Finally, this is the third part in the series of posts about Meshmixer being a tool of choice for medical professionals and researchers when it comes to driving innovation in the healthcare industry and making a difference in patients’ lives. Part 1 and Part 2 covered stories from Toronto, New York and Melbourne. This story comes from Winnipeg.
Today I’m having a conversation with Dr. Daniel Rickey, medical physicist for CancerCare Manitoba. Dr. Rickey received his Ph.D. in Medical Biophysics for work on quantifying Doppler ultrasound instrumentation. He holds appointments at the University of Manitoba as an assistant professor of radiology and adjunct professor in the Department of Physics and Astronomy. He teaches graduate-level courses in medical imaging. He also delivers lectures on imaging physics to radiology residents. He is past chair of the Imaging Committee for the Canadian Organization of Medical Physicists.
RS: Hi Daniel, can you please give us some background; what does your lab do?
Dr. Daniel Rickey: I work with a small group of imaging physicists who provide support to all of the hospitals located in Manitoba. (Note that although we are based in a cancer centre, this is an unusual arrangement. Most of our work is directed outside of the building.) We help the radiology sites with the technical aspects of the medical imaging equipment, such as setting up their quality control programs. As a result, we commonly work with many different groups including regulators, technologists and radiologists.
I am a medical physicist who specializes in medical imaging, mostly ultrasound and magnetic resonance imaging. One of my biggest achievements is working with a small group to update the radiation protection legislation for Manitoba.
RS: This is a very modest description! What impact does your foray into 3D printing have on patients? How many of them benefit from this service?
Dr. Daniel Rickey: I started working with 3D printing a few years ago, purely out of interest. I quickly found that imaging physics is well positioned to take a lead role in implementing 3D printing within healthcare. Currently, I routinely make 3D-printed models for surgeons. These are for trauma or cancer patients who require reconstructive surgery. To date, I have made models for about 40 patients.
RS: Is there a difference in what gets printed for cancer patients vs. trauma patients?
Dr. Daniel Rickey: All of the models are used for pre-surgical planning. Specifically, they are used to help the surgeon pre-bend a titanium reconstruction plate. The idea is that the plate will be an exact fit to the patient’s anatomy. The advantage is that the plate bending takes place in advance of the surgery, which is less stressful and more cost effective. In addition, printed models enable the surgeons to better plan the surgery and anticipate any problems.
RS: How does it make you feel knowing that your work saves people’s lives?
Dr. Daniel Rickey: (The models probably don’t save lives.) The impact of these 3D prints is best summarized by a comment made by a plastic surgeon I work with. He said prints “make the procedure more accurate, faster, less stressful, with more predictable outcomes.” It’s great knowing that each model helps a specific patient.
RS: Is there something unique or cutting-edge about what you do?
Dr. Daniel Rickey: We have worked together to introduce other advancements, including cutting guides used in reconstructive surgeries of the mandible for cancer patients. These guides are used during the surgery to show the surgeon where to cut. This is a large increase in complexity as the entire surgery, including the resection of the tumour and reconstruction using a fibula, is planned in advance (in Meshmixer). It is necessary to work very closely with the surgeons to plan the surgery and design the cutting guides.
RS: What are your typical workflows?
Dr. Daniel Rickey: Requests for models come directly from the surgeons. I then segment the patients anatomy from computed tomography scans. This gives me nice STL models of the relevant bones. Editing of the models and designing cutting guides is done within Meshmixer. I print the resulting models and guides on a low-cost stereolithography printer.
RS: How do you use Meshmixer in your workflow?
Dr. Daniel Rickey: Meshmixer is used for all cases. Most models need to be cropped using the Plane Cut tool. For trauma patients, it is common to move bone fragments back to their proper locations. For cancer patients, I have designed cutting guides entirely within Meshmixer.
RS: What are your favourite Meshmixer features? Do you have any feature requests that would make your work easier?
Dr. Daniel Rickey: The most important features in Meshmixer are the pivots and selection tools. For example, I use pivots to align bones. I use the selection tool to constrain the plane cut and do all sorts of cleanup work. It would be great to have a way to lock an object so it couldn’t be inadvertently edited, but would otherwise be visible. Also required is an easy way to add text to an object. It would be nice to have another way of performing cuts besides the plane cut. Think of a surgeon’s saw and you get the idea.
What other tools do you use?
Dr. Daniel Rickey: For this work, we have found that relatively low-cost printers are suitable. We currently use a stereolithography printer (FormLabs, Form2) for most of our work. Biocompatible materials (e.g., Dental SG Resin, FormLabs) are highly desirable for cutting guides as they come into direct contact with the exposed patient. For cutting guides, both the mandible and fibula are segmented (3D-Doctor, Able Software) and saved as STL files. For pre-surgical planning and designing cutting guides, we used Autodesk Meshmixer.
RS: You recently gave a presentation titled “The Role of the Imaging Physicist in Implementing Three-Dimensional Printing for Surgical Applications” with Tom Hayakawa, Richard Nason, Christian Petropolis, Kevin Vint, Imran Ratanshi, and Michal Brichacek. What is the role of 3D printing in jaw surgeries, an area you focus on?
Dr. Daniel Rickey: A typical application is a surgery where a tumour must be removed from a patient’s mandible. Because a section of bone is removed, the remaining mandible pieces are held in alignment with a titanium reconstruction plate, which must be carefully bent and shaped to conform to the anatomy. The problem is that at least thirty minutes of valuable operating room time is required for the surgeon to bend this plate, and because of time constraints the result will never be exact. A simple solution is to bend the plate in advance of the surgery. However, for this the surgeon needs to know the exact shape of the patient’s mandible. 3D printing is perfect for this application.
Using computed tomography images, we print an exact model of the mandible and the surgeon uses this model to bend the plate in advance of the surgery. In addition, printed models enable the surgeons to better plan the surgery and anticipate any problems. The result is a reduction in operating room time, improved quality and a better outcome for the patient.
Three-dimensional printing has rapidly become a valuable tool in these complex surgeries. In order to implement this technology, the imaging physicist has developed working relationships with oncologic and plastic surgeons, nurses, technologists and radiologists. To be successful, our experience shows it is necessary for the imaging physicist to be in the radiology department to discuss the requirements of the imaging studies with the technologists and radiologists. More importantly, the physicist must be in the operating room to understand the surgeries and to assist the surgeons and nurses with using the 3D-printed devices. A consequence of these interactions is that we have worked together to introduce other advancements, including cutting guides used in reconstructive surgeries of the mandible. This is a large increase in complexity as the entire surgery, including the resection of the tumour and reconstruction using a fibula, is planned in advance.
It is necessary to work very closely with the surgeons to plan the surgery and design the cutting guides. These guides are used during the surgery to show the surgeon where to cut, and it is necessary for the physicist to be present during the surgery to assist with their use.
These are long and complex surgeries, lasting up to 12 hours. The cutting guides save considerable time and improve the accuracy of the cuts thus giving better bone-to-bone contact.
RS: Thank you so much for sharing your work with us!
This interview concludes my blog posts series “Meshmixer Saves Lives”. If you have amazing stories how you use Meshmixer in your life and you’d like to share them, please drop me a line at Ruslana.Steininger@autodesk.com.