Expansive Laminoplasty Versus Laminectomy Alone Versus Laminectomy and Fusion for Cervical Ossification of the Posterior Longitudinal Ligament: Is There a Difference in the Clinical Outcome and Sagittal Alignment?

Abstract

Intervention comparison study. To assess postoperative cervical lordosis, clinical outcome, and progression of ossification of the posterior longitudinal ligament (OPLL) in patient of cervical spondylotic myelopathy (CSM) by the OPLL. The posterior approach is usually used for multilevel (≥3) CSM and is decided based on cervical lordosis and instability. OPLL, 1 cause of CSM, makes decreased neck motion and is progressed by neck motion. In OPLL patients, it may be asked whether motion-preserving surgery is still helpful. We reviewed 57 patients of CSM by OPLL who underwent 3 posterior surgeries, laminoplasty, laminectomy alone (LA), and laminectomy with fusion (LF), and followed up minimum 24 months. Postoperative cervical sagittal balance was measured using by the C2-C7 sagittal vertical axis (SVA), cervical curvature index, and C2-C7 Cobb angle. The clinical outcome was analyzed by the neck disability index and the visual analog scale for axial pain. OPLL progression was measured by length and depth growth. A linear mixed model was used to evaluate the differences between each time point and baseline score. Cervical lordosis, C2-C7 Cobb angle, and cervical curvature index decreased gradually in all patients. SVA was maintained in the LF group only and increased in the others (P=0.01). Clinical outcomes, neck disability index, and visual analogue scale were evenly improved in all groups. In patients showing SVA≥40 mm at baseline, neck pain increased in the laminoplasty group but was stationary in the LF group. Progression of OPLL was observed more frequent in the LA group than in the LF group. Posterior surgeries resulted in clinical improvements although with loss of cervical lordosis in CSM with OPLL patients. OPLL may worsen more frequently after LA. LF and laminoplasty are preferable techniques in this condition, with the former better for patients with high baseline SVA distances.