Craniofacial reconstruction with computer-generated HTR patient-matched implants: use in primary bony tumor excision

The aim of this clinical series is to report the effectiveness and safety of using computer-generated alloplastic hard tissue replacement (HTR) implants for the reconstruction of large defects of the cranio-orbital region when combined with simultaneous bone tumor excision. Seven patients who had large nonmalignant bony lesions of the anterior cranial vault and orbit underwent simultaneous bony excision and reconstruction with preoperatively fabricated custom alloplastic implants. Preoperatively, a 3D computed tomography (CT) scan was obtained from which an anatomical model was fabricated. On the anatomical model, the predicted amount of bone excision was performed. The defect in the model was then used to create an alloplastic (HTR polymer) implant for reconstruction and surgical placement. At the time of surgery, the implant was secured into position with either metal or resorbable plates and screws. In cases where the frontal sinus was in proximity to the implant, it was either cranialized and covered with a pericranial flap or obliterated with hydroxyapatite cement. All computer-generated implants required some modification intraoperatively due to a larger amount of bony excision than was preoperatively planned. This was accomplished by modifying the sterile back-up of the implant as an addition to the original implant or completing reconstruction of the bony defect with hydroxyapatite cement. All patients have healed uneventfully with a minimum of 1 year follow-up (average, 2.6 years). In all cases, excellent contours have been maintained and all patients have remained infection-free. In the management of large benign bony tumors of the cranio-orbital region, simultaneous reconstruction with custom implants fabricated from porous, hydrophilic HTR polymer can be preoperatively fabricated based on an estimate of the subsequent bony defect. The successful use of this approach depends on a favorable tissue quality of the recipient site, a generous preoperative estimate of the amount of bone that will be resected so that the implant is adequate, intraoperative techniques of expanding the implant reconstruction, and intraoperative methods to assure a partitioning of the implant from the frontal sinus.