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Surgeons don 3D glasses, get 'remarkable' depth perception for keyhole surgery

01/24/2012 04:43 EST | Updated 03/25/2012 05:12 EDT
TORONTO - It's a technology that had audiences for movies such as "Avatar" and "Harry Potter and the Deathly Hallows" virtually leaping out of their seats. And soon, that 3D sense of being in the centre of the action could go beyond the cinema to hospital operating rooms.

Several surgeons in Canada have test-run a prototype 3D system for laparoscopic surgeries, one form of the minimally invasive operations performed with a camera-tipped scope and instruments fed through tiny incisions in the body.

Conventional equipment allows the surgeon to see the patient's organs, blood vessels and other interior structures, and to manipulate instruments with the aid of a computer monitor. But the two-dimensional image is flat, similar to watching a broadcast on TV.

"With laparoscopic surgery, or any kind of minimally invasive surgery, we lose our tactile sense, so we only rely on visual cues," says Dr. Teodor Grantcharov, a general surgeon at St. Michael's Hospital in Toronto who specializes in gastric procedures.

"This has been one of the challenges with minimally invasive surgery, to convert the two-dimensional image which we see on a computer screen or monitor to a three-dimensional field, because we work in a three-dimensional field."

Some surgeons have great difficulty trying to manipulate delicate instruments inside a clearly three-dimensional body with the aid of only a two-dimensional image on a screen, he says. "And this visual perception has been a problem for many years, and that's been one of the limiting factors in laparoscopic surgery."

Indeed, a study by the hospital a few years ago found eight per cent of surgical trainees were unable to make the visual-spatial leap needed to master standard 2D laparoscopy.

"No matter how much they train, no matter how much they exercise, they will never be able to be proficient with laparoscopic techniques just because of this issue with visual perception," says Grantcharov.

Yet minimally invasive operations are often considered the standard of care, trumping traditional open surgery for many procedures. And the number of operations that can be performed with so-called "keyhole" surgery is growing.

"We've reached the point where there is no procedure that cannot be done laparoscopically and there is a lot of evidence that suggests that the laparoscopic approach is superior than the open (surgery)," Grantcharov says of operations involving the abdominal and pelvic areas.

For patients, the tiny incisions mean quicker healing, smaller scars and less post-operative time in hospital.

"The difference in recovery and quality of the procedure's success is spectacular," he says.

The 3D system could allow those doctors who are unable to visually navigate using the standard two-dimensional system to successfully perform minimally invasive surgeries, he believes.

Late last year, Grantcharov test-drove the prototype 3D system created by German-headquartered medical instrument company Karl Storz to perform a gastric bypass aimed at helping a patient lose weight.

Wearing high-tech 3D glasses, he was able to manipulate his instruments — including a double-lens scope — and view the patient's stomach and surrounding anatomical structures on a special 3D colour monitor.

"You're really feeling as if you're inside the abdomen, it's quite remarkable," says Grantcharov, adding that all the members of the surgical team don the special glasses so they also can watch and assist with the operation.

"If we're working around the major blood vessels, you can really appreciate when you can touch it so you don't apply too much force on it, how you can come around it and make sure you don't injure it. You just feel very safe when you're working with vital structures."

The stereoscopic image delivered by the 3D system is similar to normal vision of the human eye, says Karl Storz.

"While the system is not intended to replace 2D imaging systems, the enhanced depth perception of the 3D system can be advantageous during certain laparoscopic procedures and represents significant new capabilities for surgeons," a company statement explains.

Dr. Gerald Fried, a laparoscopic surgeon at McGill University Health Centre in Montreal, recently field-tested the system to repair a hernia involving the stomach.

"I think it has certain benefits and certain drawbacks in comparison to what we're used to using," says Fried, who has been performing minimally invasive surgeries for close to 25 years and teaches the technique to other surgeons.

One of his major criticisms is that while depth perception was better with the 3D set-up, he found the current 2D system with its high-definition monitors had better clarity of image. The 3D glasses also seemed to restrict the light somewhat, so the image wasn't quite as bright as with traditional laparoscopy.

And because the double-lens scope requires a bigger incision in the abdominal wall — 10 millimetres versus the usual five — he worries there's a slightly higher chance of complications, including the risk of a hernia in the incision and possibly extended post-operative pain for the patient.

"So I think all of these things need to be evaluated," he says.

While Fried didn't get the same sense as Grantcharov — "I don't find it immersive like a science fiction thing where you feel as if you're actually inside the patient" — he is nevertheless excited about the technology's promise.

"I think it won't be long to leap from where we are now to a high-definition 3D optical system and that would be the time when I'd be very interested in upgrading our existing system."

Karl Storz won't release the cost of its 3D system, which will likely be commercially available towards the end of the year.

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