Customized cranioplasty implants using three-dimensional printers and polymethyl-methacrylate casting

Objective: The prefabrication of customized cranioplastic implants has been introduced to overcome the diffculties of intra-operative implant molding. The authors present a new technique, which consists of the prefabrication of implant molds using three-dimensional (3D) printers and polymethyl-methacrylate (PMMA) casting. Methods: A total of 16 patients with large skull defects (>100 cm²) underwent cranioplasty between November 2009 and April 2011. For unilateral cranial defects, 3D images of the skull were obtained from preoperative axial 1-mm spiral computed tomography (CT) scans. The image of the im-plant was generated by a digital subtraction mirror-imaging process using the normal side of the cranium as a model. For bilateral cranial defects, precraniectomy routine spiral CT scan data were merged with postcraniectomy 3D CT images following a smoothing process. Prefabrication of the mold was performed by the 3D printer. Intraoperatively, the PMMA implant was created with the prefabricated mold, and ft into the cranial defect. Results: The median operation time was 184.36±26.07 minutes. Postoperative CT scans showed excellent restoration of the symmetrical con-tours and curvature of the cranium in all cases. The median follow-up period was 23 months (range, 14-28 months). Postoperative infection was developed in one case (6.2%) who had an open wound defect previously. Conclusion: Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects.