Predictors of Outcome in Patients with Cervical Spondylotic Myelopathy Undergoing Unilateral Open-Door Laminoplasty

Abstract

OBJECTIVE: This study aimed to analyze prognostic factors affecting surgical outcomes of expansive laminoplasty for cervical spondylotic myelopathy (CSM). METHODS: Using the Frankel scale and Japanese Orthopaedic Association (JOA) scale, we retrospectively reviewed the outcomes of 45 consecutive patients who underwent modified unilateral open-door laminoplasty using hydroxyapatite spacers and malleable titanium miniplates between June 2008 and May 2014. The patients were assigned to the good and poor clinical outcome groups, with good outcome defined as a JOA recovery rate >75%. RESULTS: The mean preoperative JOA scale was significantly higher in the good outcome group (14.95+/-3.21 vs. 10.78+/-6.07, p<0.001), whereas the preoperative cervical range of motion (ROM) in this group was significantly lower (29.89 degrees +/-10.11 vs. 44.35 degrees +/- 8.88, p<0.001). In univariate analysis, a high preoperative JOA scale (odds ratio (OR) 1.271, 95% confidence interval (CI) 1.005-1.607) and low preoperative cervical ROM(OR 0.858, 95% CI 0.786-0.936) were statistically correlated with good outcomes. Furthermore, these factors demonstrated an independent association with clinical outcomes (preoperative JOA scale: OR 1.344, 95% CI 1.019-1.774, p=0.036; preoperative cervical ROM: OR 0.860, 95% CI 0.788-0.940, p=0.001). CONCLUSION: In this study, a high preoperative JOA scale was associated with good clinical outcome after laminoplasty, whereas a higher preoperative cervical spine ROM was associated with poor clinical outcome. This may suggests that cervical mobility and preoperative neurological status affect clinical outcomes of laminoplasty.