title: Computer-Assisted Orthognathic Surgery for Patients with Cleft Lip/Palate: From Traditional Planning to Three-Dimensional Surgical Simulation.
abstract: BACKGROUND
  Although conventional two-dimensional (2D) methods for orthognathic surgery planning are still popular, the use of three-dimensional (3D) simulation is steadily increasing. In facial asymmetry cases such as in cleft lip/palate patients, the additional information can dramatically improve planning accuracy and outcome. The purpose of this study is to investigate which parameters are changed most frequently in transferring a traditional 2D plan to 3D simulation, and what planning parameters can be better adjusted by this method.
  
  
  METHODS
  This prospective study enrolled 30 consecutive patients with cleft lip and/or cleft palate (mean age 18.6±2.9 years, range 15 to 32 years). All patients received two-jaw single-splint orthognathic surgery. 2D orthodontic surgery plans were transferred into a 3D setting. Severe bony collisions in the ramus area after 2D plan transfer were noted. The position of the maxillo-mandibular complex was evaluated and eventually adjusted. Position changes of roll, midline, pitch, yaw, genioplasty and their frequency within the patient group were recorded as an alternation of the initial 2D plan. Patients were divided in groups of no change from the original 2D plan and changes in one, two, three and four of the aforementioned parameters as well as subgroups of unilateral, bilateral cleft lip/palate and isolated cleft palate cases. Postoperative OQLQ scores were obtained for 20 patients who finished orthodontic treatment.
  
  
  RESULTS
  83.3% of 2D plans were modified, mostly concerning yaw (63.3%) and midline (36.7%) adjustments. Yaw adjustments had the highest mean values in total and in all subgroups. Severe bony collisions as a result of 2D planning were seen in 46.7% of patients. Possible asymmetry was regularly foreseen and corrected in the 3D simulation.
  
  
  CONCLUSIONS
  Based on our findings, 3D simulation renders important information for accurate planning in complex cleft lip/palate cases involving facial asymmetry that is regularly missed in conventional 2D planning.
authors.affiliation: Department of Plastic and Reconstructive Surgery and Craniofacial Research Center, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lonic
authors.affiliation: Department of Craniofacial Orthodontics, and Craniofacial Research Center, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Betty Chien-Jung
authors.initials: BC
authors.lastname: Pai
authors.affiliation: Department of Plastic and Reconstructive Surgery and Craniofacial Research Center, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Division of Plastic Surgery, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Peerasak
authors.initials: P
authors.lastname: Chortrakarnkij
authors.affiliation: Craniofacial Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Hsiu-Hsia
authors.initials: HH
authors.lastname: Lin
authors.affiliation: Department of Plastic and Reconstructive Surgery and Craniofacial Research Center, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Lun-Jou
authors.initials: LJ
authors.lastname: Lo
mesh_terms: D000293:Adolescent; D000328:Adult; D002971:Cleft Lip / Q000601:surgery*; D002972:Cleft Palate / Q000601:surgery*; D005146:Facial Asymmetry / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D057909:Orthognathic Surgery / Q000379:methods*; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D011446:Prospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D055815:Young Adult