腰椎前凸重建不足对腰椎融合术后邻近节段疾病发生的预测价值

Predictive value of postoperative hypolordosis in the occurrence of adjacent segment disease after lumbar fusion surgery

目的探讨相对腰椎前凸(relative lumbar lordosis,RLL)与腰椎前凸分布指数(lumbar distribution index,LDI)对腰椎融合术后邻近节段疾病(adjacent segment disease,ASDis)的预测效能。方法回顾性分析163例行腰椎后路内固定融合手术且随访时间2年以上患者的病历资料,男58例,女105例;年龄(58.7±9.4)岁(范围40~78岁)。行单节段固定74例,双节段71例,三节段18例。根据患者随访期间是否出现ASDis,将患者分为ASDis组和无ASDis组。于全脊柱侧位X线片上测量术前及术后的脊柱-骨盆矢状位参数。RLL为术后测量的腰椎前凸角(lumbarlordosis,LL)与理想LL之差,依据差值划分为平衡、前凸不足、严重前凸不足和前凸过大。LDI为术后下腰椎前凸角与LL的比值,依据百分比划分为平衡、前凸分布不均、重度前凸分布不均和下腰椎前凸过大。采用趋势χ2检验和logistic回归分析RLL、LDI与ASDis的相关性。结果在术后(46±14)个月(范围25~134个月)的随访期间,有24例(14.7%)诊断为ASDis。ASDis组患者的年龄(t=3.13,P=0.002)和融合节段数量(χ2=10.27,P=0.006)明显高于无ASDis组患者,差异有统计学意义。两组患者的性别、体质指数(body mass index,BMI)、疾病种类、漂浮固定、邻近节段椎间盘退变程度及随访时间的差异均无统计学意义(P>0.05)。ASDis组重度前凸不足和前凸不足患者的比例高于无ASDis组,差异有统计学意义(χ2=16.92,P<0.001);随着前凸不足严重程度的上升,ASDis的发生率也逐渐上升。两组依据LDI划分四种状态构成比的差异无统计学意义(P>0.05)。在控制混杂因素后,logistic回归分析结果显示年龄与ASDis的发生密切相关,OR=1.07,95%CI为(1.01,1.13),P=0.018;RLL也是预测ASDis发生的独立危险因素,前凸不足与平衡状态相比,OR=4.34,95%CI为(1.03,18.41),P=0.046,而重度前凸不足与平衡状态相比,OR=11.64,95%CI为(1.30,104.49),P=0.028。结论RLL与腰椎融合术后ASDis的发生密切相关,根据理想LL重建的腰椎前凸能够降低ASDis的发生率。未发现LDI与ASDis发生存在明显相关性。

Objective To investigate the value of relative lumbar lordosis(RLL)and lumbar distribution index(LDI)in predicting the occurrence of adjacent segment disease(ASDis)after lumbar fusion surgery.Methods This study retrospectively reviewed 163 consecutive patients(58 males and 105 females)who had undergone lumbar fusion and had been followed over 2 years,with an average age of 58.7 years;among them,74,71,and 18 patients had undergone fusion of one-level,two-level,and three-level,respectively.They were divided into the non-ASDis group and ASDis group based on the presence of ASDis or not.Pre-and post-operative spinopelvic parameters were measured on the upright lateral radiographs.RLL was calculated as measured lumbar lordosis(LL)minus ideal LL,and LDI was calculated as the ratio of postoperative low lumbar lordosis(LLL)to LL.Each parameter was stratified into 1"aligned"subgroup and 3"disproportioned"subgroups in accordance with values.Cochran-Armitage test of trend andlogistic analysis were performed to investigate the association between these two parameters and the occurrence of ASDis.Results The average follow-up duration after initial surgery was 46±14 months(range,25 to 134 months).Twenty-four(14.7%)patients were diagnosed as ASDis.The age(t=3.13,P=0.002)and the proportion of 2-level and 3-level fusion(χ2=10.27,P=0.006)in the ASDis group were significantly higher than those in the non-ASDis group(P<0.05).There were no statistically significant differences between groups with respect to other general data.The ratios of moderate and severe hypolordosis of RLL were significantly higher in the ASDis group than that in the non-ASDis group(χ2=16.92,P<0.001).There was also a significant linear trend with higher degree of hypolordosis being associated with higher rates of ASDis.However,distribution of four statuses of LDI did not differ statistically between groups.After controlling the confounders,the logistic regression analysis revealed that age,odd ratio(OR)=1.07,95%CI:(1.01,1.13),P=0.018),moderate[OR=4.34,95%CI:(1.03,18.41),P=0.046]and severe hypolordosis[OR=11.64,95%CI:(1.30,104.49),P=0.028]were significantly associated with the occurrence of ASDis.Conclusion A significant association between postoperative RLL and occurrence of ASDis after lumbar fusion surgery were detected.Setting surgical goals according to RLL may help reduce the ASDis rate.However,LDI is not identified to be predictive factors of the occurrence of ASDis.