title: Precise positioning of an intraoral distractor using augmented reality in patients with hemifacial microsomia.
abstract: BACKGROUND
  Through three-dimensional real time imaging, augmented reality (AR) can provide an overlay of the anatomical structure, or visual cues for specific landmarks. In this study, an AR Toolkit was used for distraction osteogenesis with hemifacial microsomia to define the mandibular osteotomy line and assist with intraoral distractor placement.
  
  
  METHODS
  20 patients with hemifacial microsomia were studied and were randomly assigned to experimental and control groups. Pre-operative computed tomography was used in both groups, whereas AR was used in the experimental group. Afterwards, pre- and post-operative computed tomographic scans of both groups were superimposed, and several measurements were made and analysed.
  
  
  RESULTS
  Both the conventional method and AR technique achieved proper positioning of the osteotomy planes, although the AR was more accurate. The difference in average vertical distance from the coronoid and condyle process to the pre- and post-operative cutting planes was significant (p < 0.01) between the two groups, whereas no significant difference (p > 0.05) was observed in the average angle between the two planes. The difference in deviations between the intersection points of the overlaid mandible across two cutting planes was also significant (p < 0.01).
  
  
  CONCLUSIONS
  This study reports on an efficient approach for guiding intraoperative distraction osteogenesis. Augmented reality tools such as the AR Toolkit may be helpful for precise positioning of intraoral distractors in patients with hemifacial microsomia in craniofacial surgery.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Rd, Shanghai, 200011, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Qu
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Rd, Shanghai, 200011, China.
authors.forename: Yikang
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Rd, Shanghai, 200011, China.
authors.forename: Yourong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Rd, Shanghai, 200011, China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Shen
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Rd, Shanghai, 200011, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhu
authors.affiliation: National Digital Manufacturing Technology Center, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Le
authors.initials: L
authors.lastname: Xie
authors.affiliation: National Digital Manufacturing Technology Center, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Rd, Shanghai, 200011, China. Electronic address: zhangyanh129@outlook.com.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Rd, Shanghai, 200011, China. Electronic address: 13918218178@163.com.
authors.forename: Gang
authors.initials: G
authors.lastname: Chai
mesh_terms: D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000379:methods; D003196:Computer Graphics; D017076:Computer-Aided Design; D057918:Fiducial Markers; D006053:Goldenhar Syndrome / Q000601:surgery*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007223:Infant; D016268:Internal Fixators; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery; D008335:Mandibular Condyle / Q000000981:diagnostic imaging; D017090:Occlusal Splints; D019857:Osteogenesis, Distraction / Q000295:instrumentation*; D010027:Osteotomy / Q000295:instrumentation; D011897:Random Allocation; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D014584:User-Computer Interface
keywords: Augmented reality; Hemifacial microsomia; Intraoral distractor; Mandibular distraction osteogenesis; Three-dimensional real time imaging