Which type of diffuse emphysema is adequately contracted by the Nd:YAG laser. An ex-vivo experiment

Diffusely emphysematous lungs are not always effectively contracted by laser therapy; however, which type of diffuse emphysema that responds to laser therapy remains unclear. We macroscopically and histopathologically examined human lung tissue, which was resected from patients with carcinoma, after irradiation with an Nd:YAG laser. Forty-six lung lobes were irradiated with a non-contact mode Nd:YAG laser at a power setting 15 watts. Macroscopically, twenty samples of normal lungs revealed moderate contraction, fourteen samples of predominantly centrilobular diffuse emphysema showed significant contraction, and eight samples of predominantly panlobular diffuse emphysema with a slight elastic network showed slight contraction. Histopathologically, the normal lungs showed amorphous change of the collagen and severely contracted elastic fibers (amorphous degeneration) at the pleura and some parenchymal coagulation; the predominantly centrilobular diffuse emphysema showed contraction of elastic fibers and collagen (coagulative degeneration) in the pleura and adequate contraction of the elastic fibers in the parenchyma and the predominantly panlobular diffuse emphysema showed only slight coagulation of the visceral pleura and very little coagulation of the parenchyma. On ex-vivo lung, panlobular emphysema was inadequately contracted by laser therapy, due to elastic recoil. Centrilobular emphysema responded to laser treatment, due to the severe contraction of the elastic fibers.