The application of 3D printing technology in the domestic medical industry began in the late 1980s and was initially mainly used to rapidly manufacture 3D medical models. At that time, 3d printing technology was mainly used to help doctors communicate with patients, accurately judge their condition, and carry out surgical planning. It can be said that China’s exploration of the application of 3d printing technology in the medical industry has long originated, and is accompanied by the development of 3d printing technology.
In recent years, with the development of
and the growth of demand for precision and personalized medicine, 3d printing technology has been significantly developed in the breadth and depth of application in the medical industry. In terms of the breadth of applications, from the initial rapid manufacturing of medical models, gradually developed to 3d printing direct manufacturing of hearing aid casings, implants, complex surgical instruments, and 3d printed pharmaceuticals. In terms of depth, the 3d printing of non-living medical devices is developing in the direction of printing artificial tissues and organs with biological activity.
3D-printed medical models and surgical guides
A medical model is obtained by three-dimensional modeling based on the patient’s CT or MRI data before surgery, and then the model is printed out by a 3d printer. The most important role of 3d printed medical models is to allow doctors to visually see the three-dimensional structure of the surgical site before surgery, which helps doctors to plan the surgery. Especially for complex surgery, it is helpful to reduce the risk of surgery and improve the success rate of surgery. Surgical guides are an important tool for doctors to assist surgery during surgery, and 3d printing technology is especially suitable for manufacturing special-shaped or personalized guides.
From orthopedic surgery to heart surgery to liver surgery… More and more surgeries are using 3d printed medical models. For example, in 2015, Professor Peng Zhihai, director of the General Surgery Center of Shanghai First People’s Hospital, and his team used 3d printing technology to perform living donor liver transplantation for a patient from Guizhou who suffered from congenital autoimmune cirrhosis with portal hypertension. To accurately formulate surgical plans before surgery, experts thought of 3d printing technology. 3d printing will be the patient’s liver, biliary and pancreatic organs, and the corresponding lesion site in the form of a 1:1 “physical” in front of the doctor, through the accurate assessment of the scope of the lesion and the three-dimensional spatial relationship between adjacent organ tissues, the expert team determined to remove 307 grams of the patient’s liver. During hepatectomy, experts take the model into the operating room for real-time comparison during the operation. By adjusting the 3d printed model and placing it in the best anatomical position, intuitive real-time navigation is provided for key steps of the operation, and key parts are quickly identified and positioned. By accurately locating the lesions and blood vessels, real-time guidance of the joints of important vessels can improve surgical accuracy and effectively reduce surgical risk.
The accurate design of the 3D-printed surgical guide is an important guarantee for the success of the surgery. Shanghai Yidao Medical Technology Co., Ltd. uses the world-leading SSM_Knee® technology in the field of orthopedic surgical guidance to conduct three-dimensional Statistical Shape Modeling (SSM) and three-dimensional force line measurement and analysis of knee joints from multiple weight-bearing X-ray data. The whole process of osteotomy plane and artificial total knee replacement is simulated on the computer, and the guide plate for osteotomy is designed virtually and 3d printed with medical materials. During the operation, doctors only need to attach the guide plate to the joint’s surface and then implement the positioning osteotomy. The accuracy is higher than that of traditional methods, avoiding human factors, and the operation is simple without destroying the pulp cavity.
3D printing rehabilitation equipment
The real value of 3d printing for rehabilitation devices such as orthotic insoles, bionic hands, and hearing AIDS is not only to achieve accurate customization but also to replace manual production with accurate and efficient digital manufacturing technology and shorten the production cycle. Let’s take the hearing aid housing industry, which has achieved 3d printing mass customized production, as an example. Traditionally, the technician needs to make an injection mold from a model of the patient’s ear canal. The plastic product is then produced by ultraviolet light. The final shape of the hearing aid is obtained by drilling sound holes and manual processing of the plastic product. If something goes wrong in this process, the model needs to be remade. Using a 3d printer to make a hearing aid begins with the design of a silicone mold or impression of the patient’s ear canal, which is completed by a three-dimensional scanner. CAD software is then used to convert the scan data into a design file that can be read by the 3d printer. Designers can use software to modify 3D images and create final product shapes. EnvisionTec printers can print 65 hearing aid cases or 47 hearing aid models in 60 to 90 minutes.
3D printed implants
Due to bone tumors, car accidents and other bone defects, maxillofacial injuries, skull repair, etc., can not be treated with general repair products, and 3d printing products provide an effective solution, especially since these printed prostheses are tailored according to the patient’s characteristics and manufacturing.
However, the four words “tailored” only sum up one of the meanings of 3d printing technology in implant manufacturing. Another significance of 3d printing technology in this field is that it can print bionic bone trabecular micropore structures integrated with implants, which is conducive to the growth of human bones. The same is true for 3d printed standardized implants. In the past, trabecular structures were achieved by coating the surface of the implant, which did not guarantee the long-term survival of the implant. In 2015, the 3d printed artificial hip joint jointly developed by Professor Zhang Ke’s team of Peking University Third Hospital and Aikang Yicheng Company was approved by the State Food and Drug Administration, becoming the first 3D-printed implant approved for industrialization in China.
However, common implant 3d printing materials lack versatility, which limits their application in the treatment and repair of defects caused by orthopedic diseases (e.g., bone tumors). The Biomaterials Research Center at the Shanghai Institute of Silicate, Chinese Academy of Sciences, has made progress in this field. The research center is mainly engaged in the research of 3d printing multi-functional bioactive ceramics for bone repair and treatment. The research team used 3d printing technology to design a variety of experimental schemes, including the use of nutritional elements, bionic structures and functional interfaces, and thermal therapy, to develop a new type of multi-functional materials that are both therapeutic and restorative.
3D printed medicine
The impact of 3d printing technology on pharmaceuticals is mainly reflected in four aspects: first, it can achieve personalized customization of drug active ingredients; second is the personalized customization of dosage to provide patients with personalized treatment plans. This method of layer-by-layer printing allows the different coatings to be tightly bound to each other so that the maximum dose of a substance can be put into a single pill. This allows the patient to swallow smaller or smaller pills; Third, the shape can be customized. This may be a good idea for children who do not like to take medicine. Through 3d printing technology to print out a variety of interesting shapes, and coax the baby to take medicine; The fourth is to make the drug have a special microstructure through 3d printing technology, improve the release behavior of the drug, to improve the efficacy and reduce side effects. In 2015, for example, the US Food and Drug Administration (FDA) approved the world’s first tablet made entirely from 3D printing. The drug, called Spritam, was developed by Aprecia Pharmaceuticals of the United States to treat epilepsy patients. The most important significance of the Zipdose 3d printing technology used by Aprecia is to enable the drug to quickly disintegrate high doses of drugs in a small amount of water, which brings great convenience to patients when they are sick.
3D bioprinting of tissues and organs
The development time point of 3d printing applications in the medical field can be presented with a chart. Among them, the proportion of biological 3d printing on the chart is the largest: 2013-2018 biomedical implant technology gradually matured, 2013-2022 in-situ biological manufacturing technology began to appear and gradually mature, 2013-2032, 3d printing complete human organs gradually into the best.
Although the current bio-printed organs are not functional and structurally complete, they have begun to play a role in the field of drug screening testing and disease research. The clinical conversion rate of common drug screening technology is low, and the best drug test object is the human body. However, this practice is not realistic, because a person can not undertake the preliminary screening work of drugs, and second, the individual differences of patients are large, and the body structure is complex. It is an effective way to substitute the human body for drug screening after constructing tissue from human body cells in vitro. For example, Hangzhou Genofei’s mass-produced 3D-printed liver unit has been used by the pharmaceutical company Merck for drug toxicity testing. The liver is an important organ to bear the toxicity of drugs, and the demand for artificial liver is also great. The adult liver is made up of 500,000 to 1 million units called hepatic lobules, which are the basic units of liver structure and function, and mimicking the structure of the lobules to create liver units is a key step in creating an artificial liver. The tissue 3d printed by human cells and the construction of pathological models can accurately reflect the pharmacological activity of chemical and biological drugs in the human body, thereby improving the success rate of drug screening.
3D printing and stomatology
The cost of dental restoration and treatment is an important factor for dental clinics and laboratories to consider, and many prescient dental clinics and laboratories have introduced digital oral technology to improve efficiency and reduce costs. In recent years, dental restorations based on software design have become popular, and many dental clinics, laboratories, or professional denture manufacturers have introduced 3d printing technology. Digital oral technology combined with 3d printing brings high precision, low cost, high efficiency, and oral data consistent with the standardized production chain to the dental industry. 3D Science Valley believes that the more important significance of digital dental technology, including 3d printing, is to reduce the time that doctors spend manually making dental products such as models and dentures, and return their energy to the diagnosis of oral diseases and the implementation of oral surgery itself. For dental technicians, although far away from the doctor’s office, as long as the patient’s oral data, they can customize accurate dental products according to the doctor’s requirements. The process and main applications of 3D dental products can be illustrated in the following picture:
3D printing and medical device manufacturing
Manufacturing medical devices like other products, in the research and development stage of new products, need to produce product prototypes for design verification. 3d printing is an economical and fast way to prototype products, and rapid prototyping can usually be done using plastic 3d printing technologies such as FDM or SLA, which goes without saying. The potential of metal 3d printing technology in the field of medical devices has gone beyond prototyping to take on the task of manufacturing complex surgical instruments. For example, in knee ACL injury repair surgery, doctors first remove the remaining ACL, and then accurately replace the upper graft ligament. To ensure that the surgery is accurate and minimally invasive, the doctor needs to use a precise and special surgical tool.
The nickel-chromium alloy used to manufacture this tool is a difficult material, and it is very difficult to manufacture this surgical tool using traditional machining methods, it takes a long time and high cost. In this case, the use of metal 3D printing technology for manufacturing is more suitable.
