Ask anyone who knows about R. Rox Anderson’s experiments with lasers and chances are you’re going to hear the words “Star” and “Trek” in close proximity. Then again, lower-tech analogies, such as shipyards or auto-body shops, could also spring to mind. But this is not science fiction, and it’s most definitely not conventional metalworking. Anderson works in the world of biology, and his aim is to weld wounds shut.
Wound welding is a high-tech dream that could become a clinical reality soon-if it finds the right niche. Anderson, a Harvard University dermatologist who heads a laser research lab at Massachusetts General Hospital (MGH), thinks lasers could supplant the relatively primitive sutures and staples now in widespread use. “We should not be putting people back together or doing surgery and moving organs around, tacking them in there with little bits of string and chunks of metal,” he says. “It’s archaic.”
Anderson and his research colleagues aren’t the only ones intrigued by the potential of welding the body’s cut and injured tissues back together. A handful of biomedical startups and established laser manufacturers are working feverishly on it, and larger surgical companies are keeping a close watch on the progress. The work is driven by the potential advantages of laser welding: faster surgeries, fewer complications, quicker healing. The hard commercial reality, however, is that, for most common procedures, suturing and stapling are cheap and deeply entrenched. But recent advances in surgery, especially ones in the fast-growing field of minimally invasive procedures, are creating opportunities that could make laser welding a clinical reality.
Thus far, the rush to practical applications has outpaced the scientific understanding of what happens at a bio-weld site. What is known is that when the laser heats the edges of a rent, proteins there begin to denature or “melt.” As the material cools, it solidifies and-if all goes according to plan-the edges coalesce, leaving a seam like a weld in a metal pipe. To aid this melding process, researchers often add a protein-based solder into the wound in order to reinforce the seam.
The method is attractive to surgeons because, for one thing, it might ultimately become more highly standardized than suturing, which is still more art than science. “How far away they put the needle from the edge of the tissue, how far they put one stitch from another, how tightly they tie the knot or pull the stitch between knots-all of those are subjective and every surgeon will do them differently,” explains Dix Poppas, director of pediatric urology, reconstructive and laparoscopic surgery at New York Hospital-Cornell University Medical Center and a tissue welding researcher. And while mechanical staplers take some of the craft out of joining tissues, they aren’t always practical for delicate, irregular or very small structures.
Unlike sutures or staples, welding wounds also offers a watertight seal to hold bodily fluids in, preventing blood loss, infections and repeat surgeries. And lasers don’t leave behind bits of string and pieces of metal that can inhibit healing and cause inflammation, scarring and constriction of newly repaired vessels.
The first attempts at laser tissue welding date back almost 20 years. Over that time, lasers have emerged as an invaluable tool for surgeons for cutting or destroying tissue and have, for instance, revolutionized the removal of cataracts. But with the exception of a widely used laser procedure for reattaching a retina, welding has yet to prove itself the method of choice for tissue closure.
These days, however, many biomedical researchers feel that the field is reaching critical mass. Encouraging results from lab and animal studies continue to pile up, and preliminary human studies have shown welding’s potential utility in surgeries such as vasectomy reversal, artery and vein reattachment and the correction of penile birth defects. “I’ve been doing this for 16 years and it used to be that no one even listened-now I get calls every week,” says Poppas.
Despite the enthusiasm, it remains uncertain whether tissue welding can sew up a spot in the hotly competitive surgical business. For it to become a standard medical technique, doctors will need access to safe and reliable off-the-shelf welding devices and “solders.” Some of these items are now in human clinical trials, but they still must prove themselves and gain regulatory approval from the Food and Drug Administration. And the companies developing the products will need to define and capture a market for their technology that will provide lucrative returns.