Thoracoscopic laser ablation of pulmonary bullae. Radiographic selection and treatment response

Abstract

The purpose of this study was to develop objective preoperative selection methods for predicting outcome in patients undergoing thoracoscopic laser ablation of emphysematous pulmonary bullae. Initial radiographic presentation was correlated with physiologic function both before and after the operation in 24 patients entered into a prospective clinical protocol for evaluation of carbon dioxide laser treatment of emphysematous pulmonary bullae. Nineteen surviving patients underwent follow-up evaluation 1 to 3 months after the operation. Pulmonary function test results showed improvements in spirometry (forced vital capacity increased 0.82 +/- 0.125 L, forced expiratory volume in 1 second increased 0.36 +/- 0.07 L, and maximum voluntary ventilation increased 11.69 +/- 2.6 L/m; p < 0.002); airway resistance decreased by 0.9 +/- 0.35 cm of water/L per second, and specific conductance increased 0.019 +/- 0.006 L/cm H2O per second (p < 0.02). Lung volumes improved (residual volume decreased 1.25 +/- 0.23 L, p < 0.001) without significant change in resting gas exchange. Quantitative radiographic grading of extent of preoperative pulmonary bullae correlated well with response to laser treatment in patients with preoperative and postoperative studies. Patients with large bullae accompanied by crowding of adjacent lung structures, upper lobe predominance, and minimal underlying emphysema had greatest improvement in pulmonary function results with laser bullae ablation (p < 0.05). However, some patients with multiple smaller bullae and diffuse emphysema also demonstrated objective improvement after operation. Quantitative radiographic analysis of the extent of bullous disease and the degree of associated emphysema can be used to determine short-term postoperative pulmonary response and may be useful in selecting future thoracoscopic laser bullae ablation candidates. Additional follow-up will be necessary to further improve selection criteria and help define the long-term role of thoracoscopic laser treatment of bullous emphysema.