Long-term outcome of laminectomy and instrumented fusion for cervical ossification of the posterior longitudinal ligament.

Between January 2000 and December 2003, a total of 83 patients (64 men and 19 women, average age: 56.4 years, range: 42-78 years) who underwent posterior laminectomy and instrumented fusion for ossification of the posterior longitudinal ligament (OPLL) were included in this study to investigate the long-term outcome of this surgical option and clarify which factors affect the prognosis. After an average 4.8-year follow-up, the mean Japanese Orthopaedic Association (JOA) score significantly increased from 9.2 +/- 1.3 points before operation to 14.2 +/- 0.9 points at the latest follow-up (P < 0.01). The improvement rate (IR) of neurological function ranged from 11.1 to 87.5%, with a mean of 62.4 +/- 13.2%. Among 83 patients, 59 (71.1%) patients had a good prognosis (IR > or = 50%), and the other 24 (28.9%) patients had a poor prognosis (IR < 50%). Postoperative nerve root palsy was the main complication in this series. Radiographic study showed that whilst improving cervical lordosis could provide a better decompression effect and good prognosis, it could have simultaneously contributed to the high incidence of postoperative nerve root palsy.