Abstract
Trauma, cranial tumours, infected craniotomy bone flaps, and neurosurgical external decompressions are the main causes for large cranial defects. The main indications for cranial reconstruction of these patients are for cosmetic reasons and for protection of intracranial structures from mechanical impact. The success of reconstructive craniofacial surgery depends on a good preoperative evaluation of the deformity, formation of the surgical planning, accurate execution of the operation and preparation of precise-fitting custom implants [1].
A new method of directly producing moulds for Polymethylmethacrylate (PMMA) implants using Selective Laser Sintering (SLS) is conceived, with the aim of reducing cost and time for fabricating cranioplasty implants, by cutting down on the number of steps from the existing manufacturing techniques. Using imaging software, the three dimensional model of the skull is obtained. The implant model is constructed in Pro/Engineer by mirroring symmetrical skull profile onto the defect. MAGICS RP is used to generate a set of mould from the implant model, complete with the sprue and guide pins. This mould is then built directly on the Sinterstation 2500. After some simple post-processing, the mould is used to shape the implant using cold-cure PMMA material.
Computer Aided Verification (CAV) of the implant is carried out by 3D Scanning using the ATOS Digitizer. Comparison made between the scanned image and the initial. stl image from the CT data shows that minimal deviation has been achieved.
The application of image-based pre-fabricated custom cranioplasty implants has been proven to decrease the operating time and surgical complexity to a great extent. Further research can be carried out in the area of investigating the optimal density of the PMMA material for improved mechanical properties, and even the direct fabrication of biocompatible implants using RP techniques properties, and even the direct fabrication of biocompatible implants using RP techniques.