Impact of lamina closure on long-term outcomes of open-door laminoplasty in patients with cervical myelopathy: Minimum 5-year follow-up study

Study Design: A prospective follow-up study. Objective: To elucidate the impact of lamina closure on long-term outcomes after open-door laminoplasty. Summary of Background Data: In a previous study, we did not find significant associations between lamina closure and short-term outcomes. Methods: Of the original cohort of 82 patients who underwent open-door laminoplasty, 69 were included in this study (52 men, 17 women; mean age, 60.9 yr; mean follow-up, 6.2 yr; 56 with spondylosis or disc herniation, 13 with ossification of posterior longitudinal ligament). Lamina closure was previously observed in 23 of these patients (closure group) but not in 46 (nonclosure group). The Japanese Orthopaedic Association (JOA) scores and Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire were recorded. Results: The JOA score was 9.9 ± 3.2 in the closure group and 11.2 ± 2.3 in the nonclosure group before surgery (P = 0.1), 13.8 ± 2.3 and 13.8 ± 2.2 at 1.8 years (P = 0.99), and 13.6 ± 2.2 and 14.2 ± 2.7 at final follow-up (P = 0.29). The recovery rate of the JOA scores was 56.7 ± 30.0% and 46.7 ± 29.2% at 1.8 years (P = 0.22) and 51.0 ± 32.5 and 57.6 ± 31.1 at the final follow-up (P = 0.42). The subdomains assessed by the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire at follow-up were cervical spine function, 68.7 ± 27.5 in the closure group and 67.7 ± 30.0 in the nonclosure group (P = 0.93); upper extremity function, 78.6 ± 24.3 and 87.6 ± 15.4 (P = 0.40); lower extremity function, 69.9 ± 26.0 and 73.9 ± 22.5 (P = 0.68); bladder function, 74.6 ± 22.6 and 84.9 ± 29.2 (P = 0.18); and quality of life, 53.9 ± 25.3 and 56.2 ± 18.1 (P = 0.96). Conclusion: Lamina closure did not significantly impact the long-term surgical outcomes of laminoplasty for cervical myelopathy. Although not statistically significant, the recovery rate tended to decline in the closure group compared with the nonclosure group during the long-term follow-up period, and the utilization of a laminar retention device to prevent the laminar closure should be considered.