CHYLOUS FISTULA OF THE NECK

Abhilash

OVERVIEW

Introduction Anatomy Pathophysiology Complications Etiology Investigation

Management› Medical› Surgical

What is Chyle? Alkaline,milky, odourless fluid 2-4L produced everyday

PROBLEM

Chylous fistulas are known to lead to prolonged hospitalization.

Clinically, chylous fistulas may be difficult to manage because of significant electrolyte, fluid, and protein imbalance.

FREQUENCY

Complication rate 1 - 2.5% of neck dissection involving level IV.

predilection for the left side of the neck, but up to 25% of cases involve the right side of the neck.

ETIOLOGY

Post operative complication› Radical neck

dissection› Selective neck

dissection› Anterior neck surgery

Penetrating trauma Node biopsy Cervical rib excision

ETIOLOGY

• Other potential causes of Chyle Leak– Lymphoma– Tuberculosis– Lymphangioleiomyomatosis– Liver cirrhosis– Congenital chylothorax (neonates)– Central venous cannulation– Idiopathic

PATHOPHYSIOLOGY

The thoracic duct is the conduit for lymph and dietary fat to reach the venous bloodstream.

The flow of chyle is around 2-4 L per day

Consists of fat 1-3% composed of TG (70% long chain), protein(3%), electrolytes content is the same as plasma except of lower calcium concentration, and lymphocytes (T lymphocyte).

Its daily production is dependent on the diet and daily dietary intake.

PATHOPHYSIOLOGY

Chemical composition of chyle is similar to that of tissue lymph, with higher concentration of cholesterol, phospholipids, and fat particles, particularly triglyceride rich chylomicrons and long-chain (>10 carbon atoms) esterified fats.    .

PATHOPHYSIOLOGY

The flow of chyle against gravity is supported by the interplay of› thoracic and abdominal pressures,› transmission of peristaltic bowel contractions,› contraction of the lymphatic vessels walls› Venturi effect at the junction of the thoracic duct

and the subclavian vein

FAT METABOLISM

• 95% of ingested fats are triglycerides with long chain fatty acids (LCT).

• These fats are re-esterified in the mucosal cells of the bowel wall, combined with an apolipoprotein and phospholipid and transported into the lymphatic system as chylomicrons.

• Middle chain fatty acids (MCTs), length C12 or less, are absorbed directly into the portal system without the formation of chylomicrons, bypassing the lymphatics; this is important in dietary therapy of chylous fistulas.

The challenges in patient with chyle leak

Hypoproteinemia Hyponatremia Hypochloremia Dehydration Emaciation Lymphocytopenia and immunosupression Pleural effusion - chylothorax Wound problems - infection, suture breakdown,

hemorrhage Chylopharyngeal fistula Peripheral edema Secondary sepsis

INVESTIGATION

– Excessive drainage, >500ml/ day for more than 3 days

– Milky white appearance on enteral feeding– Clear fluid on withholding enteral feeding

• Biochemical– Triglycerides > 100mg/dL and chylomicrons>4%Dyes– Sudan III stains chylomicrons

(No quantitative criteria have been established)

- Ether

Imaging

Plain radiograph CT scan Lymphangiography Lymphoscintigraphy

MANAGEMENT OF CHYLE FISTULA

Outline of management › Prevention› Nutritional modification› Medical management› Surgical management

PREVENTION AND INTRAOP RECOGNITION

Meticulous surgical technique and knowledge of anatomy.

PPV/Raise IAP to detect small leaks. Trendenlenburg position ? Role of ingesting high fat content

preoperatively. Posterior approach of dissection

All chyle leaked discovered intraoperatively should be identified and ligated with non-absorable suture material [3/0 or 4/0]

The needle should not pass directly through the duct

Over sewing the duct continuously with the fascia attached to the duct stump using black silk.

If a chylous fistula was treated intra-operatively, medical management strategies should be initiated post-operatively without delay.

Suction drains in wound beds.

Local and regional flaps.

Scalenus anterior muscle flap. Sternocleidomastoid flap. Pectoralis major flap.

Other adjuncts

Sclerosing agents – OK 432 or tetracyclines. Induce inflammatory reaction in the wound

bed. Intraoperative or postoperatively through

drain. - report of phrenic nerve paralysis Cynaoacrylate adhesives Fibrin glue adhesives.

Postoperative recognition of chyle leak

High drain outputs after resuming feeding. Greasy white fluid in the drains. Confirmation by biochemical tests.

Medical management of chyle leaks.

Bed rest. ?Pressure dressings avoided in setting of flaps. Negative pressure wound therapy and

aspirations I/O charts, s.urea and electrolytes daily. Liver function tests including albumin.

Nutritional Management

Goals of therapy

› Reduce chyle fluid production› Replace fluid and electrolytes› Maintain replete nutritional status and prevent

malnutrition

Nutrition intervention Fat free diet (< 0.5g fat per serving)

Fat free diet supplemented with MCT

TPN

MCT vs TPN No clear consensus. Reports of increase output with MCT.

Enteral nutrition – if <1L per day Low fat, semi elemental if <500ml/day (MCT

diet – Lucente et al Elemental diet for 500ml to 1L TPN if > 1 L per day Addition of intralipids to TPN.

Patients who are only on fat free/MCT diet as the only fat source for any duration of time will have to supplement essential fatty acids (EFA)

EFA cannot be produced endogenously and must be taken in form of diet.› Linoliec acid› -linolenic acidἀ

Other important unsaturated fatty acids can be made from these EFA.› Arachidonic acid is synthesized from linolenic acid and

is the precursor molecule for prostaglandins, leukotrienes and thromboxane molecule

EFA deficiency can occur within 5 days of fat free diet.› Eczema › Impaired wound healing › Thrombocytopenia

Guideline in the Nutritional Management of Chyle Leak

Adequate protein intake› Chyle contains significant amounts of protein (22–60

g/L)› Recommendations for protein intake should account

for such losses if an external drain is present or with repeated chylous fluid “taps”

› Adequate intake may be a challenge for patients on a fat free oral diet

Essential fatty acid deficiency (EFAD)› 2%–4% of total calories from EFA required to avoid

EFAD› May occur within 1-3 weeks of a fat free diet› Diagnosis: triene to tetraene ratio of >0.4 &/or

physical signs of EFAD (see section on MCT oil for more details)

› IV fat emulsion may be required if a patient is unable to tolerate any oral/enteral fat or if it is unwise to try adding oral/enteral fat

› MCT oil does not provide significant EFA

Fat soluble vitamins› Fat soluble vitamins are also carried by the lymphatic

system› A multivitamin with minerals is generally

recommended for patients on a restricted oral or enteral regimen

› Water soluble forms of vitamins A, D, E, and K may be better utilized

Practical Gastroenterology,2004University of Virginia Health System Nutrition Support Traineeship Syllabus

Somatostatin It decreases the intestinal

absorption of fats, therefore TG concentration in the thoracic duct is lowered.

Somatostatin › reduces gastric, pancreatic and

intestinal secretion.› It inhibit the motor activity of the

intestine › slows the process of intestinal

absorption › reduces splanchnic blood flow › decreases hepatic venous pressure

DECREASES THE THORACIC DUCT LYMPH FLOW RATE

Orlistat – blocks the enzyme responsible for breakdown of fat and intestinal absorption

? SURGICAL MANAGEMENT

High output fistulas >500ml per day Usually after 5 -7 days of no reduction in chyle. Most surgeons recommend thoracoscopic

approach

SURGICAL MANAGEMENT

LOCAL PROCEDURES – › reexploration of wound site after fat rich diet.› And suturing with non absorbable suture or clips

and local flap.› Vicryl mesh overlay has been described.

SURGICAL MANAGEMENT

DISTANT PROCEDURE Transabdominal cannulation of thoracic

duct following lympgangiography Embolisation coils and cyanoacrylate glue

› 60% success Thoracoscipic ligation of TD. Right sided

approach