Laser applications in the trachea and bronchi: a comparative study of the soft tissue effects using contact and noncontact delivery systems.

A comparative study of laser soft tissue effects using carbon dioxide (CO2) and neodymium-yttrium aluminum garnet (Nd-YAG) lasers in contact and noncontact endoscopic delivery systems was done in the canine tracheobronchial tree to determine the best laser system for the specific disease. The CO2 laser bronchoscopic coupler, CO2 laser waveguide, Nd-YAG laser fiber, and Nd-YAG laser contact probe were used. A 5 mm diameter soft tissue injury exposing tracheal cartilage was made, and the power density for each laser modality was measured. Soft tissue effects were documented histologically using routine techniques and scanning electron microscopy acutely and at 1 week and 2 weeks after injury. The effects were similar with the CO2 laser coupler and the CO2 laser waveguide with comparable power densities. Compared with the CO2 laser, the Nd-YAG laser fiber caused more extensive and more difficult to control thermal damage in tissue. The Nd-YAG laser contact probe was capable of precise soft tissue ablation with minimal surrounding tissue damage and was associated with the most rapid healing. This study concluded that high power density with short exposures is desirable when treating benign disorders, such as tracheal stenosis, making the CO2 laser or Nd-YAG laser contact probe application a good choice. On the other hand, malignant tumors with a potential for hemorrhage are best treated with the Nd-YAG laser noncontact fiber system because of its superior coagulative effects.