Cutting-edge technology at local hospital

Physician assistant Corbin Rasmussen holds a demonstration leg in place while orthopedic surgeon Dr. Micah Pullins explains the new robotic-assisted knee and hip replacement system now in use at Evanston Regional Hospital. The system uses detailed computer mapping of an individual joint along with a robotic-assisted cutting process to make extraordinarily precise measurements and cuts for joint replacement surgery. (HERALD PHOTO/Sheila McGuire)

EVANSTON — Patients in the southwest Wyoming area now have the opportunity to have state-of-the-art technology used for knee and hip replacements, thanks to the new robotic-assisted joint replacement surgery system at Evanston Regional Hospital. On Jan. 26, orthopedic surgeon Dr. Micah Pullins utilized the innovative new technology to perform the first surgical case at ERH.

On Thursday, Feb. 18, Pullins and ERH invited Herald staff, elected officials and students in robotics clubs at Evanston High School and both middle schools to a demonstration of the new technology, which uses advanced computer mapping and robotic assistance to help make more precise measurements and cuts for patients undergoing partial or total knee replacement or total hip replacement surgery.

During the demonstration, which Pullins jokingly referred to as “like wood shop but with bones,” he utilized an artificial knee to go through the motions of an actual procedure. That procedure starts pre-operatively, when a CT scan is used to create detailed three-dimensional mapping of an individual joint. That allows Pullins to do significant planning and preparation prior to even entering the operating room, which also ensures the surgeon is aware of deformities and issues such as bone spurs prior to making an incision.

Once in the OR, array sensors are placed on the leg itself and, together with arrays on a robotic arm, those sensors send information to an advanced computer system that creates a 3D image of where a joint is in space in “real time.” The surgeon, who has to train extensively and become certified to use the technology, runs a joint through a range of motion, including flexion and extension, while the sensors are in place to help with the three-dimensional mapping.

That mapping then creates an image — actually multiple images of joint surfaces — to be used to determine where to make precise cuts in tissue and bones for best fit of prosthetic parts. The robot is then used to make those cuts, guided by the surgeon and utilizing bounded haptic technology, which means the program has created a zone in which cuts should be made to prevent cuts from being made outside of that zone.

Though the robot assists, Pullins remains in control throughout the surgery, using his knowledge and experience to do what the robot can’t — determine which prosthetics and design make the joint feel “right.” He said the robot and computer are remarkable tools for providing precise objective data, yet there is a subjective element to surgery that, thus far anyway, requires a human touch.

“Robots could put in the artificial knee but balancing the ligaments is what makes it feel right,” he explained.

The surgery requires the work of several people in addition to the surgeon, including an assistant, a scrub tech, a circulating nurse and representatives from the implant and technology company who travel up from Utah for every procedure.

Joint replacements utilize a combination of polished metal and high-grade plastic components that can be either cemented or compacted into place in a PressFit system. Pullins said PressFit is preferable because cement isn’t required, and the bones will actually grow around and into the artificial surfaces. The new technology helps ensure PressFit components are able to be used. Pullins explained the PressFit system requires accuracy to within 1 mm; with the robotic assistance, cuts can be made to within 0.5 mm.

The benefits to patients are numerous, including decreased surgery and anesthesia times due to the preoperative preparation and often improved recovery times and patient satisfaction due to more precision.

“With this highly advanced technology, I know more about my patients than ever before and I’m able to cut less,” Pullins said.

He said with total knee replacements, patients are up and weightbearing on the first day after surgery, which helps with rehabilitation and other risks associated with immobility, such as pneumonia and blood clots. Though admittedly painful, he said by about three weeks following surgery, patients are usually happy they decided to have the procedure done; by about three months post-surgery, they’re back participating in activities they may have avoided for years due to joint pain and loss of function.

“For patients suffering from severe arthritis, activities like grocery shopping or playing with grandkids can be painful,” Pullins said. “While medication or physical therapy may ease pain, sometimes surgery may be more of a long-term solution. In addition to relieving pain, these procedures can enhance mobility and function and help patients rediscover the activities they love.”

Pullins is now utilizing the robotic assistance for all partial and total knee replacement and total hip replacement surgeries, with the only exception for patients who have an allergy to metal, which makes it impossible to utilize the metal blades on the robotic arm.

To add some fun to the demonstration, the robotics students were asked to submit name suggestions for the robot, which will be voted on by the public. Suggestions thrown out by students following the demonstration included Eddie, Buckaroo Banzai, Jerry and RAD (Robot Arm Dude).

Evanston Regional Hospital is the only facility in southwest Wyoming or the Park City, Utah, area with both the robotic-assisted system and a surgeon certified to utilize it. ERH is also only one of about 1,300 hospitals around the country with the technology.

Cheri Willard, ERH CEO, said, “This addition to our orthopedic service line means that our community doesn’t need to travel far, fight traffic or breathe in polluted air to get a great experience while having major surgery. We offer the comforts of home alongside great physicians and advanced technology right here in Evanston.”


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