Feasibility of clinician-facilitated 3D printing of synthetic cranioplasty flaps

Objectives: 3D scanning and stereolithographic printing technology becoming increasingly common, however its implementation into clinical practice is in its primacy. These technologies may be esoteric to the practicing neurosurgeon. We explored a range of 3D scanning and stereolithographic techniques to create patient-specific synthetic implants. Methods: We simulated bilateral craniectomies from a single cadaveric specimen to create 3 methods of creating stereolithographically-viable virtual models. Firstly, we used pre-and-post operative CT derived bony windows to create a virtual skull model, from which the flap was extracted. Secondly, we used an entry-level 3D light-scanner to scan and render models of the individual bone pieces. Thirdly, we used an arm-mounted, 3D laser-scanner to create virtual models using a real-time approach. Results: Flaps were printed from the CT scanner and laser scanner models only, in a UV-cured polymer. The light scanner did not produce suitable virtual models for printing. The CT scanner derived models required extensive post-fabrication modification to fit the existing defects. The laser-scanner models assumed good fit within the defects without any modification. Conclusions: The methods presented varying levels of complexity in acquisition and model rendering. Each technique required hardware at varying in price points from $0 to $100,000. The laser-scanner models produced the best quality parts which bore near-perfect fit with the original defects. We discuss potential neurosurgical applications of this technology.