The effect of azygos vein preservation on mediastinal lymph node harvesting in thoracic esophagolymphadenectomy

SUMMARY.  The standard surgical procedure for esophageal cancer is transthoracic esophagectomy with en bloc resection of the azygos vein, thoracic duct and mediastinal lymph nodes. To reduce morbidity of esophago-lymphadenectomy, minimally invasive techniques are increasingly being applied. In (robot-assisted) thoracoscopic esophagolymphadenectomy, the azygos vein is generally left in place, as the scopic ligation of the numerous intercostal veins is technically difficult and time-consuming. This could affect the extent of mediastinal lymph node dissection. Therefore, in this study, the effect of azygos vein preservation during thoracic esophagectomy on mediastinal lymph node harvesting was assessed. In 15 human cadavers, a right-sided thoracotomy was performed, followed by esophagectomy with mediastinal lymph node dissection after ligation of the azygos arch (representing the situation in robot-assisted thoracoscopic esophagolymphadenectomy). Subsequently, the remaining azygos vein with surrounding tissue was resected. The number of lymph nodes in both specimens was determined. A mean of 17.3 (95% Poisson CI 15.3–19.6) lymph nodes was dissected en bloc with the esophagus, and 0.67 (95% Poisson CI 0.32–1.23) around the separately resected azygos vein. The additional azygos vein resection did not add to the number of lymph nodes dissected in 60% (9/15) of cadavers. In conclusion, the extent of mediastinal lymph node dissection was not substantially affected by leaving the azygos vein in situ . Time-sparing azygos vein preservation in (robot-assisted) thoracoscopic esophagolymphadenectomy may therefore be considered justified.