Postoperative lung volume calculated by chest computed tomography in patients with esophageal cancer

It has been reported that, due to the severe surgical stress of thoracotomy, respiratory function after esophagectomy under thoracotomy worsened as late as a month after surgery. To investigate the mechanism of the reduction of the respiratory function, we utilized chest CT to analyze separately the changes in the lung volume of the thoracotomized side and the other side. Here, we reported the results of our comparative study of lung volume and respiratory function, which was performed by spirogram before esophagectomy and 6 months afterwards. We selected twenty-three patients who had undergone esophagectomy under right thoracotomy. Fourteen of the selectees received standard thoracotomy, while the other nine had the anterior serratus muscle and the latissimus dorsi muscle preserved. Total lung volume was found to have decreased from a preoperative value of 4077 +/- 674 ml (mean +/- SD) to a postoperative value of 3964 +/- 774 ml, and right-lung volume significantly decreased from 2229 +/- 397 to 2023 +/- 397 ml, while left-lung volume tended to increase. While right-lung volume in standard thoracotomy displayed a significant decrease from 2264 +/- 334 to 1949 +/- 424 ml, that in muscle-preserving thoracotomy showed almost no change. Spirogram revealed that vital capacity had decreased from 3574 +/- 601 to 2666 +/- 576 ml, and forced expiratory volume in the first second showed a significant decrease from 2680 +/- 500 to 2249 +/- 485 ml. Comparing the decreasing rate, the correlation coefficients between right-lung volume and %VC was 0.58. These results suggested that a change of lung volume in the thoracotomized side could play a role in the post-operative decrease of vital capacity and that muscle-preserving thoracotomy might induce less surgical stress than standard thoracotomy.