Cranioplasty: PEEK implant 3D printing at point of care saves costs and follows regulatory pathways
Point-of-care 3D printing becomes more and more popular, and the range of clinical applications continuously grows. With this new variety of possibilities, physicians and hospital managers face the growing challenge to deal with regulatory requirements.
This trend is clearly visible in a survey by the American Society of Mechanical Engineers (ASME) for its “Year In Review 19-20” on Medical 3D Printing (see p 21). The responses to the “greatest challenges” question given by more than 300 members of the medical 3D printing community confirm that stakeholders in medical 3D printing request clarity on regulatory frameworks, processes, and quality management.
Kumovis has developed an application-specific solution to meet these challenges and proudly introduces the manufacturing of PEEK cranial implants at the point of care. Medical technology companies and hospitals that apply this new cranial plate manufacturing framework will benefit from high patient satisfaction, gained efficiencies and cost savings, despite regulatory challenges and increasing cost pressure.
4 cornerstones of point-of-care manufacturing for cranial implants
The following four cornerstones help look into major topics of 3D printing individualized implants for cranioplasty at the point of care.
During the preparation phase, an engineer converts DICOM data into STL files and creates an individual implant design based on the patient’s data. Numerous planning software types are commercially available and compatible to the workflow outlined. Kumovis provides transparent design rules to specify parameters such as thickness and hole position. In addition, sharing specifications of part orientation in the printer’s build chamber and strategies for different implant designs and process parameters is part of the solution.
Despite the Kumovis R1 3D printer being an open filament system, the material of choice for this application-specific workflow is Evonik VESTAKEEP® i4 3DF PEEK. The medical-grade polymer is suitable for permanent implantation and can therefore be used for patient-matched cranial implant manufacturing.
The duration of the actual print job varies from 1 to 5 hours. Kumovis covers a broad range of geometries matching individual patients’ anatomies and surgeons’ preferences. We use the methodology of a design envelope to describe the patient population which is covered in the Kumovis workflow to manufacture cranial plates.
Kumovis gathered a critical quantity of implant designs to understand the variations and define worst-case geometries which represent the boundaries of the design envelope. All geometries within these boundaries will be 3D printed reliably and reproducibly following the regulatory pathway to medical device manufacturing.
Both static compression and impact test results on worst-case geometries of 3D printed implants can be compared to conventionally manufactured implants. Compression testing for cranial plates reach with Evonik VESTAKEEP® i4 3DF PEEK 3D printed on Kumovis R1 exceed the 4-fold safety factor.
Manufacturers of medical devices must work with qualified machines and fulfil regulatory requirements. In addition to the technical feasibility described above, Kumovis provides regulatory data to manufacturing patient-matched implants for cranioplasty, including machine qualification and both mechanical and biological validation.
During the process of machine qualification, acceptance criteria on mechanical properties, density and size accuracy are being defined. The influence of both part orientation and position in the build envelope will be documented and verified.
The mechanical validation process includes the definition of worst-case geometries and acceptance criteria. It also defines different 3D printing parameter sets for clustered geometries of cranial plates and defines the manufacturing process in detail. Mechanical testing procedures of static and impact tests are included in the mechanical validation, too.
The regulatory requirement of biological validation includes testing according to various norms. Beside others, Kumovis covers cytotoxicity (ISO 10993-5), sensitization (ISO 10993-10), implantation (ISO 10993-6), as well as chemical characterization and toxicological risk assessment (ISO 10993-18) to name a few. Kumovis – as the provider of the 3D printer to manufacture PEEK cranial plates – delivers an end-to-end solution from CT scan to surgery meeting both the regulatory and technological needs of medical practitioners.
Use PSI and reduce costs for cranioplasty
The cost savings resulting from the use of filament-based manufacturing for PEEK cranial plates compared to other 3D printing processes will further accelerate the adoption of patient-specific implants (PSI). Titanium printing based on powder bed technology, for example, is usually more cost intensive in terms of initial 3D printing hardware investments and post-processing requirements.
For cranioplasty, PEEK implant manufacturing using the Kumovis workflow enables affordable individualized approaches. The solution suits a broad range of healthcare systems by introducing a pay-per-part model. And it eliminates upfront investments in hardware and allows hospitals to become manufacturers of PSI using the regulatory data Kumovis provides in its license model. Let’s find your way to start 3D printing PEEK cranial implants at the point of care.