The concentration of medicine, engineering, and medical device companies in Boston provides fertile ground for surgical innovation.

Rachael Moeller Gorman

It’s not hard for surgeons in the Boston area to knock elbows with engineers, imaging specialists, and biologists. Such connections have spurred the development of new techniques and devices designed to make surgery more precise and less invasive, and to lower the rate of complications. Here are three examples.

Tiny beacons for tumors

In operations to remove cancer tumors, surgeons still rely largely on their eyes and visible light to find all of the cancerous tissue. But they can’t always see all of it, so researchers from Massachusetts General Hospital’s Center for Molecular Imaging Research, MIT’s Center for Cancer Research, and Siemens Medical Solutions in Charlestown have developed a technique that uses tumor-recognizing fluorescent probes to help surgeons spot small groups of cancer cells during surgery.

The probes consist of nanoparticles attached to molecules that are designed to fluoresce when the nanoparticles have been engulfed by specific tumor cells. In a mouse cancer model, surgeons injected the nanoparticles into the bloodstream before the surgery and used a set of handheld cameras developed by the Siemens team to pinpoint fluorescing regions during the procedure.

This handheld device consists of two cameras for imaging tumors during surgery. (Photo courtesy of Siemens)

In preliminary studies with mice, the researchers showed that this technology enabled them to find and extract cancerous tissue consisting of about one or two dozen cells. The team hopes to begin testing the technology in humans by 2008.

Towards incision-free surgery

Some of the biggest problems associated with surgery occur after the procedure is done: infections, pain, long hospital stays. Gastroenterologist Chris Thompson from Brigham and Women’s Hospital aims to lower the risk of complications with a new technique that uses the body’s natural openings—the mouth, urethra, vagina, and anus—to access the interior of the body, rather than making new incisions.

For this technique, Thompson and other surgeons have used conventional endoscopes—long, flexible tubes with tiny cameras or simple instruments on the end—but these devices aren’t optimal. Because Thompson goes into the body through only one opening at a time, he can approach the target site from only one direction with a single endoscope. He needed an endoscope that can better manipulate tissue on its own, without the help of other instruments.

So Thompson and collaborators from medical device giant Boston Scientific in Natick, MA, came up with an endoscope that has two bendable arms on the end, allowing surgeons to dissect, suture, and tie knots with a single instrument. “It’s like having a hand with a wrist at the end of the endoscope,” says Thompson. ”It may change the way we do procedures altogether.”

Their prototype has been tested in animals; three more will soon be built for testing in other labs.

“Glue gun” for new knees

Orthopedic surgeon Martha Murray at Children’s Hospital has worked closely with MIT professor Alex Slocum and his graduate-level machine design class to come up with a surgical device to help repair a knee ligament, the anterior cruciate ligament (ACL), that is commonly torn by athletes. The ACL can’t heal itself, so surgeons typically remove the damaged tissue and install new tendons taken from below the kneecap or the hamstring—a procedure that requires a long recovery and does little to forestall early arthritis, a common result of an ACL tear.

The ideal solution would be to stimulate the cells in the knee to rebuild the ACL. But, as Murray has discovered, the cells first need a “bridge” between the ACL fragments. Murray created a gel made of collagen and key blood cells involved in wound healing that acted as this bridge to trigger ACL repair when injected into the knees of lab animals. But she needed a device to mix, heat, and inject the gel into precise locations in the joint.

Slocum’s class created a prototype “gun” for this task, which a medical device company, TNCO of Whitman, MA, used to produce a better version in 2006. It has so far been used in animal studies and more optimization work is needed before it can be used on humans.

This “gun” injects a gel into the knee that stimulates healing of a torn ligament. (Photo courtesy of TNCO)

Murray’s work has been funded in part by the Center for Integration of Medicine and Innovative Technology, a consortium of Boston-based universities and research hospitals that in recent years has given out about $5 million in grants annually for interdisciplinary work on new medical devices and procedures.