Hausinterner 3D Druck von patientenspezifischen Polyetheretherketon (PEEK) Implantaten zur Deckung von großen Schädeldachdefekten - technisches Konzept und klinische Anwendung.

3D printing is commonly used to aid implant molding with Polymethylmethacrylate for cranioplastic surgery of large skull defects. 3D printing of cranial implants itself has not been implemented in a clinical setting yet, mainly due to medico-legal concerns and missing of an implant ready printing material. With a 3D printer developed for printing medical applications and implant-grade Polyetheretherketone (PEEK) filament commercially available, we established a novel workflow in compliance with the European Union Medical Device Regulation (EU MDR) to 3D print PEEK implants for cranioplastic surgery at the point of care.

A design and 3D printing process in accordance with the EU MDR under the health institution exemption (Article 5.5, Regulation (EU) 2017/745) was developed: Implants are digitally designed (Geomagic Freeform 1.0, 3D Systems) upon pre- and post-craniectomy cranial CT scans by trained 3D printing experts from the department of medical engineering at our institution. Implants are then 3D printed on a medical 3D printer (3D Systems EXT 220 MED) with implant-grade PEEK filament (Vestakeep i4 3DF, Evonik Industries) using the Fused Filament Fabrication process. After post-processing and steam sterilization, implantation for reconstruction of the cranial skull can be performed.

The first cranioplastic surgery with a 3D printed PEEK implant in a patient with a large fronto-temporo-parietal skull defect after traumatic brain injury with consecutive decompressive craniectomy was performed at our institution. No intra- or postoperative complications occurred. Postoperative cranial CT scans showed optimal reconstruction of pre-craniectomy skull shape. The esthetic result was promising and satisfactory to the patient.

This is the first published 3D printing workflow to facilitate 3D printing of patient specific cranial PEEK implants for the reconstruction of large skull defects directly at the point of care. Clinical implementation of the concept has been successfully performed. This marks an innovative technological and medico-legal advancement in the field of patient specific cranial implants, with the hospital infrastructure delivering additive manufacturing of patient specific customized skull implants. With the described 3D printing workflow cranioplastic implants – equivalent to Computer Animated Design implants – can be designed, produced and implanted at the point of care in accordance with medical device regulations.