Chylous fistula is a complication of neck surgery where the thoracic duct is damaged, causing a leak of milky white fluid known as chyle. It occurs in 1-3% of major neck surgeries and presents with drainage from the surgical site. Prolonged chyle leaks can cause electrolyte imbalances, malnutrition, and increased risk of infection if not properly managed. Treatment involves initially conservative measures like drainage and a low-fat diet to reduce chyle flow and allow the fistula to close. Surgery to repair the leak may be needed if conservative treatments fail or complications arise. Surgical options include direct repair, thoracic duct ligation or embolization, with the goal of preserving duct

1. Chylous fistula of neck
Mounika.T

2. Introduction
 Damaging or cutting a thoracic duct while operating low on the left side
of the neck does not occur infrequently, even in experienced hands.
 In fact, transecting the duct when carrying out radical surgery low down in
the neck or the mediastinum may often be necessary.
 What should be avoided, however, is the failure to recognize this
complication at the time of surgery, which could lead to serious
consequences.

3. Incidence
 Chylous fistula is an infrequent complication of head and neck surgery,
with an incidence reported in 1-3% of patients undergoing major neck
surgery.
 This condition has a predilection for the left side of the neck, but up to
25% of cases involve the right side of the neck.

4. Etiology
 Radical neck dissection is the most frequent operation associated with
chylous fistulas,
 Chylous fistulas may be found after selective neck dissection, penetrating
neck trauma, cervical node biopsy, cervical rib resection, anterior neck
surgery, and central venous cannulation

5. Clinical presentation
 Patients with a chylous fistula present with drainage of "milky white" fluid;
however, in patients who are nil by mouth or on a fat-free diet, it may
present as a leakage of clear fluid.
 The volume of drainage ranges from low output (< 500 mL/day) to more
than 3 L per day in high-output fistulas.
 Persistent chyle loss leads to electrolyte disturbance, hypovolemia,
hypoalbuminemia, coagulopathy, immunosuppression, chylothorax,
peripheral edema, wound infection, and local skin breakdown.
 Prolonged chyle leak can therefore lead to mortality.

6. Management
 Prevention is widely believed to be the optimum management for a
chylous fistula. Once a chylous fistula has occurred, medical management
focuses on measures to reduce chyle flow, with closure of the fistula as a
result. This should be done while paying close attention to the patient's
nutritional status.
 Two different conservative postoperative management techniques have
been proposed: (1) drain removal and aspiration
(2) negative pressure wound therapy (NPWT).
The use of adjunctive somatostatin therapy has also been suggested. Data
does not delineate the exact parameters for the use of these techniques.

7. Medical management
 Drain removal and aspiration has been shown effective in low-output
fistulas with surrounding healthy tissue. Utilizing this technique,
postoperative drains remain on continuous suction, a pressure dressing is
applied, and bed rest is prescribed. Once chyle production plateaus, the
drains are removed, and serial aspirations are performed.
 NPWT involves reopening the surgical incision, covering the wound with a
sealant, and applying subatmospheric pressure. This technique has also
proven successful in the management of low-output chylous fistulas.
Caution should be taken to avoid rupture of major local blood vessels
when NPWT is applied to the head and neck region.

8. Surgical therapy
 Chyle leaks may be identified intraoperatively or postoperatively, as
previously detailed.
 Intraoperative chyle leak during dissection of the left lower neck, the leak
should be repaired with nonabsorbable 3-0 or 4-0 sutures and an overlying
material.
 Fibrin sealant, collagen felt, polyglactin 910 mesh, and muscle flaps have
been suggested. The sutures should be placed to include some of the
surrounding tissues without penetrating the duct wall.
 If possible, functional repair of the thoracic duct injury should be attempted
rather than use of an approach that obliterates the thoracic duct, as the
latter can produce distal complications.

9.  Despite intraoperative measures, a chyle leak may persist postoperatively,
mandating secondary repair, embolization or ligation.
 The decision to explore a patient's neck because of a chyle leak and the
timing of it is still controversial. A step-wise approach is sensible, with
surgery undertaken only after failure of medical treatment.

10. Indications of surgery
Surgery was advised by Kassel et al in each of the following cases:
 More than 500 mL of drainage per day persisted after 1 week of medical treatment.
 Persistent low-output drainage occurred over a prolonged period.
 Complications developed.
Spiro et al found that if the peak 24-hour drainage was greater than 600
mL, medical management was likely to be unsuccessful.

11. Various surgical options
 Although the aforementioned criteria can assist in identifying patients
who would benefit from surgical intervention, a comprehensive,
algorithmic approach to the type of surgical repair that should be
performed does not exist at this time.
 Direct repair, thoracic duct embolization, therapeutic lymphography,
thoracic duct ligation, and microsurgical lymphatic venous anastomosis
are potential repair options.
 It has been suggested that functional repair is preferable to ligation, as
distal lymph flow complications are possible. Thus, ligation and
embolization should typically be reserved for difficult-to-locate or massive
leaks

12. Surgical management
 Reexploration of the neck needs to be undertaken by an experienced head
and neck surgeon, as severe inflammation is likely to be present at this
stage.
 Once the previous incision has been opened, the subplatysmal flaps
should be lifted and retracted to gain access to the lower neck.
 Gier et al used fibrin sealant and a pectoralis myofascial flap, without
trying to find the leak, although targeted repair of an obvious leak is
sensible.

13. Surgical management
 Velegrakis et al used a fibrin adhesive set, a 2-component sealant. This combines
fibrinogen, plasma fibronectin, factor XIII, and plasminogen in component A with
aprotinin in component B.
 Sclerosing agents like tetracycline and talc powder were advocated by Kassel et al.
 Doxycycline sclerotherapy has been used, but a case report of phrenic nerve
paralysis was followed by further work showing the neurotoxicity of doxycycline.
 Lymphangiography with lipiodol compounds also has occluding properties, but
there is the possibility of an anaphylactic reaction. Thus, side effects have limited the
use of sclerotherapies.

14. Surgical management
 Embolization of the thoracic duct has also been described.
 Research indicates that this technique has a 70-75% clinical success rate and that it
has the greatest efficacy in patients with a chyle leak volume of less than 1 L.
 Ligation of the thoracic duct is an option for massive leaks or if other treatment
options fail.
 Thoracoscopic ligation of the thoracic duct is the currently favored minimally
invasive approach; this technique avoids an open right thoracotomy and its
associated complications.
 Lymphatic venous anastomosis is an effective, but technically demanding, repair
technique. It perseveres the function of the thoracic duct but requires
microsurgical equipment and expertise.

15. Follow up
 A prolonged hospital stay is associated with chylous fistulas.
 Nutritional follow-up is important.