Evaluation of decortication in patients with chronic tuberculous empyema by three-dimensional computed tomography densitometry

Background Decortication for chronic pleural empyema (CPE) is to restore lung volume by removing empyema sac and thickened pleura. Extent of lung volume restoration after decortication has been undefined. This study aims to evaluate lung volume restoration using densitometry with three-dimensional reconstruction computed tomography (CT). Methods We studied 23 patients with CPE who underwent decortication and follow-up CT. CT and pulmonary function test (PFT) were evaluated at a median of 19.1 months postoperatively. The volumes of operated and nonoperated lung were measured by pre- and postoperative CT-densitometry. Preoperative and postoperative values of lung volumes, PFTs, and thoracic asymmetry rates were compared statistically. Results The mean preoperative volumes of operated and nonoperated lung were 1,239 and 2,094 mL, respectively and 1,848 and 2,311 mL postoperatively. The postoperative lung expansion rate was 71% on the operated side (p < 0.001) and 15% on the nonoperated side (p = 0.026). The mean improvement rate of total lung volume was 31%. The postoperative value of forced vital capacity, forced expiratory volume during 1 second and lung diffusion capacity of carbon monoxide improved 28.0%, 27.4% (p < 0.001), and 17.9% (p < 0.012), respectively. The thoracic asymmetry decreased from 4.3% before surgery to 2.8% after surgery (p = 0.026). Conclusions With the use of CT-densitometry, we quantified the changes of each lung volume. Decortication for CPE can improve re-expansion of diseased and healthy lung. Improvement of nonoperated lung may be due to the overall improvement of chest wall elasticity. Coincidentally, we discovered that the improvement of total lung volume was positively associated with the improvement of PFT after decortication.