Lymphatic leakage often occurs after disruption of the lymphatic system and is classified as congenital, traumatic, or neoplastic. It may manifest as lymphatic fistula, chylous ascites, or chylothorax.
Lymphatic fistulas commonly develop after retroperitoneal, femoral, or other lymphadenectomy procedures and after aortic aneurysm repairs. They can occur with the lymphatic channels and surrounding structures, such as the bladder, gastrointestinal (GI) tract, uterine cavity, or skin. [1, 2] Chylous ascites is a collection in the abdomen or retroperitoneum resulting from injury to the thoracic duct or cisterna chyli. Chylothorax is a collection of lymph in the chest, usually resulting from disruption of the thoracic duct.
Congenital causes of chylothorax include thoracic duct atresia, birth trauma, and pleural thoracic duct fistula. Traumatic causes include surgery, blunt trauma, penetrating trauma, and diagnostic procedures (eg, lumbar arteriography and subclavian vein catheterization).
Surgical procedures most commonly resulting in chylous leakage include lymphadenectomy, radical neck dissection, ligation of patent ductus arteriosus, surgery for coarctation of the aorta, aortic aneurysm repair, esophagectomy,  excision of mediastinal tumors, pneumonectomy, and sympathectomy. Chylothorax has been reported after heart-lung transplantation. 
A small proportion of lymphatic injuries can result in significant morbidity, necessitating further medical or surgical management. An injury to the infrainguinal lymphatic vessels during vascular reconstruction may result in lymphatic fistula or lymphocele. Chylous ascites might develop after injury to the para-aortic or mesenteric lymphatics during abdominal aortic reconstruction. Thoracic duct injuries during thoracoabdominal aortic reconstruction may result in chylothorax.
History of the Procedure
The advent of infrainguinal reconstruction for lower-limb salvage introduced the complication of lymphatic fistula after this procedure. In 1991, Kalman et al described the most comprehensive series of patients with postoperative lymphatic fistulas after infrainguinal reconstruction.  Other case reports and smaller collected series were described before this comprehensive review.
Several case reports and much smaller clinical series (beginning in 1970) describe the development of chylous ascites after abdominal aortic reconstruction. 
A few case reports describing chylothorax following thoracoabdominal aortic reconstruction were submitted beginning in 1979. A more extensive review began in 1996 with the advent of congenital aortic coarctation repair.
Lymphatic fistula is an epithelialized tract that develops between the lymphatic system and the epidermis after lymphatic injury during infrainguinal reconstruction.
Chylous ascites is an effusion of chyle into the intra-abdominal cavity after lymphatic injury to the para-aortic or mesenteric lymphatics (eg, the cisterna chyli).
Chylothorax is an effusion of chyle into the pleural cavity, usually after a thoracic duct injury.
In the most comprehensive review of lymphatic fistulas after infrainguinal reconstruction, Kalman et al reported an incidence of 1.1%.  Smaller series have reported an incidence of 0.8-6.4% after reconstructive procedures.
Chylous ascites can result from abdominal aortic aneurysm (AAA) repair, open cholecystectomy, gynecologic cancer surgery, liver transplant, and lymphatic abnormalities. The majority have been described after open AAA repair, accounting for 81% of all cases of postoperative chylous ascites reported and 38 cases from 1970.  The incidence of chylous ascites after AAA repair is 0.03-0.1%. 
Chylothorax after surgery involving the mediastinum and neck has a reported incidence of 0.42% for all general thoracic surgery procedures [9, 10] and an incidence of 3.9% for esophagectomy procedures. [9, 11]
Etiologic factors contributing to lymphatic fistulas after infrainguinal reconstruction include failure to ligate injured lymphatic vessels and failure to approximate tissue layers meticulously at closure. Other risk factors for the development of lymphatic fistulas include diabetes mellitus, wound infections, reoperation, use of prosthetic grafts for vascular conduits, and excessive postoperative ambulation.
Failure to dissect meticulously around the abdominal aorta and failure to ligate the larger lumbar, para-aortic, and mesenteric lymphatic vessels may result in postoperative chylous ascites. Other causes of chylous ascites include neoplasms (eg, lymphoma), cirrhosis, trauma, congenital lymphatic abnormalities, infections (eg, peritoneal tuberculosis), inflammatory disorders, and surgical procedures (eg, pancreaticoduodenectomy, abdominothoracic esophagectomy, inguinal lymph node resection, and renal transplant). 
Inadvertent transection of the thoracic duct results in chylothorax. As for chylous ascites, many nontraumatic etiologies exist for chylothorax, including malignancy, congenital disorders, and various infectious and inflammatory processes.
With a lymphatic fistula, transection of the infrainguinal lymphatic vessels results in lymphatic leakage. Collection of lymphatic fluid in the groin may result in wound infection, prosthetic graft infection, and lymphocele.
In chylous ascites, lymphatic leakage occurs from the para-aortic or mesenteric lymphatic vessels into a closed compartment (the intra-abdominal cavity); this has much greater implications for postoperative morbidity. When lymphatic leakage outstrips reabsorption, progressive abdominal distention occurs and can subsequently lead to pulmonary compromise. Malnourishment and infectious complications may result from the loss of proteins, fats, and vital immunologic complexes.
With a chylothorax, lymphatic leakage from the thoracic duct also occurs into a closed compartment (the thoracic cavity), inevitably resulting in respiratory difficulty. Malnourishment and infectious complications may also result from such a substantial lymphatic leak.
The diagnosis of a lymphatic fistula may be established by the leakage of clear yellow fluid from an infrainguinal incision that occurs days to months after infrainguinal vascular reconstruction. A lymphocele may be diagnosed by the presence of lymphatic drainage in a soft, fluid-filled cyst.
Patients with chylous ascites usually develop progressive abdominal distention and pain accompanied by nausea and vomiting several days to weeks following abdominal aortic reconstruction. The presence of a fluid wave indicating ascites may be appreciated on abdominal examination. Lymphopenia and anemia may also develop.
The presence of decreased breath sounds at the lung bases and dullness to percussion may suggest the presence of an effusion and chylothorax. Pulmonary compromise ensues several days after thoracoabdominal aortic reconstruction or repair of aortic coarctation. Hematologic depression, such as lymphopenia and anemia, may also develop.
High output (>1000 mL/day)
Low output (< 500 mL/day)
Other authors have categorized chylous ascites as high-output when more than 7000 mL is obtained by paracentesis.  Low-output chylous leakage (< 500 mL/day) can often be successfully treated with medical therapy. 
Low-output lymphatic fistulas respond to medical therapy, drainage, and parenteral nutrition. Failure of such treatment is an indication for diagnostic and therapeutic lymphangiography. Persistent leakage is an indication for operative repair. High-volume leakage (>1000 mL/day) should be aggressively treated with therapeutic lymphangiography, thoracic duct embolization, pleurodesis, surgery, or some combination thereof.
High-output chyle leak is associated with a 50% mortality when surgical intervention is postponed; this is associated with nutritional, immunologic, or metabolic deterioration from large-volume lymph loss. Mortality is reduced to 10% when surgical therapy is initiated in these patients. [13, 9, 19, 20, 21, 7]
Relevant anatomic considerations include the following:
Lymphatic fistula - Demonstration of isosulfan blue leakage within the reexplored infrainguinal incision aids in the repair of a lymphatic fistula; blue droplets appear from the site of lymphatic injury, which may then be suture-ligated, cauterized, or fibrin-glued
Chylous ascites - Several large mesenteric lymphatics located on the anteroinferior aspect of the left renal vein, along with the right and left lumbar lymphatics, form the cisterna chyli, which lies between the inferior vena cava and the abdominal aorta at the level of the second lumbar vertebra
Chylothorax - The thoracic duct lies to the right of the aorta and to the left of the azygos vein, beginning at the cisterna chyli and entering the posterior mediastinum through the aortic hiatus; in the superior mediastinum, the thoracic duct lies behind the aortic arch and subclavian artery, to the left of the esophagus, and enters the left brachiocephalic vein
The only contraindication to operative repair of lymphatic fistulas, chylous ascites, and chylothorax involves standard preoperative comorbidities that necessitate continuance of nonsurgical therapy (eg, recent myocardial infarction). As with any surgical therapy, the risk-benefit ratio must be assessed.
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