Nils Weyer

Semiautomatic procedure for individual preforming of titanium meshes for orbital fractures.

Background: Three-dimensional reconstruction of the orbital floor is a key procedure in primary or secondary orbital deformity. A new procedure for individually bending and preforming implants preoperatively for the reconstruction of orbital fractures is presented. Methods: By using diagnostic computed tomographic scan data, the topography of the orbital floor and wall structures can be recalculated. After mirroring the unaffected side onto the affected side, the defect can be reconstructed virtually. Data of the individual virtual model of the orbital cavity are sent to a template machine that reproduces the surface of the orbital floor and medial walls automatically. A titanium mesh can then be adjusted preoperatively for exact three-dimensional reconstruction. Twelve patients with orbital fractures were treated using individually preformed titanium implants. Results: All patients treated with this procedure showed normal eye mobility and function after primary reconstruction. The accuracy of the preformed implants lies in the range of 1 mm. Conclusions: This procedure offers an individual anatomical reconstruction of the orbital cavity true to original, especially when the deep orbital cone is affected. Navigation-aided procedures guarantee intraoperatively an exact placement of the preformed mesh even for precise reconstruction of extensive orbital defects.

Suppurative Maxillary Sinusitis in Patients With Bisphosphonate-Associated Osteonecrosis of the Maxilla: Report of 2 Cases

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Increased Safety in Computer-Assisted Skull Base Surgery by Navigation-Guided Transmandibular Approach

Introduction: Computer-assisted surgery (CAS) is very helpful in the preoperative planning of surgical procedures of both soft- and hard-tissue tumors, treatment of fractures, and even in the insertion of dental implants. Intraoperative important anatomical landmarks can be identified more easily. In cases of the resection of soft-tissue tumors after chemotherapy or radiation, the old margins of the tumor can be found more easily by using the CAS and resection of the tumor is safer. Method: We present a case of a child at age 9 years who presented with increased mouth opening and swelling of the right cheek. MRI revealed a tumor in the right pterygopalatinal fossa affecting the skull base and the mandible. The biopsy showed an embryonal rhabdomyosarcoma. Result: After performing MRI and CT scans, image fusion was done for planning of the surgical procedure. The tumor and safety margins were marked. Prior to surgery, chemotherapy was performed for decreasing the tumors size. For the surgical procedure a transmandibular approach was chosen. Intraoperatively, the tumor was resected within the planned safety margins using CAS. Histologically, the tumor was resected in clean margins. Postoperatively, a radiation therapy was conducted. After 3 years, the child is still free of recurrence of the tumor. Conclusion: Using computer-assisted surgery in planning a surgical procedure, especially in soft- and hard-tissue tumors, is very helpful. Intraoperative computer-assisted surgery increases the safety of the resection of a tumor in the old margins, especially if presurgical treatment using chemotherapy and/or radiation was performed. For the treatment of an embryonal rhabdomyosarcoma, an interdisciplinary approach should be performed.