Disclaimer: The information contained within the Grand Rounds Archive is intended for use by doctors and other health care professionals. These documents were prepared by resident physicians for presentation and discussion at a conference held at Baylor College of Medicine in Houston, Texas. No guarantees are made with respect to accuracy or timeliness of this material. This material should not be used as a basis for treatment decisions, and is not a substitute for professional consultation and/or peer-reviewed medical literature. Cervical Chylous Fistula Historical Interest Cheevers (1875) was credited with the first description of a chyle fistula. In 1907 Stuart summarized 40 cases and found the mortality for cervical fistula was 12.5% In the early 1900s ligation of the thoracic duct was thought to be fatal and treatment consisted of packing of the supraclavicular fossa. Later, reimplantation of the thoracic duct into the venous system was performed in an attempt to control fistula output. In 1955 Slaughter and Southwick showed that the cervical portion of the thoracic duct could be ligated without high morbidity. They used a scalene muscle flap over the site of ligated duct to help promote closure. Anatomy The lymphatic system drains excess fluid from the interstitial spaces. About one-tenth of the fluid filtered by the capillaries reenters circulation via the lymphatics rather than via the venous system. All lymph fluid eventually drains into one of two main lymphatic channels, the right lymphatic duct and the thoracic duct. The right lymphatic duct drains the right side of the head and neck, the right arm, lung, chest, a good part of the left lung, and the heart, and terminates in the right innominate vein at the junction of the right subclavian and right internal jugular veins. The thoracic duct receives lymph from everywhere else in the body. The thoracic duct originates at the cysterna chyli below the diaphragm (L2) and ascends into the thorax via the aortic hiatus and ascends in the posterior mediastinum crossing over to the left of the esophagus at T5 level. The thoracic duct ascends into the neck posterior to the left common carotid and arches superiorly and anteriorly to its termination in the venous system. The thoracic duct is classically described as terminating at the junction of the left subclavian and internal jugular veins; however, it has a notoriously variable course in the neck. Greenfield (1956) studied 75 cadavers and charted the course of the thoracic duct in each. Significant variation was found in the sites and patterns of termination. In one of the 75 cases the thoracic duct remained on the right side and entered into the right internal jugular vein. In the other cases the thoracic duct arose from the posterior mediastinum passing posterior to the innominate vein. In two-thirds of these cases the thoracic duct coursed posterior to the common carotid artery and in the other cases it passed anterior to the internal jugular vein towards its termination. Termination sites were found on the internal jugular vein in 45 of 74 cases. Other sites identified included innominate vein, subclavian vein, distal subclavian vein, external jugular vein - subclavian junction, and external jugular vein. The termination sites were often found to have multiple terminal branches. Chyle composition The main components of chyle are as follows: protein, predominately albumin - 2 to 4.5 gm/% (1/2 - 2/3 serum protein); Na , K+, Cl-, Glucose - values like plasma; WBC's - 1K-20K cu/mm (mostly T lymphocytes); and fat - 1% to 3% or more. Fat Metabolism Ninety-five percent 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. Lymphatic production can be up to 2 to 4 L per day. Like the venous system, reabsorption of interstitial fluid is affected by capillary pressure, interstitial protein, capillary permeability, and decreased plasma oncotic pressure. Flow may also be stimulus dependent and act as a water overflow system, with an increased volume of lymph following ingestion of water (lymph had decreased protein). Lymph formation and flow rate are also influenced by diet, respiratory movements, movements of the upper extremities, coughing, intestinal peristalsis and rhythmic muscular contractions of the thoracic duct wall. Causes of injury
Radical neck dissection (1-2% of cases; left more common but occurs on right, 25% of cases in Crumley's series.) Lymph node biopsies Subclavian vein access attempts Cervical rib resection for thoracic outlet syndrome Trauma, penetrating Trauma, blunt (case report) XRT, preoperative - risk factor for chylous fistula Complications of fistula Chylous fistulas are of significant clinical importance because of the associated complications and difficult treatment. The composition of chyle as just discussed makes understanding of the complications obvious. These patients can get: hypoproteinemia; hyponatremia; hypochloremia; lymphocytopenia and immunosupression; dehydration; pleural effusion; chylothorax; wound problems - infection, suture breakdown, hemorrhage; chylopharyngeal fistula; secondary sepsis and debilitation. Wound management Management of chylous fistula consists of two main principles: local wound care and control of chyle output. Medical management is several fold. Patients are put at bedrest - activity increases chyle flow. Pressure dressings have been the standard treatment for many years (Crumley, 1975; Spiro, 1990). Recently, several authors (Lucente, 1981; Havas, 1987) have advised against pressure dressings because of potential problems with flap viability, but pressure dressings will probably continue to be the dressing of choice. Repeated aspirations using sterile technique are advocated when a drain is absent or fluid has become loculated. Closed low-pressure suction (Spiro, 1990; Havas, 1987) or closed gravity (Crumley, 1975) drainage systems have been advocated and each has its supporters. Tetracycline sclerotherapy had been advocated by some to promote closure. Tetracycline impregnated surgicel has been used intraoperatively at the site of known and ligated thoracic duct injury with reported success in preventing post-operative fistula. Injection of this agent into the supraclavicular wound bed of established chylous fistula has also been reported. Advantages include avoidance of a reoperations, and a shortened stay. Disadvantages include impairment of skin flap, and a more difficult reoperation if this fails. Dietary management An important aspect of dietary care of these patients is their metabolic management. Strict I/O's, daily SMA7 and weekly albumin are necessary for proper management of this problem. Chyle production and flow can be altered by dietary manipulations. But the dietary management of these patients is a source of much controversy. As discussed earlier, the flow and production of chyle are particularly dependent on the amount of dietary fat ingested and chyle quantity is noted to decrease when dietary fat is eliminated. Hashim (1964) showed very significantly decreased loss of chyle in patients with chyluria and chylothorax when treated with MCT. The mainstay of dietary control had been the use of enteral feedings or TPN; each has its proponents. (Vivonex TEN - >99% fat free or Portagen 40% fat, but 86% MCT.) Holding early postoperative feeding in patients with known thoracic duct injuries repaired in the OR has been advocated to help prevent the occurrence of chylous fistula. Ramos and Faintuch (1986) reported the only comparative study in recent literature. In this study a total of 18 patients with thoracic duct fistula were studied. These patients had high output fistulas, 1200/d avg. Eleven cases were treated with TPN and 7 cases given fat-free, nonelemental NG diet. Closure of the fistula occurred in 10 of 11 (TPN) and 3 of 7 (enteral diet) with mean time to closure 10.1 days and 13.7 days, respectively; patients were treated for 18 days and then returned to OR if chyle flow did not abate. They found that fistula volume reduced sooner and more with TPN. They concluded that oral feeding worked in some but not as consistently as TPN. Another author retrospectively reported 3 patients who underwent unsuccessful re-explorations and then responded to treatment with TPN (10 days average). Al-Khayat (1991) reported three cases of thoracic duct fistula with low volume fistulas treated with dietary modification (one given TPN and two given NG feeds with Osmolite +/- arachis oil); they did not see any increase in chyle output and had closure of all 3 fistulas. They suggest therefore that the use of NG feeds with or without MCT is practical and appropriate and that the risks and costs of TPN are not justified. The use of somatostatin to hormonally control chyle output has been suggested. A report of one case treated with somatostatin had chyle flow decreased to half on day three and stopped on day five of infusion. The choice of dietary treatment of patients with thoracic duct fistula depends on an analysis of the patient's overall nutritional status and amount of chyle losses. Surgical Management Surgical treatment of chylous fistula can be divided into two periods: intra-operative and postoperative (or re-exploration.) If chyle leak is seen or suspected intraoperatively then exploration for a thoracic duct injury is mandated. This examination can be facilitated by placing the patient in Trendelenburg position and having the anesthesiologist apply positive pressure ventilation. If the injury is found then the thoracic duct should be ligated or oversewn with silk or a nonabsorbable suture. Reoperation for chylous fistulas can be very unrewarding and the initial operation is the best time to identify and control lymphatic leaks. There is no universal consensus for the appropriate time for consideration of reoperation on patients with thoracic duct fistula. The patient's nutritional status should play a role in this decision process, as should the ability or inability to keep up with the chyle losses. Re-exploration for a thoracic duct injury is obviously warranted for patients with massive leaks (more than 2 L per day). Surgery can also be justified for patients with fistula outputs of more than 500 cc per day for more than four days. At re-operation give the patient cream two hours preoperatively and in the OR perform the same maneuvers as stated previously but with saline irrigation in the wound to see the point at which the creamy chyle rises in the saline. Exploration with ligation of the fistula is the preferred treatment, but often it is not possible to identify the site of leak. In these cases several options exist. Authors have suggested the use of gelfoam, surgicel, fibrin glue, or surgical glue placed in the neck in the suspected region of leak or the use of a muscle stump sutured over the site to help control chyle flow and promote fistula closure. Leaving the wound open with iodoform packing and allowing secondary closure is always an option in difficult cases. Several authors have reported success with the use of supradiaphragmatic ligation of the thoracic duct in difficult cases of thoracic duct injuries and this remains a viable option for complicated cases. Summary and Recommendations In summary, the intraoperative identification and treatment of thoracic duct injuries remains the best treatment. Holding postoperative feedings in at-risk patients may also be beneficial. When a chylous fistula is identified postoperatively, patients are placed at bedrest, local wound care is initiated, drainage or aspirations are performed as needed, patients are placed on fat- free diet and commencement of TPN considered. Reoperation is performed as indicated by poor or no response to aggressive medical management. Case Presentation A 32-year-old white man initially presented to his physician with a two-month history of a nontender left supraclavicular mass. An incisional biopsy was diagnostic for metastatic medullary carcinoma of the thyroid. The patient was then referred here for treatment. He was otherwise healthy and asymptomatic and had no palpable thyroid mass. A thyroid scan was negative. There was no family history of MEN II; the patient was not hypercalcemic and he had no signs of excessive catecholamine production. He went to the operating room and underwent a total thyroidectomy, anterior compartment dissection, left regional lymph node dissection and reimplantation of the right inferior parathyroid into the right sternocleidomastoid muscle. The dissection was difficult due to the fibrous nature of the tumor and its extension into the soft tissues of the neck. His postoperative course was complicated by transient hypocalcemia and left pleural effusion. On the sixth postoperative day while stretching to have a CXR, the patient felt a "pop" in his left neck. Later that afternoon 140 cc of milky, yellow fluid had collected in the Davol drain. Fluid continued to accumulate in the drain and a diagnosis of chylous fistula was made. The patient was switched to a fat-free diet. The fistula continued to drain over the next 14 days with a maximal output of 1700 cc on the 14th postoperative day, slowing thereafter. The leak resolved with aggressive nonsurgical management and ceased on the 20th postoperative day. The patient went home and, one month postoperatively, was doing well. Bibliography al-Khayat M, Kenyon GS, Fawcett HC, Powell-Tuck J. Nutritional support in patients with low volume chylous fistula following radical neck dissection. J Laryngol Otol 1991;105:1052-1056. Crumley RL, Smith JD. Postoperative chylous fistula prevention and management. Laryngoscope 1976;86:804-813. De Hert S, Heytens L, Van Hee R, Adriaensen H. Current management of traumatic chylothorax. Acta Anaesthesiol Belg 1988;39:101-107. Fitz-Hugh GS, Cogwill R. Chyle fistula: complication of neck dissection. Arch Otolaryngol 1970;91:543-547. Gault DT. Chylo-pharyngeal fistula after radical neck dissection. Br J Plast Surg 1987;40:538-539. Greenfield J, Gottlieb MI. Variations in the terminal portion of human thoracic duct. Arch Surg 1956;73:955-959. Guyton AC. Textbook of Medical Physiology, 6th edition. 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Patterson GA, Todd TRJ, Delarue NC, et al. Supraradiaphragmatic ligation of the thoracic duct in intractable chylous fistula. Ann Thorac Surg 1981;32:44-49. Pollack CV Jr, Kob JC, Griswold JA. Chylous drainage from a stab wound to the neck. Ann Emerg Med 1990;19:1450-1453. Ramos W, Faintuch J. Nutritional management of thoracic duct fistulas. A comparative study of parenteral versus enteral nutrition. JPEN J Parenter Enteral Nutr 1986;10:519-521. Sachs PB, Zelch MG, Rice TW, Geisinger MA, Risius B, Lammert GK. Diagnosis and localization of laceration of the thoracic duct: usefulness of lymphangiography and CT. AJR Am J Roentgenol 1991;157:703-705. Sinclair D, Woods E, Saibil EA, Taylor GA. 'Chyloma': a persistent post-traumatic collection in the left supraclavicular region. J Trauma 1987;27:567-569. Slaughter DP, Southwick HQ. Cervical thoracic duct fistulas. Ann Surg 1955;142:307-310. Spiro JD, Spiro RH, Strong EW. The management of chyle fistula. Laryngoscope 1990;100:771-774. Spotnitz WE, Dalton MS, Baker JW, Nolan SP. Successful use of fibrin glue during 2 years of surgery at a university medical center. Am Surg 1989;55:166-168. Strong EW. Preoperative radiation and radical neck dissection. Surg Clin North Am 1969;49:271-276. Thawley SE. Chylous fistula prevention and management. Laryngoscope 1980:90:522-525. Tilney NL, Murray JE. Chronic thoracic duct fistula: operative technique and physiologic effects in man. Ann Surg 1968;167:1-8. Ulibarri JI, Sanz Y, Fuentest C, Mancha A, Aramendia M, Sanchez S. Reduction of lymphorrhagia from ruptured thoracic duct by somatostatin. Lancet 1990;336:258. Younus M, Chang RW. Chyle fistulae. Treatment with total parenteral nutrition. J Laryngol Otol 1988;102:384.
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