Surgical Outcome and Features of C7 Spondylolisthesis with Myelopathy: A Case Series.

Introduction: Reports of myelopathy with C7 anterior spondylolisthesis are extremely rare, and the surgical outcomes, clinical features, and their effects remain unknown. We describe six patients who underwent surgery for C7 spondylolisthesis with myelopathy.

Methods: Six patients who underwent operative treatment for C7 spondylolisthesis with myelopathy were retrospectively reviewed. C7 spondylolisthesis was defined as an anterior slippage of more than 2 mm on X-ray or computed tomography (CT). The images were evaluated using radiography, magnetic resonance imaging (MRI), and CT. Clinical outcomes were evaluated using the thoracic Japanese Orthopedic Association (T-JOA) score and Frankel grade.

Results: Facet joint arthrosis was observed in all patients at the C7/T1 level. MRI revealed a juxta-facet cyst in the spinal segment in three cases and a high signal change in four cases. We could visualize C7 anterior slippage from the lateral radiograph in one case. The mean time from onset to diagnosis was 95 (range, 7-280) months. Posterior spinal fusion using pedicle screws and interlaminectomy was performed in five cases. Cystectomy with partial laminectomy was performed in one case with a juxta-facet cyst. The mean JOA score was 6±0.7 preoperatively and improved to 9±1.5 at the final follow-up. The Frankel grades of all patients improved by more than one grade.

Conclusions: In this study, myelopathy with C7 spondylolisthesis was relatively severe, and we believe that the mechanical stress between the rigid thoracic vertebrae and the movable cervical spine may cause C7 spondylolisthesis. Posterior spinal fusion and partial laminectomy for C7 spondylolisthesis with myelopathy resulted in satisfactory outcomes.