Designing a Smarter Surgical Drill
By Matt Dozier
"Aim for my finger.”
The drill whined, its five-inch stainless steel bit penetrating bone and flesh at 1,500 rpm. Dr. Lew Schon watched as a surgical resident guided the tool through the patient’s ankle in the direction of his waiting index digit. Easing forward, the young doctor bored into the fibula, then tibia. Suddenly, the drill hit a weaker patch of bone and surged ahead, plunging toward Dr. Schon’s finger. He jerked his hand away, barely escaping serious injury.
Dr. Schon, a 20-year veteran of orthopedic surgery, wondered if there was a better way to teach novice surgeons in the operating room, so he brought his dilemma to Dr. Robert Allen’s Biomedical Design Team class at Johns Hopkins University.
Biomedical engineering students Leyla Isik, Emilie Yeh, Michael Shen and Salina Khushal dove into the project, spending summer 2009 planning and brainstorming ideas for a device that could make orthopedic surgery safer and decrease the training time for new surgeons. Their solution: an “intelligent” drill that could provide better feedback to someone learning the art of surgical drilling.
The field of orthopedics, which includes skeleton- and muscle-related maladies ranging from broken legs to torn ligaments, often involves drilling to stabilize and repair damaged bones. Compared to brain or heart surgery, which take a stable environment and a steady hand (think “Operation”), orthopedic surgery is much more dynamic: limbs need to be repositioned, joints flexed, appendages rotated to find the best angle (think “Twister”). It’s a procedure that relies more on experience and intuition than technology, requiring surgeons to complete six long years of residency training.
“Orthopedic surgery is still quite low-tech,” said Isik, leader of the design team. “Right now, the training is really a trial-and-error process.”
In the fall, the Johns Hopkins team, now 10 members in total, started building prototypes of their invention — some more successful than others. “We’re not the most skilled electrical engineers,” Yeh admitted. “There were a couple of fires, and lots of smoke.” Team members worked on the project for the rest of the year, testing their designs and getting feedback from residents at Union Memorial Hospital, where Dr. Schon, one of the team’s sponsors, practices medicine.
By spring 2010, their perseverance had paid off. Their invention, a small box that can clip to the back of any standard surgical drill, uses lights to tell a surgeon if the drill veers off its intended course. It can also trigger an alarm or even shut off the power if the drill speeds up too quickly, making it a tremendous learning tool in terms of visual feedback and safety.
Isik said she hopes the device, currently undergoing further development by Bioactive Surgical, will be able to gain support as a training tool in a surgical community that is notoriously suspicious of technology, based on its small size and relatively low cost — estimated at $3,000, compared to $10,000 camera-tracking systems.
“We would love to see it in the O.R.,” she said. “This whole experience has been amazing.”