Impact Of T1 Slope On Sagittal Balance Of Cervical Spine After Laminoplasty With Fusion

Objective:To analyze impact of T1 Slope on sagittal balance of cervical spine after Laminoplasty with Fusion for cervical spondylotic myelopathy.Methods:Chosing patients from 2012.4-2015.4,37 patients who underwented LPF were followed for 29.7 months.Radiological measurements were performed to analyze the following parameters:(1)C2-C7 sagittal vertical axis;(2)T1 slope;(3)C2-C7lordosis;(4)C0-C2 lordosis.We also measured VAS,JOA and NDI.All statistical analyses were performed using the Statistical Package for the Social Sciences(version 22.0)to to analyze correlation of T1 Slope between Clinical and Radiological Parameters of cervical spine after LPF for CSM.Results: Including 28 males(75.7%)and 9 females(24.3%),37 patients whose mean age was 58.62,(range,29-74)were followed for 29.7 months(range,24.0-62.0).Patients were divided into 2 groups according to the median preoperative T1 slope.There were no postoperative kyphosis in radiological paraments of patients with higher preoperative T1 slope.Two patients with postoperative kyphosis were found in lower preoperative T1 slope cohort,one of which was postoperative occurrence.Overall postoperative sagittal balance of cervical spine was maintained and postoperative clinical parameters of 2groups were improved.There was a significant difference in preoperative and postoperative cervical lordosis between patients with higher and lower preoperative T1 slope.Patients with higher preoperative T1 slope had more postoperative C2-C7 SVA and C2-C7 SVA change.There was no significant difference in preoperative C2-C7 SVA,C0-C2 Cobb,postoperative C0-C2 Cobb,C2-C7 Cobb change and C0-C2 cobb change between 2 groups.Scatter plots showing correlation between C2-C7 Cobb and T1 slope,as well as C2-C7 SVA and T1 slope.We also found correlation between preoperative C2-C7 Cobb and C2-C7 SVA change,preoperative and postoperative correlation between C2-C7 SVA and C0-C2 Cobb.In preoperative parameters,only VAS present significant difference between 2 groups,and there was no significant difference in postoperative VAS,JOA,NDI,demographic,operation segments and fellow-up.(P >0.05)Conclusion: Overall sagittal balance of patients was maintained and clinical parameters was improved.Cervical lordosis of patients with higher preoperative T1 slope were reserved.LPF could contribute to maintain cervical lordosis and sagittal balance.