Use of a new ICG-dye-enhanced diode laser for percutaneous laser disc decompression

Background and Objective: The lasers used today for Percutaneous Laser Disc Decompression (PLDD) can not selectively ablate the nucleus pulposus (NP). We hypothesized that if indocyanine green dye were injected into the NP, 8 05 nm diode laser irradiation would result in selective and safe removal of NP tissue without damaging nearby tissues. Study Design/Materials and Methods: Twelve beagle dogs were used for three experiments, i.e., determination of attenuation coefficients of NP and AF, determination of weight of NP before and after laser irradiation, and histo pathological study. Results: The attenuation coefficient at 805 nm of NP which had been homogen ized in the presence of ICG was 2521.3/cm. Upon application of the diode la ser at a power of 1, 3, or 5 W (the intensity of laser irradiation: 0.353, 1.061, or 1.768 x 10(3) W/cm(2)) to NPs into which ICG had been injected, t he weight of the NPs decreased by a mean 20, 45, and 65%, respectively. Mac roscopic and microscopic examination of the discs after PLDD showed that on ly the NP where the tissues were stained by ICG were removed. Conclusions: These results indicated that the combined use of ICG and diode laser irradiation effectively and selectively ablates the NP with low lase r power. (C) 2001 Wiley-Liss, Inc.