Evaluation of the Residual Lung Function After Thoracoscopic Segmentectomy Compared With Lobectomy

Segmentectomy has shown a beneficial effect on preserving lung function after resection. However, the preservable lung volume and changes after thoracoscopic segmentectomy remain unknown. We compared the residual lung function after thoracoscopic segmentectomy and lobectomy, using a novel three-dimensional computed tomography-based volumetric method.Seventy-four patients who received thoracoscopic segmentectomy were matched to the 74 patients who received thoracoscopic lobectomy. Spirometry and computed tomography were performed before and 6 months after resection, and the ipsilateral residual preserved and nonoperated lobe volume and the contralateral lung volume were calculated using three-dimensional computed tomography. The percentage of actual/predicted regional forced expiratory volume in 1 second (the preservation rate) in each lobe (measured by volumetry and spirometry) was compared with the extent of resection and procedural difficulty (typical or atypical segmentectomy).The postoperative lung function was significantly more well preserved in segmentectomy than in lobectomy. After segmentectomy and lobectomy, the regional forced expiratory volume in 1 second of the ipsilateral unaffected lobe was increased in comparison with the preoperative value, whereas that of the residual lobe rescued by segmentectomy was decreased. The preservation rates of the residual and unaffected lobes were inversely and positively correlated, respectively, with the extent of the resected segment. The preservation rates of the residual lobe after typical or atypical segmentectomy were not significantly different.Although the decrease in the actual lung function of the residual lobe was greater than predicted and increased with increasing extent of resection, segmentectomy preserved the whole lung function better than lobectomy.