EFFECTS OF ND-YAG LASER IRRADIATION ON MORPHOMETRY AND LUNG-FUNCTION IN ELASTASE-INDUCED EMPHYSEMA IN RATS

Background & Objective: Although thoracoscopic laser ablation therapy has been hailed as an effective surgical treatment for diffuse emphyse ma, no one has as yet made an in-depth study of the efficacy of this t reatment. This investigation was under taken to research the effects o f laser pneumoplasty on an animal model of emphysema. Study Design Mat erials and Methods: Eight weeks after elastase treatment, the rats' le ft lungs were irradiated using contact Nd:YAG laser. Pulmonary functio n tests were performed 4 weeks after irradiation and the lungs were pr epared for histologic examination. Results: Dense fibrous scars beneat h the pleura were observed at 4 weeks after irradiation. Although mean linear intercept values of irradiated lungs were not much lower than those in the non-irradiated elastase-treated group, laser irradiation caused a significant decrease in lung volume. While there was no signi ficant difference in quasistatic compliance, elastic recoil pressure o f the lung increased to control levels at total lung capacity volume. Conclusion: We conclude that laser therapy does not cause normalizatio n of compliance, or improvement in the deeper part of the emphysematou s lung, but rather a peripheral volume reduction and ''encasement effe ct'' on the lungs as a result of fibrotic scars. (C) 1998 Wiley-Liss, Inc.