The Pros and Cons of Computer-Aided Surgery for Segmental Mandibular Reconstruction after Oncological Surgery

Abstract

Computer-aided surgery (CAS) started being used for head and neck reconstruction in the late 2000s. Its use represented a paradigm shift, changing the concept of head and neck reconstruction as well as mandible reconstruction. Reconstruction using CAS proceeds through 4 phases: planning, modeling, surgery, and evaluation. Thus, it can overcome a number of trial-and-error issues which may occur in the operative field and reduce surgical time. However, if it is used for oncologic surgery, it is difficult to evaluate tumor margins during tumor surgery, thereby restricting pre-surgical planning. Therefore, it is dangerous to predetermine the resection margins during the pre-surgical phase and the variability of the resection margins must be taken into consideration. However, it allows for the preparation of a prebending plate and planning of an osteotomy site before an operation, which are of great help. If the current problems are resolved, its applications can be greatly extended.

Keywords: Computer-aided surgery; Mandible; Mandibular reconstruction; Microsurgical free flaps; Resection margin.

Fig. 1. (A, B) Computer-aided reconstruction of an extensive composite mandibular defect. A 67-year-old male patient with invasive squamous cell carcinoma on the right lower lip. (C, D) A transparent view of the tumor invading the mandibular bone with the vascular pedicle candidates for reconstruction. (E) The tumor-invading mandible was reconstructed as a three-dimensional (3D) object and the resection extent was estimated (dark cyan). (F) Given this estimation, an actual scale rapidly-prototyped patient mandible was manufactured for prefabrication of the reconstruction plate in order to shorten the operation time. (G) For precise preoperative planning and measurement of length, the image slicing plane was calibrated to a plane containing the axis of the donor fibular bone and peroneal artery, and the images were reconstructed as a 3D object. (H) Intraoperative markings and (I) the surgeon's view of the pedicle while harvesting the fibular flap. (J, K) A postoperative 3D view taken four weeks after mandibular reconstruction showing excellent restoration of the mandibular contour and continuity. (L, M) Six-month follow-up view of the patient after adjuvant radiation therapy.