腰椎肿瘤全脊椎切除术后不同时期钛网下沉与上下位椎体CT值的相关性研究

Correlation between the subsidence of titanium mesh and CT values of the upper and lower vertebrae of lumbar tumors at different periods after total en bloc spondylectomy

目的:测量腰椎肿瘤的上下位椎体的术前CT值,参照骨质疏松的CT值标准分组,判断分析术前CT值与术后不同随访时期的钛网下沉的关系.方法:回顾性分析2008年1月~2018年5月在我院行全脊椎切除钛网重建术的29例腰椎肿瘤患者的临床资料,其中男12例,女17例;年龄42.4±14.5岁(23~69岁);随访时间121.2个月(48~175个月).在术后3个月、6个月、12个月和24个月时通过腰椎CT测量钛网的上位椎体和下位椎体的椎体间高度,将椎体间高度较出院时下降超过1mm纳入下沉组,未超过1mm纳入无下沉组.收集两组人数、性别、年龄(依照中位年龄分组)、肿瘤发生部位和术后是否辅助放疗等资料;测量肿瘤节段的上、下位腰椎椎体的术前CT值,并参照骨质疏松的CT值标准分为低CT值和正常CT值.比较术后不同时间点下沉组和无下沉组的临床参数的差异,并采用ROC分析判断术前上下位椎体CT值在钛网下沉预测中的价值.结果:术后3个月钛网下沉组3例,无下沉组26例;术后6个月钛网下沉组11例,无下沉组18例;术后12个月钛网下沉组18例,无下沉组11例;术后24个月钛网下沉组22例,无下沉组7例.术后不同随访时间点钛网下沉组和无下沉组患者的年龄、肿瘤发生部位、术后辅助放疗的比较,差异无统计学意义(P>0.05).术后6个月,钛网下沉组和无下沉组的上位椎体、下位椎体的低CT值率的比较,差异有统计学意义(P<0.01);术后12个月,钛网下沉组和无下沉组的下位椎体的低CT值率的比较,差异有统计学意义(P<0.01).而在术后3个月和24个月,两组的上、下位椎体的低CT值率的比较无统计学意义(P>0.05).ROC曲线下面积在0.7~0.9之间,术前上、下位椎体低CT值对术后6个月和12个月的钛网下沉的预测准确性为中等.结论:术前肿瘤累及椎体的上下位椎体的低CT值可能与腰椎肿瘤全脊椎切除术后重建钛网早期下沉有关.

Objectives:To measure the preoperative CT values in hounsfield unit(HU)of the upper and low-er vertebrae of lumbar tumor and analyze and determine their relationships with the subsidence of titanium mesh at different follow-up periods after total en bloc spondylectomy(TES).Methods:The data of 29 patients with lumbar tumors who underwent TES with titanium mesh reconstruction in our hospital between January 2008 and May 2018 were retrospectively analyzed,including 12 males and 17 females.The age of the pa-tients was 42.4±14.5 years(23-69 years),and the follow-up period was 121.2 months(48-175 months).The inter-vertebral height of lumbar spine was measured on CT at postoperative 3,6,12,and 24 months.Accord-ing to the difference of intervertebral height between postoperative follow-up and discharge,the patients were divided into subsidence group(>lmm)and non-subsidence group(≤lmm).The number of patients,gender,and age(categorized by median age),tumor location,and postoperative adjuvant radiotherapy of the two groups were collected,and the preoperative CT values(HU)of the upper and lower vertebrae of tumor segments were measured,which were subdivided into low CT value and normal CT value with referrence of the CT value standard of osetoporosis.The differences of clinical parameters between the two groups at different postoperative periods were compared,and ROC analysis was employed to analyze and determine the roles of preoperative CT values of upper and lower vertebral bodies in predicting titanium mesh subsidence.Results:At three months after operation,there were 3 cases in the subsidence group and 26 cases in the non-subsidence group;at 6 months after operation,there were 1l cases in the subsidence group and 18 cases in the nonsubsidence group;at 12 months,there were 18 cases in the subsidence group and 11 cases in the non-subsidence group;at 24 months,there were 22 cases in the subsidence group and 7 cases in the non-subsidence group.There was no statistically significant difference in the age,tumor location,and postoperative adjuvant radiotherapy between the two groups at different follow-up time points(P>0.05).At postoperative 6 months,there was statistically significant difference between the two groups in terms of the low CT values of the upper and lower vertebrae(P<0.01).At postoperative 12 months,there was a statistically significant difference in the low CT values of the lower vertebra between the two groups(P<0.01).However,there was no significant difference in the the low CT values of the upper and lower vertebrae between the two groups at 3 and 24 months after operation(P>0.05).The area under the R0C curve was 0.7-0.9,and the accuracy of the preopeative low CT value of upper and lower vertebrae at 6 and 12 months after surgery in predicting titanium mesh subsidence was medium.Conclusions:The preoperative low CT value of the upper and lower vertebrae of the tumor involved vertebral body may be related to the early subsidence rate of the titanium mesh after TES with titanium mesh recontstruction of lumbar tumors.