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Interventional Radiology |
1 Department of Radiology, Hadassah University Hospital, Ein-Kerem, PO Box
12000, Jerusalem 91120, Israel.
2 Department of Gastroenterology, Hadassah University Hospital, Ein-Kerem,
Jerusalem 91120, Israel.
3 Department of Oncology, Hadassah University Hospital, Ein-Kerem, Jerusalem
91120, Israel.
Received December 4, 2003; accepted after revision March 1, 2004.
Address correspondence to A. I. Bloom.
One article has appeared in the English-language literature describing intraductal cooling of the biliary tract using chilled saline during intraoperative radiofrequency ablation [3]. We present a case of a 43-year-old woman with a solitary metastasis of ocular melanoma to the liver and a known stricture in the right hepatic duct. In an attempt to prevent further injury to the bile duct, sonographically guided percutaneous radiofrequency ablation of the metastasis was performed while cooling the biliary tree during the procedure by constant infusion of chilled saline through a nasobiliary tube. To our knowledge, this is the first report in the literature describing this technique.
Subjects and Methods
A 43-year-old woman with ocular melanoma, who was treated with brachytherapy, developed three liver metastases 6 years after diagnosis. These were treated by hepatic resection and placement of a catheter in the hepatic artery for intraarterial chemotherapy. A stricture in the right hepatic duct developed and was managed by endoscopic placement of a biliary stent. During the subsequent 3 years, she developed two episodes of cholangitis and two episodes of obstructive jaundice that necessitated stent exchange. Three years after resection of the metastases, a new solitary hypodense liver lesion, 13 mm in diameter, developed in the right lobe of the liver, which was interpreted as a metastasis without biopsy proof.
Because of increased surgical risk, radiofrequency ablation was chosen as the optimal treatment. The metastasis was immediately adjacent to the right hepatic duct (Fig. 1A), which was minimally dilated. This raised the concern of possible thermal damage to the duct during radiofrequency ablation. Therefore, we decided to cool the biliary tree during the procedure by infusion of chilled isotonic saline (0.9%), which had been refrigerated overnight, through a nasobiliary tube. The patient gave written informed consent to the procedure. IV broad-spectrum antibiotics were commenced before the procedure and continued for 5 days.
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The indwelling biliary stent was initially removed in the endoscopy suite,
and a nasobiliary tube was inserted in its place. The patient was transferred
to the interventional radiology unit under general anesthesia; sonographically
guided radiofrequency ablation was performed using a 20 cm x 20 mm
Cool-tip needle (Radionics) that was activated for a single 12-min pulsed
algorithm with the following maximum radiofrequency parameters: 1.37 amperes;
impedance, 89 
; power output, 129 W; and temperature range,
19–20°C, during needle cooling. The maximum temperature measured in
the ablation zone was 68°C. Throughout the procedure, chilled saline was
slowly and constantly dripped with 1-m gravity through the nasobiliary tube in
an attempt to avoid overheating of the bile ducts. The nasobiliary tube was
identified sonographically within the right hepatic duct. At the end of the
procedure, the patient was transferred back to the endoscopy unit and the
nasobiliary tube was exchanged for a new biliary stent.
A sonographic examination performed 1 day after the procedure showed a
heterogeneous lesion, 23 mm in diameter, in the region of the radiofrequency
ablation. No free intraperitoneal fluid, subcapsular collection, or other
abnormality was shown. The results of patient's liver function tests were
normal before radiofrequency ablation and showed a mild and transient
elevation in aspartate transaminase, alanine aminotransferase, and
-glutamyltransferase 24 hr after the procedure.
At follow-up 1 month after the procedure, contrast-enhanced abdominal CT showed a fluid density with no foci of enhancement measuring 19 mm in diameter at the location of the metastasis. No increased biliary dilatation was seen. However, two new liver metastases in the right lobe of the liver were identified under the diaphragm. The patient was therefore treated with immunotherapy (interleukin-2, interferon, and granulocyte-macrophage colony-stimulating factor) resulting in stabilization of the disease. Follow-up CT during the subsequent 16-month period showed no evidence of local recurrence at the site of the radiofrequency ablation and no evidence of injury to the bile ducts (Fig. 1B).
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Discussion
Ocular melanoma is the most common primary intraocular malignancy. It is an uncommon tumor with 12,000 cases per year in the United States. Approximately 15–30% of patients develop metastases within 5 years, the most common site being the liver (80%) [4]. Despite therapy, survival ranges from 1 to 59 months (median, 7 months) [5]. The treatment options for metastatic uveal melanoma include surgery, systemic chemotherapy, chemoembolization, intraarterial chemotherapy, chemoimmunotherapy, and radiofrequency ablation. Surgery is suitable for a small group of patients with solitary liver metastasis who are surgical candidates. It was found that resection of solitary liver metastasis is the best treatment to improve 5-year survival, which reaches 33% with a median survival of 10–17 months [6]. However, in a retrospective study of 201 patients with uveal melanoma metastatic to the liver who were treated between 1968 and 1991 [5], it was found that the type of therapy did not significantly alter the survival rate. Treatment included systemic chemotherapy, hepatic artery chemotherapy, and hepatic artery chemoembolization or bland embolization. Immunotherapy is a new experimental treatment technique that uses biologic response modifiers such as interferon and interleukin-2. As opposed to radiofrequency ablation, immunotherapy has the advantage of treating the entire liver.
The patient in our report had a recurrent solitary liver metastasis 3 years after resection of metastases together with intraarterial chemotherapy. She was not considered a suitable candidate for repeat surgery. The combination of high surgical risk and poor prognosis led to a decision to treat the patient with radiofrequency ablation. Because of the increased risk of thermal injury to the already strictured bile ducts, chilled saline was constantly infused during the procedure through a nasobiliary tube. We theorized that the infusion might create a pseudo "heat sink" effect [7] resulting in protection of the wall of the bile duct by causing heat loss at the margin of the ablation zone to the liquid "flowing" at a lower temperature in the adjacent bile duct. It might also result in a reduced tumor response in the area of the duct wall because of diminished heat deposition, although this does not appear to have occurred in other studies in which paranephric water instillation or intraperitoneal saline infusion was performed to protect adjacent structures from thermal injury [8, 9]. Dominique et al. [3] described a similar technique for intraoperative cooling of the biliary tree by introducing a catheter via an incision in the common bile duct. The procedure was successfully performed in three patients who each had a tumor located near the hepatic hilum.
Our decision to use isotonic saline is controversial because of a report by Goldberg et al. [10] who showed that injection of saline in the ablation zone may increase the coagulation of normal liver tissue in an unpredictable manner in an animal model. Conversely, no such effect was mentioned in a report by Ohmoto et al. [9], who used saline infusion in a patient with a hepatoma in the hepatic dome. To our knowledge, ours is the first report of cooling of the bile ducts during percutaneous radiofrequency ablation by using a nasobiliary tube. No procedure-related complications occurred, a complete local tumor response was seen, and there was no evidence of bile duct injury at the 16-month follow-up.
Thermal injury of structures adjacent to the ablation zone (gallbladder, bile ducts, and gastrointestinal tract) is a complication unique to radiofrequency ablation. In a recent report [1] of the experience at 41 Italian centers that included 2,320 patients with either hepatocellular carcinoma or liver metastases, thermal injury to the biliary tree was uncommon but led to at least one fatality and significant morbidity. Thermal injury of the bile ducts can lead to delayed stenosis and biloma formation. Dilatation of small, peripheral ducts distal to a treated tumor is a common incidental observation after radiofrequency ablation and does not result in any meaningful complication. However, stricture of the main biliary ducts is a major complication that may cause recurrent cholangitis and significant morbidity. Recent reports have suggested that a biliary–enteric communication, such as hepaticojejunostomy, may increase the risk of major infectious complications after percutaneous ablation therapies of liver tumors [11]. In this case, the presence of an endobiliary stent was considered to be equivalent to a biliary enterostomy, thereby increasing the risk of infectious complications after radiofrequency ablation. For this reason, the patient was given a full course of broad-spectrum antibiotics for therapy.
Some researchers have recommended that radiofrequency ablation not be performed in tumors located near the hepatic hilum [1]. Cooling the biliary ducts by infusing chilled saline through a nasobiliary tube may facilitate the treatment of lesions in close proximity to the hepatic hilum by percutaneous radiofrequency ablation. Further research is necessary to validate the technique and define the ideal fluid for bile duct irrigation.
References
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This article has been cited by other articles:
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  T. Hiraki, K. Yasui, H. Mimura, H. Gobara, T. Mukai, S. Hase, H. Fujiwara, N. Tajiri, Y. Naomoto, T. Yamatsuji, et al. Radiofrequency Ablation of Metastatic Mediastinal Lymph Nodes during Cooling and Temperature Monitoring of the Tracheal Mucosa to Prevent Thermal Tracheal Damage: Initial Experience Radiology, December 1, 2005; 237(3): 1068 - 1074. [Abstract] [Full Text] [PDF]
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 P. F. Laeseke, L. A. Sampson, T. C. Winter III, and F. T. Lee Jr. Use of Dextrose 5% in Water Instead of Saline to Protect Against Inadvertent Radiofrequency Injuries Am. J. Roentgenol., March 1, 2005; 184(3): 1026 - 1027. [Full Text] [PDF]
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