4D Printing and Computed Tomography Scans Used to Enhance Surgical Preparation

Earlier this month, thousands of surgeons from the Royal Australasian College of Surgeons and Royal College of Surgeons of England gathered into the Brisbane Convention and Exhibition Centre for the Annual Scientific Congress, an event centered around a series of workshops, discussions, plenaries, and master classes that cover a wide-range of surgical topics based on the current state of medical field. One of these discussions was focused on a case study that recently researched the use of dynamic 4D printing for preoperative planning in hand surgery.

Headed by Dr. Michael Chae, a plastic surgery resident and PhD candidate at the Melbourne, Australia-based Monash University, the research team explained how implementing the dimension of time into 3D printed haptic models helps provide improved anatomical information about the movement of the bones in a hand. The research team used 4D computed tomography (CT) to scan the bones within a patient’s hand, which helped portray an accurate representation of their hand movements during thumb abduction, opposition, and key pinch.

“Over the past decade 3D printing has transformed the way surgeons conduct preoperative planning. Here we were able to explore the application of 4D printing in surgical planning,” Dr. Chae said. “We demonstrated how 4D printing can accurately depict the translation of metacarpals during various thumb movements. With the the increasing availability of 4D CT scanners, 4D printing has the potential to become widely accessible for surgical planning and improve clinical outcomes for patients.”

3D printed haptic models representing carpal and metacarpal bones during various hand movements: abduction (left), opposition (center), and key pinch (right)

The research team utilized a 320 multidetector row Aquilion One CT scanner from Toshiba America Medical Systems, which captured the patient performing three different thumb movements, all of which were uploaded into OsiriX software, where the images were rendered and prepared for 3D printing. After exporting these 3D haptic models into .STL files and uploading them to Cubify, the research team printed the models using a Cube 2 desktop 3D printer by 3D Systems. In order to validate their research, Dr. Chae and his colleagues compared the angle between the first and the second metacarpals from the 4D CT data and the 4D printed model, which helped ensure anatomical accuracy.

Process from CT scan data to Cubify software

The case study, which is entitled “Four-Dimensional (4D) Printing: A New Evolution in Computed Tomography-Guided Stereolithographic Modeling. Principles and Application”, was published last year in the Journal of Reconstructive Microsurgery. Along with Dr. Chae, the case study was supervised and co-authored by professor David Hunter-Smith, Dr. Inoka De-Silva, Stephen Tham, Robert Spychal, and Warren Rozen.

Essentially, the research team has demonstrated the value of adding the “fourth dimension of time” into 3D printed surgical models, which in this case helped to showcase the transition in the position of metacarpals during thumb movement. These 4D printed models offer a more dynamic and fluid look into the patient’s anatomy, which will help surgeons obtain accurate and detailed patient-specific information prior to intensive surgical operations.

In other recent applications, 4D printing has been used to print with enhanced composite materials, and has also been a major tool for biomimetic printing research as well. By utilizing the 4D printing technique detailed in Dr. Chae’s research, which offers more complex spatiotemporal anatomical details in models, surgeons can greatly enhance preoperative planning. Their case study concludes that, in the near future, as 4D CT scanners become more readily available, 4D printing will help provide superior patient-specific anatomical information, which in turn will greatly improve clinical outcomes. Discuss this new technology further in the 4D Printed Surgical Models forum over at 3DPB.com.