Chylothorax after pleuro-pulmonary surgery: a rare but unavoidable complication.

The incidence of chylothorax after pleuro-pulmonary operations as well as its treatment is reported. Of 1744 operations performed postoperative chylothorax developed in 13 (0.74%). It resulted in two cases from the transection of the thoracic duct, in six from the transection of the so-called minor lymph channels, which drain lymph from mediastinal nodes straight into the thoracic duct or drain lung segments into the thoracic duct via the pulmonary ligament; the transection of these channels occurred during mediastinal lymphadenectomy or during the section of the pulmonary ligament. In 5 patients the site of leakage was not determined as reoperation was not required. Conservative treatment with low-fat diet and medium-chain triglycerides and/or total parenteral nutrition was attempted in all but one patient but was successful only in 5 cases whose mean losses were 292 ml/day. Seven patients were reoperated after a mean of 11 days; their mean losses were 930 ml/day. One patient was reoperated on the third postoperative day without attempting conservative treatment; his mean loss was 850 ml/day. Lymphadenectomy seems to be an important risk factor for postoperative chylothorax. Chyle leakage around 500 ml/day or higher that tends to decrease below 500 ml/day after a few days of dietary manipulation usually stops within 10-20 days, while leakage over 500 ml/day that does not tend to decrease below 500 ml/day seldom if ever stops without surgery, so that a more aggressive attitude is justified.