Anthony Doesburg: Surgical robots at cutting edge of medicine

The surgeon-guided da Vinci robot in action. Photo / Supplied

We might think of neurosurgery as the ultimate in modern medical intervention. But for one thing, brain surgery is thousands of years old. And for another, today's cutting-edge operations are being carried out elsewhere in the body, by human-guided robots.

As Catherine Mohr points out, humans have been opening up other living humans' skulls for 10,000 years or longer, and not just during mortal combat.

Cutting or drilling a hole in the skull is called trepanation, and archaeologists have skulls from all over the world with deliberately made holes that show signs of healing - which means the patients survived the procedure. It's evidence of the dawn of interventional surgery.

New Zealand-born Mohr and colleagues at United States company Intuitive Surgical are the inheritors of those pioneering Stone Age surgeons. The company makes the da Vinci surgical robot, which allows a human surgeon to precisely control tiny cutting and suturing instruments through small openings, or ports, in a patient.

Mohr, a passport-carrying Kiwi, says the decade-old da Vinci system is being used for heart, abdominal, gynaecological and urological procedures, shortening operating and recovery times.

"Eighty per cent of prostatectomies [partial or complete prostate removal] in the United States are done using da Vinci robots," says Mohr. "It was the first major application where it was enthusiastically adopted."

US hospitals have bought about 1200 of the systems and the rest of the world more than 400, including New Zealand, where there are four. They produce better results for patients but also give hospital balance sheets a healthy glow, undoubtedly what persuades managers to part with the US$1.5 million to US$2.5 million ($1.9 million to $3.17 million) price tag.

According to Intuitive Surgical, a mitral (heart) valve repair using the da Vinci system will put a patient in hospital for less than five days, compared with 8 days for open heart surgery. The da Vinci system will leave a number of centimetre-long incisions, whereas open heart surgery involves slicing open and splitting apart the entire rib cage.

A robotic prostatectomy patient will be out of hospital after 1.2 days instead of 3 days for open prostatectomy; they will lose about 10 per cent of the blood and have a third fewer complications.

"If a hospital is paid a flat fee for the removal of a prostate, it will make more money if the patient is healthy enough to go home early," Mohr says.

The da Vinci system surgeon sits at a console with the patient on a nearby cart. The ports are cut manually before the "docking" - insertion of instruments and video camera - of the robot. The surgeon sees a close-up view inside the patient and manipulates the robot's four arms with a controller that reduces the scale of movements by as much as seven times.

"There was concern that it would have to be the video game generation that would be able to pick up this technology," Mohr says, "but what we have been seeing in some of the literature is that surgeons with open surgical skills are adapting quite readily to the robots.

"The instruments are analogues of their hands and they're inside the patient carrying out the procedure pretty much as though their hands were in there."

The origins of the technology were in a US Army-funded effort to develop a system for performing remote battlefield surgery.

Intuitive Surgical could see its wider potential for robotic keyhole - or laparoscopic - surgery.

Mohr is sceptical about using the technology so a surgeon in one location can operate on a patient in another, because of the risk of failure of the high-capacity telecommunications links that would be required. However, the system lends itself to a senior surgeon walking a less experienced operator through a procedure while "looking over their shoulder" from a distant location.

As Intuitive Surgical's director of medical research, Mohr evaluates future uses of the da Vinci system. "The things I'm looking at are how could we change the face of surgery." One area of interest is finding an alternative to gastric bypass operations as a way of tackling type 2 diabetes.

Mohr's parents, a biochemist and bio-statistician, left the University of Otago for further study in the US in 1970, when she was 2 years old. They never managed to find jobs to return to in New Zealand.

Mohr studied mechanical engineering and then medicine, and ended up combining the two at Intuitive Surgical. She made one of many visits to New Zealand last week, speaking at the Running Hot conference for researchers in Wellington.

Ironically, says Mohr, for all the da Vinci system's cleverness, it can't match the facility of a Stone Age surgeon using a razor-sharp rock to relieve a fellow cave-dweller's headache.

"You'd want to design your robot differently for intracranial work."

Rapid Growth

While it is relatively new, robot-assisted surgery is already big business. Intuitive Surgical, which is listed on the Nasdaq exchange, has a market value of almost US$11 billion ($13.9 billion)

Anthony Doesburg is an Auckland technology journalist