Surgical outcomes of posterior cervical laminectomy with instrumented fusion managing regional kyphotic cervical spondylotic myelopathy and k-line negative ossification of the posterior longitudinal ligament: Is the decompression sufficient?

Abstract Purpose To evaluate the efficiency of single-staged posterior cervical laminectomy with instrumented fusion (PLF) for patients with regional kyphotic cervical spondylotic myelopathy (KSM) and negative K-line ossification of the posterior longitudinal ligament (NKO).Methods Patients who were initially diagnosed as cervical stenosis with myelopathy with KSM or NKO were analyzed and compared retrospectively. Posterior shift of the spinal cord was measured comparing preoperative C3-C7 column-cord distance and that of the final follow-up in mid-sagittal MRI. Neurological status was evaluated by the Japanese Orthopaedic Association (JOA) score and recovery rate of JOA score. Postoperative complications were calculated and statistically analyzed. Results For KSM group (n = 12), the preoperative JOA score was 8.250±2.261 points, improved to 13.333±1.875 points at final follow-up. The JOA score improved from 8.421±1.575 points perioperatively to 12.316±1.493 points at final follow-up in NKO group (n = 19). The JOA score changes of both group were larger than 2.5 points of the minimum clinically important difference. The posterior shift of the spinal cord is 12.167±5.762 mm in KSM group and 9.600±6.124 in NKO group. No significant difference of the surgical outcomes was observed between the two group. 2 patients (16.7%) in KSM group had postoperative axial pain. 1 patient (8.3%) in KSM group and 2 patient (10.5%) in NKO group had C5 palsy.Conclusion PLF is safe and efficient for both KSM and KNO. There are similar surgical outcomes of regional kyphotic CSM and negative K-line OPLL after PLF while postoperative axial pain was more likely to happen in regional kyphotic CSM.