Application of real-time surgical navigation for zygomatic fracture reduction and fixation.

Background: Inappropriate treatment of zygomatic fractures can reduce esthetic and functional outcomes. The aim of this study was to answer the research question: "Among patients with a unilateral zygomatic fracture, is the use of computer-assisted real-time navigation system during fracture reduction precise and accurate to create postoperative facial symmetry?"

Methods: Using a retrospective cohort study design, we enrolled a cohort of unilateral zygomatic fractures undergoing open reduction and internal fixation (ORIF) with the aid of the computer-based navigation system at Chang Gung Memorial Hospital, Taiwan, during January 2015 and March 2018. The predictor variable was the comparison before and after surgery. The main outcome variables included (1) two-dimensional (2D) reduction of the displacement at five anatomical landmarks: zygomaticofrontal, inferior orbital rim, zygomaticosphenoidal, zygomaticomaxillary, and zygomaticotemporal lines/buttresses and (2) three-dimensional (3D) differences on distances between zygomatic surface to the porion plane and the midpoint of zygomatic arch (ZA) to the mid-porion (MP) plane. The Wilcoxon signed-rank test was computed to compare between pre- and postoperative data, and a p-value less than 0.05 was considered statistically significant.

Results: The cohort comprised 24 subjects (50% females, 75% left-sided) with a mean age of 30.5 +/- 13.8 years. On 2D analysis, the significant fracture reduction was found: 4.78 vs. 1.22 mm, 1.78 vs. 0.40 mm, 3.50 vs. 0.07 mm, 3.06 vs. 0.55 mm, and 2.55 vs. 0.50 mm at zygomaticomaxillary, zygomaticofrontal, inferior orbital rim, zygomaticosphenoidal, and zygomaticotemporal landmarks. The 3D evaluations revealed the significant reduction of the differences between the left and right zygomatic surface to the porion plane (4.09 ± 2.12 vs. 0.46 ± 0.35 mm) and between the left and right ZA midpoints to the MP plane (4.89 ± 2.59 vs. 0.71 ± 0.44 mm) (p<0.001 for both 2D and 3D analyses).

Conclusions: The results of this study suggest that the real-time surgical navigation system can effectively guide the ORIF of zygomatic fractures. Future research studies should focus on the learning curve and cost-effectiveness analysis of this technique.