Spirometric and radiological evaluation of the remnant lung long after major pulmonary resection: Can compensatory phenomena be recognized in clinical cases?

Purposes: The purpose of this study was to investigate the compensatory phenomena after lung resection in clinical cases by evaluating the spirometric and radiological parameters. Methods: Forty patients undergoing lobectomy for stage IA lung cancer were divided into the following groups: (A) patients with <10 (n = 20) and (B) patients with ≥10 resected subsegments (n = 20). Comparisons were made of the predicted and observed postoperative values of spirometry and radiological parameters, such as lung volumetry and the "estimated lung weight". Predicted values were based on the number of resected subsegments. The postoperative time to re-evaluation was at least 1 year for both groups. Results: The predicted postoperative values of spirometry underestimated the actual values, and the differences were more significant in group B (forced vital capacity, p = 0.006, forced expiratory volume in 1 s, p = 0.011). Focusing on the remnant lungs on the surgical side, group B had significantly larger % postoperative lung volumes (161 ± 6.0 %) and % estimated lung weight (124 ± 5.4 %) than did group A (114 ± 3.8 %, p < 0.0001; 89.5 ± 4.4 %, p < 0.0001, respectively). Conclusions: Major lung resection in clinical cases causes a compensatory restoration of the pulmonary function and tissue.