Thirty-six years experience of cervical extension osteotomy in ankylosing spondylitis: techniques and outcomes.

Study Design: A retrospective review of the cervical extension osteotomy in the past 36 years for the treatment of flexion deformity of patients with ankylosing spondylitis was conducted.

Objectives: To review the conventional and current surgical techniques of cervical extension osteotomy in ankylosing spondylitis and to evaluate the clinical outcomes.

Summary Of Background Data: Cervical osteotomy is a challenging procedure in the correction of flexion deformity in ankylosing spondylitis. Some authors prefer using general anesthesia and prone position for their surgery, and some, including the authors, use the sitting position.

Methods: A review of 131 cases of cervical spine osteotomy was carried out. The accumulation of 131 cases was classified into two phases: 114 cases from 1967 to 1997 (conventional technique group) by our senior author and 17 cases from 1997 to 2003 (current technique group) by our first author. Patient follow-up was obtained by a combination of retrospective chart review and telephone interview by 2 independent physicians. The flexion deformity was measured before surgery and after surgery using chin-brow to vertical angle.

Results: There were 114 patients in the conventional group and 17 patients in the current group. The average preoperative and postoperative angle was 56 degrees and 4 degrees , respectively, in the conventional group and 49 degrees and 12 degrees , respectively, in the current group.

Conclusions: The sitting position with local anesthesia is safe and allows for correction of deformity in a controlled manner. The increased lateral resection area reduces the possibility of nerve root impingement and provides ample room for the spinal cord. The cranial halo can also be adjusted after surgery to modify the head/neck position and can be adjusted to alleviate any C8 nerve root impingement. The procedure demands great attention to detail to minimize risk.