Customized Cranioplasty Implants Using Three-Dimensional Printers and Polymethyl-Methacrylate Casting

TLDR

Customized cranioplastic implants were introduced to overcome intra‑operative molding difficulties. The study presents a technique for prefabricating implant molds with 3D printers and PMMA casting to treat large skull defects. The method uses 3D CT imaging, mirror‑image or merged data modeling, 3D‑printed molds, and intra‑operative PMMA casting to create the implant. In 16 patients, the technique achieved excellent contour restoration, a median operation time of 184 min, a 23‑month median follow‑up, and a 6.2% infection rate, demonstrating its usefulness.

Abstract

The prefabrication of customized cranioplastic implants has been introduced to overcome the difficulties 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.A total of 16 patients with large skull defects (>100 cm(2)) 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 implant 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 fit into the cranial defect.The median operation time was 184.36±26.07 minutes. Postoperative CT scans showed excellent restoration of the symmetrical contours 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.Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects.