Managing Chyle Leakage Following Right Retroperitoneoscopic Adrenalectomy: A Case Study

Introduction

Chyle leakage after adrenectomy is a rare complication of urologic surgery. The diagnosis of chyle leakage can be confirmed by its milky appearance, or by laboratory analysis of the liquid, which contains high levels of triglycerides (>110 mg/dl) and protein (>3 g/dl), but contains small amounts of cholesterol [1]. The creatinine value of the drainage fluid was close to that of the serum creatinine and far from that of the urine. It is necessary to manage chyle leakage properly after surgery, as it can sometimes last for weeks and lead to dehydration, fluid imbalance, and severe nutritional and immune deficiencies. To date, only 3 cases of chyle leakage after left adrenalectomy have been reported in the literature [2,3], but no confirmed cases of right retroperitoneoscopic post-adrenalectomy have been reported. This report describes a 46-year-old woman with retroperitoneal lymphatic (chylous) leak following right adrenalectomy for a nonfunctional adrenal adenoma. To the best of our knowledge, this is the first reported case of chyle leakage after a right retroperitoneoscopic adrenalectomy.

Case Report

A 46-year-old woman presented with a medical history of hypertension. An adrenal tumor (3.2×2.0 cm) was identified by computed tomography (CT) (Figure 1). Enhanced CT showed a mildly heterogeneous enhancement of the right adrenal gland (3.2×2.0 cm) (Figure 2A, 2B). Physical and laboratory examination did not reveal any significant findings. Upon evaluation, serum metanephrine and normetanephrine levels were normal. Serum cortisol levels were suppressed in the overnight dexamethasone suppression tests. A diagnosis of nonfunctional adenoma of the right adrenal gland was made. The patient actively requested surgery and underwent laparoscopic adrenalectomy via retroperitoneal approach.

Postoperatively, she was transferred to the ward and a clear fluid diet was started, to be advanced as tolerated. On postoperative day 1, the drain output was 50 mL of sero-sanguinous fluid.

The retroperitoneal space drainage began to increase on the second day after the operation when eating began, which included fat. On postoperative day (POD) 3, the patient had milky white turbid drainage fluid (approximately 400 mL) (Figure 3).

The creatinine level of the drainage fluid was 53 umol/l, closing to that of serum creatinine (50 umol/l). The fluid sample was sent for analysis, revealing an elevated triglyceride concentration of 435 mg/dL (reference range 40–170 mg/dL). The chyle leak was confirmed clinically.

We reviewed the video of the operation to try to find the cause of the lymphatic fistula. However, no coarse lymphatic vessel injury was found. Considering that the small lymphatic vessels were damaged by energy equipment such as ultrasound knife during the operation, some lymphatic vessels were re-opened after surgery. The patient was fed a high-protein, fat-restricted diet. In addition, 3 mg somatostatin acetate was administered daily. On POD 6, the chyle leak decreased to 200 ml, on POD 8 to 90 ml, on POD 10 to 30 ml, and on POD 11 the leak had almost completely stopped (Figure 4). The drain was removed on POD 11. The patient was discharged on POD 14.

The histology showed a benign adrenal cortical adenoma contained beneath the adrenal capsule and composed of regularly arranged cells with foamy cytoplasm and distinct cell membranes, with some irregularity of cell nuclei, but no mitoses (Figure 5). Although some lymphocytes were seen within the tumor, there were no features of malignancy. No necrosis, no hemorrhage, and no lymphovascular invasion were seen. The chylous effusion did not recur for 5 months.

Discussion

Lymphatic (chylous) leakage may be a complication of retroperitoneal urological surgery; in particular, it is rarer after adrenalectomy, but it should be taken seriously. Retroperitoneal lymph node dissection is one of the main causes [4]. The occurrence of postoperative chyle leakage needs to meet 2 basic conditions: the destruction of lymphatic circulation in the local area and lymphatic pressure at the site of the lymphatic damage being greater than the intraperitoneal pressure [5]. Studies have shown that perivascular lymphatic control may be inadequate in minimally invasive techniques, such as nephrectomy using energy sources such as harmonics, ligature, and electro-cautery. The literature on chylous ascites following laparoscopic radical nephrectomy suggests that these approaches may not be as effective as suture ligation or clamping in lymphatic vessel control [6]. In terms of pathogenesis, retroperitoneal chyle leakage is caused by an unrecognized interruption of the cisterna chili or other major retroperitoneal lymphatic channels. Eating can also trigger chyle leakage. Consequently, it usually occurs after feeding on POD 2. The increase in lymphatic production with feeding enhances local lymphatic pressure, which is greater than that in the abdominal cavity.

Cysterna chili, anatomically located anterior to the second lumbar vertebra, receives lymph from right and left lumbar and intestinal trunks [7]. Some large lymphatic vessels were found beneath the right renal artery, which connected the retroperitoneal and sub-mesenteric lymph nodes and mixed the right lumbar trunks. The right lumbar trunk was ascending along the right side of the inferior vena cava with the right lumbar ascending vein [8]. The anatomical position was located from the 12th thoracic vertebra to the 2nd lumbar vertebra. Extensive retroperitoneal surgeries (eg, retroperitoneal lymph node dissections) can result in injury to these trunks or cysterna chili itself, leading to chyle leak. Some studies have shown that even if retroperitoneal lymph node dissection and extensive separation are not performed during the operation, there is still a possibility of lymphatic leakage after the operation, possibly because of the electrical damage to the lymphatic vessels during the operation, and some lymphatic vessels reopen after the operation and form lymphatic leakage [2]. Therefore, surgeons need to be careful to avoid damaging right lumbar trunk or large lymphatic vessels during the retroperitoneal surgery. We reviewed the video of the operation and found that the dissociation of the inferior adrenal pole was close to the renal vascular level, and the interior was close to the inferior vena cava. Therefore, we believe that the right lumbar trunk or lymphatic vessels near the renal vascular level may have been injured.

The clinical manifestation of lymphatic leakage is that the drainage volume of the postoperative drainage tube increases after eating, and the drainage fluid is milky white [1]. In this case, the retroperitoneal space drainage began to increase on the second day after the operation when eating began. On postoperative day (POD) 3, the patient had milky white turbid drainage fluid. Chu and Yadav reported that the drainage tube drained a large amount of milky white fluid after postoperative eating [2,3].

The diagnosis of chylous leakage is confirmed by a typical milky white appearance, as well as by laboratory analysis of fluids consisting large amounts of triglycerides (>110 mg/dl) and protein (>3 g/dl) but small amounts of cholesterol. In this case, the patient had milky, turbid discharge. The triglyceride level was 435 mg/dl and the protein level was 3.8 g/dl. The creatinine level of the drainage fluid was 53umol/l, which is close to the serum creatinine level. It is necessary to treat chylous leakage promptly and appropriately after surgery, as it can sometimes last for weeks and lead to dehydration, fluid imbalances, and severe nutritional and immune deficiencies due to the loss of essential proteins, lipids, and electrolytes.

Whether early surgical intervention is superior to conservative management remains controversial. Conservative treatment is highly effective, but it extends the length of hospital stay and can worsen the patient’s physical condition due to nutritional imbalance and decreased immune function [9]. Conservative treatment is noninvasive and easily accepted by patients. We present our clinical experience with the treatment of chylous leakage.

In cases of persistent chyle leakage, dietary interventions are recommended to provide a low-fat or medium-chain triglyceride diet; medium-chain triglycerides can be absorbed directly into the portal vein without increasing lymphatic flow. These methods are effective in 75% of cases [10]. More active dietary control with TPN and an elemental diet can help with intestinal rest, which in turn can reduce lymphatic flow. The usefulness of somatostatin was reported for the closure of postoperative lymphorrhea in 1990 [11]. Somatostatin and octreotide, alone or in combination with TPN, are effective in the treatment of lymphorrhaphy, with an 87% success rate [12]. It usually takes 24 to 72 hours to become effective [13]. Two pathways of somatostatin are thought to decrease lymph production. First, they act on somatostatin receptors (SSR) on the intestinal wall, which in turn reduces secretion of pancreatic and intestinal fluid [14]. The second pathway is the drying effect on the lymphatic system, with an unknown mechanism [15]. Negoro reported 2 patients with retroperitoneal chyle leakage, one receiving total parenteral nutrition and the other receiving a low-fat diet. Total parenteral nutrition is more effective in controlling chylous complications, but in the case of low chylous excretion, combined use of octreotide and a low-fat diet is reasonable [9]. Our patient was started on a high-protein-and fat-restricted diet. Somatostatin acetate (3 mg) was then administered daily. On POD 10, the chyle leak decreased to 30 ml and on POD 11 it had almost completely stopped. The drain was removed on POD 11.

Retroperitoneal chyle leakage is restricted to a limited space and does not affect important nearby organs; therefore, sclerotherapy should be considered. Curing agents include injection of 50% glucose solution, Pseudomonas aeruginosa, tetracycline, iodoform, and talcum powder [16]. Negoro reported the case of a patient with retroperitoneal chyle leakage who could not tolerate prolonged eating. After it was confirmed that the leakage was not related to the abdominal cavity, the drainage tube was removed after sclerosis therapy with povidone iodine injection [9]. We reviewed a video of our patient’s surgery and verified that lymphatic leakage did not communicate with the abdominal cavity. In addition to dietary interventions, we also injected curing agents, including a 50% glucose solution.

Surgical treatment is a major concern in patients who do not respond to conservative treatment. The key to treatment is to pinpoint the site of the lymphatic injury. When metabolism-related complications occur and the symptoms persist for more than 2 weeks, or when the drainage volume is greater than 1 L for 1 week, surgery can be performed [17]. The advantage of laparoscopic surgery is that it is more minimally invasive and can provide a clearer and enlarged surgical field of view. Geary et al and Molina et al each reported a case of chylorrhea treated by laparoscopy, in which multiple clamps, fibrin glue, and argon beam coagulation were applied to the leak [18,19].

In the 3 reported cases of postoperative chyle leak, 2 cases responded to conservative, non-surgical management, and they all included a fat-free diet, similar to our practice [2,20]. The remaining case underwent an invasive intervention (micro-surgical intra-abdominal lymphaticovenous anastomosis) after conservative treatment failed [3].

Conclusions

This report has highlighted that lymphatic (chylous) leak can be a complication of retroperitoneal surgery. The most important factor is the prevention of chylous complications. Even if no lymphatic leakage is found, it is necessary for the laparoscopic surgeon to fully coagulate the lymphatic channels. Most cases can be managed with conservative treatment.