title: Four-Dimensional (4D) Printing: A New Evolution in Computed Tomography-Guided Stereolithographic Modeling. Principles and Application.
abstract: BACKGROUND
  Over the last decade, image-guided production of three-dimensional (3D) haptic biomodels, or rapid prototyping (RP), has transformed the way surgeons conduct preoperative planning. In contrast to earlier RP techniques such as stereolithography, 3D printing has introduced fast, affordable office-based manufacturing. We introduce the concept of 4D printing for the first time by introducing time as the fourth dimension to 3D printing.
  
  
  METHODS
  The bones of the thumb ray are 3D printed during various movements to demonstrate four-dimensional (4D) printing. Principles and validation studies are presented here.
  
  
  RESULTS
  4D computed tomography was performed using "single volume acquisition" technology to reduce the exposure to radiation. Three representative scans of each thumb movement (i.e., abduction, opposition, and key pinch) were selected and then models were fabricated using a 3D printer. For validation, the angle between the first and the second metacarpals from the 4D imaging data and the 4D-printed model was recorded and compared.
  
  
  CONCLUSIONS
  We demonstrate how 4D printing accurately depicts the transition in the position of metacarpals during thumb movement. With a fourth dimension of time, 4D printing delivers complex spatiotemporal anatomical details effortlessly and may substantially improve preoperative planning.
authors: Department of Plastic and Reconstructive Surgery, Frankston Hospital, Victoria, Australia.
authors: Michael P
authors: MP
authors: Chae
authors: Department of Plastic and Reconstructive Surgery, Frankston Hospital, Victoria, Australia.
authors: David J
authors: DJ
authors: Hunter-Smith
authors: Department of Surgery, Monash University, Victoria, Australia.
authors: Inoka
authors: I
authors: De-Silva
authors: Department of Surgery, Monash University, Victoria, Australia.
authors: Stephen
authors: S
authors: Tham
authors: Department of Plastic and Reconstructive Surgery, Frankston Hospital, Victoria, Australia.
authors: Robert T
authors: RT
authors: Spychal
authors: Department of Plastic and Reconstructive Surgery, Frankston Hospital, Victoria, Australia.
authors: Warren Matthew
authors: WM
authors: Rozen
mesh_terms: D005260:Female; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D050279:Metacarpal Bones / Q000000981:diagnostic imaging*; D009068:Movement; D011327:Printing / Q000379:methods*; D013933:Thumb / Q000000981:diagnostic imaging* / Q000502:physiology*; D014057:Tomography, X-Ray Computed / Q000379:methods*