title: Three-dimensional computer-assisted orthognathic surgery: experience of 37 patients.
abstract: OBJECTIVE
  Three-dimensional computer-assisted orthognathic surgery has been applied to improve planning and outcome. This study presents our experience with this promising modality for simulation of surgery, prefabrication of positioning guides, and navigation of the surgery.
  
  
  METHODS
  Thirty-seven patients who received surgical simulation and intraoperative navigation for 2-jaw orthognathic surgery were recruited. Preoperative 3-dimensional cone-beam computed tomographic images were used for surgical simulation and design of intraoperative guidance. An initial surgical plan was developed and transferred for 3-dimensional virtual surgery. Modification of the surgical plan was made if facial symmetry and skeletal harmony or collision of ramus segments were concerned. The result of virtual surgery was used to design and manufacture positioning guides and perform preoperative navigation planning. During the operation, the positioning guides were used to transfer the virtual planning to actual surgery, and a real-time navigation system was used to confirm the predetermined position of the maxillomandibular complex. For assessment of the computer-assisted surgical system, the simulation image was superimposed to the postoperative image for comparison.
  
  
  RESULTS
  The computer-assisted orthognathic surgery was successfully carried out in all patients. The initial surgical plan was modified in 17 patients in whom the position of maxillomandibular complex was changed. The positioning guides were helpful in controlling the spatial position of the maxillomandibular complex. The BrainLabTR navigation system was useful to further confirm the position of the facial bone. Superimposition of the simulation and postoperative images revealed satisfactory result with acceptable errors. The difference ranged from 0.05 to 1.46 mm, with a mean value of 0.66 mm, for patients using the positioning guides; and the difference ranged from 0.07 to 2.30 mm, with a mean value of 1.20 mm, for patients using the navigation system. Overall, patient and doctor satisfaction was high.
  
  
  CONCLUSIONS
  This computer-assisted orthognathic surgery system helps to improve surgical planning, reduce surgical difficulty, facilitate positioning and fixation of the maxillomandibular complex, and improve outcome.
authors.affiliation: From the *Craniofacial Research Center, and †Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Hsiu-Hsia
authors.initials: HH
authors.lastname: Lin
authors.forename: Hsin-Wen
authors.initials: HW
authors.lastname: Chang
authors.forename: Chien-Hsuan
authors.initials: CH
authors.lastname: Wang
authors.forename: Sun Goo
authors.initials: SG
authors.lastname: Kim
authors.forename: Lun-Jou
authors.initials: LJ
authors.lastname: Lo
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D011446:Prospective Studies; D025321:Surgery, Computer-Assisted; D055815:Young Adult