Allograft plus OP-1 enhances ossification in posterolateral lumbar fusion: A seven year follow-up.

PURPOSE: To study the results of the combination of allograft plus BMP-7 in comparison with allograft alone in posterolateral lumbar arthrodesis.

PATIENTS AND METHODS: A blinded controlled consecutive prospective cohort of skeletally mature patients study. One hundred and ten patients underwent posterolateral lumbar instrumented arthrodesis. Allograft randomly compacted onto either the right or the left side of the articular and the posterior aspect of the transverse processes of lumbar spine. The same procedure performed on the contralateral side, but allograft was previously mixed with osteogenic protein (OP-1). Clinical, x-ray and CT-scan long follow-up performed. Univariable and multivariable logistic regression analyses.

RESULTS: More bone continuity was found with allograft plus OP-1 than with allograft alone (p>0.0038). The amount of bone mass was greater on the OP-1 side (p<0.001). No local or systemic adverse effect were noted.

CONCLUSIONS: Allograft on one side plus allograft with BMP-7 on the other achieved a fusion rate of 93 per cent. Allograft combined with BMP-7 was more effective than allograft alone.