Yinggang Zheng

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° and 4°, respectively, in the conventional group and 49° and 12°, 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.

Value of Magnetic Resonance Imaging and Discography in Determining the Level of Cervical Discectomy and Fusion

Study Design. The correlation between magnetic resonance imaging and discography of the cervical spine in degenerative disc disease was studied. In addition, the results of cervical discectomy and fusion were evaluated. Objectives. To compare the value of cervical magnetic resonance imaging versus discography in selecting the level for discectomy and fusion and to evaluate the surgical outcome. Summary of Background Data. The value of magnetic resonance imaging and discography in patients with cervical discogenic pain is less clear. Also, the status of a hypointense signal (dark) cervical disc and/or a small herniated disc on magnetic resonance imaging has not been determined. Methods. The magnetic resonance imaging studies and discography followed by computed tomography in 55 patients with cervical discogenic pain were evaluated. Surgical planning was based on the complete information of clinical symptoms, magnetic resonance imaging, and discography as well as computed tomography discography. Anterior cervical discectomy and keystone fusion was performed. Postoperative pain relief was assessed by the patients, and the follow-up radiographs were viewed by an independent reviewer. The overall surgical outcome was evaluated using Odom’s criteria. Results. There were 161 disc levels that successfully underwent cervical discography with 79 positive levels. A positive discography result was found in 63% of dark (hypointense signal) discs and 45% of speckled discs. Fifty-nine percent of small herniated discs and 59% of torn discs had a positive discography, respectively. There were 100 abnormal cervical discs on magnetic resonance imaging. Magnetic resonance imaging had a false-positive rate of 51% and a false-negative rate of 27%. Successful cervical fusion was achieved in 95% of patients, and the overall satisfactory result was 76%. Conclusions. Magnetic resonance imaging can identify most of the painful discs but still has relatively high false-negative and false-positive rates. There is a high chance that hypointense signal and small herniated discs are the pain generators, but they are not always symptomatic. Discography can save the levels from being unnecessarily fused. The combination of clinical symptoms, magnetic resonance imaging, and discography provides the most information for decision making and can improve the management of cervical discogenic pain.