Chyle leak formation is an uncommon but serious sequela of head and neck surgery when the thoracic duct is inadvertently injured, particularly with the resection of malignancy low in the neck. The thoracic duct is the primary structure that returns lymph and chyle from the entire left and right lower half of the body. Chyle extravasation can result in delayed wound healing, dehydration, malnutrition, electrolyte disturbances, and immunosuppression. Prompt identification and treatment of a chyle leak are essential for optimal surgical outcome. In this article we will review the current treatment options for iatrogenic cervical chyle leaks.
Chyle leak (CL) from iatrogenic thoracic duct injury is a rare but serious complication of head and neck surgery that occurs in 0.5–1.4% of thyroidectomies [
The thoracic duct forms during the 8th week of gestation as two distinct vessels anterior to the aorta, connecting the superior jugular lymph sacs to the inferior cisterna chyli. These vessels develop into the embryonic right and left thoracic ducts and share a number of anastomoses. As the fetus matures, the embryonic thoracic ducts fuse partially to form two distinct lymphatic divisions within the body. The adult thoracic duct is the product of the fusion of the lower 2/3 of the embryonic right duct, the upper 1/3 of the left duct, and their numerous interconnections [
Lymphatic division. The right lymphatic duct collects lymph from the right side of the body, above the diaphragm. The thoracic duct receives lymph from the entire left side of the body and the right side of the body below the diaphragm.
The thoracic duct originates from the cisterna chyli, a dilated sac at the level of the 2nd lumbar vertebra that receives lymph from intestinal and lumbar lymphatics [
Within the abdomen, the thoracic duct ascends along the anterior surface of the lumbar vertebra, between the aorta and azygous vein, to enter the thorax via the aortic hiatus in the posterior mediastinum. Within the thorax, the thoracic duct veers leftward as it continues to ascend, passing posterior to the aortic arch, and enters the root of the left neck lateral to the esophagus. At the root of the neck, the thoracic duct is bordered anteriorly by the left common carotid artery, Vagus nerve, and IJV, medially by the esophagus, laterally by the omohyoid muscle, and posteriorly by the vertebra. From there, the thoracic duct arches superiorly and laterally, anterior to the anterior scalene muscle and phrenic nerve [
Cervical course of the thoracic duct. The thoracic duct enters the neck lateral to the esophagus, ascending superiorly and laterally behind to the carotid and internal jugular vein before turning inferiorly and anteriorly to join the venous circulation at the confluence of the internal jugular vein and subclavian vein.
Within this 1 cm region the thoracic duct may terminate into the venous circulation at a number of sites. The most common site is the IJV (46%), followed by the confluence of the IJV and subclavian vein (32%) and the subclavian vein (18%) [
The thoracic duct generally empties into the venous system as a single duct (76%) [
The typical length of the adult thoracic duct is 36–45 cm with an average diameter of 5 mm [
The thoracic duct is the primary structure that returns lymph from the left body and the right body below the diaphragm to the venous circulation. This includes chyle derived from intestinal lacteals [
Chyle is composed of lymphatic fluid and chylomicrons from the gastrointestinal system. Its lymphatic fluid contains protein, white blood cells, electrolytes, fat-soluble vitamins, trace elements, and glucose absorbed from the interstitial fluid, to be returned to the systemic circulation [
Chyle is propagated within the thoracic duct primarily by the muscular action of breathing and further facilitated by the duct’s smooth muscles and internal valves, which prevent retrograde flow. Factors that modulate chyle flow include diet, intestinal function, physical activity, respiration rate, and changes in intra-abdominal and intrathoracic pressure [
Due to its proximity to the IJV and thin vessel wall, the thoracic duct is particularly susceptible to inadvertent injury during dissection low in the neck [
Prompt diagnosis and intervention aimed at addressing a CL are essential for favorable surgical outcome. The impact of acute large volume CL includes the loss of protein, fat, and fat-soluble vitamins, trace elements, and lymphocytes in quantities that result in hypovolemia, electrolyte imbalances (hyponatremia, hypochloremia, and hypoproteinemia), malnutrition, and immunosuppression [
Wound healing complications can result from the disruption of the normal biochemical milieu, manifesting as delayed wound healing, infection, or wound breakdown with fistula formation. Within the wound bed, extravasated chyle provokes an intense inflammatory reaction, prompting the release of proinflammatory cytokines and tissue proteases that interfere with the healing process. The pressure of accumulated chyle beneath skin flaps may decrease tissue perfusion, resulting in flap necrosis [
A cervical CL can spread from the root of the neck into the mediastinum. With sufficient hydrostatic pressure, the collection of chyle may penetrate the pleural, forming a chylothorax, which presents clinically with shortness of breath, tachypnea, and chest pain.
Chyle leaks may be identified intraoperatively or postoperatively. Due to the potential significant morbidity associated with a CL, leaks identified at the time of surgery should be repaired immediately.
In general, the supraclavicular region should be examined carefully at the conclusion of a head and neck procedure, particularly if the case involves dissection low in the neck. If creamy or milky fluid is noted, the thoracic duct should be identified and ligated [
Postoperatively, sudden high increases in drain output, especially following resumption of feedings that contain fat, should raise suspicion of a CL. On examination the neck may exhibit erythema, lymphedema, or a palpable fluid collection in the supraclavicular region. The drain output would have a creamy or milky appearance. A CL can be diagnosed clinically; however, biochemical assay may be helpful for equivocal cases. Drain fluid with triglyceride level greater than 100 mg/dL [
Diagnosing a chyle leak.
Clinical | Drain output biochemical assay |
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(i) Sudden increase in drain output, especially immediately following enteral feeding | (i) Triglyceride > 100 mg/dL |
When a CL is identified during surgery, the thoracic duct may be ligated with surgical clips or oversewn with nonabsorbable suture. Additionally, locoregional flaps may be incorporated for additional coverage of the surgical bed. The clavicular head of the sternocleidomastoid can be dissected free and sutured to the wound bed [
Following surgery, management of a CL depends on drain output, patient comorbidities, available institutional expertise, and surgeon preference. Chyle leaks may be broadly categorized as low output (<500 mL/day) or high output (>500 mL/day) based on drain output to assist with treatment decision making. In general, low output CL can be treated effectively with conservative management [
Because chyle flow is propelled by physical activity, patients with suspected CL should be restricted to bed rest. The head of bed should be elevated (30–40°) [
With potential high volume fluid shift with protein and electrolytes loss, patients with CL need to be monitored for dehydration and malnutrition. Fluid balance and electrolytes should be checked daily and albumin weekly [
Dietary management plays a crucial role in the nonsurgical management of a CL. All patients with suspected CL should be transitioned to a nonfat diet, low-fat diet, or medium-chain fatty acid (MCFA) diet [
Orlistat, a pancreatic lipase inhibitor, interferes with lipid metabolism in the duodenum and prevents lipid absorption and may be given as an adjunct to decrease chyle production [
Alternatively, patients can be made NPO if the drain output is low and suspected duration of CL is short. NPO is rarely implemented today, as alternative superior dietary options are available that do not contribute to ongoing hypovolemia and malnutrition.
Patients with persistent or high output CL will likely require total parental nutrition (TPN), which bypasses the lymphatic system completely [
The use of pressure dressings remains controversial. Some recommend its use to expedite closure of a CL [
Suction drainage, placed at the time of surgery, is invaluable in the evacuation of extravasated chyle and monitoring of drain output to assess both severity of the CL and treatment effectiveness. While helpful in evacuating high output CL, however, some advocate for the timely removal of suction drainage once its output has diminished sufficiently, to avoid the possibility that the drain suction may prohibit the complete resolution of a CL [
Negative wound pressure therapy, or vacuum-assisted closure, with placement of an air-tight seal over the wound and application of negative pressure to the entire wound bed to remove fluid and shrink wound size has had promising results in preliminary reports, but additional studies are needed to test its true effectiveness [
Somatostatin is a neuroendocrine hormone discovered in 1973, with numerous effects on the digestive and lymphatic systems [
Somatostatin decreases chyle production via reduction of gastric, pancreatic, and intestinal secretions [
Somatostatin’s major drawback is its short half-life, which requires continuous intravenous infusion. This problem was solved with the development of octreotide, somatostatin’s long-acting analog, which permitted administration with long-lasting subcutaneous injections [
From 2001 to 2015 seventeen studies investigating the effectiveness of octreotide in the management of cervical CL were published (Table
Literature review of somatostatin and octreotide for treatment of chyle leak.
Author | Year | Patients | Surgery | Treatment dosage | Treatment duration | Treatment start to leak cessation | Additional measures | Comments |
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Somatostatin | ||||||||
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Coşkun and Yildirim [ | 2010 | 1 | Thyroidectomy + L MRND | 3 mg iv Qday | 5 days | 1 day | Suction drainage | |
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Ulíbarb et al. [ | 1990 | 1 | Supraglottic laryngectomy + L MRND | 6 mg iv Qday | 12 days | 5 days | Suction drainage | |
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Octreotide | ||||||||
| ||||||||
Ahn et al. [ | 2012 | 2 | L MRND (1) | 100 | 11 days | 11 days | Suction drainage | |
| ||||||||
Al-Sebeih et al. [ | 2001 | 1 | Total laryngectomy + B MRND | 100 | Not specified | 3 days | Suction drainage | B chylothoraces requiring chest tubes |
| ||||||||
Harlak et al. [ | 2008 | 1 | R MRND | 100 | 15 days | 15 days | Suction drainage | Metastatic breast cancer |
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Jain et al. [ | 2015 | 19 | Left neck dissection (19) | 100 | Low output 5 days | Low output 2–4 days | Suction drainage | Low output <500 mL/24 hours, |
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Jiménez et al. [ | 2008 | 1 | Thyroidectomy + B MRND | 100 | 11 days | N/A | Suction drainage | Right sided chyle leak |
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El Dabe Mikhail et al. [ | 2009 | 1 | Thyroidectomy | Not specified | 5 days | 5 days | Dietary modifications | |
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Nyquist et al. [ | 2003 | 1 | Thyroidectomy + L MRND | 100 | 8 days | 1 day | Suction drainage | |
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Ogi et al. [ | 2013 | 1 | Thyroidectomy + B MRND | 100 | 3 days | 3 days | Suction drainage | |
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Prabhu and Thomas [ | 2015 | 1 | L radical neck dissection | 100 | 14 days | 14 days | Suction drainage | L chylothorax |
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Rodier et al. [ | 2011 | 1 | Thyroidectomy + central & L MRND (1) | 100 | 6 days | 6 days | Suction drainage | |
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Srikumar et al. [ | 2006 | 1 | L radical neck dissection | 200 | 14 days | 14 days | Suction drainage | B chylothoraces requiring chest tubes |
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Suver et al. [ | 2004 | 1 | B MRND + mediastinal dissection | 4 | 7 | 7 | Suction drainage | Lymphatic malformation in 10-month-old child |
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Suslu et al. [ | 2014 | 3 | Thyroidectomy + L MRND (1) Thyroidectomy + B MRND (1) | 100 | 7.5 | 6.5 | Suction drainage | L chylothorax (1) |
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Swanson et al. [ | 2015 | 12 | L MRND (3) | 100 | 9.4 | 5.5 | Suction drainage | |
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Touska et al. [ | 2002 | 1 | R completion thyroid lobectomy | 200 | 17 | 10 | Suction drainage | No suction drain initially |
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Valentine et al. [ | 2002 | 1 | Thyroidectomy + L MRND | 50–100 | 24 | 24 | Suction drainage | Octreotide dose increased from 50 ug to 100 |
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Khurana et al. [ | 2009 | 1 | Thyroidectomy + B MRND | 100 | Not specified | Not specified | Suction drainage | B chylothoraces requiring chest tubes |
L = left; R = right; B = bilateral; MRND = modified radical neck dissection.
To date, there are no consensus guidelines on the optimal octreotide treatment dose and duration in CL management. In our literature review, the decision of what dosage to use was often anecdotal and occasionally increased by some of the authors when perceived ineffective. Octreotide dosage ranged from 100
The most commonly associated side effects of octreotide are nausea, abdominal discomfort, and diarrhea. Rare but serious complications include hypoglycemia and cholecystitis secondary to cholestasis [
Octreotide has emerged as a powerful adjunct in the conservative management of CL and should be a part of the armamentarium of every head and neck surgeon. However, not every CL will respond completely to octreotide therapy alone. In our literature review, two patients required surgical reexploration for control of their CL, despite a trial of octreotide [
Sclerosing agents such as OK-432 or tetracycline administered at the time of surgery or postoperatively through drainage tubing or percutaneous injection can generate fibrosis to seal a CL [
Cyanoacrylate adhesives, fibrin glue [
Surgical reexploration should be considered only after conservative measures have either been exhausted or deemed ineffective. Suggested criteria for reexploration range from outputs of >500 mL/day to >1000 mL/day output for 5 days [
At the time of reexploration, local inflammation from extravasated chyle can make thoracic duct identification difficult. Trendelenberg positioning and maneuvers that raise intrathoracic and intra-abdominal pressure can facilitate identification of the site of the CL. Having the patient ingest a fatty diet before surgery can stimulate chyle production and aid in CL localization as well.
As described above, when identified, the leaking thoracic duct can be ligated, covered with a muscle flap, or treated with any number of sclerosing agents, adhesive agents, or mesh. It is imperative that a suction drain is placed at the conclusion of the case.
In certain instances, when there is a persistent CL after surgical reexploration or when reexploration may not be ideal because of distorted anatomy or tenuous in the case of a microvascular free flap, the head and neck surgeon may seek the assistance of his interventional radiology or thoracic-foregut colleagues for distant management of a thoracic duct leak.
Percutaneous transabdominal cannulation of the thoracic duct at the cisterna chyli with lymphography and selective distal embolization with coils or tissue adhesive is a safe and minimally invasive technique for the treatment of CL that do not respond to conservative management, with a reported success rate of 45–70% [
For patients with failed surgical ligation, thoracoscopic ligation can be an effective salvage procedure that addresses the thoracic duct proximally [
The variable course and fragile composition of the thoracic duct make it vulnerable to iatrogenic injury during head and neck procedures that involve dissection low in the neck. In certain instances, inadvertent injury to the thoracic duct is unavoidable, particularly with the extirpation of malignancy. Fear of iatrogenic CL should not preclude sound oncologic resection. Rather, identification and ligation of a CL during surgery or its timely recognition and treatment in the postoperative period are essential for best surgical outcomes.
An appreciation of the anatomy, variable course, and possible termination patterns of the thoracic duct will lead to a more comprehensive management of any potential intraoperative CL. Additionally, increases in intrathoracic and intra-abdominal pressure and preoperative feeding of a fatty meal can help with localization of a CL.
The surgical care team should be vigilant for a CL if the surgery involved dissection in the vicinity of the confluence of the IJV and subclavian vein, on either side of the neck. High drain output, sudden increase of drain output after resumption of enteral feeds, or a creamy appearance of the drain output should all raise suspicion of a CL. A CL can be diagnosed clinically; however, in ambiguous cases, biochemical assay of drain contents may be helpful.
Chyle leaks can significantly impact wound healing and cause hypovolemia, malnutrition, electrolyte disturbances, and immunosuppression. Therefore, conservative management should be initiated immediately when a CL is diagnosed following surgery. This includes bed rest and head of bed elevation with a MCFA/nonfat diet or TPN. Fluid balance, electrolytes, and protein status should also be monitored closely.
If a CL does not respond satisfactorily to conservative management alone, surgical control locally or distantly should be considered. There is much debate about the exact criteria for and timing of surgical reexploration. Muscle flaps, sclerosing agents, and adhesives can be applied at the time of surgery as an adjunct to thoracic duct ligation. Suction drainage is essential for evacuation of chyle from the wound bed and to monitor output. For recalcitrant CL or circumstances that preclude reexploration, CL can be addressed distantly with thoracic duct catheterization and embolization or thoracoscopic thoracic duct ligation. The services available at each medical institution may differ and should be taken into account when deciding on the best management plan (Figure
Proposed treatment algorithm for the postoperative chyle leak.
Chyle leak formation is an uncommon but serious sequela of head and neck surgery, particularly with the resection of malignancy low in the neck. Chyle extravasation can result in delayed wound healing, dehydration, malnutrition, electrolyte disturbances, and immunosuppression. Prompt identification and treatment of a chyle leak are essential for optimal surgical outcomes.
Chyle leak
Total parental nutrition
Internal jugular vein
Middle chain fatty acid.
The authors declare that they have no competing interests.