Long-term fate of C3-7 arthrodesis: 4-level ACDF versus Cervical Laminectomy and Fusion.

INTRODUCTION: Cervical spondylotic myelopathy (CSM) most commonly occurs at the C3-7 levels and is successfully treated by multilevel anterior cervical discectomy and fusion (ACDF) or cervical laminectomy and fusion (CLF), but no procedure has clearly demonstrated superiority. Most prior investigations comparing approaches are limited by marked heterogeneity in the composition of the study groups. This investigation compares ACDF versus CLF surgery specifically at C3-7 in terms of long-term neurological outcome and the fate of the adjacent levels.

METHODS: Over a twelve-year period, surgeries to treat CSM at C3-7 by ACDF or CLF were retrospectively reviewed. Demographic/clinical data were recorded, pre/post- operative modified Japanese orthopedic association scores (mJOA) were calculated, and any complications were noted.

RESULTS: Of 781 cervical surgery patients, 15 underwent C3-7 ACDF and 49 CLF. There were no differences in patient characteristics or pre/postoperative mJOA scores. Mean follow-up was 52 and 44 months for the anterior and posterior groups respectively. A complication occurred in 3/15 (21%) of the anterior and 14/49 (28%) of the posterior group. No infections occurred in ACDF patients, but there were three in CLF patients. Pseudoarthrosis occurred in two ACDF patients, neither associated with symptoms. Four in the CLF group had asymptomatic pseudoarthroses; two others needed reoperation for kyphosis at the inferior level.

CONCLUSIONS: Long-term neurological improvement occurs following C3-7 ACDF and CLF to a similar degree. While not statistically significant, fewer complications, were seen following ACDF. The absence of symptomatic adjacent segment degeneration (ASD) following ACDF in this series raises a question for further study whether the statistical likelihood of ASD changes once the C3-7 levels are already fused.