Thoracoscopic treatment of spontaneous pneumothorax using carbon dioxide laser. In an effort to improve the success rate of the previously described thoracoscopic electrocautery ablation technique of spontaneous pneumothorax, the carbon dioxide laser was evaluated in 12 patients. The recurrent (5 patients) or persistent (7 patients) spontaneous pneumothoraces were caused by rupture of (1) blebs in 6 patients, (2) intrapulmonary apical type II bullae in 3 patients, and (3) diffuse bullous emphysema, type III, in 3. The air leaks were successfully sealed in all but 1 patient with ruptured type II bulla. Surgical specimen from this single failure suggested that the entire inner lining of the bullae must be thermocoagulated. This technical modification led to successful outcome in 2 subsequent cases. With the use of carbon dioxide laser, it was possible to treat not only small blebs but all types of bullae causing spontaneous pneumothorax. Laser thoracoscopy is effective and safe in treating spontaneous pneumothorax. 