Customized Polymethylmethacrylate Cranioplasty Implants Using 3-Dimensional Printed Polylactic Acid Molds: Technical Note with 2 Illustrative Cases.

Objective: Prefabricated customized cranioplasty implants are anatomically more accurate than manually shaped acrylic implants but remain costly. The authors describe a new cost-effective technique of producing customized polymethylmethacrylate (PMMA) cranioplasty implants with the use of prefabricated 3-dimensional (3D) printed molds.

Methods: The first patient had a left frontal cranial defect after a craniotomy for a glial tumor. A 3D image of his skull was obtained from axial 0.6-mm computed tomography (CT) scan images. The image of the implant was generated by a digital subtraction mirror-imaging process using the normal side of his cranium as a model. The second patient had a bifrontal defect after the resection of an infected customized polyetheretherketone implant. A 3D image of the infected implant was directly obtained from an axial 0.6-mm CT scan before discarding it. The images were then used to produce for each patient a mold of the external surface of the cranium using a low-cost polylactic acid 3D printer. Intraoperatively, each mold was put in a sterile bag and then used to cast a customized PMMA implant subsequently trimmed before fixation.

Results: Both patients had excellent cosmetic results and underwent postoperative CT scans that showed excellent restoration of the symmetrical contours of the cranium. No neurologic or infectious complications occurred over a 6-month follow-up for either patient.

Conclusions: Making customized PMMA cranioplasty implants via 3D printed polylactic acid molds is a cost-effective technique for delayed reconstruction of various cranial defects.