Ultrasound-guided lymphangiography and interventional embolization of chylous leaks following esophagectomy

Patients

Four patients with chylous leaks following esophagectomy were included in the retrospective analysis. The patients’ characteristics are displayed in Table 1. Three patients underwent transthoracic esophagectomy for esophageal carcinoma, and one patient had a transhiatal esophagectomy because of an esophageal perforation. The chylothorax was diagnosed between postoperative day (POD) 1 and 16. In all patients, the chylous leak was classified as high-output fistula.

Due to anonymous data analysis, institutional review board approval and written informed consent were not required for this retrospective case study at the investigators’ institution.

Radiologic technique of Lipiodol lymphangiography

In general, the thoracic lymphatic vessels were visualized through an injection of Lipiodol (Guerbet LLC, Bloomington, IN, USA) through an inguinal approach. The inguinal lymph node was identified using a high-frequency linear US transducer and punctured using a 20-G needle (Becton Dickinson S.A., Madrid, Spain) under US guidance. After verifying the position of the needle tip at the nodal hilum, Lipiodol was intermittently injected at a slow flow rate (approximately 2–3 mL/min) under fluoroscopy to a maximum of 10 mL (Figure 1). The time interval until the cisterna chyli and the thoracic duct became visible was about 20–30 min. Due to the fact that Lipiodol lymphangiography might also have a therapeutic effect and stop lymphatic leakage, the intervention was finished at this point. In case of a persistent leakage, a follow-up intervention using US-guided puncture of a lymph node at the contralateral groin and a repeat lymphangiography using Lipiodol was performed. In a second step, the thoracic lymphatic system was accessed through a percutaneous (cone beam) computed tomography (CT)-guided puncture of the contrast-filled cisterna chyli using a 21-G needle (Cook, Bloomington, IN, USA) during the same procedure or consecutively (Figure 2A–D). The attempt to advance a guide wire through the needle followed by a microcatheter into the thoracic duct failed. Therefore, embolization of the leak through the application of microcoils and/or glue was not possible. Instead, disruption/maceration of the cisterna chyli and/or the thoracic duct was used as an additional treatment option in one patient. For this purpose, the cisterna chyli and/or the thoracic duct were punctured several times using the above-mentioned needle to promote leakage of the high-viscosity, iodinated oil contrast agent, as well as to provoke a local hematoma in order to decrease the lymphatic flow and therefore allow the chest leak to occlude itself.

Figure 1:

Bilateral groin lymphangiogram: after ultrasound-guided bilateral lymph node puncture, Lipiodol is infused into the lymphatics. The spot radiograph shows the initial phase with opacification of inguinal lymph nodes and lymphatic drainage of the pelvis.

Figure 2:

Radiologic intervention with detection and treatment of chylous leak.

(A) Spot radiograph of the thorax showing leakage site at the mediastinum (arrow). Radiopaque Lipiodol accumulates in the pleural space on the right side (asterisk). (B) Spot radiograph showing the course of the thoracic duct in another patient. A right-sided chest drain was placed to evacuate a chylous pleural effusion. (C) Cone beam CT-guided puncture of the cisterna chyli. (D) Parasagittal multiplanar reformation shows the “needle disruption technique.” If the thoracic duct cannot be successfully cannulated for embolization after needle placement, multiple needle passes can be used to macerate the cisterna chyli. This promotes chyle flow into retroperitoneum, as shown by the extravasation (arrow), thereby allowing healing of the leak in the mediastinum.

General management of chylothorax

Iatrogenic injury of the thoracic duct during cardiothoracic surgery is by far the predominant etiology of chylothorax. Chylous leaks after transthoracic esophagectomy are rare events; however, this postoperative complication is a life-threatening condition in particular for high-output fistula of >1000 mL/day and its reported 30-day mortality exceeds 17% [10]. Chylous fistula causes dehydration with electrolyte imbalance, malnutrition, as well as lymphopenia with an impaired immunological status and consecutive pneumonia. Owing to the low incidence of this complication, no generally accepted treatment algorithm has been established thus far. Conservative management with reduction of the enteral loading including a fat-reduced diet and adequate parenteral fluid administration is considered as standard care for low-output (type A) leaks according to the ECCG classification [4]. The medical management of high-output (type B) leaks is difficult because of the severe fluid loss; thus, surgical occlusion of the leaking thoracic duct is necessary. However, due to anatomical variations or the concomitant mediastinitis with inflammatory tissue, the leakage site cannot always be detected intraoperatively. In addition, as the surgical procedure of a re-thoracotomy itself is associated with considerable morbidity, the timing of surgery is still a matter of discussion.

Technique of interventional lymphangiography and embolization

In this setting, radiologic intervention seems to be a favorable option completing the present treatment strategy. Clinical experience with intranodal lymphangiography followed by embolization of the thoracic duct or disruption of the cisterna chyli is limited, and only a small number of case series have been published thus far. Lymphangiography aims not only to localize the chylous fistula but also offers the possibility to embolize and thereby cure the chylous leak. The interventional technique is based on the visualization of the thoracic lymphatic vessels through an injection of Lipiodol via both a pedal and an inguinal approach [5], [6], [11]. The latter offers a more feasible access to the lymphatic system, reduces the radiation dosage due to the shorter time of investigation, and therefore has replaced pedal lymphangiography nowadays [12]. Although the use of significantly higher amounts of Lipiodol of up to 40 mL has been reported, in this series of four patients, the maximum of 10 mL Lipiodol was sufficient to localize the leakage site [13]. After injection of Lipiodol, an observation period of 2–5 days is justified because Lipiodol application itself has a therapeutic effect and might occlude the lymphatic leakage [14]. A second option to occlude the visualized leak is the percutaneous (cone beam) CT-guided puncture of the contrast-filled cisterna chyli with catheterization of the thoracic duct and mechanical obstruction of the leakage site by microcoils and/or a mixture of iodized oil and N-butylcyanoacrylate [15], [16]. In the largest series published by Itkin et al., the technical success rate of thoracic duct catheterization was 67%, and the clinical success rate of thoracic duct embolization by either technique to occlude the chylous leak was as high as 90% [5]. In case of a persisting chylothorax, disruption/maceration of the cisterna chyli and/or the thoracic duct has been described as an additional treatment option [17]. The possible complications of the described intervention include the development of an arterio-venolymphatic shunt with consecutive Lipiodol embolism as well as bleeding from the puncture sites. None of these complications were observed in the four patients of this series.

Treatment algorithm including radiologic embolization

The present series of four cases demonstrates the feasibility and safety of this interventional technique and confirms previous reports [6], [8], [9]. However, despite these encouraging results, the limitations of case reports must be acknowledged. It is important to realize that US-guided lymphangiography with thoracic duct embolization requires an experienced interventional radiologist to perform this complex and time-consuming procedure. With increasing centralization of esophageal cancer surgery, interventional radiologists with expertise in this field need to become part of the team approach for this tumor entity, and a close cooperation of these two specialties is important to decide on the best treatment option. Although it is difficult to compare the success rates of the surgical and radiologic approach due to the low incidence of this postoperative complication, interventional thoracic duct embolization should precede the surgical approach in patients with a high-output fistula. The rationale of this strategy is the less invasive character of this intervention and therefore lower complication rate compared to re-thoracotomy or re-thoracoscopy. For patients with low-output fistulas of only a few hundred milliliters per day, the conservative approach with standardized dietary pathways is still the preferred strategy.