C2及C7倾斜角与退变性颈椎节段后凸矢状位力线及临床功能相关性研究

Associations between C2 slope,C7 slope and sagittal alignment,clinical outcomes in patients with degenerative cervical focal kyphosis

目的:分析退变性颈椎节段后凸患者行颈椎前路减压融合术前及术后C2倾斜角(slope)、C7 slope与颈椎矢状位力线和临床功能的相关性。方法:回顾性分析我院2015年1月~2020年3月因颈椎退变性疾病入院行颈椎前路减压融合术的患者。定义颈椎后凸角度为正值,颈椎前凸角度为负值。依据颈椎标准侧位X线片,将颈椎节段后凸角度大于4°者纳入退变性颈椎节段后凸组,使用倾向性评分1∶1匹配颈椎前凸组患者,匹配因素包括年龄、性别、手术节段和数量及内固定方式。共纳入146例患者,包括退变性颈椎节段后凸组患者及匹配的颈椎前凸组患者各73例。退变性颈椎节段后凸组中,S型42例,R型31例。测量患者术前和术后1年随访时的C2 slope、C7 slope、C2-C7曲度、颈椎融合节段角度及C2-C7矢状位垂直轴(sagittal vertical axis,SVA),记录术前和术后1年随访时的疼痛视觉模拟评分(visual analogue scale,VAS)、颈椎功能障碍指数(neck disability index,NDI)及日本骨科学会(Japanese Orthopaedic Association,JOA)评分。使用Pearson相关分析术前和术后1年随访时的C2 slope、C7 slope与C2-C7曲度、颈椎融合节段角度、C2-C7 SVA、VAS、NDI、JOA评分的相关性。结果:退变性颈椎节段后凸组患者,术前C2 slope与术前NDI呈正相关(r=0.433,P<0.001),术后1年C2 slope与术后1年NDI呈正相关(r=0.334,P=0.004);术前C7 slope与术前C2-C7 SVA呈正相关(r=0.595,P<0.001),与术后1年融合节段角度呈负相关(r=-0.617,P<0.001)。颈椎前凸组患者,术前C2 slope与术前NDI无明显相关(P>0.05),术前C7 slope与术后1年融合节段角度无明显相关(P>0.05)。两组患者术前及术后1年随访C2 slope和C7 slope与术前及术后1年随访VAS和JOA评分均无明显相关(P>0.05)。结论:与颈椎前凸患者不同,在退变性颈椎节段后凸患者中,C2 slope越大,则相应的颈椎功能越差;而术前C7 slope越大,则术后颈椎整体及融合节段前凸角度越大。

Objectives:To analyze the associations between C2 slope,C7 slope and sagittal alignment,clinical outcomes in patients with degenerative cervical focal kyphosis patients.Methods:A retrospective study was conducted among patients underwent anterior cervical decompression and fusion for cervical degenerative disease between January 2015 and March 2020 in our hospital.The angle of cervical kyphosis was set as a positive value and the angle of lordosis as a negative value.Degenerative cervical focal kyphosis group was defined as cervical focal kyphosis angle>4°.After 1∶1 propensity score matching,cervical lordosis group was determined,based on the age,sex,distribution of the levels treated,number of segments fused and type of instrument.A total of 146 patients were involved.There were 73 patients with degenerative cervical focal kyphosis,including 42 S-type and 31 R-type patients,and 73 patients with cervical lordosis.C2 slope,C7 slope,C2-C7 curve,cervical focal angle of fused levels,and C2-C7 sagittal vertical axis(SVA)were measured,visual analogue scale(VAS),neck disability index(NDI),Japanese Orthopaedic Association(JOA)score were obtained before surgery and at 1-year visit after discharge.Pearson correlation analyses were performed between C2 slope,C7 slope and C2-C7 curve,cervical focal angle of fused levels,C2-C7 SVA,VAS,NDI,JOA score before surgery and at 1-year visit after discharge.Results:Positive correlation was found between preoperative C2 slope and preoperative NDI in patients with degenerative cervical kyphosis(r=0.433,P<0.001),so was there at postoperative 1-year visit(r=0.334,P=0.004).Positive correlation was found between preoperative C7 slope and preoperative 1-year visit C2-C7 SVA in patients with degenerative cervical focal kyphosis(r=0.595,P<0.001).Negative correlation was found between preoperative C7 slope and postoperative 1-year visit focal angle of fused levels in patients with degenerative cervical focal kyphosis(r=-0.617,P<0.001).There was no correlation between preoperative C2 slope and preoperative NDI in patients with cervical lordosis(P>0.05).There was no correlation between preoperative C7 slope and postoperative 1-year visit focal angle of fused levels in patients with cervical lordosis(P>0.05).There was no correlation between preoperative or postoperative 1-year visit C2 slope or C7 slope and VAS or JOA scores(P>0.05).Conclusions:In patients with degenerative cervical focal kyphosis,preoperative and postoperative C2 slope correlates with worse clinical outcomes postoperative C7 slope correlates with larger postoperative cervical global lordosis and focal lordosis of fused levels.Such correlations could not be found in patients with cervical lordosis.