Comparison Of ACAF And Single Open-door Laminoplasty For The Treatment Of Patients With Severe Cervical OPLL:Clinical Outcomes And MRI Changes

Purpose To investigate the clinical outcomes and MRI changes for patients with severe cervical OPLL treated by ACAF and single open-door laminoplasty.Materials and methods The medical records of 63 patients with severe cervical OPLL who underwent ACAF or single open-door laminoplasty in our hospital between January 2014 and December 2017 were respectively reviewed.32 patients were divided into group A(ACAF)and31 in group P(single open-door laminoplasty).All patients underwent X-ray,CT and MRI before and after surgery.The clinical outcomes were evaluated by Japanese Orthopaedic Association score(JOA),and Visual Analogue Score(VAS)during the follow-up.The area and ratio of cerebrospinal fluid(CSF)and spinal cord,intramedullary signal change,and the position of spinal cord were measured on T2-weighed MRI based on PACS software.According to the compression of the cord and the morphology of the postoperative area of CSF,we gave the corresponding scores to CSF band: score 0(non-compression and continuous),score 1(non-compression and intermittent),score 2(non-compression and disappearing),and score 3(compression).The spinal cord alignment was also classified into three grades: 0(lordosis),1(straight),and 2(kyphosis)We also evaluate the spinal cord rotation angle,deviation angle and spinal shift.Results No significant differences were observed between two groups in terms of age,duration of symptoms,occupying rate of spinal canal,blood,and the duration of follow-up.The operation time in group A was longer than that in group P.Both groups had one patient with CSF leakage.One patient in group A had C5 nerve palsy,while four patients in group P experienced C5 nerve palsy.No spinal cord injury occurred in both groups.At the final follow-up,the improvement rate of JOA score and VAS score were both better than in group P(p<0.05).On t2-weighed MRI,no significant differences were observed in both groups regarding preoperative area of spinal cord and score of spina cord signal(p>0.05).However,at the final follow-up,the area of CSF,area of spinal canal,area ratio of CSF and spinal canal,spinal cord rotation angle,and deviation angle were all improved in group A than those in group P(all p<0.05).In addition,area ratio of spinal cord and spinal canal,CSF score,and spinal cord alignment in group A were all lower than those in group P(p<0.05).The spinal cord shifted anteriorly in group A and shifted posteriorly in group P.Conclusion Patients with severe cervical OPLL could acquire sufficient decompression and good clinical outcomes by ACFA or signal open-door laminoplasty.However,patients whounderwent ACAF could achieve better improvement of the area and morphology of spinal cord and CSF band.Notably,ACAF could acquire in situ decompression(better recovery of the position and curvature of spinal cord)with lower occurrence of C5 nerve palsy,which we believe is significant important to recovery of neurological function.