Medical 3DP: Orthopedic implant, Stryker chief engineer study

Abtin Eshraghi is the head of Stryker ElStree's custom design department. During his tenure at Stanmore, he worked as an implant design engineer for seven years, designing more than 750 personalized implants for patients, including in 2011, the first personalized 3D printed pelvic bone replacement in the UK. Abtin is good at implant design for bone tumors and other joint replacements. He has continuously improved the control process of implant design and has become an expert in the field of supervision and risk assessment, helping products meet international regulations such as FDA CFR 820.30 and ISO13485 as much as possible.

Personalized implants and their applications:

Personalized implants can be designed more specific to the location of the disease, the bone condition of the patient, and the usage habits of the physician to achieve a better treatment effect. For example, in the treatment of bone tumors, it is necessary to remove the bone mass from the bone tumor and then implant the prosthesis. The personalized implant can be designed according to the specific needs of the disease as the location, shape and size of the bone tumor, and the patient's bone density, age, etc. can also be included in the design parameters of the prosthesis. Also, the prosthesis can be designed according to the specific needs of the physician.

For areas with more complex bony structures such as the pelvis and skull, personalized implants have more advantages. For example, for the treatment of pelvic defect fractures, it is necessary to implant a semi pelvic prosthesis to achieve pelvic function. Due to the individualized differences of pelvic fractures, it is required to design individualized sizes for different pelvic prostheses so that they can fit the human bone structure to achieve functional reduction. For the treatment of long bones with bone tumors, it is also necessary to replace the backbone with a personalized prosthesis.

Semi- Pelvic Prosthesis

At present, personalized implants are widely used in various parts of the body such as the acetabulum, knees, upper limbs and lower limbs, including long bones such as femur and tibia and irregular bones such as pelvis and humerus. More and more companies have begun to develop and produce extendable personality. Modified implants to suit different usage needs.

Extendible Prosthesis

Comparison of different registration procedures and standards in Europe and the United States:

Currently, most medical device registration regulations are based on mass production and standardized products. Although personalized implants are devices produced according to the needs of a certain patient and will not enter mass production, they must also comply with relevant medical device regulatory regulations like other medical devices. For example, customized pelvic implants must comply with ISO7206-2. As each medical device manufacturer has its regulations and standards, there is no unified standard in the market, but there are two more mainstream standards: ISO 13485 (International Standard for Medical Device Quality Management System) and CFR 21 Part 820 (Medical Device Quality System Standard, FDA).

For personalized prostheses, there are three ways to enter the European and American markets: (1) obtain product identification; (2) humanitarian exemption; (3) customized channels. The specific methods and precautions are as follows:

1. European Union

(1) Register to obtain the CE mark. This method requires registration of product parameters, worst-case inspection, etc. The process is the same as that of standardized products, so it is more difficult and time-consuming.

(2) Humanitarian immunity. This method depends on national or regional policies and can only be targeted at specific cases. Generally speaking, a series of risk-benefit assessment certificates and doctor's consent is required, and specific applications and patient conditions are required.

(3) Customized channels. Entering the market by registering customized devices requires specific certifications.

2. United States

(1) Obtain 510k certification. The registration process is the same as for standardized products, so it is also time-consuming.

(2) Humanitarian immunity. This method requires a qualified surgeon to make a request, and submit an application report with the notarized consent of other independent doctors, the consent of the patient, and the permission of the ethics committee (IRB). The whole process takes about ten days.

(3) Customized channels. It also needs to comply with specific certifications, and there are quantitative restrictions.

Although the above mentioned EU and US registration methods are roughly the same, there are still some differences in specific implementation details. For example, in terms of customized channels, the United States allows the addition of customized modifications to the design of standard devices to form customized devices, while it is not the same in EU standards.

Overview of the registration process:

Based on years of experience in the market and clinical registration, Abtin proposed a complete set of customized product processes, from patient needs to final shipment and use, covering various aspects such as risk management systems design and production processes, so that products better meet international standards.

Flow chart of customized product production

Stryker: Stryker is the world's largest orthopedic medical technology company, headquartered in Michigan, USA. Its products involve joint orthopedic implants, spinal fixation, pain intervention equipment, and personalized orthopedic implants. In 2016, Stryker acquired the implant company Stanmore Implants, making it more competitive in the field of personalized orthopedic implants.