Effects of Preoperative Cervical Range of Motion on Clinical Outcomes Following Posterior Decompression: A Multicenter Study of Patients With Cervical Ossification of the Posterior Longitudinal Ligament

Study Design: Retrospective multicenter study. Objectives: To investigate the impact of preoperative cervical range of motion (ROM) on clinical outcomes after posterior decompression for cervical ossification of the posterior longitudinal ligament (OPLL). Methods: We analyzed data from 156 patients with cervical OPLL who underwent posterior decompression and were followed for at least 2 years. Patients were divided into two groups based on preoperative gap ROM, which was a novel indicator representing the difference between flexion and extension ROM: the gROM <0° and >0° groups, and their outcomes were compared. Results: There were no significant differences in patient demographics or surgical details between the gROM <0° and >0° groups. The gROM <0° group exhibited less lordosis in C2-7 angles before and after surgery compared to the gROM >0° group. Cervical ROM significantly decreased following posterior decompression regardless of whether preoperative gROM was <0° or >0°. Meanwhile, the incidence of perioperative complications was similar between the two groups. Furthermore, both groups showed significant improvement in Japanese Orthopaedic Association (JOA) scores postoperatively; however, there were no significant group differences in JOA scores, recovery rates, or visual analog scale for neck pain between the two groups at the preoperation and final follow-up. Conclusions: The incidence of perioperative complications and postoperative clinical outcomes were comparable regardless of the magnitude of preoperative cervical gROM. Although cervical ROM decrease postoperatively, posterior decompression for cervical OPLL can offer favorable clinical outcomes irrespective of the preoperative cervical ROM magnitude, consequently.