个体化数字导航模板引导儿童髋部锁定加压接骨板置入的应用

Locking compression pediatric hip plate placement assisted by individualized navigation templates for pediatric hip diseases

目的探讨利用计算机辅助设计和3D打印技术制作的个体化手术导航模板实现儿童髋部锁定加压接骨板（locking compression pediatric hip plate，LCP-PHP）精确置入的可行性。方法2012年1月至2014年12月需使用LCP-PHP治疗的8例患儿，4例股骨颈骨折，4例发育性髋关节脱位。依据CT数据使用3D打印机打印个体化股骨近端模型，计算机辅助模拟骨折复位和LCP-PHP经颈螺钉置入过程，通过软件设计并打印出与股骨近端匹配的经颈螺钉置入导航模板，术前3D模型模拟手术验证可行后，术中在导航模板辅助下置入导针及LCP-PHP。结果3D打印的个体化手术导航模板术中与股骨近端骨性标志均匹配良好，能够辅助2～3枚螺钉精确置入股骨颈，螺钉置入后经术中X线检查与术前设计基本一致。LCP-PHP置入的手术时间平均约为27．5min，术中使用X线透视平均6．0次，较9例同期传统手术组显著降低（P〈0．05），术后伤口均一期愈合。术后X线片示殷骨颈骨折复位良好，股骨近端内翻截骨角度合适，髋关节对股骨头的包容较好。应用导航模板辅助置入的LCP-PHP的进钉点、进钉方向、螺钉长度均与术前设计方案基本一致，螺钉未损伤骺板。术后随访6～12个月，股骨颈骨折处及股骨近端截骨处均愈合、无1例发生股骨头坏死、髋内翻或再脱位。按ratliff评价标准评价髋关节术后功能情况优4例，良4例。结论3D打印个体化手术导航模板可以辅助LCP-PHP的精确置入，达到预期手术效果，减少医源性股骨颈骨骺及血供损伤，而且可以节省手术时间，减少术中出血，减少患儿及手术操作人员的射线暴露，值得推广应用。

Objective To explore the feasibility and accuracy of a navigation template for placing screws in locking compression pediatric hip plate （LCP-PHP） based on digital design and three-dimensional （3D） printing technology. Methods From January 2012 to December 2014, the preoperative images of computed tomography （CT） were collected for 8 children of femoral＇ neck fracture （n = 4） and development dysplasia of hip （n = 4）. Individual proximal femur model was established by 3D printer. Reduction of fracture and cannulated screw of femoral neck or placement of LCP-PHP were simulated by computer. The screw through femoral neck was designed by software and printed to match proximal femur After reduction, it was placed into navigation template. After the preoperative feasibility of 3D modeling was confirmed, guide pins and screws were inserted with the intraoperative assistance of navigation template. Results During operation, navigation template with individualized design matched the bony markers of proximal femur. And 2-3 screws were accurately inserted into femoral neck for stabilizing the end of fracture. The results were basically the same between postoperative radiography and preoperative design. The implantation of screw took an average of 27. 50 min. Radiology was used intraoperatively for an average of 6. 0 times and wounds healed within one stage. Postoperative radiography showed excellent outcomes. Osteotomy of proximal femur was appropriate and posterior hip joint improved. Entry point, orientation and screw length were all consistent with virtual schemes and there was no screw wear-out. During a follow-up period of 6-12 months, femoral neck fracture and proximal femur osteotomy healed and the functions of hip joint were excellent （n = 4） and fair （n = 4） according to the Ratliff criteria. Conclusions Accurate placement of individualized navigation template of LCP-PHP may he achieved by 3D printing. This technology reduces iatrogenic damage of femoral neck epiphysis and blood supply, saves operative duration, minimizes intra-operative hemorrhage and decreases intraoperative patient-operator radiation exposure. It is worthy of wider popularization.