3D Printing Leads to Improved Precision and Reconstruction in Limb Salvage Surgery in Bone Tumors, Soft Tissue Sarcomas

Partner | Cancer Centers | <b>UC Davis</b>

R. Lor Randall, MD, FACS, discusses limb salvage surgeries that have been made possible through 3D printing, and the technological advances that are helping to increase precision and turnaround times.

The advent of 3D printing has led to an exciting revolution in limb salvage surgery for patients with bone tumors and soft tissue sarcomas, and have resulted in more precise resection and high-fidelity reconstruction, according to R. Lor Randall, MD, FACS.

“Technology in the form of digital interface, as well as 3D printing, are allowing new frontiers in our ability to do complex, anatomy-sparing procedures in orthopedic oncology that weren't possible 10 years ago,” said Randall. “It's an exciting time for orthopedic oncologists with this technology. Patients will see improved results in the near future with [it].”

3D printing technology, he added, has equipped surgeons with the ability to create custom implant devices with a faster turnaround time and better affordability for patients. The technology goes a step further with the use of mobile apps that allow surgeons to check in on the manufacturer’s progress and make real-time modifications to the implant device–all right from their phones.

In an interview with OncLive, Randall, the David Linn Endowed Chair for Orthopedic Surgery, as well as professor and chair of the Department of Orthopedic Surgery at University of California Davis Comprehensive Cancer Center, discussed limb salvage surgeries that have been made possible through 3D printing, and the technological advances that are helping to increase precision and turnaround times.

OncLive®: How have limb salvage techniques improved over recent years?

Randall: Orthopedic oncology is a very technical field. Any given surgical oncologic operation in basically [consists of] 2 acts: to get the cancer out and to replace the anatomy with something functional, so the patient has as much function as possible. Rarely do we need to do ablative surgery, such as amputations. Over the last decade, we have developed these limb salvage techniques where, back in the 1970s and early 1980s, we would have to build custom prostheses to reconstruct the defect when we took out the tumor. These are usually bone tumors, but they can sometimes be in soft tissue. As the field advanced, they became more and more off-the-shelf, modular-type sets, where you put pieces together and assemble them to reconstruct the defect.

As imaging advanced, we went from plain radiographs, to CT scans, to MRIs, [and] as we got more and more anatomic detail, we started to realize that we didn't need to take out big blocks of tissue; we could make more refined cuts to remove the tissue and spare joints. For example, if you have a tumor of the femur, you might be able to save a sliver of the distal femur, so you wouldn't have to sacrifice the knee; the same could be said of the tibia or the humerus. You can actually do a joint-sparing procedure. Initially, these were done using relatively crude technology, such as rulers, marking pens, or wax pencils on radiographs. It was tremendous what could be done, but there were a lot of complications or results that weren't really where we wanted them to be.

How has the emergence of 3D printing technology impacted limb salvage surgeries?

Now that 3D printing has come along, [we have] the ability to make a custom device in a much quicker turnaround and with [better] affordability than these big implants that were being produced before. With the digital technology, [you can now] preoperatively plan where you're going to make your osteotomy. You can now do these boney resections with such precision using custom jigs and sometimes navigation.

When the tumor is out, you have this geometric crevasse from which you can implant the reconstruction device, whether that's a bone allograft or a metal prosthesis in the pelvis. It fits in there [perfectly], and then you can affix it to the native bone. The ability to do that with such precision and fidelity has been so remarkable in the last 5 or so years. It has really reinvigorated our ability to think creatively [about] how we can do joint- or anatomy-sparing procedures as opposed to en bloc resections.

There are a variety of manufacturers that do this now. The turnaround times are getting shorter and shorter. It used to be 1 or 2 months, [if not longer]. They can sometimes make jigs and they'll have models; it's really a dynamic process.

Are there any studies that support the use of 3D printing technology in this capacity?

At this point, there aren't head-to-head comparison trials or anything like randomization trials, but it's something that is definitely getting the interest of surgeons [rethinking how we] do things. The preliminary results are pretty favorable, but with the uniqueness of each case, it is as if each case is a case study itself. It's hard to do any sort of a trial on this, but a lot of the surgeons who are gaining experience with this are pooling their data and showing them at medical meetings. It's really paradigm changing [in regard] to how [surgeons] approach limb salvage surgery.

What challenges still need to be addressed with this 3D printing technology?

The unmet need is now being met by industry. Digital technology is now the interface of the surgeon with the manufacturer [and] can be done in real time. You can literally plan your surgical resection and your reconstruction in real time on a digital, virtual [platform]. The manufacturer takes that information, comes up with a preliminary plan [from] what the surgeon has said, and then you meet back in the virtual [platform] and go through it in real time. They are now developing mobile apps where the surgeon can check in on the progress and make modifications, so they don't need to necessarily coordinate a formal meeting. This is just coming out. You can get a prompt through the app that the latest rendition of your plan is up, you can look at it at your convenience, put in your feedback, and they can make the modification. You can keep the process moving in real time because, obviously, there's a patient on the other end of this waiting for their implant. That unmet need is the dynamic interface to make this technology more real time for the patient and that's coming online as we speak.

Do you feel this technology is ready for prime time?

Prime time in orthopedics is still a very small niche. One of the reasons [publications are interested] in orthopedic oncology is because compared to the volume of oncology, we're a very small fraction. Within that fraction, all surgeons are looking at using this technology, particularly, the younger ones who grow up with this technology at hand literally, whereas [more senior surgeons] need to retrain themselves in order to use this technology.