Correlation Between The Changes Of Cervical Sagittal Parameters And Clinical Outcome After ACDF In Patients With Multilevel Cervical Spondylotic Myelopathy

Objective: The aim of the study was to evaluate the clinical outcomes and cervical sagittal parameters after ACDF in the patients with MCSM and to identify the risk factors of poor clinical outcomes.Methods: A retrospective study was conducted on 85 patients with MCSM treated with ACDF from January 2011 to December 2016.All patients were followed up for at least 2 years.JOA score was used to evaluate the improvement of neurological function before operation and at the last follow-up.Based on the average JOA recovery rate,patients were divided into the good-outcome group(Group GO)and the poor-outcome group(Group PO).The cervical sagittal parameters including Cobb angle,C2-C7 SVA,T1 S,cranial tilt and cervical tilt were measured.?Cobb,?C2-C7 SVA,?T1S,?Cervical tilt and ?Cranial tilt were the differences between the values measured at the last follow-up and those before operation.Multivariate Logistic regression was used to identify risk factors affacted the clinical outcomes.Results: The average JOA of all patients before operation was 7.69±2.79,and that of JOA at the last follow-up was 13.19±2.71,which was significantly higher than that before operation(P<0.001).The average values of Cobb angle,C2-C7 SVA,T1 S and Cranial tilt before operation were 12.19°±9.39 °,23.15 mm ±11.22 mm,24.36°±11.29° and 5.13 °±6.60°,respectively,and the average values at the last follow-up were 15.36°±8.93°,18.91 mm ±10.69 mm,27.09°±11.76° and 7.52°±6.36°(P<0.001).The average Cervical tilt of all patients was 19.61°±6.39° before operation and 17.36°±6.67° at the last follow-up.There was no significant difference between the two groups(P=0.084).52 patients(61.18%)were divided into the Group GO,others were the Group PO.There was no significant difference in Cobb angle between the two groups before operation(P=0.601),but at the last follow-up,the Cobb angle of Group GO was higher than that of Group PO(P=0.040),and ?Cobb of Group GO was higher than that of Group PO(P=0.008).There was no significant difference in preoperative C2-C7 SVA between the two groups(P=0.677).However,at the last follow-up,C2-C7 SVA in Group GO was lower than that in Group PO(P=0.025),and ?C2-C7 SVA in Group GO was significantly lower than that in Group PO(P=0.022).There was no significantly statistical difference in both last follow-up T1S(P=0.843)and ?T1S(P=0.795)between two groups.No significantly statistical difference was found in preoperative Cranial tilt(P=0.610),last follow-up Cranial tilt(P=0.521)?Cranial tilt(P=0.856),preoperative Cervical tilt(P=0.459),last follow-up Cervical tilt(P=0.582)and ?Cervical tilt(P=0.582)between two groups.Longer symptom duration,lower preoperative JOA score,smaller ?Cobb angle and larger ?C2-C7 SVA was identified as risk factors of poor clinical outcomes.Conclusions: ACDF is effective in the treatment of patients with MCSM.The changes of cervical sagittal parameters before and after operation play an importance role in the patients with MCSM after ACDF.The cervical sagittal parameters should be paid attention to in surgery.