Computer-aided manufacturing of implants for the repair of large cranial defects: An improvement of the stereolithography technique

The objective of this study is to demonstrate the utility of geometric mode ling in cranioplasty; in other words, to use geometric modeling to generate a prototype that will be used as the base structure of a composite prosthe sis for covering cranial defects. This geometric model is easy to manipulat e and can be modified To achieve this goal, the top surface of a cranial bo ne Nap is digitized using a portable coordinate measurement machine. Intent ionally, a sub-surface of the bone flap, representing the skull defect, was not digitized. A geometric model of the bone flap is generated that includ es the undigitized region. With the technique described in this paper the a uthors generated the geometric model of the undigitized region (the skull d efect). The geometric model of the bone flap is further manipulated and a s eries of conical cavities are introduced. Prototypes of the geometric model s are manufactured using stereolithography. The clinical implications of th is technique are discussed.