While collaborative robots are not generally seen as precise enough for robotically assisted surgery, they do offer advantages for certain procedures. When Advanced Osteotomy Tools AG needed a cobot that was both responsive and precise enough for its CARLO laser surgical system, it incorporated a KUKA LBR Med.

Dr. Alfredo Bruno, a laser researcher, had wondered why precision lasers weren’t used to cut bone while educating himself about a complicated jaw surgery on his daughter. He then met Dr. Hans-Florian Zeilhofer, head of the oral and maxillofacial surgery department at the University of Basel Hospital and the Aarau Canton Hospital. In 2010, they co-founded Advanced Osteotomy Tools (AOT) in Basel, Switzerland.

“Our goal was to achieve radical improvement in the results of bone surgery by replacing mechanical cutting instruments with non-contact ‘cold’ laser photo-ablation and medical robots,” stated Bruno, who is chief scientific officer (CSO) at AOT.

Challenges

Despite more than 50 years of progress in medical lasers, particularly in dermatology and ophthalmology — think of tattoo removal and cornea correction, respectively — challenges remained in bone surgery. Maintaining the integrity and health of bone tissue around incision sites was difficult.

AOT claims that its CARLO (Cold Ablation Robot-guided Osteotome) robotic surgical product can cut bones without contact or generating excess heat.

In addition, AOT needed a high-precision robot to work with its laser, as well as 3D planning, navigation, and control software and hardware. It needed to be small enough to fit into existing operating rooms, while balancing autonomy with responsiveness to surgeons.

Solution

According to AOT, CARLO’s design “allows the surgeon to perform bone operations with unprecedented precision and in freely-defined, curved, and functional sectional configurations, which are not achievable with conventional instruments.”

The custom-designed system uses a lightweight “tactile” robot arm with navigation and control software for an “ergonomic” and precise system, said the company.

For that robot, AOT chose the LBR Med from KUKA. It is based on the seven-axis LBR iiwa cobot, which includes force-torque sensors, so AOT did not need to develop safety measures from scratch.

Another advantage of the LBR Med is that it is the only robotics component that has CB Scheme certification for integration into medical products. That has saved a lot of time in the medical device-approval process, which is ongoing, said AOT. The Oral and Maxillofacial Surgery Department at the University Hospital Basel has successfully used it in its first clinical trial.

“Since CARLO is the first system of its kind, the supervisory authorities are understandably placing very high requirements on its safety,” explained Bruno.

The Robot Report is launching the Healthcare Robotics Engineering Forum, which will be on Dec. 9-10 in Santa Clara, Calif. The conference and expo will focus on improving the design, development and manufacture of next-generation healthcare robots. Learn more about the Healthcare Robotics Engineering Forum.

Results with CARLO

A physician using CARLO starts by taking the CT scan and conducting preoperative planning. Then, technical staffers feed the planning data into CARLO’s navigation system. The interface for the surgical robot is designed to be intuitive and guides the team through initialization step by step.

The software-guided laser system supported by LBR Med allows for highly precise cuts in any pattern required for bone surgery, explained Zeilhofer.

The cobot is sensitive enough that a surgeon merely needs to touch it gently, and it will stop immediately.

“The LBR Med has a whole range of extremely fine sensors. It is quicker than stopping a human assistant,” said Zeilhofer. “The robot then moves to a wait position and resumes the procedure from precisely this position as soon as it receives the all clear.”

“When there is even a little, unplanned contact, it remains still and interrupts its tasks,” he added. “This sensitivity can also be used to operate the system intuitively and manually.”

AOT is already working on the development of the second generation of CARLO with enhanced safety and performance features that will place further demands on the LBR Med.

“CARLO represents the future of surgery,” Zeilhofer said. “There are far more options open to the surgeon than with previous procedures.”