Predictors of surgical outcome in ossification of the posterior longitudinal ligament

• It is a clinical trial.
• Previous study aimed to investigate cervical spondylosis rather than OPLL.
• This study aimed to evaluate the predictors of the surgical outcomes of OPLL.
• The predictors of surgical outcome of OPLL is unclear.
• This is a 2-year follow up. In this study, we found that the predictors of OPLL is different from cervical spondylosis.

Study designA retrospective study.ObjectiveTo clarify the predictors of the operation results for ossification of the posterior longitudinal ligament (OPLL).Summary of background dataDetailed analyses of surgical outcomes of OPLL have been rare because most survey aimed to investigate cervical spondylotic myelopathy.MethodsAll patients who underwent cervical operation for OPLL between January 2011 and December 2011 were included in this analysis. We investigated the patients’ characteristics and surgical approaches, and compared the radiographical characteristics of OPLL.ResultsThe mean mJOA score improved from 8.312 ± 3.021 points preoperatively to 11.24 ± 3.43 points at 24 months after operation (P < 0.001). The average change in mJOA score was significantly greater in patients with a higher Nirik score than in those with lower Nirik scores (P < 0.0001). The average change in mJOA score was also significantly different in patients with trauma history (P < 0.0001). The average recovery ratio was 42 ± 26.3% in young patients and 30 ± 31.6% in the group older than 50 years (P = 0.012). The average recovery ratio in patients with acute and chronic symptoms was 48 ± 22.9% and 26 ± 33.9%, respectively. There was great difference between the two groups.ConclusionOPLL patients with myelopathy would receive good result after the operation. Age and symptom duration are related to the surgical outcomes. Patients with lower Nirick grade and without trauma history would receive better results before and after the operation.