Application of a Computer-Assisted Navigation System (CANS) in the Delayed Treatment of Zygomatic Fractures: A Randomized Controlled Trial

Purpose: The delayed treatment of zygomatic complex (ZMC) fracture presents a difficult challenge to surgeons. The aim of this study was to compare the treatment effects of delayed surgery of ZMC fractures with and without a computer-assisted navigation system (CANS). Materials and Methods: In this observer-blinded single-site randomized clinical trial, patients with unilateral ZMC fracture were included and randomized 1: 1 to delayed treatment with or without CANS. The primary outcome measurement was the absolute bilateral differences of the ZMC eminence and width based on computed tomographic (CT) measurements 48 to 72 hours after surgery. Results: One hundred three patients with unilateral ZMC fracture without immediate treatment were enrolled, and 78 were randomized to each group. Postoperative CT measurements showed that the bilateral difference in ZMC eminence was significantly less for the navigation group than for the control group (1.24 vs 2.22 mm; P <.001). The bilateral difference in ZMC width was not significantly different between the 2 groups (0.94 vs 1.36 mm; P = .061). The percentage of patients exhibiting a morphologically symmetrical face (bilateral differences <= 2 mm in ZMC eminence and width) was 71.8%(28 of 39) for the navigation group and 35.9% (14 of 39) for the control group (P =.001). Photogrammetry showed that the average difference between the postoperative CT data and the preoperative design was smaller in the navigation group (1.30 vs 2.40 mm; P =.012). Conclusions: Use of CANS improved ZMC symmetry in patients with unilateral ZMC fracture who had delayed treatment by allowing for more accurate implementation of the preoperative plan. (C) 2016 American Association of Oral and Maxillofacial Surgeons