Hospital tests lag time for robotic surgery 1,200 miles away from doctor

Doctors may someday be able to operate using robots on patients on the other side of the globe, or even in space

Remote robotic surgery tested
Mimic Simulation

A Florida hospital has successfully tested lag time created by the Internet for a simulated robotic surgery in Ft. Worth, Texas, more than 1,200 miles away from the surgeon who was at the virtual controls.

Next, the hospital plans to test lag times for remote robotic or "telesurgery" in Denver and then Loma Linda, Calif.

"Based on these tests, we have determined that telesurgery is possible and generally safe for large areas within the United States," said Roger Smith, CTO at the Florida Hospital Nicholson Center in Celebration, Fla., where the tests were performed. "Limitations are no longer due to lag time but factors associated with reliability, social acceptance, insurance and legal liability.

The experiment wasn't performed on live patients, but rather on virtual patients using a machine called "Mimic Simulator." The training hospital was taking a first step in testing Internet lag time between when a surgeon moves a remote robotic instrument and when it reacts.

suture simulation Mimic Mimic Simulation

A Mimic Simulator teaches a surgeon how to suture an incision using laparoscopic instruments.

Physicians watching the virtual telesurgery using laparoscopic instruments on video couldn't even detect a lag time, according to Smith.

The Florida Hospital's simulator mimics procedures performed by a da Vinci robotic surgical system, the most common equipment in use today; it's used for hundreds of thousands of surgeries every year around the world.

Today, da Vinci surgical robots allow physicians to perform surgeries yards away from patients, sometimes even behind glass in spaces adjoining operating rooms.

"What we're researching is when can we take the next step -- when can a surgeon go from being 20 or 30 feet away from a patient... to being connected by the Internet and be 20 or 30 miles away or 12,000 or 13,000 miles away?" Smith said.

Ultimately, the hospital hopes to enable surgeries for remote patients here and abroad who wouldn't otherwise have access to the world's top surgeons.

The Florida Hospital's experiment tested two things: As the distance from the robot increases, how does that effect lag time, and if there's lag time, how much of it can the attending surgeon tolerate?

The problem has less to do with the speed of light at which electrons travel via fiber optics and more to do with Internet provider processing times. A single movement of a robotic arm by a surgeon in a remote location requires bidirectional data-packet transfer: One data packet to control the robot's movement and the other to view the result in real time on a video display.

The Mimic Simulator was able to first artificially dial up lag times, starting with 200 milliseconds (100 milliseconds is one-tenth of a second) all the way up to 600 milliseconds.

At 200 milliseconds, surgeons could not detect a lag time. From 300 to 500 milliseconds, some surgeons could detect lag time, but they were able to compensate for it by pausing their movement. But at 600 milliseconds, most surgeons became insecure about their ability to perform a procedure, Smith said.

Telesurgery lag times The Nicholson Center

The effects of lag times on remote telesurgery.

In real time, the Internet lag had no effect on the surgeon's ability to perform a remote robotic procedure, Smith said.

For example, the lag time between four Orlando campus hospitals measured 5 milliseconds; between Orlando and Tampa, 10 to 150 milliseconds. "There was no difference between that and [robotic] surgery 10 feet away," Smith added.

When the hospital tested lag time between Celebration, Fla. and a partner hospital in Ft. Worth, Texas, the lag time ranged from 30 to 150 milliseconds -- completely undetectable by surgeons.

So what if the Internet goes down?

"These results indicate that modern, well-connected facilities possess the communication bandwidth needed to safely perform telesurgery today," Smith said. "It appears that we have the technology, but we are still waiting for business cases and regulatory permissions to open the door for telesurgery."

A major hurdle to long distance telesurgery is Internet resilience. While a healthy Web connection may enable undetectable lag times, what about when a major news announcement leads to an explosion of bandwidth devouring social media activity?

Or, what happens when a bad actor decides to launch a denial of service attack?

Smith said that to date, the Nicholson Center has been able to compensate for any unforeseen Internet slowdowns or outages by using backup connections. And, if all else fails, the hospitals in which the telesurgeries are being performed will have a surgeon on call if needed. In other words, the patient will need to be in a hospital, at least in the immediate future, so a local surgeon can respond in case of an emergency.

Then, of course, there are major liability questions, such as who do lawyers go after if a telesurgery procedure goes south? Do they go after the hospital performing the procedure, the hospital with the robotic surgery equipment or do they go after AT&T or Verizon because the connection was lost?

But Smith said the benefits could outweigh the risks.

For example, wounded soldiers could be transferred to a nearby facility where a specialist thousands of miles away could provide topflight care.

da Vinci Robotic surgery Nicholson Center

A surgeon practices on a da Vinci robotic surgery system.

In fact, the Nicholson Center's current telemedicine tests are being funded by a $4.9 million grant from the U.S. Department of Defense.

Additionally, medical volunteer services, such as Doctors Without Borders, could offer surgery to the rural masses, without the burden of having to fly around the world.

The benefits of robotic surgery

As laparoscopic surgery has gained popularity over the past 30 years, advancements have allowed greater precision with instruments; some laparoscopic procedures are so exact that surgeons can no longer perform them without robotic assistance.

For example, Smith said, when scopes use magnification, surgeons holding the long knitting needle-like laparoscopic instrument experience tremors from their slight, but uncontrollable body movements. Surgeons spend years developing muscle control in an attempt to quell the tremors. As surgeons age, though, tremors increase.

Robotic laparoscopic instruments, however, are able to compensate for unintended movement, holding instruments utterly still as a surgeon performs a task. Robotic laparoscopic instruments are also able to act as third and fourth arms, holding tissue or organs out of the way of surgeons.

"Robots are also much more reliable. Their arms don't get tired after 30 minutes," Smith said.

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