影响外侧入路腰椎椎间融合器置入后早期椎间隙高度的因素

Factors affecting the height of early intervertebral space after lumbar interbody fusion via lateral approach

背景:术后椎间隙高度下降可能是机械负荷的自然结果,这种现象是万向螺钉头部的弯曲和融合器嵌入终板过程导致的。当这一现象与融合器沉降相结合时,椎间隙会明显变小,最终导致间接减压的效果丧失。目的:分析影响外侧入路腰椎椎间融合后早期椎间隙高度降低的因素。方法:选择2018年1至12月在青海红十字医院接受单节段或多节段外侧入路腰椎椎间融合合并后路内固定治疗的37例退行性腰椎病变患者,其中男22例,女15例,平均年龄(62.3±9.2)岁,总计72个融合节段。术前及术后即刻、术后1,3和6个月X射线侧位片被用于测量椎间隙前、后高度、平均椎间隙高度、腰椎间隙角和节段角。对椎间隙高度的降低和年龄、固定节段长度、术前腰椎弧度、术后腰椎弧度、椎间隙高度、融合器尺寸以及融合器位置等进行相关性分析。结果与结论:①外侧入路放置的椎间融合器能够显著增加术后椎间隙前高度、椎间隙后高度、平均椎间隙高度和间隙角(P <0.05);②所有的术后椎间隙参数尤其是平均椎间隙高度的增加量与术后椎间隙高度的降低呈正相关关系(r=0.413,P <0.05);③椎间隙高度显著降低(≥25%)的节段在术后即刻的椎间隙高度增加明显,从(4.5±3.0) mm增加到(10.5±5.3) mm,增加了135.6%;然而术后椎间隙高度下降不显著(<25%)的节段术后即刻椎间隙高度相较于术前仅增加57.4%;④术后椎间隙高度增加越多,在早期随访中椎间隙高度损失越大;⑤因此,外侧入路腰椎椎间融合术中获取一个合理的椎间隙高度相较于过度矫正在手术策略的考量中更为重要。

BACKGROUND:Mechanical loading could naturally cause postope rative disc height loss.Two main reasons causing this phenomenon were yielding of the polyaxial screw head and settling of the cage to the endplate.When cage subsidence appeared,significant reduction in the interbody space would emerge,which would compromise the indirect decompression.OBJECTIVE:To analyze the factors affecting the disc height loss after lateral lumbar interbody fusion in the early follow-up.METHODS:Totally 37 patients(22 males and 15 females with the mean age of 62.3±9.2 years)with degenerated lumber disease,who were treated with single or multi segmental lateral lumbar interbody fusion combined with posterior internal fixation in Qinghai Red Cross Hospital from January to December 2018,were included in this study.There were totally 72 fusion segments.Ante rior disc height,poste rior disc height,mean disc height,disc space angle,and segmental angle were measured on lateral plain X-ray images before,immediately,1,3,and 6 months after operation.The correlation of disc height loss with age,constructed segment length,preoperative lordosis,postoperative lordosis,disc height,cage paramete rs,and cage position was analyzed.RESULTS AND CONCLUSION:(1)Cage placement in lateral lumbar interbody fusion significantly increased anterior disc height,posterior disc height,mean disc height,and disc space angle after surgery(P<0.05).(2)There was a significant positive correlation between disc height para m eters,especially the amount of mean disc height increase,and disc height loss after operation(r=0.413,P<0.05).(3)Segments demonstrating significant height loss(≥25%)also achieved remarkable height increase immediately after ope ration,which increased by 135.6%from(4.5±3.0)mm to(10.5±5.3)mm.Otherwise,segments with height loss less than 25%had only 57.4%in postoperative height increase.(4)The greater the postoperative disc height increase,the greater the disc height loss across early follow-up.(5)Therefo re,it is important to achieve a proper inte rvertebral space height rather than ove rcorrection when determining surgical strategy for late ral lumbar interbody fusion.