Laser Biomedical Engineering: Clinical Applications in Otolaryngology

Abstract

The first lasers, ruby, neodymium-in-glass and argon, were tried experimentally in various areas of biological and medical research. In the field of otolaryngology, Stahle and Hoegberg (1965) used pulsed lasers for inner-ear irradiation, Conti and Bergomi (1966) for irradiation of the posterior labyrinth, and Sataloff (1967) for experimental irradiation of otosclerotic stapes. Kelemen et al. performed studies on the effects of massive irradiation in the ears of mice using pulsed ruby and neodymium lasers. In 1965, with Dr. M. Polanyi at the American Optical Company, I studied the possibility of cutting into the vocal cords with the laser. Human cadaver specimens were used for the initial study, with a high-output pulsed neodymium-in-glass laser operating at 1.06 µm (Fig. 15.1). The limited tissue absorption of the wavelength of this laser was increased by painting the specimen with a 5% copper sulfate solution. With rather high energy levels, only small lesions could be affected in the vocal cords. Histologic studies demonstrated tissue destruction. Experiments with these high-output short-pulsed lasers were performed by various researchers in the mid-1960s. They soon realized that these lasers created explosive effects in tissue. After irradiation of experimental tumors, scattered cells and tissue fragments could be found in the operative area. Naturally, this ruled out the use of lasers, especially in tumor surgery.