For much of its brief history, robot-assisted surgery has been synonymous with Intuitive Surgical, Inc.’s da Vinci system. It’s the only robot with U.S. Food and Drug Administration (FDA) approval to help surgeons perform a number of laparoscopic soft-tissue procedures, including hysterectomies, gall bladder and kidney removals, prostate cancer treatment and heart valve operations. Da Vinci has improved vastly since Intuitive introduced it more than a decade ago. Like many new technologies, however, it has experienced growing pains, leading some engineers and medical professionals to question whether a single company can meet growing demand while still delivering a safe product.
A team of researchers is looking to address these issues by developing a robotic surgery system based on hardware designs and software that are freely available. In this open-source approach, the builders would keep whatever intellectual property they’ve invested in the project but must make their knowledge and discoveries available to others.
The researchers, from the University of California, Santa Cruz, and the University of Washington (U.W.), hope their efforts will lead to a number of advances in surgical-robot technology that would stem from a basic design that wouldn’t change from device to device. The idea is that the costs of building—and buying—multimillion-dollar robotic surgery systems would decrease, as would the learning curve to use them.
The open-source model has worked well in the software industry, enabling startup companies to challenge Goliaths like Microsoft and Oracle by offering lower prices as well as collective review of new advances. Some of the more visible products of open-source innovation include Google’s mobile Android operating system, which is based on Linux, and Mozilla’s Firebox Web browser. Engineers and designers have also launched efforts to collaboratively develop open-source general-purpose robots as well as prosthetic limbs. Brewers have even applied the approach to making beer, tweaking and redistributing one original recipe to a broader community of enthusiasts.
Gold standard
Da Vinci has been assisting surgeons since it received FDA approval in 2000, helping them operate quickly and efficiently in tight spaces. The device’s four arms can wield any number of instruments, including scalpels, forceps, graspers and scissors to, for example, make incisions, remove organs, place catheters and close incision points. A surgeon controls these tools while sitting comfortably in front of an ergonomically designed console with the aid of a high-definition 3-D camera, reducing concerns about fatigue during long procedures. Despite its nearly $2-million price tag, the da Vinci’s popularity has grown steadily in recent years. In 2012 doctors used the system to perform more than 350,000 surgeries in U.S. hospitals, a 60 percent increase from 2010.
Intuitive designed the da Vinci to improve on existing laparoscopic surgery—also referred to as minimally invasive surgery because the surgeons perform most of the repair work inside the body by passing tiny video cameras and tools through small incisions. Physicians have reported several advantages to using da Vinci, including less patient bleeding and shorter surgery times, both of which lead to reduced hospital stays and recovery times. T. Sloane Guy, chief of robotics and section chief of cardiovascular surgery at Temple University School of Medicine, likens conventional laparoscopic tools to “chop sticks” and says da Vinci’s computer-controlled tools provide greater freedom of movement in snug spaces during surgery.
Despite advantages, adverse reports related to these surgeries have grown along with their use. The FDA received 3,697 adverse reports from Intuitive and hospitals using the system that involve deaths, injuries or malfunctions linked to robotic surgery procedures from January through November 2013, compared with 1,595 in all of 2012. The agency has acknowledged that there are likely many more events that go unreported, and patients have begun to file lawsuits against both Intuitive and hospitals following complications during procedures in which da Vinci was used.
A small group of surgeons shed some light on problems with da Vinci in an FDA study published in November. (pdf) These included a crack in a robot arm that caused an instrument to fail, an arm that drifted during a procedure and collisions between arms during surgery. No injuries to patients were reported as a result of these specific incidents, but the study provides insight into da Vinci’s successes and failures as well as the training required to use the system. The FDA cautions, however, that this report is in no way comprehensive—it includes feedback from only 11 surgeons, although each performed 70 to 600 surgeries using da Vinci over the last three years.
Open-source alternative
The researchers from U.C. Santa Cruz and U.W. have been developing iterations of their robot—called the Raven—for more than a decade. Thus far they’ve shipped 14 Raven II robots to universities in the U.S., Canada and France, including Harvard University, Johns Hopkins University, the University of Nebraska–Lincoln, University of Montpellier and the University of Western Ontario. Each of these systems has a unique Internet Protocol (IP) address and has been networked to the others, to create a common platform through which the researchers can share software, replicate experiments and collaborate in various ways.

Each Raven II includes two mechanized arms, a screen that lets the surgeon operate remotely, a camera that provides the visuals for the screen and software that enables these elements to work together.
In the early 2000s the researchers were interested in writing software for da Vinci but they became frustrated when Intuitive would not provide some of the information needed to complete their coding. “We realized that to be active in the field we needed a research platform that we have full control over,” says Jacob Rosen, associate professor of computer engineering in Santa Cruz’s Baskin School of Engineering and principal investigator on the Raven project.
Rosen, then at U.W., and his colleagues received funding from the U.S. Army to build their own robotic surgery system. Five years later, in 2007, the Raven I was born. Rosen redesigned the Raven when he moved to Santa Cruz in 2008 and the following year created a four-armed version he dubbed Raven IV. “I was thinking that if you want to replace the two surgeons in an operating room, you need four arms and two cameras,” he says.
By 2010, Rosen had reteamed with Blake Hannaford, director of U.W.’s Biorobotics Laboratory, to improve on the original two-armed Raven I. The collaboration ended up receiving $850,000 in National Science Foundation funding, and used that money to build eight Raven II systems they could give to other institutions pursuing robotic surgery research. This time Rosen and Hannaford stuck with two arms because they agreed that that would be more affordable for all of the research teams moving forward.
Inevitable comparisons
The Raven and da Vinci are designed to perform essentially the same tasks, but they differ in a few key ways. For starters, the Raven costs about $300,000, and its arms are anchored in different positions around the operating table. Da Vinci’s arms connect back into a single base—they essentially originate from the same spot. Intuitive did this to take up less space in the operating room.
The Raven’s design attempts to emulate the way a team of surgeons can work from either side of a patient during an operation, Rosen says. “By distributing the Raven’s arms in a similar way to how humans use their arms, you can avoid many of the problems with arms hitting each other,” particularly when four or even more arms are introduced into the limited space above the patient, he adds.
Unlike da Vinci, Raven is not approved to operate on humans. The researchers did, however, perform several simulated surgeries on pig cadavers while developing the Raven in 2006. Subsequent Raven experiments were done on individual organs extracted from dead animals, but much of the most recent work has focused on developing software to increase the system’s performance and expand its capabilities. Rosen and his colleagues last year formed the company Applied Dexterity, Inc., to produce the Raven as a robotic surgery research platform for other institutions.
Surgeons would be better served by having multiple robotic surgery systems to choose from, says Guy, the Temple University surgeon who has used da Vinci to perform numerous cardiac operations. “In general, I’m a big believer in open source,” he adds, but he raises the caveat that the open-source model is largely unproved when it comes to developing medical technology that requires “ little to no tolerance for problems.”
Taking flight
In addition to developing the Raven to perform soft-tissue surgeries, Rosen has been considering what is needed to make a robotic system that can perform even more complicated procedures, such as brain surgery. Also on the to-do list is programming the robot so that it could switch tools when needed during surgery without any human help.
Fully automated robot surgeons are much farther out on the horizon, if ever. Rosen points out that once a surgeon cuts into a patient’s skin or internal organs, the tissue changes shape and moves in ways that are difficult to program into a computer. “You would need to constantly use computer vision to extract information about the evolving environment in which the robot is operating,” he says. “This is very challenging to do in robotics. You want to automate the mechanical parts of the surgery, not the decision-making parts, which humans are good at.”