title: Pre-operative simulation of periacetabular osteotomy via a three-dimensional model constructed from salt.
abstract: BACKGROUND
  Periacetabular osteotomy (PAO) is an effective joint-preserving procedure for young adults with developmental dysplasia of the hip. Although PAO provides excellent radiographic and clinical results, it is a technically demanding procedure with a distinct learning curve that requires careful 3D planning and, above all, has a number of potential complications. We therefore developed a pre-operative simulation method for PAO via creation of a new full-scale model.
  
  
  METHODS
  The model was prepared from the patient's Digital Imaging and Communications in Medicine (DICOM) formatted data from computed tomography (CT), for construction and assembly using 3D printing technology. A major feature of our model is that it is constructed from salt. In contrast to conventional models, our model provides a more accurate representation, at a lower manufacturing cost, and requires a shorter production time. Furthermore, our model realized simulated operation normally with using a chisel and drill without easy breakage or fissure. We were able to easily simulate the line of osteotomy and confirm acetabular version and coverage after moving to the osteotomized fragment. Additionally, this model allowed a dynamic assessment that avoided anterior impingement following the osteotomy.
  
  
  RESULTS
  Our models clearly reflected the anatomical shape of the patient's hip. Our models allowed for surgical simulation, making realistic use of the chisel and drill. Our method of pre-operative simulation for PAO allowed for the assessment of accurate osteotomy line, determination of the position of the osteotomized fragment, and prevented anterior impingement after the operation.
  
  
  CONCLUSIONS
  Our method of pre-operative simulation might improve the safety, accuracy, and results of PAO.
authors.affiliation: Department of Orthopedic Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Fukushima
authors.affiliation: Department of Rehabilitation, Kitasato University School of Allied Health Sciences, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
authors.forename: Naonobu
authors.initials: N
authors.lastname: Takahira
authors.affiliation: Department of Orthopedic Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
authors.forename: Katsufumi
authors.initials: K
authors.lastname: Uchiyama
authors.affiliation: Department of Orthopedic Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Moriya
authors.affiliation: Department of Orthopedic Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Takaso