Enlarged laminectomy and lateral mass screw fixation for multilevel cervical degenerative myelopathy associated with kyphosis

Abstract

Background contextEither an anterior approach or a posterior approach, which aims to decompress the spinal cord and restore the sagittal alignment, has been adopted to treat multilevel cervical degenerative myelopathy (CDM) associated with kyphosis. However, there is controversy on the optimal surgical strategy for the treatment of multilevel CDM with kyphotic deformity because of the complications of each surgical approach. PurposeThe purpose of this study was to investigate the surgical efficacy of enlarged laminectomy (removing the inside edge of facet joints and decompressing the nerve foramina) and lateral mass screw fixation for the treatment of multilevel CDM associated with kyphosis. Study designA retrospective radiographic and clinical study to access the efficacy of enlarged laminectomy with lateral mass screw fixation in the treatment of multilevel CDM related to kyphosis. Patient sampleA total of 43 patients (28 men and 15 women; average age, 59.6 years) with multilevel CDM correlated to kyphosis were obtained in the study. Outcome measuresAll radiological data were recorded on computer-based measurement from preoperative or postoperative X-ray, magnetic resonance imaging (MRI), and computed tomography. All neurological parameters were accessed in each patient. MethodsAnalysis consisted of: Japanese Orthopedic Association (JOA) score, recovery rate, curvature index (CI), the expansion degree and drift-back distance of the spinal cord, axial symptom severity, and C5 root palsy. The recovery rate based on the JOA score was calculated for each patient. Cervical CI as well as the expansion degree and drift-back distance of the spinal cord was measured using MRI. Axial symptom severity was quantified by a visual analog scale (VAS). Statistical analysis was performed using paired t test with significance set at p<.05. ResultsEnlarged laminectomy was performed over a mean of 3.97 levels (range, 3–5 levels). Follow-up information was obtained at a mean of 2.8 years (range, 1.5–5 years) after surgery. Analysis of the final follow-up data showed significant differences before and after surgery in the JOA score (t=24.17, p<.001), CI improvement (t=21.89, p<.001), the anteroposterior diameter at the level of maximum compression of the spinal cord (t=9.54, p<.001), and VAS score (t=13.30, p<.001). The mean spinal cord posterior shift was 4.72±1.10 mm (range, 0–6.71 mm). X-rays confirmed that bone grafts were completely fused at a mean of 3 months after surgery. During the follow-up period, only two patients (4.7%) did not obtain complete recovery, four patients (9.3%) experienced axial symptoms; there were no C5 root palsy and instrument failures noted in this series. ConclusionEnlarged laminectomy with fixation for the management of multilevel CDM is demonstrated to be an effective strategy for improving neurological function, restoring the normal cervical lordosis, and decreasing the incidence of axial symptoms and C5 root palsy, but there is a need for randomized controlled studies with long-term follow-up to confirm and clarify these results.