title: Verifying three-dimensional skull model reconstruction using cranial index of symmetry.
abstract: BACKGROUND
  Difficulty exists in scalp adaptation for cranioplasty with customized computer-assisted design/manufacturing (CAD/CAM) implant in situations of excessive wound tension and sub-cranioplasty dead space. To solve this clinical problem, the CAD/CAM technique should include algorithms to reconstruct a depressed contour to cover the skull defect. Satisfactory CAM-derived alloplastic implants are based on highly accurate three-dimensional (3-D) CAD modeling. Thus, it is quite important to establish a symmetrically regular CAD/CAM reconstruction prior to depressing the contour. The purpose of this study is to verify the aesthetic outcomes of CAD models with regular contours using cranial index of symmetry (CIS).
  
  
  METHODS
  From January 2011 to June 2012, decompressive craniectomy (DC) was performed for 15 consecutive patients in our institute. 3-D CAD models of skull defects were reconstructed using commercial software. These models were checked in terms of symmetry by CIS scores.
  
  
  RESULTS
  CIS scores of CAD reconstructions were 99.24±0.004% (range 98.47-99.84). CIS scores of these CAD models were statistically significantly greater than 95%, identical to 99.5%, but lower than 99.6% (p<0.001, p = 0.064, p = 0.021 respectively, Wilcoxon matched pairs signed rank test). These data evidenced the highly accurate symmetry of these CAD models with regular contours.
  
  
  CONCLUSIONS
  CIS calculation is beneficial to assess aesthetic outcomes of CAD-reconstructed skulls in terms of cranial symmetry. This enables further accurate CAD models and CAM cranial implants with depressed contours, which are essential in patients with difficult scalp adaptation.
authors.affiliation: Department of Exercise and Health Promotion, College of Education, Chinese Culture University, Taipei, Taiwan ; Department of Neurosurgery, Lo-Hsu Foundation, Lotung Poh-Ai Hospital, Luodong, Yilan, Taiwan ; Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Woon-Man
authors.initials: WM
authors.lastname: Kung
authors.forename: Shuo-Tsung
authors.initials: ST
authors.lastname: Chen
authors.forename: Chung-Hsiang
authors.initials: CH
authors.lastname: Lin
authors.forename: Yu-Mei
authors.initials: YM
authors.lastname: Lu
authors.forename: Tzu-Hsuan
authors.initials: TH
authors.lastname: Chen
authors.forename: Muh-Shi
authors.initials: MS
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017076:Computer-Aided Design; D056424:Decompressive Craniectomy; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D019736:Prostheses and Implants; D011474:Prosthesis Design / Q000379:methods*; D012886:Skull / Q000033:anatomy & histology*