A large, prolonged chyle leak can have several adverse effects. Patients are often already malnourished and/or immunosuppressed as a result of prior surgery or illness. In the presence of a chyle leak, the nutritional and immunologic status of the patient is further compromised. Not only is there a significant loss of fluid and electrolytes (at times, greater than 1.5 L/day), but also a significant number of T-lymphocytes can be lost through the drainage of chyle fluid, resulting in lymphopenia and immunosuppression. Finally, there is depletion of nutritional stores through loss of fats and protein. Accumulation of chyle in the pleural cavity can quickly cause compression of underlying lung, respiratory compromise, and even tension chylothorax. The first priority in managing these patients is adequate drainage of chyle from the thorax, reexpansion of the lung, and assurance of pleural apposition. This is usually best accomplished through placement of a posteriorly directed chest tube of 24F caliber or larger. Replacement of IV fluids and electrolytes is begun. Drainage of chyle should drop significantly with cessation of oral intake; total parenteral nutrition should be instituted immediately if this route is chosen.
We prefer the term noninterventional over conservative because this method of management for large leaks in debilitated patients carries significant risk. Observation is considered optimal management for leaks of low or moderate output (<500 mL/day) in patients who are not severely malnourished. Once the fluid is drained adequately, it is important to have accurate measurements of daily chest tube drainage. Fluids and electrolytes must be checked and replaced. The patient is given nothing by mouth, and total parenteral nutrition is instituted. Alternatively, the patient may be maintained on a very low-fat diet with oral medium-chain triglyceride supplementation. However, any oral intake at all, even without dietary fat, is a stimulus to chyle production. After 1-2 weeks, provided the drainage decreases to less than 200 mL/day, an oral low-fat diet may be instituted. If the drainage remains low, the chest tube may be removed. If the drainage persists without feedings or increases with institution of low-fat feedings, intervention is recommended.
Chyle leaks of greater than 500 mL/day are less likely to heal without intervention. (Some surgeons may use a cutoff value of 1 L.) While observation is an option, if the output is not decreased significantly in 7 days, operative intervention should be considered. In the postesophagectomy patient, however, intervention is mandated as soon as a leak is diagnosed because it is usually high output, the patient is already malnourished and debilitated, and the leak can be fixed readily through intervention.8
The operative approach involves either direct repair of the leak or right-sided mass ligation of the thoracic duct just above the aortic hiatus. We favor mass ligation of the duct for patients who have had a prior thoracotomy, when the leak is difficult to localize, and to avoid potential injury of adjacent structures. More explicitly, this approach avoids the necessity of reopening a preexisting thoracotomy or dissecting around the site of previous aortic surgery, and for neck dissections, potential injury to nearby vital structures such as the phrenic nerve or subclavian vessels is obviated. Right-sided mass ligation of the thoracic duct above the diaphragmatic hiatus can be used to treat a leak in any location.
Alternatively, a direct repair can be attempted, with incision made in the right or left chest or neck (if secondary to prior neck surgery or dissection). Usually this repair is performed by using a limited, muscle-sparing thoracotomy because localization of the leak and ligation of the tiny structure with fine sutures are difficult with a purely thoracoscopic approach. Intraoperative enteral administration of cream can be very helpful in locating the leak.
More recently, thoracic duct embolization for leak or rupture in the cisterna chyli has been described by means of percutaneous cannulation.9 This therapy is currently investigational but seems to be effective in the majority of patients with favorable thoracic duct anatomy. A single, large duct in the upper abdomen is necessary to perform the procedure, and the anatomy is predetermined by MRI. The duct is cannulated percutaneously, and the catheter is threaded up the thoracic duct under fluoroscopic guidance. The leak is located, and coils are injected into the duct. Postembolization injections are performed to verify cessation of the leak. For a detailed description of this technique, see Chap. 111.
Chyle leaks associated with mediastinal lymphoma or neoplasia metastatic to the mediastinum can be difficult to manage. Effective treatment of the underlying malignancy, if possible, with radiation or chemotherapy, often will cause the leak to stop. In instances where the malignancy responds poorly to chemoradiation, numerous interventions have been attempted, including percutaneous embolization of the duct. Ligation or direct repair of the duct may be difficult or impossible owing to the burden of disease. Insertion of a tunneled subcutaneous valved pleuroperitoneal shunt may allow for evacuation of the pleural space and reabsorption in the peritoneum. However, the patient must pump the catheter manually throughout the day. Pleurodesis, either chemical or by complete pleurectomy, is usually the last and least favored option but may stop the leak through obliteration of the pleural space.