基于3D打印技术和微创腰椎椎间孔外椎体间融合术的设计

Design of minimally invasive extraforaminal lumbar interbody fusion （ELIF） based on 3D printing technology

目的通过3D打印技术设计微创腰椎椎间孔外椎体间融合术（ELIF），探讨3D打印技术应用于临床研究的快速性和高效性。方法通过对1名男性健康志愿者（26岁，身高172cm，体质量67kg）的腰椎行CT扫描，并采用MimicsV14．0软件进行三维重建，研究椎间孔区域骨性结构和神经结构的解剖关系。模拟切除上关节突，置入椎间融合器与椎弓根螺钉，最后通过3D打印技术得到实物进行验证，通过尸体标本验证ELIF的可行性。结果基于3D打印技术设计的ELIF的手术切口是正中线旁开6cm的纵形手术切口，45°斜向椎体的手术通道，可以充分暴露伤椎的椎间孔区域。通过ELIF手术途径可充分显露目标椎间盘和神经根以及后方的上、下关节突和关节囊，操作简便、直观。ELIF手术可以实现单纯切除上关节突，保留下关节突，通过扩大的椎间孔牵开神经根后可以显露并切除椎间盘，并能完成椎间融合器的置入。结论通过3D打印技术设计的ELIF是一种创伤更小、安全、有效的腰椎椎体间融合术式。3D打印技术可以进行精确的手术设计，效率高、速度快、成本低、可操作性强，对真实手术有较好的指导作用。

Objective To design a new operation, extraforaminal lumbar interbody fusion （ELIF）, with the help of 3D printing technology and to discuss the efficiency of using 3D printing technology in the clinical research. Methods A healthy male volunteer recruited for this study underwent CT scan of his lumbar vertebrae. He was 26 years old, 172 cm in height and 67 kg in weight. Software Mimics V14.0 was used to read and reconstruct his CT scan data into 3D images. We observed the anatomical bone structures and nerve roots of the intervertebral foramen on 3D reconstruction images in Mimics to analyze the anatomic features of this area. The self-designed ELIF, pedicle screw insertion and cage placement were simulated via digital technology in Mimics. 3D printing technology was then used to manufacture a real object to test ELIF on it. The feasibility of this new approach was further tested in a cadaveric specimen. Results In our designed ELIF, an incision of 6 cm lateral from the central line and 45° from the sagittal plane was made to fully expose the foraminal area. ELIF made it simple and visualized to fully expose the target intervertebral disk and nerve roots, and posteriorly the superior and inferior articular processes and joint capsules as well. ELIF also made it feasible to remove only the superior facet but save the inferior facet. There was enough room to fully reveal and excise the intervertebral disc, and place the cage after distraction of nerve roots through the intervertebral foramen. The test results on the 3D printing object and the cadaveric specimen were consistent. Conclusions 3D printing technology is an effective, reliable and economic method to design an operation. Our results suggest that ELIF is a safe, more minimally invasive and efficient operation to treat degenerative lumbar diseases.