胸腰椎肿瘤整块切除后应用3D打印人工椎体重建的安全性和有效性研究

Study on the safety and effectiveness of 3D printed artificial vertebral body reconstruction after en bloc resection of thoracolumbar tumor

目的:评估胸腰椎肿瘤整块切除后应用3D打印人工椎体重建脊柱稳定性的安全性和有效性。方法:回顾性分析我院2016年5月~2020年1月胸腰椎肿瘤整块切除术后应用3D打印人工椎体重建脊柱稳定性的42例患者。原发性骨肿瘤37例;转移性肿瘤5例。肿瘤均累及胸腰椎。手术实施整块切除,均使用3D打印人工椎体作为前方支撑结构。根据随访超过6个月患者的X线片、CT片评估3D打印假体与相邻椎体融合情况、有无内固定失败。结果:全脊椎切除者39例,矢状切除者3例。使用标准化3D打印人工椎体19例,其中1节段者15例,2节段者3例,3节段者1例;从后路放置15例,从前方放置4例。使用定制化假体23例,其中单节段者7例,2节段者3例,3节段者10例,4节段者2例,5节段者1例;通过椎弓根螺钉拧入假体内置钉孔与后方钉棒系统连接达到自稳19例,从前路放置并通过内置钉孔用螺钉固定于相邻椎体者4例。40例患者获得随访,随访时间3~47个月,中位随访时间22个月。影像学随访超过6个月的患者36例,包含确定融合者9例,可能融合者19例,可能不融合者8例;均无螺钉断裂或拔出、连接棒断裂和假体断裂移位情况;总体融合率为77.8%(28/36)。2例假体下陷超过2mm,但症状轻微未行内固定翻修手术。结论:3D打印人工椎体较大的终板面积有利于防止假体塌陷;微孔结构能促进骨长入增加骨融合;定制化设计能使其与内固定系统连接或直接固定于相邻椎体从而获得更好的即刻稳定性。

Objectives:To evaluate the safety and stability of 3D printed artificial vertebrae in reconstruction of thoracolumbar tumor after total en bloc resection on the early and middle follow-up results.Methods:Between May 2016 and January 2019,42 cases(19 males and 23 females)aged from 10 to 71 years old(39.7±16.2)were analyzed retrospectively.37 cases were with primary bone tumors and 5 cases with metastatic tumors.There were 10 cases of recurrent tumor.All the tumors involved thoracolumbar spine,including 22 cases of single segment,6 cases of 2 segments,11 cases of 3 segments,2 cases of 4 segments and 1 case of 5 segments.The en bloc resection was performed in all cases.All of them used 3D printed artificial vertebral body as the anterior support structure.According to X-ray and CT images of patients who were followed up for more than 6 months,the fusion of prosthesis and adjacent vertebral body was evaluated.Results:There were 39 cases of total spondylectomy and 3 cases of sagittal resection.In this group,19 cases were treated with standard 3D printed prosthesis.Among them,15 cases were in 1 segment,3 in 2 segments and 1 in 3 segments.The prostheses were placed from the posterior approach in 15 cases,and the anterior approach in 4 cases.23 cases were treated with customized prosthesis.Among them,7 cases were single segment,3 cases were 2 segments,10 cases were 3 segments,2 cases were 4 segments,and 1 case was 5 segments.In 19 cases,the pedicle screw was used to screw into the internal screw hole of the prosthesis to connect with the posterior screw-rod system to achieve self-stabilization;in 4 cases,the screws were placed from the anterior approach and fixed to the adjacent vertebral body through the internal screw hole.Except one died of cardiovascular disease 4 months after operation without follow-up and 1 case lost follow-up,the rest 40 patients were followed up between 3 and 47 months,with a median follow-up period of 22 months.36 patients were followed up for more than 6 months.There were 9 cases of fusion,19 cases of probable fusion and 8 cases of probable non-fusion.There was no screw breakage or pull-out,no rod breakage,no prosthesis breakage or displacement.The overall fusion rate was 77.8%(28/36).In 2 cases,the prostheses subsided more than 2 mm,but the pains were mild without internal fixation.Conclusions:3D printed prosthesis is conducive to prevent collapse because of its large end plate area.Microporous structure can promote bone growth and increase bone fusion.Customized design can make it connect with internal fixation system or directly fix in adjacent vertebral body to obtain better immediate stability.Therefore,3D printed prosthesis can reduce the failure rate of internal fixation after thoracolumbar en bloc resection.