Pathogenesis of so-called idiopathic spontaneous pneumothorax and related conditions.

Since the research work of Fischer-Wasels by anatomic methods, we know that in the pathogenesis of so-called idiopathic spontaneous pneumothorax certain bullae, situated on the surface of the lung, play an important part. Later our concept was further extended by pleural endoscopy which made possible not only exact diagnosis, but also effective therapy. We learned by means of biopsy that the bullae can be small or large, even gigantic, usually multiple, but sometimes isolated, particularly the large kind. The bullae are by no means limited to the apex; they may also be found on the whole surface of the lung. The bulla arising from a cicatrized region is a very frequent phenomenon but not necessarily so. According to general opinion the beginning of spontaneous pneumothorax based on bullae, comes from the rupture of a bulla. This has been proved by anatomy, endoscopy and by operation. There can, therefore, be no doubt concerning this mechanism of the origin of spontaneous pneumothorax. There also can be no doubt that another mechanism exists, that is the permeability of a bulla-without rupture, and without collapse of the latter. In 1940 I established in a monograph,t concerning spontaneous pneumothorax, that a bulla with a very attenuated wall is able to produce and maintain chronic pneumothorax without any previous rupture. This conclusion was founded on observation with the endoscope. Before the operation it had been determined by the intrapleural pressure that the air had not ceased to escape from the lung. Endoscopy showed one solitary bulla of a gigantic size, originating in the inferior lobe of the right lung with greatly attenuated walls and in a state of tension. This was treated successfully by local irritation of the bulla. The hypothesis of passage of air through the visceral pleura which has become thin, without macroscopic lesion is not without analogies. Sohrnincke in 1924 describes a case in which he supposed the pleura to be permeable because of defective develop-