Robotic Relief

SURGICAL ROBOTS GO WHERE SURGEONS CANNOT.

Surgical expertise is a prized asset, particularly to U.S. military forces facing the threats of improvised explosive devices and other asymmetric attacks that can take a heavy toll on warfighters. When soldiers are injured in such an attack, the Army must rush them to expert care as quickly as possible to avoid loss of life or limb.

At the same time, those same battlefield threats make it dangerous to send surgeons into the field to treat wounded soldiers on the spot. Should surgeons then become the targets of enemy fire, the Army has suffered more casualties and lost highly valued skills in addition.

Enter surgical robots! Designed to enable surgeons to operate from remote locations, these robots both keep doctors off the battlefield while providing quality care to wounded warfighters and enable the distribution of limited expertise in surgical procedures. At least, one day soon they will, according to Dr. Timothy Broderick, a scientist working for both U.S. Army Telemedicine and Advanced Technology Research Center (TATRC) and the Defense Advanced Research Projects Agency (DARPA).

“The primary goal is to provide quality care to the injured warfighter,” Broderick told Military Medical Technology. “Distributed telesurgical robotic care is a medical force multiplier. You could have a soldier getting expert care from a trauma surgeon at the point of injury, but you could also have a warfighter receiving expertise in a subspecialty of surgical care.

“For example, if they have sustained a head injury, they could have a neurosurgeon as a consultant,” he added. “If they had an injury to the extremity, they could have an orthopedist consulting. There are not enough of those specialty surgeons to go around. But it protects our medical assets as well.”

Broderick has been participating in a number of projects designed to improve the precision of the surgical robots as well as their reach.

“In truth, these systems are not actually surgical robots,” he noted. “That’s a misnomer. They are more properly termed telemanipulators. There is a master/servant relationship where the surgeon moves and the slave arms do exactly what the surgeon tells them to. That’s starting to change.”

FINDING NEEMO

One set of experiments heralding a great deal of change in the abilities of surgical robots, which remains a generic term in this article despite being a misnomer, is the NASA Extreme Environment Mission Operations (NEEMO) series. NEEMO is a combined project under the auspices of NASA and the U.S. Army to extend the reach of robots to remote locations and extreme environments.

Most recently, the agencies held NEEMO 9 in April 2006. The specific mission of NEEMO 9 dealt with robotic telesurgery, Broderick explained, and in this case the surgery was simulated and occurred far underwater.

“NEEMO 9 was an 18-day experiment that was a saturation mission,” Broderick described. “You are in something the size of a Winnebago with six people in it. You can’t come up until the very end of the mission because your blood is saturated with nitrogen. It is an extraordinarily small, cramped and harsh environment.”

The doctor operating an M7 robot successfully did so from Ontario, Canada, while the robot was four kilometers underwater off the coast of Key Largo, Fla. Because of the underwater environment, the U.S. Navy and the National Oceanic and Atmospheric Administration (NOAA) also were involved.

REMOTE CHALLENGES

NOAA owns the Aquarius Habitat, an undersea laboratory where the NEEMO 9 experiment was conducted using the M7 robot developed by SRI International, headquartered in Menlo Park, Calif. SRI began development of the M7 in 1998 with funding from TATRC, said Tom Low, program director for innovative product engineering and technologies at SRI International, and the robot was eventually modified for use in telesurgery scenarios.

“We have always had portability and deployability in mind,” Low explained. “Each robot arm weighs less than 10 pounds, which for a robot of any significance is really remarkable. Most robots weigh hundreds of pounds and pick up only a few percent of their weight. The M7 is only 10 pounds and can exert pretty significant forces for its size.”

Anyone can carry the two robotic arms and the controller that make up the principle parts of the robot due to their light weight. Setup of the M7 is fairly simple, as it requires only several cables, a power plug, and an appropriate place to attach the robotic arms for surgery.

But while the robot appears very simple, some of its electronics are quite advanced, enabling it to operate under intense pressure in difficult environments.

“To make the electronics compatible with the extreme environment that we were operating in, we had to do a lot of thinking about how the two atmospheres of pressure would affect the computers and the like,” Low revealed. “Things like membrane keyboards needed to be eliminated. Hard disk drives that have sealed metal boxes needed to be eliminated. All of those things would crush under the air pressure of the habitat. In general practice, spinning disc drives don’t work real well in really extreme shock and vibration environments.”

So the M7 robot contains some solidstate memory devices such as a solid-state flash disk. SRI can perform configuration and some modification of the M7 remotely through uploading software changes to its network. The M7 robot required only a few modifications to undertake the NEEMO mission.

For example, M7 originally did not have the sort of remote operation sophistication required to conduct the NEEMO experiment. Basically, SRI redesigned NEEMO’s remote communications ability to enable it to operate over the Internet. Other modifications included tackling the issue of hard disks that would not survive under pressure and software changes to allow the master and slave to communicate over an Ethernet cable.

But the robot basically had what it took to enable a surgeon to operate on a patient from the start.

“It is specifically designed to recreate the dexterity and the range of motion that a surgeon would perform in a general open surgical procedure,” Low said. “Instead of operating with small tools and small incisions, it is essentially custom designed to do the kinds of things that a surgeon would do with a patient open on an operating table.”

Each robotic arm has six degrees of freedom and can reach any point in its workspace at any orientation. Surgeons manipulate the arms through a control panel that enables forces experienced by the robot to reflect back to the surgeon and forces exerted by the surgeon on the master control to reflect to the patient.

In addition, Low noted, the M7 robot uses tools that are very rapidly interchanged. An assistant removes the tools from the robots arms very quickly by “snapping them off” at the wrist of the robotic arm and then attaching a new one.

TATRC’s Broderick, however, noted that the experiment raised two issues to tackle in the future. First, the NEEMO 9 experiment introduced some lag time in the communications between robot and surgeon. NASA was interested in a lag time of two seconds, so that was introduced to the last leg of the deployed network, which used microwave communications.

“When you are using satellites, you have at least a half second of latency. From a NASA standpoint, two seconds is the latency for operating on someone on the moon. So if you have a lunar base, there would be a couple of seconds of latency,” Broderick explained.

NEEMO 9 marked the first occasion where a surgeon was able to successfully operate with that much lag time. Still, the mission highlighted the need for the robot to conduct more autonomous functions.

“Because of problems with operational communications—the constancy and quality and bandwidth are tight—the robot is going to have to help the surgeon some. So we are going to need autonomous function with supervisory control. So it’s a fancy tool that helps the surgeon. It’s just like how a sewing machine helps someone sew instead of sewing by hand. We sew a lot when we are operating,” Broderick said.

AERIAL VEHICLES

TATRC recently teamed with the University of Cincinnati and the University of Washington to tackle challenges specific to satellite communications. The three developed a model called the High Altitude Platforms for Mobile Robotic Telesurgery (HAPsMRT), and then they ran a trial of the concept last July.

The two-day test began in southern California, where Broderick manned a surgical robot console and operated on a simulated patient, guided by a video stream fed through the Puma unmanned aerial system (UAS), manufactured by AeroVironment of Monrovia, Calif. The UAS sent data a total roundtrip of about three miles in the test.

For a second part of the test, Broderick went to Seattle to control the surgical robot from the University of Washington. The robot remained at AeroVironment’s flight test location in Simi Valley, about 1,100 miles away. The Puma once again provided the last leg of the network, providing surgery video over the Internet through an access point onboard the Puma.

“The communication lag time when you are operating from satellite is fairly high, at least a half a second,” Broderick noted. “The only satellite networks that are robust enough for us to use for telesurgery are the geosynchronous satellites that are pretty high up. We have not yet tackled the problem of communicating faster than the speed of light. So you are limited based on orbital altitudes. It became apparent that we had to bring the satellite down to us.”

The Puma UAS working under the HAPsMRT model provides the Army with a means to bridge the last tactical mile along a communication network and the surgical robot, Steve Gitlin, director of marketing and communications for AeroVironment, told MMT.

“The Army is very interested in potentially being able to deploy surgical robots as far forward in the field as possible to increase the probability of effectiveness,” Gitlin commented. “One of the big challenges in the armed services is, if somebody is injured in the field, the time it takes to get them stabilized in the field and to a facility where they can be treated is extremely critical. To the extent that timeframe can be shortened, there is an expectation that there is a higher probability that the individual can be treated effectively.”

So with surgical robots in the field, the Army can save lives by rendering care quickly when required. But the communications latency involved with attempting to operate on an injured warfighter could cause critical errors, so TATRC requires a reliable low-latency data link between the surgeon and the robot, Gitlin explained. A UAV can bridge the gap in remote or treacherous environments because it can fly out to areas where no network could deploy.

“From an unmanned aircraft system perspective, we could provide that highbandwidth low-latency link to enable them to use these kinds of systems in the field,” Gitlin observed. “One of the issues with other kinds of systems like geostationary satellites is the distance. They are over 20,000 miles into space, so there can be some latency in the communication. My understanding is that from a surgeon’s perspective, there is a desire to have as little delay between the control and the result as possible. Anything that can reduce that latency could be beneficial.”

While TATRC used the Puma UAS for the test last year, Gitlin believes the Global Observer, currently under development at AeroVironment, would provide even greater tactical advantages to U.S. forces seeking to cut down on communications lag.

“We used Puma for the test, but we believe that there can be a benefit from a system like Global Observer, which we have been developing,” Gitlin said. “Global Observer is a much larger unmanned aircraft system that is being designed to fly for seven days or more at a time without refueling and could carry aloft a payload to provide high-bandwidth, low-latency data links.”

NEXT MISSIONS

NASA and TATRC plan to conduct NEEMO 12 in May 2007. NEEMO 12 will utilize both the M7 robot and one built by the University of Washington. The mission, which will last 12 days, will require the robots to perform some tasks autonomously.

Another mission funded by NASA, the U.S. Air Force and U.S. Army will place an updated version of the M7 robot on the DC-9 hyperbolic aircraft used by NASA to simulate microgravity.

“It flies up to 40,000 feet then freefalls for about 20,000 feet,” Broderick said. “While it is freefalling, everything inside of the aircraft is floating around. Then you pull up. You pull a couple of Gs when you pull up and then you do another parabola where you are from 40,000 down to 20,000 where you have 25 seconds of weightlessness.”

Using the revised M7 robot, NASA astronauts and USAF critical care surgeons will undertake a mission to examine the potential for developing robotics for distributed surgical care. “Some of the unmet needs, for example, are neurosurgical care if someone had a traumatic head injury. You could potentially provide some care through the use of the robot when you don’t have a neurosurgeon on the aircraft with the warfighter,” Broderick said.

Another project providing life-saving surgical operations via a remote robot is Trauma Pod, a project on which TATRC has assisted DARPA. The pending phase one demonstration for Trauma Pod would provide a proof of concept using commercial robots.

“For the trauma pod at DARPA, the prime goal was to provide far-forward combat casualty care because there are some soldiers that experience mortality because it takes them half an hour or an hour to get definitive care,” Broderick said. “They get good buddy care, but the buddy can only do so much. They might be bleeding to death from a non-compressible vascular injury. So a big blood vessel, a buddy cannot put pressure on that to stop the bleeding.”

For that proof of concept, DARPA is looking to Intuitive Surgical Systems, which produces the da Vinci Surgical System.

Broderick and Gitlin agreed that the da Vinci system, although the prevalent surgical robot in use at civilian commercial facilities, does not meet the requirements for military field use. The robot is too big and complicated to withstand the pressures of the battlefield or other extreme environments.

“There are additional stages of the Trauma Pod over the next six years that will develop a trauma-specific robot, addressing for example the common injuries seen by small arms fire or improvised explosive devices. So we will be able to specifically address traumatic injury with robotics in a deployed environment,” Broderick noted.

“For the longer term in military applications, the most likely system will be a composite of the current ones,” he continued. “Most of these robotic systems were funded by the military. We have looked at a seed project to further refine and develop and find out what is good and what is bad about these specific robots in extreme environments for use on trauma patients. It is coming together on this dual TATRC/ DARPA Trauma Pod project. That project is funded well enough to develop the next generation robot that will be able to be used far forward. It will be able to be used for operational communications. That is an exciting project. That is slated to have forward deployed use in about five or six years.” ♦

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