Verifying three-dimensional skull model reconstruction using cranial index of symmetry

• Published in: PloS one Vol. 8; no. 10; p. e74267
• Main Authors: Kung, Woon-Man, Chen, Shuo-Tsung, Lin, Chung-Hsiang, Lu, Yu-Mei, Chen, Tzu-Hsuan, Lin, Muh-Shi
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 25.10.2013; Public Library of Science (PLoS)
• Subjects: 3-D graphics; Adaptation; Adult; Aged; Aged, 80 and over; Algorithms; CAD/CAM; Computer aided manufacturing; Computer engineering; Computer science; Computer-Aided Design; Contours; Decompressive Craniectomy; Defects; Female; Fractures; Health promotion; Humans; Imaging, Three-Dimensional; Implants; Male; Medical imaging; Medicine; Middle Aged; Models, Anatomic; Neurosurgery; Patients; Polymethyl methacrylate; Program verification (computers); Prostheses and Implants; Prosthesis Design - methods; Reconstruction; Scalp; Shape; Skull; Skull - anatomy & histology; Statistical analysis; Surgery; Symmetry; Three dimensional models; Titanium; Transplants & implants; Traumatic brain injury; Wounds; Taiwan
• DOI: 10.1371/journal.pone.0074267
• ISSN: 1932-6203

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). 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. 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. 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.