Inside each BeamPath fiber, fewer than 20 microscopic layers of alternating, custom-designed infrared glass and polymer form a reflective system known as a "photonic band-gap structure." (pdf) The design stemmed from research conducted by OmniGuide co-founder and CEO Yoel Fink in 1998 when he was a graduate student at the Massachusetts Institute of Technology's (M.I.T.) Plasma Science and Fusion Center. Fink and his colleagues studied ways to devise the "perfect mirror," a surface that reflects light of all wavelengths and from all angles, for the Defense Advanced Research Projects Agency (DARPA), the U.S. Defense Department's the research arm. Since its 2000 start up, OmniGuide has invested $70 million into researching and developing the materials and technology needed to produce this superthin silicon fiber.
Water, which constitutes more than 60 percent of human tissue, absorbs CO2 laser energy well, enabling such devices to make a more precise cut than a normal scalpel with minimal thermal damage to surrounding healthy tissue, says Lee Nelson, a neurosurgeon with Boulder Neurosurgical Associates in Colorado. BeamPath technology allows CO2 laser energy to be transmitted down a hollow-core fiber and used as a handheld laser scalpel, which Nelson says he used in 30 brain and spinal cord surgeries that he has performed since October. "We knew about the advantages of the CO2 laser," he says, "but it had never been practical to use."
The BeamPath allows surgeons to do some procedures that a normal scalpel cannot do. For example, when a surgeon presses a regular metal scalpel into an organ, it depresses the tissue around it, potentially causing damage to healthy cells surrounding targeted tumors. Unlike a normal scalpel, the BeamPath fiber does not require tissue manipulation, Nelson says, adding, it also controls bleeding better than a metal scalpel by cauterizing, or searing and sealing, nearby blood vessels.
The flexible CO2 laser scalpel has special appeal for lower-back surgery, an area where diseased tissue is often difficult to remove. "When you remove this tissue with standard tools, you are sometimes left with arthritic tissue in the spinal canal causing patients to continue to feel pain even after the surgery," Nelson says. "With the CO2 laser, you can dissolve that [damaged] tissue. Instead of pulling or tearing that tissue, we're now simply ablating it." Nelson says that so far, the patients he has treated this way have experienced less pain than those who have undergone traditional surgery, but he adds that he needs a few more years to expand his sample size enough to prove that the laser is the reason for the reduction in pain.
The cost of the technology—from $500 to $1,800 a fiber—has been the major reason it is not used more widely yet. Nelson says he needs to prove that the BeamPath improves patient outcomes to justify opening his wallet for more of these devices. There are two potential limitations on the fibers: their stability when energized and their inability to be sterilized, which means they must be discarded after each use, Nelson notes.