Xiangya Hospital of Central South University said on the 15th that the team of Professor Hu Yi of the Department of Orthopaedics of the hospital recently performed a 3D printed personalized custom bionic trabecular porous tantalum metal stent implantation for a femoral head necrosis patient. Foreign technology monopoly.
The most common treatment for patients with femoral head necrosis is titanium. This time, Professor Hu's team independently developed the 3D printed bionic trabecular porous tantalum metal scaffold. This product is the result of the national key research and development plan "3D printed personalized implant device clinical application research and promotion".
According to Hu Yan, compared to titanium, tantalum is more biocompatible, the human body is less prone to rejection reactions, and the elastic modulus of tantalum is closer to bone tissue, which is more suitable for bionic trabecular structure of the human body. Bone tissue growth rate is much higher than titanium metal, which can promote the rapid growth of bone cells into the pores of tantalum metal rods.
However, at present, a few companies making this material in the world are manufacturing "one-size" cylindrical tantalum metal rods, and their regular "honeycomb" pore structure does not fit the human bone trabecular structure. To this end, the Hu team and the team of Professor Zhou Kechao of the State Key Laboratory of Powder Metallurgy of Central South University jointly developed domestically produced tantalum metal powder materials, and through repeated design and 3D printing for more than a year, customized a "tantalum Baton".
"We work closely with algorithm engineers to design according to the irregular structure of the patient's bone trabeculae. Compared with the regular 'honeycomb' structure of imported tantalum metal rods, its elastic modulus and surface friction coefficient are more comparable to human cancellous bone. To get closer, it is better to “camouflage” the osteogenic trabeculae and induce bone invasion. ”Hu Yan said, this design cannot be achieved through traditional machining or chemical vapor deposition, and only 3D printing can do it.
After 3D printing the tantalum metal rod of the bionic trabecular structure, how to speed up the growth of bone tissue? Professor Hu Yi's team uses the "bionic" method for innovation. Using the "biological" characteristics of tantalum metal, the team sowed "seeds" in tantalum metal rods, and bone tissue could grow on the internal and external surfaces of the prosthesis at the same time, eventually achieving a complete fusion of porous tantalum metal rods and the human body.
"We designed a spiral self-locking device at the end of the tantalum metal rod, similar to the 'expanding screw', so patients don't have to worry about the tantalum metal rod withdrawing after the operation; we will also design a locking mechanism for press-fit blow implantation. "Lei Pengfei, an orthopedic surgeon and postdoctoral fellow in biomedical materials at Xiangya Hospital, said that the surgery also used 3D printed mold positioning technology to create a" dual-oriented "surgical guide to avoid the need to adjust the position of the prosthesis during surgery, which greatly shortened the operation. time.