Using lasers, UMN surgeon zaps cancerous brain tumors

Matthew Hunt performed the first laser ablation surgery at the University of Minnesota last month.

by Olivia Johnson

Using robot-controlled lasers to fry cancerous tumors inside the brain has become a focus for University of Minnesota surgeons.

One surgery — called laser ablation — was first performed last month at the University with the help of a robotic arm. Since then, it has been completed two more times to treat epilepsy and pediatric cancer.

Matthew Hunt, a neurosurgeon and professor at the University who performed the laser ablation, said the operation is a noninvasive method to treat tumors in parts of the brain that are hard to reach.

“Traditionally, to treat tumors, we either go in and physically remove the tumor, which … might be hard depending on the location,” he said. “Or, for some tumors … [patients] might get focused radiation in that area.”

He said most areas in the brain can be reached by at least a small tube or catheter. During laser ablation surgery, an instrument is inserted and “emits laser light” to cook and destroy the tumor.

While the laser cooks the tumor, Hunt said the temperature is monitored using magnetic resonance thermography, which can accurately track the temperature change in real-time so it doesn’t get too hot.

“The advantage is that … you don’t actually have to create a big hole in the brain,” he said. “You can basically just drill a very small hole in the skull and put the catheter in, which most people tolerate very well.”

Hunt added that many patients don’t feel any different after the surgery.

Laser ablation partly relies on a robot arm that can accurately target a spot in the head and insert the catheter.

The surgery, which relies heavily on basic neurosurgical skills, is growing in popularity, Hunt said, and the University wants to make it a major part of treating patients.

“This was kind of a trial. We need to purchase the equipment and do some other things,” Hunt said. “Our goal is to be able to offer it to any patient who we think it would be a good choice for.”

Chris Weight, a urologic oncologist at the University, said 70 percent of the surgeries he performs are completed with robots — and procedures using robots don’t require long hospital stays, usually only 24 hours.

Laurence O’Connor, an urologist in St. Paul, said he also uses robotic instruments for many of his surgeries.

O’Connor said he uses robots when performing laparoscopic surgeries, a procedure where a telescope and other instruments are inserted in a small incision in the patient.

“You can either do that and hold on to the instrument to do the surgery, or you can attach a robot to the instrument and do the surgery,” he said.

The robot has four arms, three with instruments to complete the procedure and one that holds two small cameras, giving the surgeon — located at a console near the patient — a three-dimensional picture to view what’s happening.

“The robotic instruments have additional degrees of movement,” O’Connor said, adding that they can bend at angles a human arm or hand can’t. “It makes … sewing up things inside the belly with the laparoscopic instruments a lot easier.”

He said he first started using the robot in 2007, primarily to take out prostate and kidney cancers.

“When the robot was first introduced, about 5 percent [of surgeries] were done robotically and 95 percent were done through an open incision,” Weight said. “Now it’s almost completely reversed.”

The shift happened over the last 15 years, he said, and started with the military hoping to use robots to perform surgery on soldiers in combat areas that were too far from a hospital.

Weight said the urology field was one of the leading early adopters of the technology.

“Since that time, it has moved into several other fields,” he said. “It is increasingly being used because it offers complex surgical tasks. It translates the complex movement of a hand … into small instruments that are only a couple millimeters big.”

Weight said a full robotic system costs around $2 million, but the instruments, which are a few thousand dollars, are reusable for each surgery.

“I think that sort of technology will continue to advance,” he said. “These surgical assisting robots will probably continue to spread into many aspects of surgery.”