Study design: A prospective randomized study was conducted.
Objective: To determine whether the use of a cervical carbon fiber intervertebral fusion cage improves the outcome of anterior cervical decompression and fusion, as compared with the Cloward procedure using autograft.
Summary of background data: Despite the theoretical advantages of using intervertebral cages, including reduced donor site morbidity and prevention of graft collapse, an improved clinical outcome has not yet been documented.
Methods: For this study, 103 patients were randomized to anterior cervical decompression and fusion with a carbon fiber intervertebral fusion cage (n = 52) or the Cloward procedure (n = 51). An independent observer quantified pain and functional disability. Fusion rate, segmental kyphosis, and disc height were assessed by radiographs.
Results: During a mean follow-up period of 36 months (range, 24-72 months) for 89 patients (86%), the pain and disability were similar for both treatments. Postoperative donor site pain was significantly less in the carbon fiber intervertebral fusion cage group. The fusion rate was 86% in the Cloward procedure group and 62% in the carbon fiber intervertebral fusion cage group (P < 0.05). In the latter group, patients with pseudarthrosis reported more severe pain than fused patients (51 and 33 visual analog scores, respectively), but the difference was not significant. The segmental kyphosis was less and the disc height increased in the carbon fiber intervertebral fusion cage group, as compared with the Cloward procedure group. Disc height was not correlated with outcome. Segmental kyphosis showed a weak (r = -0.3) but significant (P < 0.05) correlation with improvement of the Cervical Spine Functional Score, but not with other outcome variables.
Conclusions: Except for reduced donor site pain, the clinical outcome for the carbon fiber intervertebral fusion cage is the same as for the Cloward procedure. Use of the cage results in a more lordotic alignment and an increased disc height, but in a higher pseudarthrosis rate than use of the Cloward procedure.