Comparison of Outcomes of Surgical Treatment for Ossification of the Posterior Longitudinal Ligament Versus Other Forms of Degenerative Cervical Myelopathy

Background: Degenerative cervical myelopathy (DCM) is an all-encompassing term that includes cervical spondylotic myelopathy (CSM), ossification of the posterior longitudinal ligament (OPLL), and other spinal abnormalities that cause cervical cord compression. It is unclear whether surgery is equally effective and safe for patients with OPLL as it is for those with other forms of DCM. The purpose of this study was to compare surgical outcomes of patients with OPLL and those with other forms of DCM. Methods: Four hundred and seventy-nine patients with symptomatic DCM were prospectively enrolled in the CSM-International study at sixteen sites. Patients' functional status was evaluated using the modified Japanese Orthopaedic Association scale (mJOA) and the Nurick score. Quality of life was assessed using patient-reported outcome measures, including the Neck Disability Index (NDI) and the Short Form (SF)-36. Postoperative functional and quality-of-life outcomes were assessed at two years of follow-up, and scores were compared between patients with and without OPLL. Results: Of 479 patients, 135 (28.2%) had radiographic evidence of OPLL, and 344 (71.8%) had other forms of DCM. The two groups did not differ significantly in demographics, surgical approach, or baseline myelopathy severity. Patients with OPLL achieved similar functional outcomes by two years following surgery compared with patients with other forms of DCM. With respect to quality of life, the NDI and most of the subscales of the SF-36 were not different between the two diagnostic groups. There was a higher risk of perioperative complications in the OPLL group (p = 0.054), although this relationship did not reach statistical significance. Rates of neurological complications did not differ significantly between diagnostic groups. Conclusions: Surgical decompression for the treatment of OPLL resulted in improvements in functional status and quality of life comparable to those seen in patients with other forms of DCM. Patients with OPLL were at a higher risk of perioperative complications than patients with other forms of DCM. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.