Engineering tomorrow's care
Two architects of medicine are reconstructing how surgery is done
June 12, 2017
Dr. Victor Yang invented and commercialized a surgical navigation device to improve outcomes of spinal fusion procedures.
In early 2015, a 30-year-old woman came to see Dr. Oleh Antonyshyn, a craniofacial surgeon at Sunnybrook, because of a skull tumour. To take it out, Antonyshyn and neurosurgeon colleague Dr. Mahmood Fazl would have to remove the front of her skull, leaving a huge structural void that would be nearly impossible to fix.
They were not worried. Antonyshyn, who is a scientist at Sunnybrook Research Institute (SRI), and his partners, Dr. James Mainprize and Glenn Edwards, have developed and commercialized technology that shapes clinically approved materials into a custom-fitting implant for skull and facial reconstruction. In June of that year, Antonyshyn and Fazl operated on the young woman, who was otherwise healthy. While Fazl removed the tumour, Antonyshyn used the system to craft implants to rebuild the bony ridge of her eyebrow and restore her forehead right there in the operating room.
So, how is she now? “Excellent,” he says, happily.
In 2009, Antonyshyn, Mainprize and Edwards filed a patent for the system and formed a startup called Calavera Surgical Design. Using MRI or CT scans Mainprize makes a computer model of the patient’s skull; Edwards exports the model to a 3-D printer in the plastic surgery department, which churns out a cast of the patient’s skull. In the operating room, the surgeon presses material like titanium or polyethylene into the cast to form the implant. He then places the implant into the defect—which could be bone that has eroded from cancer or a broken eye socket, for example—and presto, a perfect fit.
“Surgeons are pretty specific about the material they like to use to reconstruct certain things,” says Antonyshyn, during a meeting in his cozy, taupe-coloured office in Sunnybrook’s plastic surgery department. On his computer, he pulls up a model of a skull that had a chunk removed to relieve swelling in the brain. “The forming tool can press whichever type of implant material [surgeons] have. We give them the ability to develop that three-dimensional shape specific for that patient that is perfect restoration of anatomy,” he says. The technology is a boon to Dr. Victor Yang, a neurosurgeon at Sunnybrook and a senior scientist at SRI, who recalls having to shape implants by hand while a patient is lying on the operating table. “That’s not the right thing to be doing in the 21st century,” says Yang.
A manually sculpted implant, because it’s not a perfect match, can be disfiguring and in rare cases lead to more surgery. Antonyshyn once had to fix a deformity resulting from inaccurately shaped eye socket implants that caused a patient to have double vision. The labour-intensive practice also increases operative time, adding cost and risking complications. With Calavera’s technology, meanwhile, one can fashion a bespoke prosthetic in minutes.
If a surgeon decides instead to buy a prefabricated custom craniofacial implant, then the bill can be a whopping $10,000 to $20,000, depending on its size and complexity. Such costs can be prohibitive, which drove Antonyshyn to create a workaround. Most people with facial fractures in Ontario are referred to Sunnybrook as a leading trauma centre. Due to budget constraints that face every hospital in the province, he was told he’d need to get approval before ordering a preformed implant. “We get about 20 cases per year, and the high cost of prefabricated implants restricted the number of cases which could be completed to two to four per year. We couldn’t keep up,” Antonyshyn says. Now, instead of purchasing a premade implant, he and colleagues like Yang can make a custom one for a fraction of the cost—about $3,500.
Top: a Ukrainian man prior to reconstruction surgery by Dr. Oleh Antonyshyn during a humanitarian mission. Antonyshyn has developed a system to craft custom craniofacial implants. Below: after surgery.
The system has been used in 57 cases at Sunnybrook since 2013; 17 more have been ordered and are pending. “It’s the go-to technology. If there’s a defect, [the surgeons] don’t even look anywhere else. They just ask us to provide the implant,” says Antonyshyn. He also has used the system on humanitarian missions to the Ukraine, where he has performed reconstructive surgery on people who have suffered horrific injuries due to that country’s civil war. To facilitate this, Calavera created a library of average skulls for situations in which an implant must be made at the point of care.
The next step is to send the technology for beta testing to other hospitals, including St. Michael’s and Toronto Western. Based on the feedback, the team will make refinements before taking the system to market.
Like Antonyshyn, Yang was also inspired to develop a device to improve outcomes and make the job of surgeons easier. He has engineered a computer-assisted navigation system that efficiently guides spinal fusion, where surgeons insert screws and rods to stabilize the backbone and encourage bones to fuse. The procedure is done for spinal fractures, herniated discs, spinal tumours and scoliosis.
The technology consists of hardware that takes intraoperative pictures of the patient’s exposed spine and software that matches the current position of a patient’s spine to a preoperative CT scan. It does this in only a few seconds, without emitting harmful radiation. The navigation system helps surgeons to place implants correctly and avoid critical errors like hitting the spinal cord. The device blends seamlessly into an operating room because the unit that scans the patient’s anatomy looks and functions like a standard operating light, a feature that appeals to Sunnybrook orthopaedic surgeon Dr. Albert Yee. “The benefit of bright surgical light illuminating the field makes this navigation unit multipurpose and compact,” he says.
Dr. Todd Mainprize, another neurosurgeon, has used Yang’s device during spinal fusion. He says he was impressed with how fast it matched preoperative CT scans and images of the patient’s spine that were generated in the OR. “Instead of taking the usual, frustrating 20 minutes to register the images to the patient’s spine, this system accomplished that within seconds,” he says.
Yang is commercializing the system through 7D Surgical, an early-stage company. The firm has more than 30 employees and continues to hire talent. The system is manufactured locally, in Brampton, Ont., to guaranteed quality standards. 7D Surgical plans to roll out new applications for brain, orthopaedic and plastic surgery.
In early 2017, the company achieved a milestone: approval from the U.S. Food and Drug Administration and Health Canada to use the device clinically, the latter ahead of schedule. “We’ve been focused on U.S. hospitals because we thought it would be a few more months until we received Canadian clearance,” says Yang, who notes neurosurgeons at Sunnybrook are using the system during spinal procedures to assess its effectiveness in a clinical trial. “Now, if any Canadian hospitals want it, we’ll say, ‘we’ll add your order.’”
Antonyshyn’s research was supported by the Federal Economic Development Agency for Southern Ontario, Health Technology Exchange and Ontario Centres of Excellence. Yang’s research was funded by Brain Canada, Canada Foundation for Innovation, Canadian Institutes of Health Research, Natural Sciences and Engineering Research Council of Canada, and the Ontario Ministry of Research, Innovation and Science. He holds the Canada Research Chair in Bioengineering and Biophotonics.
