Comparison between allograft plus demineralized bone matrix versus autograft in anterior cervical fusion : a prospective multicenter study

This study analyzed the fusion results of an allograft-demineralized bone matrix composite versus autograft in a prospective series of patients undergoing surgery for cervical disc disease. To determine the fusion rates of allograft-demineralized bone matrix composite in anterior cervical fusion as compared with the gold standard autograft. For the anterior cervical fusion, the use of freeze-dried allograft is well documented in the literature, citing its effectiveness and inferior fusion rates. The use of demineralized bone matrix in conjunction with freeze-dried allograft in anterior cervical fusion has not been reported. This study was done in a prospective fashion in two medical centers. One group received autograft from the anterior iliac crest, whereas others received freeze-dried allograft augmented with demineralized bone matrix (Grafton, Osteotech, Inc., Shrewsbury, New Jersey). For the autograft group, the standard Smith-Robinson grafting technique was used. For the allograft composite group, demineralized bone matrix was pasted onto the freeze-dried allograft and into the disc space before graft insertion. The autograft group consisted of 38 patients with age ranging 26-71 years (mean, 46.1 years) and follow-up periods of 12-33 months (mean, 18.4 months). There were 19 one-level, 17 two-level, and two three-level fusions. Similarly, the allograft group consisted of 39 patients with age ranging 28-80 years (mean, 48.0 years) with follow-up period of 12-31 months (mean, 17.5 months). There were 19 one-level, 16 two-level, and four three-level fusions. Clinical and radiographic follow-up evaluations were completed at 3-month intervals. Radiographs taken 12 months after surgery were analyzed blindly. Pseudarthrosis developed in 46.2% of patients (33.3% of levels) in the allograft-demineralized bone matrix group compared with 26.3% (22% of levels) in the autograft group (P = 0.11 for patients, P = 0.23 for levels). For patients undergoing two-level fusions, 37.5% of allograft-demineralized bone matrix failed compared with 23.5% of autografts. For single-level fusions, 47.4% of allograft patients developed a pseudarthrosis compared with 26.3% in the autograft group. Graft collapse of > or = 3 mm was noted in 11% of the autograft group versus 19% in the allograft-demineralized bone matrix group (P = 0.32). Graft collapse of > or = 2 mm occurred in 24.4% of autograft patients compared with 39.7% of the allograft-demineralized bone matrix group (P = 0.09