Prediction of postoperative alignment in patients undergoing anterior cervical fusion using autologous vertebral bone grafting

Abstract

Cervical anterior fusion is useful for the treatment of patients with cervical disease, but carries the risk of postoperative worsening of the cervical spine alignment and kyphosis. Preoperative prediction of the risk for kyphosis could help to avoid such postoperative complications. We attempted to predict the postoperative development of kyphosis in 59 patients scheduled for cervical anterior fusion using autologous vertebral bone grafting. Of these, 36 underwent single and 23 two level fusion with median follow up of 58.2 months. Whole spine alignment, fused segment alignment, and mobility of the intervertebral disc were compared using pre- and postoperative radiographs. Alignment of the whole spine changed from 13.7° to 11.1°, and the angle of the fused segment changed from 3.6° to -3.2°. Postoperative alignment was not worse than the preoperative flexion posture in any of the 59 patients. Forty-nine patients with preoperative lordotic alignment did not develop postoperative kyphosis. Nine patients with preoperative straight alignment had several types of postoperative alignment, including kyphosis. Two patients with postoperative kyphosis showed marked loss in the angle of the fused segment, which affected mobility to flexion of the fused segment. One patient with preoperative kyphotic alignment manifested postoperative kyphosis. The postoperative alignment was influenced by the preoperative alignment. Kyphosis may develop in patients with preoperative straight alignment and large mobility to flexion of the fused segment. This information is useful for surgical planning of anterior cervical fusion using autologous vertebral bone grafting.