Chyle Leak

Introduction

• • Leakage of chyle after neck dissection is an uncommon but potentially lethal complication

  • Occurs in 1% to 2.5% of cases, but its incidence has been reported to be as high as 5.8%

  • The thoracic duct drains lymph from most of the body, including the gut, and is said to terminate on the left side of the neck in 75% to 92% of cases

  • It passes into the neck by passing behind the great vessels but in front of the branches of the thyrocervical trunk and other vessels coming from the subclavian artery

  • It then loops across to enter (variable) the venous system at the junction of the internal jugular and subclavian veins

  • The duct comes into close contact with phrenic and vagus nerves and can be damaged during the process of finding and preserving these structures

Complications

• • Electrolyte abnormalities

  • Fluid imbalance - volumes of 4 to 5 L per day are not unknown

  • Protein loss 

  • Skin flap elevation and eventual necrosis of the skin with carotid exposure and even rupture

  • The delay in healing may lead to orocutaneous or pharyngocutaneous fistula formation, depending on the operation performed with the neck dissection

  • Chylous fluid may drain externally or may accumulate in the pleural cavity, either unilaterally or bilaterally producing the complication of chylothorax

  • Delay of ongoing treatment, such as radiation / chemotherapy 

Prevention

• • Know the anatomy and when to be cautious 

  • If injury suspected intraop: 

    • Several techniques may be used: tying, over-sewing, clipping with metal clips, or applying prolonged pressure

    • Additional measures, such as the use of fibrin glue with or without pedicled flaps, may be used

Diagnosis

• • Drainage after neck dissection may frequently be slightly turbid, and in such cases the examination of the fluid chemically may not be conclusive.

  • Rodgers et al (1992) examined the drainage of 23 neck dissections in 19 patients and found that triglycerides of greater than 100 mg/dL or chylomicrons of greater than 4% may indicate the likelihood of chylous leakage.

  • A chylomicron count of up to 4% may be associated with fat breakdown during normal healing.

  • One method of confirming the diagnosis is to stop enteral feedings, and if the fluid becomes clear then likely chyle leak. 

Management

• Nutritional

  • Goals

    • Decreasing the production and flow of lymph and chyle

    • Replenishing fluid and electrolytes losses

    • Preventing malnutrition

    • Options for nutritional care

    • Low-fat diet (LFD)

    • Fat-free diet (FFD)

    • Medium chain triglycerides (MCT) diet 

    • Specialized enteral feeds - Peptison 

    • Parenteral support without oral intake (TPN)

    • Some combination of the above

    • Octreotide

      • 2015: A prospective study on the role of octreotide in management of chyle fistula neck – prospective, 19 patients, octreotide 100ug SQ q8 for 5 – 7 days, all leaks stopped

  • Dressings

    • Negative Pressure Wound Dressings (low 50 mmHg) including closed bulb suction drains 

    • Pressure Dressing, in addition to the closed drain

• Surgical

  • • Thoracic duct embolization/ligation

    • Locoregional flaps

    • Microvascular lymphatic-venous anastomoses

General Strategy

• • Intraoperative care must be taken because damage at this time correlates well with postoperative chylous fistula.

  • If leakage is seen at operation, immediate intervention with fibrin sealant and collagen felt or Vicryl mesh should be undertaken if standard techniques were unsuccessful. Muscle flaps may be needed in severe cases. 

  • In cases of operative injury or postoperative suspicion of chyle leakage, MCT diet should be instituted. 

  • When drain production does not decrease, Peptison tube feedings should be given. 

  • If this strategy has not been successful, TPN is indicated. TPN should continue for about 30 days before surgical intervention.

High-Yield

• • What is the mechanism by which MCTs help resolve a chyle leak? 

    • MCTs (versus LCTs) are absorbed directly from the gut into the portal circulation, bypassing the lymphatic circulation (and chylomicron formation) and eliminating trigylcerides from chyle 

Links

• 2000: Management of chyle fistulization in association with neck dissection

• 2013: Evolution of chyle fistula management after neck dissection