To investigate the safety and feasibility of Carbon Dioxide (CO2) laser transmission through the OmniGuide Photonic Bandgap Fiber (OPBF) for treatment of airway obstruction.
Experiments using discarded human lung tumor tissue were carried out to determine the therapeutic dose for effective tumor destruction. Laser bronchoscopy was performed on 20 sheep to examine the safety and feasibility of the proposed treatment algorithm (dosages 3W to 10W). Animals were euthanized at 1 week and 4 weeks for pathological examination.
A dose response with the maximal thermal effect at the highest dose was observed. Microscopically, the maximal depth of penetration (0.5mm) was obtained only with the high dose at the shortest distance (10W, 5mm). The thermal effect to non-targeted tissue was minimal. Animal experiments demonstrated ease in maneuverability and flexibility of the procedure. Distal airways were easily accessible with the fiber. Tissue damage was highly localized and visible, facilitating a very high degree of control over penetration, ablation and cutting. No laser-related complications were observed. Application of maximal dosage (10 Watts) did not result in perforation, bleeding or other injuries. Four incidents of mild bleeding were easily and immediately controlled with laser shots at the high dosage setting.
The CO2 laser delivered through the OPBF can supply an effective dose for tumor destruction. The same dosages can be applied via flexible bronchoscopy safely in airways of live animals. Depth of penetration can be controlled by altering output power or distance from the target tissue. In no case was the penetration deeper than the superficial cartilage.
This is the first reported CO2 laser delivery through a standard flexible bronchoscope for ablative therapy in the distal airways. CO2 laser transmission through the OPBF may potentially provide a more controllable and precise modality for treatment of benign and malignant airway lesions. This precision is likely to make laser therapy safer and applicable to more lesions. Moreover, potential exists for superficial mucosal ablation of carcinoma in-situ.
Raphael Bueno, None.