ABSTRACT
I. Effects of Thoracic Surgery on the Pleura Normally, there is no pleural space because of the negative intrathoracic pressure generated by the opposing lung and thoracic recoil forces. A small amount of fluid results from the balance of fluid between parietal and visceral pleurae. Any thoracic operation either mini-invasive or by a classical open surgery constitutes a violation of the pleural space exposing it to ambient pressure and any potential source of infection. A simple primary spontaneous pneumothorax without any outside aggression of the thoracic wall provokes a strong pleural inflammation involving neutrophils, eosinophils, and lymphocytes as recently showed by De Smedt et al. (1). Not surprisingly, any thoracic surgery constitutes an aggression of the pleura, attracting inflammatory cells into the pleura and initiating a process of wound healing resulting in impaired fluid reabsorption within the pleural cavity. Accordingly, the pleura is thickened and adhesions occur between visceral and parietal pleurae leading sometimes to loculation of the pleural cavity. The thickening of the pleura (up to 10 times the normal size) gradually resolves over many weeks and the pleura recovers its single layer of mesothelial cells on both, the visceral and parietal pleurae (2).
