternative to autologous iliac crest as a graft material for spinal fusion.