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

Sir: We eagerly read the original article on virtual surgical planning outcomes for mandible reconstruction by Chang et al.1 and Dr. Hidalgo’s accompanying discussion.2 Both sections highlight important nuances of mandible reconstruction. Our institution currently uses both techniques for fibula flap contouring; thus, we felt it was important to provide additional insights. Regarding the finding that although virtual surgical planning can locate the osteotomy and determine its surface orientation, “it does not appear from this report to provide the precise angle of the osteotomy through the bone that takes into account multiple planes.” Our reply is that virtual surgical planning designs osteotomies in three planes.3,4 Cutting guides control saw position in axial, sagittal, and coronal axes for precise intraoperative execution. Traditional mandible reconstruction uses two-dimensional templates, and requires estimation to accommodate changes in the third plane.5 Therefore, reconstruction with virtual surgical planning should more accurately reflect native mandible shape. Regarding the finding that virtual surgical planning methodology “does not appear to speak to issues of graft insetting and therefore it remains a largely intuitive endeavor” for anterior and lateral defects, we believe that the virtual surgical planning flap itself provides an added normative reference that improves reconstructive accuracy. The fibula construct exactly matches the resected mandible segment, preserving anatomical proportions and positions. Thus, for anterior defects or lateral resections where the ramus portion is flail, the flap guides posterior segment positioning. Although we strongly support the use of maxillomandibular fixation to optimize occlusion, an argument could be made that it is not essential with precise virtual surgical planning execution. Does virtual surgical planning determine final graft length at the time of shaping? Typically, graft ends are left longer in case a greater resection margin proves necessary. If the oncologic resection is performed without deviation from the virtually planned resection margins using the extirpative cutting guides, the fibula construct exactly fits into the defect. Leaving longer graft ends obviates the advantages of virtual surgical planning technology. Of note, for ablative procedures, we routinely design a second wider resection virtual surgical planning in case margins change intraoperatively. Regarding the finding that shaping a reconstruction plate and then fabricating the graft to conform to it produces bone gaps, because the bone segments are fixed to the plate and not to each other, we believe that virtual surgical planning plates are bent on a stereolithographic replica of the reconstruction and conformed to the fibula construct, not the other way around. In conjunction with virtual surgical planning osteotomy accuracy, this technique practically eliminates bone gaps. Regarding the finding that there is no clear clinical difference in functional outcomes of virtual surgical planning compared to traditional methods, we agree that it is difficult to declare clinically relevant superiority with virtual surgical planning compared to traditional shaping methods in all instances. However, there are specific scenarios where the benefits of virtual surgical planning are self-evident. Large exophytic tumors and delayed reconstructions may have significantly distorted anatomy and do not provide a specimen for reference. The complex and compact geometric nature of maxillary reconstructions also may benefit from virtual surgical planning. DISCLOSURE The authors have no financial interest in any of the products or devices mentioned in this communication. Evan Matros, M.D., M.M.Sc., M.P.H.Plastic and Reconstructive Surgery ServiceDepartment of SurgeryMemorial Sloan Kettering Cancer Center John T. Stranix, M.D.Wyss Department of Plastic SurgeryNew York University Langone Medical CenterNew York, N.Y.