The Plain Dealer in Cleveland recently published the following feature story about Dr. Bernard Stulberg at St. Vincent Charity Medical Center.

Surgical robot aids in hip replacement surgery at St. Vincent 

Posted Jun 25, 2017

By Julie Washington

CLEVELAND, Ohio -- Thomas Shano's recent hip replacement surgery at St. Vincent Charity Medical Center was normal in every way, except for the robot on the surgical team.

The eight-foot surgical robot, covered in a sterile blue drape, rolled next to Shano's exposed hip joint and used a mechanical arm tipped with a drill to precisely carve out a cavity in Shano's leg bone.

The robot, developed by California-based Think Surgical Inc., can prepare bone cavities for hip replacement surgeries with sub-millimeter precision. That's much more accurate than a surgeon using hand tools and increases the chances that a patient's hip implant will work flawlessly, said Shano's physician, St. Vincent Charity Medical Center orthopaedic surgeon Bernard Stulberg.

Think Surgical's computer-assisted tool, the robot and a workstation, also created a 3D digital model of Shano's hip, which allowed doctors to accurately gauge the size of the implants and the correct angle where the implants should be positioned. "We have to find the best position for the hip for that particular patient," Stulberg said.

During an average hip replacement surgery, surgeons use hand tools to create a cavity for the implants, "feeling what you believe to be the right size," Stulberg said. If the angle of the cavity isn't correct, patients can be left with persistent pain or a dislocated hip.

Cleveland's St. Vincent Charity Medical Center is one of a handful of hospitals in the country doing robot-assisted hip replacement surgery. Stulberg has performed the procedure for about a year, and he convinced Shano, 62, that it was the best option for him.

For the past two years, something as simple as putting on his shoes and socks has been hard for Shano, who lives in Brunswick. He wasn't in a lot of pain, but an unstable hip joint made it feel as if he was stepping on sponges. He walked with a limp.

Shano suffers from avascular necrosis, also called osteonecrosis, in which inadequate blood flow to the ball portion of the hip joint makes it collapse or become deformed. He had to cut back his hours at the landscaping company where he works, and he's afraid of falling if he carries his 6-month-old granddaughter.

"I want to walk normal. My wife (Barbara) walks faster than I do now," Shano said.

It's the ball-and-socket design of the hip joint that makes climbing a flight of stairs or playing basketball possible. The ball portion is at the top of the thigh bone, or femur. The socket is part of the groin, or pelvis. The ball and socket are both lined with cartilage, allowing the two parts to glide smoothly against each other for painless motion.

If the ball or socket are damaged, the body grows more bone in the joint, which hampers mobility and causes pain, Stulberg said. An artificial hip joint replaces the bone ball and bone socket with metal and plastic devices.

An artificial hip uses a socket made of titanium and shaped like a golf ball sliced in half. During hip replacement surgery, a titanium cup is attached to the bone socket with screw. The bone grows and attaches to the cup, lending stability to the artificial joint, Stulberg said.

During hip replacement surgery, the bone ball on the top of the patient's femur is removed and replaced with a prosthetic ball, positioned at the top of a stem that fits into a hole drilled into the femur. The plastic cup inside the titanium socket glides over the prosthetic ball, mimicking the joint's natural action.

Shano's hip replacement surgery began with a CAT scan. Think Surgical used the information in the scan to create a digital 3D model of Shano's right hip, which was sent to a 3D workstation for pre-operative planning in Stulberg's office.

Stulberg and Dr. Alex Greenberg, a fellow in arthroplasty at St. Vincent and a member of the surgical team, manipulated the digital model of their patient's joint on the workstation's screen to plan every aspect of the surgery, including the size and angle of the implant's cavity in the femur and the angle of the titanium socket cup.

The final plan was burned onto a CD so that the information could be uploaded into the robot.

On the day of the surgery, Stulberg arrived at St. Vincent with the CD and a physical model of his patient's right hip joint, made with a 3D printer. The flattened part of the joint's ball, and painful bone growths called spurs, were plainly visible. "He's collapsed this part of the surface," Stulberg said about Shano's hip.

The robot, with movable arms and an attached computer screen, remained stationary on one side of the operating room while caregivers rolled a sedated Shano on his side and coated his leg and hip with an antiseptic gel. Shano's right leg was immobilized so that it would not move during the procedure.

Stulberg made an incision into the hip and removed damaged portions of bone and cartilage from the femur.

Now it was the robot's turn. Stulberg, took the robot's digitizer, which resembled a long finger, and touched it to the patient's femur about 24 times. The robot registered each touch and used them to create a 3D map of the bone in its memory. When its map of the actual bone matched the plan that had been downloaded into the robot's memory, a readout on the robot's computer screen told the surgical team that it was ready to work.

The robot made a high-pitched whine as its drill moved up and down to carve out a cavity in the patient's femur. When the robot was finished, Stulberg used a hand tool to cut off the femur's ball, leaving the femur and its cavity ready to hold the ball portion of the artificial hip.

In the second half of the two-hour surgery, the robot removed cartilage from the patient's socket to prepare it for the artificial device.

By that night, Shano was able to walk the length of a hospital hallway three times, and went home the following day, Stulberg said in a follow-up email.

"The patient's surgery went smoothly. It very successfully accomplished all of the goals we had for sizing and placement," Stulberg said. "We are very excited that we have this technology at St. Vincent Charity Medical Center as we can offer patients extremely accurate three-dimensional planning for sizing and positioning of implants for the hip, and the ability to execute that plan."