title: Excimer ablation of human intervertebral disc at 308 nanometers.
abstract: Excimer laser energy, which has been shown to photoablate tissue at a precisely controllable rate with minimal thermal damage, was applied to human intervertebral disc in an effort to develop a technique for percutaneous discectomy. Cadaveric samples of human disc were used. Excimer laser energy was produced by a XeCl, magnetically switched, long-pulse laser working at 308 nm, 20 Hz. Annulus tissue of approximately 1 mm thickness was placed in contact with the output tip of a 400 microns core diameter quartz fiber, and measurements of ablation rate were made at different radiant exposures. Ablation rates were found to vary linearly with radiant exposure, from 0.7 micron/pulse at 10 mJ/mm2 to 11.0 microns/pulse at 55 mJ/mm2, with a correlation coefficient of 0.984. Threshold radiant exposure, calculated by extrapolation, was found to be about 7 mJ/mm2. Histologic analysis showed a minimum of thermal damage in these specimens, and when ablated with modification to maintain constant fiber-tissue contact, thermal injury was nearly absent, as compared to samples ablated with Nd:YAG through a contact probe. Thermographic analysis, performed using the AGA 782 Digital Thermography system, showed increasing temperature with increasing radiant exposure, with a maximum temperature of 47.2 degrees C at 55 mJ/mm2. In that precise tissue ablation was demonstrated with minimal generated heat, and excimer energy at 308 nm is transmissible through fiber optics, excimer holds great promise for the development of a percutaneous discectomy technique.
authors.affiliation: Harbor/UCLA Medical Center, Torrance 90509.
authors.forename: M
authors.initials: M
authors.lastname: Wolgin
authors.forename: J
authors.initials: J
authors.lastname: Finkenberg
authors.forename: T
authors.initials: T
authors.lastname: Papaioannou
authors.forename: C
authors.initials: C
authors.lastname: Segil
authors.forename: C
authors.initials: C
authors.lastname: Soma
authors.forename: W
authors.initials: W
authors.lastname: Grundfest
mesh_terms: D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D053685:Laser Therapy; D014466:Ultraviolet Rays