远端固定椎选择对青少年特发性脊柱侧凸患者脊柱矢状面平衡的影响

The effect of selecting lower instrumented vertebra on sagittal balance of the spine in adolescent idiopathic scoliosis patients

目的:分析后路椎弓根螺钉矫形内固定术远端固定椎(lower instrumented vertebra,LIV)为T12或L1对Lenke 1型青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)患者脊柱矢状面平衡的影响。方法:回顾性分析2014年1月~2018年12月在我院接受后路矫形椎弓根螺钉内固定融合术的37例Lenke 1型AIS的患者的临床资料,其中男8例,女29例;年龄11~18岁(14.3±1.8岁)。将患者分为TV组(LIV固定于T12)和LV组(LIV固定于L1)。其中TV组16例,男4例,女12例,年龄11~18岁(14.7±2.1岁);LV组21例,男5例,女16例,年龄11~17岁(14.0±1.7岁),两组患者性别、年龄无统计学差异(P>0.05)。所有患者术后随访2年以上。记录患者术前Risser征、手术时间、失血量、输血量、融合节段,术前和术后2年通过SRS-22量表评分评估两组临床疗效。术前及术后2年时行站立后前位X线片检查,测量患者Cobb角、胸椎后凸角(thoracic kphyosis,TK)、腰椎前凸角(lumbar lordosis,LL)、骶骨倾斜角(sacral slope,SS)、骨盆倾斜角(pelvic tilt,PT)、骨盆入射角(pelvic incidence,PI)、脊柱矢状位轴(sagittal vertical axis,SVA)。通过独立样本t检验比较两组的统计学差异。使用Pearson相关分析探讨各矢状面影像学参数变化值之间的关系。结果:两组患者术前Risser征、手术时间、失血量、输血量、融合节段、术后2年SRS-22评分差异均无统计学意义(P>0.05)。患者术前Cobb角46.1°±6.6°,TK 24.3°±7.0°,LL 46.0°±8.4°;术后2年Cobb角15.9°±4.7°,TK 18.3°±6.7°,LL 38.8°±8.6°,Cobb角矫正率(65.6±8.9)%。两组术前及术后2年Cobb角、LL、SS、PT、PI、SVA以及LL变化值、SS变化值、PT变化值、SVA变化值均无统计学差异(P>0.05)。术前TV组TK值为24.1°±6.3°,LV组为24.3°±7.5°;术后2年TV组TK值为19.4°±5.8°,LV组为17.4°±7.4°;术前和术后2年TK两组间比较无统计学差异(P>0.05)。TV组冠状面Cobb角矫正率为(62.6±8.4)%,LV组为(67.8±8.9)%;TV组TK变化值为4.7°±3.0°,LV组为6.9°±1.6°,差异具有统计学意义(P<0.05)。TK变化值和LL的变化值存在明显相关性(r=0.602,P<0.001)。结论:远端固定至L1的患者相较于远端固定至T12的患者远期随访TK可能减小更多。后路椎弓根螺钉矫形内固定融合术治疗Lenke 1型AIS患者时,TK和LL共同参与维持矢状面平衡。

Objectives:To analyze the effect of the lower instrumented vertebra(LIV)at T12 or L1 on sagittal balance of the spine in Lenke 1 adolescent idiopathic scoliosis patients,who received posterior instrumentation and fusion using pedicle screws.Methods:The present study retrospectively reviewed the Lenke 1 adolescent idiopathic scoliosis patients,who received posterior instrumentation and fusion using pedicle screws in our hospital from January 2014 to December 2018.37 patients were included in our study,of which there were 8 males and 29 females,with a mean age of 14.3±1.8 years old(11-18).The patients were divided into TV(LIV at T12)group and LV(LIV at L1)group.In TV group,there were 16 patients,including 4 males and 12 females,with a mean age of 14.7±2.1 years old(11-18).In LV group,there were 21 patients,including 5 males and 16 females,with a mean age of 14.0±1.7 years old(11-17).There was no significant difference in gender and age between the two groups.All patients had at least 2 years follow-up.The Risser sign,operative time,blood loss,blood transfusion,and fused segments at operation were recorded.Before operation and 2 years after operation,SRS-22 scores were used to analyze the clinical efficacy.Through X-ray images in standing position,the Cobb Angle,thoracic kyphosis(TK),lumbar lordosis(LL),sacral slope(SS),pelvic tilt(PT),pelvic incidence(PI),and sagittal vertebral axis(SVA)were measured before and 2 years after surgery.Statistical difference between the two groups was assessed through the independent sample t test.The correlative relationships among the change of sagittal parameters were analyzed through Pearson coefficients.Results:There was no significant difference in Resign sign,operative time,blood loss,blood transfusion,fused segments,and SRS-22 scores of before and 2 years after operation between the two groups(P>0.05).Before operation,the Cobb angle was 46.1°±6.6°,the TK was 24.3°±7.0°,and the LL was 46.0°±8.4°;at two years after operation,the Cobb angle was 15.9°±4.7°,the TK was 18.3°±6.7°,the LL was 38.8°±8.6°,and the correction rate was(65.6±8.9)%.There was no significant difference in Cobb Angle,LL,SS,PT,PI,SVA,change in LL,change in SS,change in PT,change in PI and change in SVA between the two groups before and 2 years after operation(P>0.05).The preoperative TK was 24.1°±6.3°and 24.3°±7.5°in TV group and LV group;the TK at 2 years after operation was 19.4°±5.8°and 17.4°±7.4°in TV group and LV group;there was no significant difference between the two groups before and 2 years after operation(P>0.05).The mean corrective rate of Cobb was(62.6±8.4)%in TV group,and(67.8±8.9)%in LV group(P=0.080).The change in TK was 4.7°±3.0°in TV group,while it was 6.9°±1.6°in LV group(P=0.015),which was statistically different.In Pearson correlation analysis,a positive relation was found between the value of change in TK and the value of change in LL(r=0.602,P<0.001).Conclusions:For Lenke 1 adolescent idiopathic scoliosis patients who underwent posterior instrumentation and fusion using pedicle screws,the TK and LL coordinated to maintain sagittal balance.The TK is more possible to decrease more in those setting L1 as the LIV rather than those fixed distally to T12 at 2 years follow-up.