A Retrospective Case-Control Study on the Chest Wall and Lung Characteristics in Patients with Primary Spontaneous Pneumothorax.

BACKGROUND Primary spontaneous pneumothorax (PSP) is reported to be more common in young men who are thin and tall. This retrospective study aimed to analyze the clinical and chest wall characteristics associated with PSP. MATERIAL AND METHODS Between January 2008 to December 2017, the clinical and imaging data of 99 patients at first presentation with PSP were compared with 82 age-matched healthy controls. Computed tomography (CT) imaging was used to measure the anteroposterior and transverse diameters of the chest at four levels, including the aortic arch, tracheal bifurcation, right inferior pulmonary vein, and lower sternal edge. Chest deformity was calculated as the ratio of the transverse diameter of the hemithorax divided by anteroposterior diameter. Lung volume and average lung density of 32 cases with PSP were measured and compared with 10 patients without PSP. Intrapleural pressure of 43 cases PSP who were treated with a closed chest drain was measured and compared with 39 patients with mediastinal tumor who underwent thoracoscopic surgery. RESULTS Patients with PSP showed a normal age distribution with a median of 17-18 years. The patients with PSP had significantly reduced anteroposterior and transverse diameters of the chest when compared with controls at four levels on CT (p<0.01). The lung volumes in patients with PSP were significantly reduced when compared with the controls (p<0.05), as were the minimum intrapleural pressure and pressure difference (p<0.05). CONCLUSIONS The findings support that chest wall dimensions may be associated with lung development, which are contributing factors in PSP.