Four-Dimensional (4D) Printing: A New Evolution in Computed Tomography-Guided Stereolithographic Modeling. Principles...

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Surgical Planning

Background:

• Three-dimensional (3D) printing has revolutionized preoperative planning by enabling rapid, affordable, office-based manufacturing of haptic biomodels.
• Traditional 3D printing techniques like stereolithography have been surpassed by newer, faster methods.
• This study introduces four-dimensional (4D) printing, incorporating time as the fourth dimension into 3D printing.

Purpose of the Study:

• To introduce and demonstrate the principles of 4D printing.
• To validate the accuracy of 4D printing in representing anatomical changes over time.
• To explore the potential of 4D printing for improving surgical preoperative planning.

Main Methods:

• Bones of the thumb ray were 3D printed across various movements to illustrate 4D printing.
• 4D computed tomography with single volume acquisition was employed to minimize radiation exposure.
• Models were fabricated using a 3D printer, with validation involving comparison of metacarpal angles from 4D imaging and printed models.

Main Results:

• 4D printing successfully depicted the transitional positions of metacarpals during thumb movements (abduction, opposition, key pinch).
• Validation confirmed the accuracy of the 4D-printed models in representing anatomical changes.
• The study successfully demonstrated the feasibility and accuracy of 4D printing for dynamic anatomical structures.

Conclusions:

• 4D printing accurately represents dynamic anatomical changes, such as metacarpal movement during thumb motion.
• The incorporation of time as a fourth dimension allows for effortless delivery of complex spatiotemporal anatomical details.
• 4D printing holds significant potential to substantially improve the precision and effectiveness of preoperative surgical planning.