Quantitative Anterior Enlargement of the Spinal Canal by Anterior Controllable Antedisplacement and Fusion for the Treatment of Cervical Ossification of the Posterior Longitudinal Ligament with Myelopathy

This retrospective study aimed to investigate the effect of quantitative enlargement of spinal canal by anterior controllable antedisplacement and fusion (ACAF) for cervical ossification of the posterior longitudinal ligament (OPLL).Forty-three patients with OPLL who underwent ACAF were enrolled. According to the use of a curvature ruler (CR), patients were divided into group A (CR used, n = 21) and group B (CR not used, n = 22). The average follow-up was 9.5 months. The occupation rate (OR) of the spinal canal and the curvature of the cervical plate were recorded. The Japanese Orthopedic Association (JOA) scores were analyzed, and the recovery rate (RR) was calculated. Surgical complications were also investigated.The OR of the spinal canal in group A decreased from 66.7% ± 12.8% to 19.1% ± 10.9% after surgery (P < 0.05). In group B, the preoperative and postoperative OR was 63.9% ± 11.7% and 21.2% ± 8.7%, respectively (P < 0.05). Patients in group A had higher agreement of the curvature of the cervical plate between preoperative planning and postoperative measurement. The RR of JOA scores in group A was 73.7% ± 19.7%, higher than in group B (70.9% ± 7.3%, P > 0.05). Further comparison between the 2 groups, excluding those patients with OR <50%, showed that both JOA score and RR in group A were higher than in group B at the final follow-up (P < 0.05).The quantitative enlargement of the spinal canal by ACAF may provide a positive and favorable effect on enlarging the spinal canal and achieving better neurologic recovery for the treatment of cervical OPLL with myelopathy. CR can facilitate the achievement of better and more quantitative spinal canal enlargement.