3D打印假体重建累及干骺端的肢体长骨中段肿瘤切除后骨缺损

Application of three-dimensional printed endoprosthesis for reconstruction after metaphysis-involved intercalary tumor resection

目的探讨应用3D打印假体重建累及干骺端的肢体长骨中段肿瘤切除后骨缺损的假体设计、制造、重建过程及其疗效。方法纳入自2018年1月至2021年12月43例于北京大学人民医院采用3D打印假体重建累及干骺端的肢体长骨中段肿瘤患者43例,男25例、女18例,年龄(20.1±15.2)岁(范围4~58岁)。骨肉瘤24例、Ewing肉瘤6例、软骨肉瘤5例、多形性未分化肉瘤2例、软组织肉瘤3例(脂肪肉瘤、滑膜肉瘤、恶性外周神经鞘瘤)及其他肿瘤3例(造釉细胞瘤、复发性动脉瘤样骨囊肿、复发性骨纤维结构不良)。25例(58%)肿瘤位于股骨中段,14例累及股骨下干骺端、11例同时累及股骨上、下干骺端;11例(26%)肿瘤位于胫骨中段,4例累及胫骨下干骺端、5例累及胫骨上干骺端、2例同时累及胫骨上、下干骺端;7例(16%)肿瘤位于肱骨中段,1例累及肱骨下干骺端、3例累及肱骨上干骺端、3例同时累及肱骨上、下干骺端。假体采用半组配式设计,包含骨干固定组件、半组配式连接组件以及定制式3D打印干骺端固定组件。干骺端固定组件根据不同的截骨水平设计为Ⅰ型(截骨水平位于长骨干骺端-骨干区域)与Ⅱ型(截骨水平位于干骺端-骨端区域),其骨接触面为3D打印金属骨小梁结构。回顾性分析患者肢体功能情况及假体生存情况,通过肌肉骨骼肿瘤协会(Musculoskeletal Tumor Society,MSTS)93评分对肢体功能进行评估。结果所有手术均顺利完成,中位截骨长度为16.0(13.0,22.0)cm,截骨水平距关节中位距离为4.5(3.5,6.0)cm。43例患者共安装59个干骺端固定组件,12例采用单Ⅰ型干骺端固定组件联合骨干固定组件重建、6例采用双Ⅰ型干骺端固定组件重建、15例采用单Ⅱ型干骺端固定组件联合骨干固定组件重建,5例采用双Ⅱ型干骺端固定组件重建,5例采用Ⅰ、Ⅱ型干骺端固定组件杂交重建。中位随访时间为26.0(17,37)个月。中位MSTS 93评分为29.0(28.0,30.0)分。5例(12%)发生假体失败,包括2例无菌性松动(均发生于骨水泥固定的骨干固定组件处,干骺端固定组件未见松动征象)和3例肿瘤局部进展。2年假体生存率为90.3%(95%CI:0.81,0.99)。结论应用3D打印假体重建累及干骺端的长骨中段肿瘤切除后骨缺损可获得理想的肢体功能与假体生存,假体的半组配式设计可根据不同的截骨水平选择不同的假体组件进行组配,从而为累及干骺端的长骨中段肿瘤切除后骨缺损重建提供综合性、个性化的重建方案。

Objective To describe the design,manufacture and use of three-dimensional(3D)-printed endoprosthesis for reconstruction after metaphysis-involved intercalary tumor resection and to evaluate its outcome.MethodsForty-three patients who received metaphysis-involved intercalary tumor resection followed by 3D-printed endoprosthetic reconstruction in Musculoskeletal Tumor Center,Peking University People's Hospital between January 2018 and December 2021 were retrospectively reviewed.There were 25 males and 18 males with an average age of 20.1±15.2 years(range,4-58 years).The pathological diagnosis included 24 cases of osteosarcomas,6 cases of Ewing sarcomas,5 cases of chondrosarcomas,2 cases of pleomorphic undifferentiated sarcomas,3 cases of soft-tissue sarcomas(liposarcoma,synovial sarcoma,malignant peripheral nerve sheath tumor for each)and 3 others(adamantinoma,recurrent aneurysmal bone cyst and recurrent osteofibrous dysplasia for each).The tumors located at femur in 25 patients(58%),including 14 lesions involving distal femoral metaphysis and 11 lesions involving both proximal and distal metaphysis;the tumors located at tibia in 11 patients(26%),including 4 lesions involving distal tibial metaphysis,5 lesions involving proximal tibial metaphysis and 2 lesions involving both proximal and distal tibial metaphysis;the tumors located at humerus in 7 patients(16%),including 1 lesion involving distal humeral metaphysis,3 lesions involving proximal humeral metaphysis and 3 lesions involving both proximal and distal humeral metaphysis.The endoprosthesis was designed in a semi-modular fashion and consisted of three parts:a diaphysis-fixing component,a semi-modular lap joint component,and a custom-made 3D-printed metaphysis-fixing component which was designed as two types with 3D-printed porous bone-contacting surfaces according to the osteotomy plane(Type I on meta-diaphyseal region,Type II on meta-epiphyseal region).The functional outcome was assessed using Musculoskeletal Tumor Society(MSTS)93 system.ResultsAll surgeries were accomplished sucessfully.The median resection length and the distance from osteotomy plane to adjacent joint was 16.0(13.0,22.0)cm and 4.5(3.5,6.0)cm,respectively.59 metaphysis-fixing components were installed in 43 patients.Type I components were used in single and dual ends of endoprosthesis in 12 and 6 cases respectively.Type II components were used in single and dual ends in 15 and 5 cases respectively.Hybrid endoprosthesis with Type I and II components were used in 5 cases.The mean follow-up time was 26.0(17,37)months(range,12-54 months).The mean MSTS 93 score was 29.0(28.0,30.0)points(range,21-30 points).Implant failures were found in 5 patients,including 2 cases of aseptic loosening(loosening was observed in the cementing diaphysis-fixing stems while no evidence of loosening in metaphysis-fixing components)and 3 cases of local tumor progression.The 2-year implant survival rate was 90.3%(95%CI:0.81,0.99).ConclusionUsing 3D-printed intercalary endoprosthesis for reconstruction after intercalary resection of metaphysis-involved bone tumor shows satisfactory functional outcome and implant survival.Moreover,by assembling endoprosthetic components according to the different osteotomy plane,the semi-modularized endoprosthesis also provids a comprehensive and individualized reconstruction for patients with metaphysis-involved intercalary tumor.