Long-Term Operative Outcomes of Preoperative Computed Tomography–Guided Virtual Surgical Planning for Osteocutaneous Free Flap Mandible Reconstruction

Sir: We thank Dr. Hidalgo for his comments regarding graft shaping and insetting for osteocutaneous free flap reconstruction of mandibulectomy defects.1,2 Certainly, designing the bony segments of the osteocutaneous flap requires a significant amount of precision and accuracy to match the natural contour of the native mandible. Perhaps one of the major benefits of virtual surgical planning is assisting the reconstructive surgeon with graft shaping. Preoperative computed tomographic scans of the native mandible and donor site are obtained. During the preoperative planning session, the location and angle of the osteotomies along the mandible and osteocutaneous flap are designed in a 360-degree plane using three-dimensional images obtained from the radiographic scans. Osteotomy guides are fashioned for both the mandible and the osteocutaneous flap so that the angles are appropriately aligned. Regardless of the mandibulectomy defect, virtual surgical planning allows for precise orientation of the bony segments to each other and the native mandible in multiple planes. For lateral defects, a closing wedge osteotomy is designed resulting in two segments to account for the lateral displacement and angulation (Fig. 1). In the case of an anterior mandibulectomy, the prebent reconstruction plate based on the preoperative computed tomographic images allows placement of the holes within the mandible before resection. Once the flap is secured to the plate, the entire construct is aligned to the native mandible to maintain adequate projection and midline symmetry.Fig. 1.: (Left) Shaping of osteocutaneous free fibula flap segments for lateral mandibulectomy defect (blue, native mandible; green, fibula flap segment 1; tan, fibula flap segment 2). (Right) Insetting of osteocutaneous free fibula flap with superimposed lateral mandibulectomy defect (blue, native mandible; red, native mandible to be resected; green, fibula flap segment 1; tan, fibula flap segment 2).Virtual surgical planning precisely determines the angle and length of the bony segments to align with the native mandible. Additional length along the bone is not necessary, as virtual surgical planning measures the exact amount of mandible to be resected and the corresponding amount of bone required to reconstruct the defect. This decreases the need for revisions to the flap in terms of additional cutting, burring, or shaping of the bone. The author correctly assesses that management of the temporomandibular joint can be a difficult problem that is not addressed by virtual surgical planning. This is largely dependent on the extent of the mandibulectomy necessary for complete resection of the tumor. If there is an adequate amount of lateral bone to allow fixation of the plate, preservation of the temporomandibular joint is possible. If not, the temporomandibular joint may be resected and the lateral end of the bone segment is left free or sutured to the mandibular fossa. DISCLOSURE The author has no commercial associations or financial disclosures that might pose or create a conflict of interest with information presented in this communication. No funding was received for this work. Eric I. Chang, M.D.Division of Plastic and Reconstructive SurgeryFox Chase Cancer Center333 Cottman AvenuePhiladelphia, Pa. 19111[email protected]