Robot revolutionizes knee replacement surgery
Georgette Greene has an active lifestyle and works out at least five times a week. But six years ago, the Campbell resident realized she could no longer do a squat. She exercised even harder and lost weight. “That helped for a little while,” she said. “But from there my knees got progressively worse.” Today the 57-year-old Greene lies in a hospital bed for the first time since having her daughter— now seated by her side — 31 years ago. She’s about to undergo total knee replacement surgery.
Greene isn’t having a run-of-the-mill operation. About a week before her procedure, she received some surprising news from the pre-op nurse: Her orthopedic surgeon, Dr. Jaideep Iyengar, wanted to have a robot named NAVIO assist with the surgery on her right knee.
NAVIO is part of the new robotics programs at San Jose’s O’Connor Hospital and Daly City’s Seton Medical Center. Currently, O’Connor’s Iyengar and Dr. John Velyvis, of Seton, are the only surgeons using the robot in the Bay Area.
Developed by engineers at Carnegie Mellon Robotics Institute in Pittsburgh, Pennsylvania who eventually went on to found Blue Belt Technologies, NAVIO was initially approved to assist with partial knee replacements. A few weeks ago, its developers received approval from the U.S. Food and Drug Administration for total knee replacements, said Robert Prenter, the regional manager for NAVIO Robotics. Its major competitor, the MAKO robot of Michigan-based Stryker Co., was also just licensed to assist with the operations, in which knees are replaced with joints made of metal and plastic.
“We’re in the heart of Silicon Valley,” Prenter said. “It kind of makes sense to have the best robotics available in that marketplace.” Telling a patient that a robot will be involved in the surgery, however, usually elicits a lot of apprehension in most knee replacement patients. “The biggest question that we get is a patient asking about safety,” Iyengar said.
But Greene’s reaction wasn’t typical. Upon hearing she was Iyengar’s fifth patient at O’Connor Hospital to undergo surgery with NAVIO’s help, Greene, a regulatory compliance officer for Santa Clara Valley Health Plan with a fun-loving attitude toward life, said: “Oh, dang it. I like being the first at everything!”
During a typical knee replacement procedure, surgeons open up the knee and develop the best surgical approach based on an average measurement of similarly shaped knees that they’ve operated on before. Iyengar said it’s like trying on a pair of jeans available only in small, medium and large. You can choose the size that’s best for you, he said, but they still might not fit perfectly.
NAVIO generates a 3-D model of a patient’s knee. From there, the surgeon calibrates the robot by mapping out the exact incisions — and the angles at which he or she will make them — over the surface of the knee. “This technology really allows us to individualize the patient’s treatment,” Iyengar said. He compared the robot’s precision to “going deep into the forest with GPS tracking — versus just going into the forest.”
It’s 2:30 p.m. on May 17, and Iyengar’s team wheels Greene — now anesthetized — into the operating room. To reduce blood loss, the team applies a tourniquet to her right thigh. Then Iyengar makes his first incision. For the next half hour, Iyengar talks frequently with Jordan Smith, an account representative from London-based medical equipment manufacturer Smith & Nephew, the parent organization of NAVIO’s development team.
Smith is indistinguishable from the rest of the O’Connor Hospital staff assisting the surgery — he too is dressed in pastel blue scrubs and a surgical mask. But Smith spends a lot of his time a few feet away from the patient, behind what looks like an oversized white and blue computer with a mechanical arm holding up a monitor screen. The rather unassuming device is NAVIO.
Representatives like Smith calibrate NAVIO’s equipment —which traces the contours of the knee over the duration of the procedure using the life-size 3-D model, Prenter explained. But after 20 to 30 surgeries using NAVIO, Smith said, surgeons will be able to use NAVIO on their own.
One of the keys to NAVIO’s success is haptic technology, which causes tactile feedback. Many video game controllers have haptic technology. Think of what happens when you’re playing a football video game and the controller rumbles when you make a tackle, Iyengar said.
NAVIO’s haptic technology is slightly different. If Iyengar were to deviate — intentionally or unintentionally — from his initial plan by trying to make a differently angled incision or a different incision entirely, NAVIO turns off the mechanism cutting the bone.
If the proposed cut was unintended, Dr. Iyengar knows he has to adjust something before proceeding. If it’s intended, he has to override NAVIO and make sure the robot knows, “Hey, I’m actually changing this plan,” he said.
Iyengar said when he explains NAVIO’s precision to apprehensive patients, it usually makes them change their minds about allowing a robot in the operating room. “They’re usually enthusiastic that it’s there,” he said. Having any operation, Iyengar added, can be a nerve-wracking experience for patients. “I get a lot of questions like: Did you sleep well last night? Are you feeling at the top of your game?”’ he said. “Surgeons aren’t infallible, and this allows one more checking system.”
The true secret to success, Iyengar added, is to assess risks with the patient beforehand – something a robot can’t yet do. Those risks include blood clots, infection, heart attack, stroke and rehabilitation complications. Perhaps most importantly, he said, “we need a motivated patient like Georgette.” “She was up and walking that same day after the operation. And that evening,” he said with a laugh, “she was up so much the nurses were worried.”