Surgical Results and Prognostic Factors of Anterior Cervical Corpectomy and Fusion for Ossification of the Posterior Longitudinal Ligament

BACKGROUND: Mechanism of ossification of the posterior longitudinal ligament (OPLL) has not been elucidated clearly. Surgical decompression is usually necessary for the patients with neurological symptoms. Anterior decompression and resection of OPLL seems to be a radical surgical option, because the spinal cord is compressed from the anterior direction. METHODS: Among 229 patients who underwent ACF for OPLL between January 2001 and December 2007 in our hospital, a total of 133 patients responded to the invitation and made return visits, with a follow-up rate of 58.1%. For these patients, clinical data were collected from medical and operative records. Neurological status were evaluated by using the Japanese Orthopedic Association (JOA) scoring system. Radiological evaluations including C2-7 lordotic angle, sagittal vertical axis (SVA), occupying rate of OPLL, double-layer sign and high-intensity zone were obtained from all the patients. Complications and causes of revision surgery were also investigated. Correlations between the long-term surgical outcome and various prognostic factors were statistically analyzed. FINDINGS: Eighty-four males and forty-nine females completed the follow-up, with a mean age at operation of 56.8 years. The overall average JOA score significantly increased, with a mean recovery rate of 64.1%±14.2%. The mean C2-7 lordotic angle and SVA were also significantly improved, and fusion rate was satisfactory. The incidence of complications was consistent to the previous reports and most of them were controllable by suitable treatments. Multiple regression analysis showed that number of corpectmies and preoperative JOA score were important predictors of surgical outcome. CONCLUSIONS: ACF is a reliable and effective method for treating OPLL patients in terms of neurological recovery, maintenance of radiological parameters, fusion rate and complications. Number of corpectomies and preoperative JOA score are important predictors for the clinical outcome when this procedure is used.