Anterior cervical discectomy (ACD) versus anterior cervical fusion (ACF), clinical and radiological outcome study.

This study was conducted on 90 patients with symptomatic cervical disc disease with one or two-level disc pathology. Clinical and radiological outcome was compared to determine which technique was advantageous for patients with disc disease. Problems related to donor site as well as those related to fusion bed and grafts have stimulated investigators to avoid fusion. Patients were allocated at random for either the ACF (n=50) or the ACD (n=40) procedures. The standard Smith-Robinson technique was performed on all patients in this study. Patients were followed-up clinically and radiologically according to the study protocol. The clinical long-term outcome was comparable in both groups, though those who had ACF were more satisfied. There was significant incidence of kyphosis in the ACD group (P=0.02). Osseous union was slow and less satisfactory with ACD (64%) than with ACF (94%). Pain at the donor site was not a significant problem in the long-term. Hospital stay and operative time was shortened in ACD patients though not significantly. Spondylotic patients were less satisfied with ACD though not significantly. Conclusions. The issue of whether to fuse or not to fuse has not come to an end yet. The technique is still in need of more refinement of disc excision and graft harvesting and shaping, as well as more adequately controlled studies. Until that, ACD has to be limited to those patients with a soft single disc without spondylosis.

Variation of the groove in the axis vertebra for the vertebral artery. Implications for instrumentation.

Transarticular screws at the C1 to C2 level of the cervical spine provide rigid fixation, but there is a danger of injury to a vertebral artery. The risk is related to the technical skill of the surgeon and to variations in local anatomy. We studied the grooves for the vertebral artery in 50 dry specimens of the second cervical vertebra (C2). They were often asymmetrical, and in 11 specimens one of the grooves was deep enough to reduce the internal height of the lateral mass at the point of fixation to < or =2.1 mm, and the width of the pedicle on the inferior surface of C2 to < or =2 mm. In such specimens, the placement of a transarticular screw would put the vertebral artery at extreme risk, and there is not enough bone to allow adequate fixation. Before any decision is made concerning the type of fixation to be used at C2 we recommend that a thin CT section be made at the appropriate angle to show both the depth and any asymmetry of the grooves for the vertebral artery.