INDIVIDUAL PREFABRICATED TITANIUM IMPLANTS IN RECONSTRUCTIVE CRANIOFACIAL SURGERY - CLINICAL AND TECHNICAL ASPECTS OF THE FIRST 22 CASES

The reconstruction of craniofacial bone defects by intraoperative mode ling of implants restricts the choice of material and its biocompatibi lity and also reduces the predictability of the aesthetic result. Thes e shortcomings go hand in hand with a prolonged surgical procedure tim e and increased stress on the patient. In contrast, modern industrial computer-aided design and computer-aided manufacturing systems allow t he prefabrication of titanium implants, i.e., individual computer-base d three-dimensional models of the bone defect are generated after acqu isition, transfer, and evaluation of helical computed tomographic data . Based on these data, the individual shape of the implant is designed using freeform-surfaces geometries and is fabricated by a numerically controlled milling machine in a direct fashion. The conical margins o f this implant are designed with a precision of 0.25 mm to the borders of die defect, and the surface contours are generated harmonically to the nonaffected neighboring contours with a constant thickness of 1.5 mm. Individual constructions for fixation with the dimensions of micr oplates are integrated in this process if screw holes cannot be drille d in thin overlapping implant margins. The reconstruction of 22 posttr aumatic, postoperative, or primary cranial and craniofacial defects me asuring up to 18 cm was performed using this new method. Wound healing was uneventful in all but one case, although some of the patients had been operated on several times before. The result was always predicta ble and constant using this highly precise technique, and duration of surgery was reduced dramatically.