Iatrogenic disruption of the thoracic duct is an uncommon but potentially serious complication of thoracic surgery, particularly esophagectomy.¹ The thoracic duct conveys chyle and lymph from the liver, intestines, abdominal wall, and lower extremities into the systemic venous circulation, and depending on diet and activity, the flow of chyle through the thoracic duct can reach several liters per day.² Among other components, this fluid contains essential proteins, lipids, and lymphocytes. The clinical sequelae of unremitting chylous effusions can be severe and life-threatening, including immunosuppression, respiratory compromise, dehydration, cachexia, and death.

Conservative management of chylous pleural effusions includes chest tube drainage, cessation of oral intake, and institution of total parenteral nutrition to decrease the physiologic production of chyle. If lymph production can be minimized, low-output leaks of less than 500 mL per day can sometimes heal spontaneously, although this process may take several weeks, during which time the patient may become nutritionally and immunologically depleted. As a result, some have called for earlier diagnosis and intervention to avoid metabolic compromise.^3,4 Repeat thoracotomy and direct thoracic duct ligation typically are performed early to stop high-output leaks; however, the morbidity and mortality of reoperation in this patient population is a serious consideration, with complication rates approaching 40%.⁵

Recently, percutaneous thoracic duct embolization (TDE) has been introduced as a minimally invasive technique for controlling high-output chylothorax (Fig. 131-1).⁶ In this chapter, we review the indications, preprocedural assessment, and techniques of percutaneous TDE.

The method of TDE for the control of chylothorax requires a comprehensive understanding of the anatomy of the lymphatic system, especially of the thoracic duct and cisterna chyli and their many anatomical variations. TDE is a two-stage procedure, beginning with pedal lymphangiography which is used to visualize the cisterna chyli or dominant upper lumbar lymphatics for possible cannulation. Alternatively, pelvic intranodal lymphangiography can be employed. Once a suitable retroperitoneal target has been identified, the thoracic duct is accessed percutaneously and embolized, typically from a right anterior oblique transabdominal approach to avoid the aorta, or a right posterior oblique transhepatic approach. If the thoracic duct cannot be cannulated, maceration of the cisterna chyli and upper lumbar lymphatics is undertaken to divert the flow of chyle into the retroperitoneum. One variation of TDE entails retrograde cannulation of the thoracic duct via its ostium near the left angulus venosus, using a coaxial catheter system delivered from a left brachial or basilic vein approach. The retrograde transvenous approach is less reliable, however, owing to the difficulties encountered in locating and seating a catheter in the ostium of the thoracic duct under fluoroscopy and the complexity of passing a wire and microcatheter through its competent terminal valves.

The primary indication for TDE is an incessant chylous pleural effusion arising in the setting of suspected traumatic thoracic duct disruption. TDE is generally ineffective for managing nontraumatic chylothorax secondary to infiltrative, obstructive, or malignant disease. True chylous effusions must also be distinguished from pseudochylous effusions, which can result from tuberculosis or rheumatoid disease. A true chylous effusion will contain chylomicrons and exhibit triglyceride levels greater than 110 mg/dL, whereas a pseudochylous effusion will have cholesterol as the dominant lipid component (greater than 200 mg/dL) and chylomicrons will be absent.^7,8

Preoperative imaging is critical to determining the safest approach because of the close proximity of the cisterna chyli to the right renal artery and aorta. Thin-slice, fat-suppressed, heavily T2-weighted MR imaging of the thoracolumbar region in the coronal and axial planes is used to localize the cisterna chyli and determine its relationship to adjacent structures (Fig. 131-2A). It is also important for the patient to have a normal coagulation profile because the needle will traverse many abdominal and retroperitoneal structures on the way to its periaortic target.

TDE is a 4- to 6-hour event and can be separated into two distinct procedures. A lymphangiogram is performed first to visualize the thoracic duct (see Fig. 131-2B). Once opacified, the thoracic duct is cannulated and embolized. The transit time for oil-based contrast material to travel from the dorsal foot (i.e., lymphangiogram site) to the upper abdomen is extremely variable and is the rate-limiting step for the procedure.

Pedal Lymphangiography

The patient is positioned supine on a fluoroscopy table, and both feet are sterilely prepped. Moderate procedural sedation is employed for patient comfort. Prophylactic intravenous antibiotics are administered.

Because the cisterna chyli is more commonly located in the right upper abdomen, right pedal lymphangiography generally provides for more efficient and definitive opacification of this structure, but either or both feet may be used. Standard pedal lymphangiography is performed by injecting 0.25 to 0.5 mL of methylene blue dye between the web spaces of the toes. The dye is taken up by the lymphatics, which can be visualized as blue streaks under the skin. After 1% lidocaine local anesthesia, a small incision is made on the dorsum of the foot, and a lymphatic vessel is isolated and cannulated with a 30-gauge needle lymphography catheter. The lymphatic is secured to the needle with silk ties, and a gentle test injection is performed with a 3-mL saline syringe to assess for leaks. The lymphography catheter is then connected to an injector, and iodized oil (Lipiodol, Laboratoire André Guerbet, Aulnay-sous-Bois, France) is infused at a rate of 8 to 12 mL per hour to a maximal administered volume of 20 mL. During infusion, serial spot radiographs are obtained of the lower extremity, pelvis, and abdomen to track the cephalad opacification of the lymphatic system (Fig. 131-3). Transit times from the foot to the cisterna chyli are typically 1 to 3 hours. A saline bolus can be administered behind the column of iodized oil, if necessary, to speed its transit through the lymphatics. Once the thoracic duct is visualized, the infusion can be stopped and attention turned to the cisterna chyli and/or dominant lumbar lymphatics for needle cannulation or disruption. The foot incision is closed with 3-0 Prolene vertical mattress sutures and covered with a sterile dressing.