Successful thoracic duct identification with patent blue V during thoracic duct ligation for chylothorax: a case report

Background: Chylothorax after thoracic surgery is a rare but severe complication. When thoracic duct ligation is performed for chylothorax, identification of the leakage site and the thoracic duct course is necessary. Administering milk orally or through a nasogastric tube and injecting indocyanine green into lymph nodes and lymphatic vessels can be performed to identify the leakage site and the thoracic duct course. However, the injection of patent blue V into the inguinal lymph nodes has not been reported. Case presentation: A 69-year-old man underwent aortic replacement surgery for an aortic aneurysm of the distal arch. On postoperative day 3, after resuming oral intake, the patient was diagnosed with chylothorax. The patient was treated with fasting and total parenteral nutrition, but the chylous pleural effusion continued at 500–1000 ml daily. A plan for thoracic duct ligation was made. We injected patent blue V into the inguinal lymph node to identify the leakage site and the thoracic duct course. The blue-stained thoracic duct was identified and ligated, but the leakage site could not be identified because of the surrounding lung adhesions. The thoracic drain was removed on day 6 post-second operation, and the chylothorax did not recur. Conclusion: Identifying the thoracic duct course using patent blue V is useful during thoracic duct ligation for chylothorax.