How Accurate Is Computer-Assisted Orbital Hypertelorism Surgery? Comparison of the Three-Dimensional Surgical Planning with the Postoperative Outcomes.

Abstract

Importance: Surgery of orbital hypertelorism (ORH) remains an imprecise surgical procedure depending on the experience and habits of the craniofacial surgical teams. Computer-assisted surgery (CAS) has developed dramatically in craniofacial surgery, but there is no current study assessing its accuracy for ORH surgery. Objective: This study aimed to assess the input of CAS and especially the accuracy of the cutting guide-based procedures. The authors presented the computer-assisted box osteotomy or facial bipartition techniques and compared the preoperative surgical planning with the postoperative results. Design, Setting, and Participants: A monocentric retrospective study included the patients who underwent surgical correction of ORH from 2016 to 2019 at the University Hospital Center of Tours, France. All the patients had a computer-assisted orbital hypertelorism surgery (CAOHS) using cutting guides and tailored fixation plates. Of 10 patients included, 7 were treated by box osteotomies and 3 by facial bipartitions. Intervention: Each patient had a preoperative computed tomography (CT) scan enabling a virtual simulation of the reconstruction and the manufacturing of patient-specific cutting guides and customized osteosynthesis plates. The postoperative CT scans were compared with the three-dimensional (3D) virtual simulation using the distances between the sagittal plane and orbital and infraorbital reference points, and from the measurement of the orbital advancement (i.e., 10 reference measurements). Results: All patients had satisfactory clinical and aesthetical outcomes with a mean interorbital distance of 22.8 ± 2.8 mm. The postoperative measurements were significantly higher than for the surgical planning (p < 0.0001). The average absolute differences between the 3D virtual planning and the postoperative CT scans were <1.30, 1.90, and 0.80 mm for the orbital, infraorbital, and orbital advancement measurements, respectively. The overall accuracy of the CAOHS (root mean square deviation) was 1.39 mm. Conclusions: The use of computer-assisted design and computer-aided manufacturing device, such as cutting guides and tailored plates, facilitates the bony surgical correction of ORH using box osteotomy or facial bipartition and allows for valuable, reproducible, and satisfactory clinical outcomes.