椎间融合器的置入方式对腰椎融合效果的影响

Influences of different cage implantation techniques on posterior lumbar interbody fusion

目的 :探讨椎间融合器置入方向和位置对腰椎椎间融合术患者临床疗效的影响。方法 :回顾性分析2010年6月~2014年6月在我院行L4/5或L5/S1单节段腰椎融合术患者的临床资料,依据融合器置入方式分为斜向置入组(斜向组,100例)和横向置入组(横向组,100例)。记录两组患者年龄、性别、骨密度、体重指数(body mass index,BMI)及手术节段,术前和末次随访时行Oswestry功能障碍指数(Oswestry disability index,ODI)及疼痛视觉模拟(visual analog scale,VAS)评分。术后1周、6个月、12个月及末次随访时行X线片、CT检查,测量术前、术后1周和末次随访时融合节段的椎间隙高度,术后1周和末次随访时的植骨面积、椎间融合器距离椎体边缘的距离;术后6个月、12个月和末次随访时采用改良Brantigan评分评估椎间融合情况。统计随访过程中内固定断裂和再发生腰背部疼痛情况。结果:两组患者年龄、性别、骨密度、BMI及手术节段均无统计学差异(P>0.05),术前手术节段椎间隙高度、ODI及VAS评分无统计学差异(P>0.05);两组患者均获得24个月以上随访,术后1周和末次随访时的ODI和VAS评分较术前均有显著性改善(P<0.05);两组患者术中使用融合器的高度无统计学差异(P>0.05),术后融合节段椎间隙高度较术前增加无统计学差异(P>0.05);术后1周椎间隙平均植骨面积横向组(322.26±32.36mm2)大于斜向组(198.40±22.08mm2)(P<0.05);斜向组椎间融合器距离椎体左右侧距离分别为8.5±1.2mm、21.2±1.5mm,距椎体后缘距离4.2±0.5mm,横向组椎间融合器距离椎体左右侧距离分别为13.1±1.8mm、14.2±1.4mm,距椎体后缘距离9.8±0.8mm,两组比较有统计学差异(P<0.05)。术后6个月融合率横向组(90%)大于斜向组(71%)(P<0.05),12个月、24个月两组融合率比较无统计学差异(P>0.05);末次随访椎间隙高度丢失度横向组(1.8±1.6mm)低于斜向组(2.6±1.7mm)(P<0.05),植骨面积横向组(423.56±23.29mm2)大于斜向组(299.64±21.68mm2)(P<0.05);随访过程中斜向组4例出现断钉,5例再发生腰背部疼痛;横向组无断钉,2例再发生腰背部疼痛,两组比较有统计学差异(P<0.05)。结论:腰椎融合手术采取斜向和横向置入椎间融合器均能取得满意的疗效,但椎间融合器横向置入能更好地维持椎间隙高度,早期融合率更高,可减少术后钉棒断裂、腰背部疼痛再发生等并发症的发生。

Objectives:To explore the influence of the cage implantation methods on lumbar fusion.Methods:Two-hundred patients underwent the L4/5 or L5/S1 single-level lumbar interbody fusion from June 2010 to June 2014 were reviewed.According to the cage implanted methods,the patients were divided into oblique implantation group(100 cases)and transverse implantation group(100 cases).The age,sex,bone mineral densi-ty(BMD),body mass index(BMI)and operative level of the two groups were recorded.Oswestry disability index(ODI)and visual analog scale(VAS)score were recorded before operation,postoperation and at the last followup.The X-ray and CT examinations were performed at 1 week,6 months,12 months and last follow-up after operation.The height of intervertebral space was measured preoperatively,1 week after operation and at the last follow-up.The area of bone graft and the distance between the cage and the edge of the vertebral body were measured at 1 week and the last follow-up after operation.Reform Brantigan scores were used to evaluate intervertebral fusion at 6 months,12 months and the last follow-up after operation.The breakage of screws and rods and recurrent back pain during follow-up were recorded.Results:There were no statistical differences in age,gender,BMD,BMI index and surgical segments between the two groups(P>0.05).Preoperative intervertebral space height,ODI and VAS scores were not significantly different between the two groups(P>0.05).All patients were followed up for more than 24 months.In both group,the ODI and VAS scores at the last follow-up were significantly improved compared with those before the operation(P<0.05).There was no statistical difference in the height of cage between the two groups(P>0.05),and there was no statistical difference in the height of intervertebral space after operation compared with that before operation(P>0.05).One week after operation,the average area of bone graft in transverse implantation group(322.26±32.36 mm2)was larger than that in oblique implantation group(198.40±22.08 mm2)(P<0.05).In oblique implantation group,the distance between the fusion cage and the left and right sides of the vertebral body were 8.5±1.2 mm and21.2±1.5 mm respectively,and the distance from the posterior margin of the vertebral body was 4.2±0.5 mm.In transverse implantation group,the distance between the fusion cage and the left and right sides of the vertebral body were 13.1±1.8 mm and 14.2±1.4 mm,and the distance from the posterior margin of the vertebral body was 9.8±0.8 mm.There was significant difference between the two groups(P<0.05).The fusion rate in transverse implantation group(90%)was higher than that in oblique implantation group(71%)at 6 months after operation(P<0.05),but there was no significant difference between the two groups at 12 and 24 months follow-up(P>0.05).At the last follow-up,the loss of intervertebral space height in transverse implantation group(1.8±1.6 mm)was lower than that in oblique implantation group(2.6±1.7 mm),the bone graft area in transverse implantation group(423.56±23.29 mm2)was larger than in oblique implantation group(299.64±21.68 mm2),and there was significant difference between the two groups(P<0.05).During follow-up,4 patients in the oblique group had screw and rods breakage,5 patients had back pain recurred;there was no screw or rods breakage in the transverse group,and 2 cases had back pain recurred.There was significant difference between the two groups(P<0.05).Conclusions:Both transverse and oblique implantation methods of cage in posterior lumbar interbody fusion can achieve satisfactory clinical results.However,transverse implantation can better maintain the height of the intervertebral space,and the early fusion rate is higher,which can reduce postoperative screw or rods breakage,recurrence of back pain and other complications.