A LASER powerful enough to cut through steel may ease the agony of people suffering from severe burns by removing dead skin more quickiy and accurately than conventional surgical techniques. Massachusetts General Hospital and Sandia National Laboratories, New Mexico, are collaborating to develop the laser system, and they hope that their portable laser workstation will be in use in general hospitals by 1996.
鈥淭he initial procedures for burn patients haven鈥檛 changed much in the past fifty years,鈥� says Ned Godshall, a Sandia materials scientist working on the project. Doctors first remove all the dead tissue so that the patient鈥檚 blood supply can reach any skin grafts that are placed over the wound. The removal process is called debridement.
鈥淭hey do this essentially by 鈥榝illeting鈥� the area,鈥� says Godshall. Using a scalpel, surgeons carefully carve away layers of tissue. 鈥淭hey can only be sure they have reached intact tissue when the wound begins to bleed heavily, since the burn-destroyed tissue does not bleed,鈥� he says.
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The laser debridement workstation uses a 250-watt carbon dioxide laser to burn away the dead flesh, while a vacuum system removes the debris. Although this is still a painful process, it is much faster and more accurate than using a scalpel. 鈥淭he laser will improve recuperation time because less healthy skin is removed than with current procedures,鈥� says Godshall.
The computer-controlled laser beam travels in a series of parallel lines or 鈥渞aster鈥�, similar to the pattern that an electron beam traces as it scans rapidly across a TV screen to generate a picture. Precise control is vital because of the power of the laser. 鈥淚f directed at one spot for ten seconds, it could burn a hole through half a centimetre of steel,鈥� says Godshall. But the computer ensures that only a very thin layer of healthy tissue is removed. 鈥淲e remove about 150 microns 鈥� thinner than an onion skin 鈥� of healthy tissue,鈥� he says.
The researchers are still experimenting to find a better way of detecting the boundary between burnt and healthy tissue. Wellman Laboratories, the research arm of Massachusetts General, is experimenting with indocyanine dye, which is injected into the patient鈥檚 body before debridement begins. The indocyanine in the patient鈥檚 blood fluoresces bright green under ultraviolet or infrared light. Since the dye does not penetrate tissue destroyed by the burn, a bright signal alerts surgeons when they have reached healthy tissue. 鈥淎t this point the dye technology is not mature enough for commercialisation,鈥� says God shall.
