Surgical Outcomes After Anterior Controllable Antedisplacement and Fusion Compared with Single Open-Door Laminoplasty: Preliminary Analysis of Postoperative Changes of Spinal Cord Displacements on T2-Weighted Magnetic Resonance Imaging

This retrospective cohort study aimed to investigate the change of spinal cord displacements and the occurrence of C5 palsy between anterior controllable antedisplacement and fusion (ACAF) (group A) and single open-door laminoplasty (group L).From January 2016 to December 2017, a total of 80 patients with cervical ossification of the posterior longitudinal ligament (OPLL) were enrolled. All patients underwent computed tomography and magnetic resonance imaging. The types and extent of OPLL, spinal cord rotation, deviation angle, and distance between the vertebral arteries line and spinal cord (DVS) were measured. Patients with postoperative C5 palsy were recorded. Neurologic function was evaluated by Japanese Orthopaedic Association (JOA) score.Three days after surgery, patients in group A had better recovery (6.7° ± 2.4°) of spinal cord rotation than group L (3.1° ± 0.8°; P < 0.05). Deviation angle showed similar changes to spinal cord rotation. At the final follow-up, patients in group A had decreased DVS (11.0 ± 0.7 mm), whereas patients in group L had increased DVS (15.1 ± 0.8 mm) compared with preoperation (P < 0.05). Five patients (1 in group A and 4 in group L) developed postoperative C5 palsy (P > 0.05). Patients in group A had a higher JOA score at the final follow-up than those in group L (P < 0.05).ACAF could achieve in situ decompression in terms of spinal cord rotation, deviation angle, and spinal cord shift with better clinical outcomes and relatively lower incidence of C5 palsy compared with single open-door laminoplasty.