ULTRASTRUCTURAL FINDINGS IN PLEURAL BLEBS OF PATIENTS WITH SPONTANEOUS PNEUMOTHORAX

Lung biopsies obtained by conventional thoracotomy from five patients (mean age 33.6 years, range 21-45) following recurrence of spontaneous pneumothorax were studied by light, scanning, and transmission electr on microscopy. The purpose of the study was to define abnormalities th at predispose to air penetration through the intact wall of pleural bl ebs. Two types of blebs were identified either with a complete or with an incomplete layer of mesothelial cells. In those areas where the me sothelial cells were lacking, the walls only consisted of irregular, d iscontinuous collagen fibers. Increasing intraalveolar pressure may di stort the net of collagen fibers and air penetration appears to be pos sible. The wall of pleural blebs is generally weakened by degenerative changes and may predispose to recurrence of pneumothorax. Therefore, wedge resection of the blebs including the underlying lung parenchyma is suggested for surgical therapy of pneumothorax.