Open Radiofrequency Ablation Research Articles

Clinical study on safety of radiofrequency ablation for advanced pancreatic cancer

Objectives To evaluate the safety of radiofrequency ablation (RFA) for unresectable advanced pancreatic cancer. Methods During January 2002 to December 2007, seventy patients with advanced pancreatic cancer were treated by open cool-tip RFA. Clinical records of complications were retrospectively studied. Results Temporary fever occurred in all patients, and transient elevated blood amylase occurred in part of patients, and no celiac bleeding, no celiac abscess, no acute severe pancreatitis. The incidence of post-operation complications was 5.71% (4/70), and the mortality was 2.86 % (2/70). In the four cases, two were pancreatic leakage, one was upper gastrointestinal bleed-ing, and the other was vassular complication. Conclusions Radiofrequency ablation for advanced pan-creatic tumors is generally safe and feasible. However, it may cause severe and life-threatening compli-cations. The management of RFA must be prudent and careful. Key words: Pancreatic cancer; Radiofrequency ablation; Complication

Needle track seeding: A real hazard after percutaneous radiofrequency ablation for colorectal liver metastasis

Neoplastic needle track seeding following percutaneous radiofrequency ablation (RFA) of secondary liver tumors is exceedingly rare. Reports on cutaneous tumor seeding after percutaneous RFA for colorectal liver metastasis are even rarer in the literature. Here we report a case of a 46-year-old female who developed an ulcerating skin lesion along the needle track of a previous percutaneous RFA site around 6 mo after the procedure. The previous RFA was performed by the LeVeen needle for a secondary liver tumor from a primary rectal cancer. The diagnosis of secondary skin metastasis was confirmed by fine needle aspiration cytology. The lesion was successfully treated with wide local excision. We believe that tumor seeding after percutaneous RFA in our patient was possibly related to its unfavorable subcapsular location and the use of an expansion-type needle. Hence, prophylactic ablation of the needle track should be performed whenever possible. Otherwise, alternative routes of tumor ablation such as laparoscopic or open RFA should be considered.

A 5-year clinical experience with bipolar radiofrequency ablation for permanent atrial fibrillation concomitant to coronary artery bypass grafting and aortic valve surgery

This study analyses the 5-year results of permanent atrial fibrillation (pAF) bipolar radiofrequency (RF) ablation surgery concomitant to coronary artery bypass grafting (CABG) and/or aortic valve (AV) surgery. Eighty-five patients with pAF (0.5-30 years) underwent bipolar RF ablation procedure concomitant to CABG/AV surgery. All patients were restudied to assess survival, conversion rate to stable sinus rhythm (SR) and New York Heart Association (NYHA) class at 8+/-1 days and at 3+/-1 and 32+/-15 months after surgery. Survival at time of re-examination was 100%, 98% and 96%, respectively (three non-cardiac deaths), SR could be documented in 61%, 74% and 78% of patients. Long-term AF before surgery and larger size of the left atrium (LA) were predictive for postoperative AF return (P=0.005, P=0.03); 88% of patients with small preoperative LA-size (<50 mm) and 85% with pAF-duration time <5 years had stable SR at late follow-up. Cardiac rhythm at three months was predictive for long-term rhythm-prognosis (P<0.0001). NYHA-class improved significantly after surgery (P<0.0005), particularly when SR was achieved (P=0.046). Permanent AF bipolar RF ablation surgery revealed excellent results in AV/CABG patients. It could be demonstrated that established SR remained stable over time. Preoperative pAF-duration time and LA-size are useful variables to predict the success rate of ablation.

Evaluation of an online navigation system for laparoscopic interventions in a perfused ex vivo artificial tumor model of the liver

Background. Laparoscopic radiofrequency ablation (RFA) is a safe and effective method for tumor destruction in patients with unresectable liver tumors. However, accurate probe placement using laparoscopic ultrasound guidance is required to achieve complete tumor ablation. After evaluation of an ultrasound navigation system for transcutaneous and open RFA, we now intend to tranfer this technique to laparoscopic liver surgery. This study aimed to evaluate an electromagnetic navigation system for laparoscopic interventions using a perfusable ex vivo artificial tumor model. Materials and methods. First a special adapter was developed to attach the ultrasound and electromagnetic tracking-based navigation system to a laparoscopic ultrasound probe. The laparoscopic online navigation system was studied in a laparoscopic artificial tumor model using perfused porcine livers. Artificial tumors were created by injection of a mixture of 3% agarose, 3% cellulose, and 7% glycerol, creating hyperechoic lesions in ultrasound. Results. This study showed that laparoscopic ultrasound-guided navigation is technically feasible. Even in cases of angulation of the ultrasound probe no disturbances of the navigation system could be detected. Artificial tumors were clearly visible on laparoscopic ultrasound and not felt during placement of the RFA probe. Anatomic landmarks and simulated ‘tumors’ in the liver could be reached safely. Discussion. Laparoscopic RFA requires advanced laparoscopic ultrasound skills for accurate placement of the RFA probe. The use of an ultrasound-based, laparoscopic online navigation system offers the possibility of out-of-plane needle placement and could increase the safety and accuracy of punctures. The perfused artificial tumor model presented a realistic model for the evaluation of this new technique.

Morbidity and mortality of laparoscopic vs. open radiofrequency ablation for hepatic malignancies

Aims Surgical radiofrequency ablation (RFA) of hepatic malignancies is associated with superior oncological outcome as compared to percutaneous RFA. The aim of this prospective non-randomized cohort study was to compare morbidity and mortality of laparoscopic (LRFA) vs. open (ORFA) radiofrequency ablation of liver cancer. Methods Between October 1999 and November 2006, RFA was performed in 154 consecutive patients (percutaneous 12, LRFA 93, ORFA 49) for a total of 291 hepatic tumours (HCC 81, colorectal metastases 157, other 53). Seventy-four patients simultaneously underwent additional surgery. Laparoscopic RFA was performed in 45/54 patients with HCC, and in 44/54 patients with cirrhosis. Laparotomy was performed in 14/22 patients who underwent simultaneous colorectal resection, and in 12/22 patients with hepatic resection. Results Postoperative complications occurred in 25 patients with subsequent mortality in 2. As compared with LRFA, ORFA was associated with significantly ( p < 0.01) higher intra-operative blood loss (median 20 (range 0–1700) vs. 10 (0–900) ml), longer duration of surgery (180 (25–440) vs. 75 (30–390) min), more postoperative complications (17 vs. 8), and longer postoperative hospital stay (8 (1–127) vs. 4 (1–51) d). According to the therapy-oriented severity grading system (TOSGS) classification, postoperative complications in the ORFA-group were more severe than those in the LRFA-group ( p < 0.01). These findings were consistent in patients without simultaneous colorectal and/or hepatic resection and in patients with liver tumours measuring 3 cm or less. In univariate analysis the following factors were significantly ( p < 0.01) related to the presence of postoperative complications: simultaneous colorectal resection, laparotomy, duration of surgery, tumour location in right liver, liver segment 7 ( p = 0.01), absence of cirrhosis ( p = 0.02), liver segment 8 ( p = 0.03), and metastatic liver cancer ( p = 0.04). Conclusion LRFA for hepatic malignancies seems preferable above ORFA, provided good patient selection, surgical expertise, and long-term oncological control.

High operative risk of cool‐tip radiofrequency ablation for unresectable pancreatic head cancer

To report and discuss the effect, complications and mortality of cool-tip radiofrequency ablation (RFA) for unresectable pancreatic cancer. During October 2003 to July 2004, sixteen patients with unresectable pancreatic cancer were treated by open cool-tip RFA. One-half of the 16 patients had tumors located in the pancreatic head. A 5-mm minimum safe distance between RFA site and major peripancreatic vessels was kept to avoid injury to the vessels. Six of twelve patients with back pain got pain relief postoperatively. Pancreatic fistula occurred in three patients (18.8%) and healed smoothly in 7-10 days with routine abdominal drainage. The mortality was 25% (4/16). In the four death cases, tumors were all located in the pancreatic head; three patients with tumor close to portal vein died suddenly of massive gastrointestinal hemorrhage on the 4th, 30th, 40th postoperative day respectively and a 79-year-old patient died of acute renal failure on the 2nd postoperative day. Standard use of cool-tip RFA was dangerous for pancreatic head cancer close to portal vein, in which a 5-mm minimum safe distance between RFA site and major peripancreatic vessels might not be enough to avoid injury to the vessels.

Results of a Single-Center Experience With Resection and Ablation for Sarcoma Metastatic to the Liver

A subset of patients with sarcoma liver metastasis may benefit from hepatic resection and/or ablation. Retrospective review of prospectively collected cancer center database records. Sixty-six patients who underwent hepatic resection and/or open radiofrequency ablation of metastatic sarcoma between July 1, 1996, and April 30, 2005, were identified from the database. Clinicopathologic, operative, recurrence, and long-term survival data were analyzed. The primary sarcoma site was the abdomen or retroperitoneum (n = 22), stomach (n = 18), small or large bowel (n = 17), pelvis (n = 4), uterus (n = 3), or other (n = 2). Tumor pathologic types included gastrointestinal stromal tumor (n = 36), leiomyosarcoma (n = 18), and sarcoma not otherwise classified (n = 12). Thirty-five patients underwent resection, 18 underwent resection plus radiofrequency ablation, and 13 underwent radiofrequency ablation only. With a median follow-up of 35.8 months, 44 patients (66.7%) had recurrence (intrahepatic only, n = 16; extrahepatic only, n = 11; both, n = 17). Treatment with radiofrequency ablation (either alone or combined with resection) (P = .002) and lack of adjuvant chemotherapy (P = .01) predicted shorter disease-free survival. The 1-, 3-, and 5-year overall survival rates were 91.2%, 65.4%, and 27.1%, respectively. Patients with gastrointestinal stromal tumor who were treated with adjuvant imatinib mesylate had the longest median survival (not reached) (P = .003). Long-term survival can be achieved following surgical treatment of sarcoma liver metastasis, especially in patients with gastrointestinal stromal tumor. Patients with sarcoma liver metastasis should be evaluated by a multidisciplinary team, as recurrence is common and adjuvant therapy may prolong survival.

Factors Influencing the Local Failure Rate of Radiofrequency Ablation of Colorectal Liver Metastases

The prognosis of patients with colorectal cancer is poor, especially when there is distant metastatic disease. Local ablation of tumor by radiofrequency ablation (RFA) has emerged as a safe and effective new treatment modality, but its long-term efficacy may be hindered by renewed local tumor growth at the site of RFA. The objectives of this study were to identify risk factors for local RFA failure and to define exclusion criteria for RFA treatment of colorectal liver metastases. A total of 199 lesions in 87 patients were ablated with RFA. Factors influencing local failure rates were identified and compared with data from the literature. The local failure rate was 47.2%, and the average time to local disease progression was 6.5 months. Factors that significantly correlated with increased failure rates were metachronous occurrence of liver metastases, large mean lesion size, and central tumor location. Because accurate electrode placement is pivotal in achieving adequate tumor necrosis, RFA should not be performed percutaneously when electrode placement is impaired. We suggest that lesions >5 cm and lesions located near great vessels or adjacent organs should be treated with open RFA, thus allowing vascular inflow occlusion and complete mobilization of the liver. Lesions that are difficult to reach by electrodes should be approached by an open procedure.

Clinical evaluation of radiofrequency ablation therapy in patients with hepatic cavernous hemangiomas

To evaluate the feasibility, safety and efficacy of radiofrequency ablation (RFA) therapy in patients with hepatic cavernous hemangioma (HCH) and investigate its optimal operative approach. Between March 2001 and June 2004, a total of 68 patients, 18 males and 50 females, age 43.1 (30-64), with 104 HCHs 2.5-11 cm in diameter with the mean size of 5.6 cm, were treated by ultrasound-guided RFA, via percutaneous (n = 19), laparoscopic (n = 29), or open surgical (n = 20) approach. In 7 patients with hepatic lesions larger than 7 cm in diameter, Pringle maneuver was used to occlude the hepatic blood flow during the laparoscopic and open RFA therapy. All patients were followed up with helical computed tomographic (CT) scans and ultrasonography for 19 months (6-36 months). Additional intrahepatic lesions not detected preoperatively were found in 2 patients (with 2 new lesions) via laparoscopy and 3 patients (with 4 new lesions) via celiotomy. All patients were treated with RFA successfully. The mean blood loss in the Pringle group (90.0 ml +/- 22.4 ml) was significantly fewer than that in the non-Pringle group (249 ml +/- 56 ml) (P < 0.01). The mean RFA time per lesion in the Pringle group (29.0 min +/- 7.5 min) was shorter markedly compared to the non-Pringle group (55.4 min +/- 12.4 min) (P < 0.01). In the laparoscopic RFA group, laparoscopic cholecystectomy was performed simultaneously in 15 patients with chronic calculous cholecystitis and in another 2 patients because of tumors abutting the gallbladders, and laparoscopic fenestration with intraperitoneal drainage was performed in 3 patients with simple hepatic cysts. In the open RFA group, cholecystectomy was performed in 5 patients with gallbladder diseases, partial cystectomy was performed in one patient with a hepatic cyst, and choledochotomy was performed in 3 patients with common bile duct stones. Postoperative fever and abnormal serum transaminase (ALT and AST) levels were observed in 29 patients (42.6%). A transient hematuria occurred in one patient after open RFA. No specific complications developed during or after RFA. The follow-up showed a complete lesion necrosis rate of 99% (103/104). One patient showed an incomplete lesion necrosis in the margin of RFA site 6 months after percutaneous RFA therapy and obtained retreatment with percutaneous RFA. RFA therapy is a safe, feasible and effective treatment options for patients with HCHs. This procedure can be performed via percutaneous, laparoscopic, or open approach. To prevent the RFA-related complications and to increase the therapeutic efficacy of RFA, the choice of optimal operative approach should be based on the lesion size, number, and location and on the patient's clinical status. Hepatic inflow occlusion by Pringle maneuver during laparoscopic or open RFA therapy can reduce the blood loss and increase the therapeutic efficacy significantly.

Significant Long-Term Survival After Radiofrequency Ablation of Unresectable Hepatocellular Carcinoma in Patients with Cirrhosis

Radiofrequency ablation (RFA) offers an alternative treatment in some unresectable hepatocellular carcinoma (HCC) patients with disease confined to the liver. We prospectively evaluated survival rates in patients with early-stage, unresectable HCC treated with RFA. All patients with HCC treated with RFA between September 1, 1997, and July 31, 2002, were prospectively evaluated. Patients were treated with RFA by using a percutaneous or open intraoperative approach with ultrasound guidance and were evaluated at regular intervals to determine disease recurrence and survival. A total of 194 patients (153 men [79%] and 41 women [21%]) with a median age of 66 years (range, 39-86 years) underwent RFA of 289 sonographically detectable HCC tumors. All patients were followed up for at least 12 months (median follow-up, 34.8 months). Percutaneous and open intraoperative RFA was performed in 140 (72%) and 54 (28%) patients, respectively. The median diameter of tumors treated with RFA was 3.3 cm. Disease recurred in 103 (53%) of 194 patients, including 69 (49%) of 140 patients treated percutaneously and 34 (63%) of 54 treated with open RFA (not significant). Local recurrence developed in nine patients (4.6%). Most recurrence was intrahepatic. The overall complication rate was 12%. Overall survival rates at 1, 3, and 5 years for all 194 patients were 84.5%, 68.1%, and 55.4%, respectively. Treatment with RFA can produce significant long-term survival rates for cirrhotic patients with early-stage, unresectable HCC. RFA can be performed in these patients with relatively low complication rates. Confirmation of these results in randomized trials should be considered.

Open Radiofrequency Ablation for the Management of Intractable Epilepsy Associated with Sessile Hypothalamic Hamartoma

Sessile hypothalamic hamartoma (HH) often causes intractable epilepsy, which is difficult to control even by microsurgical resection and gamma knife surgery (GKS), especially when the hamartoma is intrahypothalamic, large, or irregularly shaped. We successfully applied radiofrequency ablation (RFA) to reduce its epileptogenicity and to disconnect seizure propagation. The patient was a 26-year-old man who presented with refractory epilepsy and severe mental retardation from age 6 months. He had undergone three surgeries yielding partial resection and conventional irradiation treatments. The residual HH was thin and shaped like a bent plate, attached widely to the floor of the third ventricle. He underwent open RFA via the transcallosal sub-choroidal approach under strict image guidance, which resulted in immediate and remarkable seizure remission without complications. This suggests that open RFA is a minimally invasive technique for an irregularly shaped HH that is difficult to treat by other modalities.

Radiofrequency ablation for the treatment of non–small cell lung cancer in marginal surgical candidates

Treatment options for patients with non-small cell lung cancer who are not surgical candidates or who refuse operation are limited. Radiofrequency ablation represents a potential less invasive option for these patients. Our initial experience with radiofrequency ablation for peripheral, primary non-small cell lung cancer is reported. We treated 21 tumors in 18 patients. Median age was 75 (range 58-86) years. Cancer stages were I (n = 9), II (n = 2), III (n = 3), and IV (n = 4). Patients with stage IV disease included 3 with recurrence after previous lobectomies and 1 with a synchronous liver metastasis also treated with radiofrequency ablation. Median tumor diameter was 2.8 cm (range 1.2-4.5 cm). Radiofrequency ablation was delivered by minithoracotomy in 2 cases and by a computed tomography-guided percutaneous approach in 16 patients. Computed tomographic and positron emission tomographic scans were used to evaluate recurrence and radiographic response in ablated nodules. One postoperative death occurred from pneumonia after open radiofrequency ablation. Median hospital stay was 2.5 days. A chest tube or pigtail catheter was required in 7 patients (38.9%) for procedure-related pneumothoraces. At a median follow-up of 14 months, 15 patients (83.3%) were alive. Local progression occurred in 8 nodules (38.1%). Mean and median progression-free intervals were 16.8 and 18 months, respectively. For stage I cancers, mean progression-free interval was 17.6 months. Median progression-free interval was not reached. This study demonstrates the feasibility of radiofrequency ablation for small, peripheral non-small cell lung cancer tumors. Local control is comparable to, if not better than, that provided by radiotherapy. Radiofrequency ablation should continue to be evaluated by thoracic surgeons as a noninvasive therapy for the high-risk patient with non-small cell lung cancer.

Three years experience with monopolar and bipolar radiofrequency ablation surgery in patients with permanent atrial fibrillation☆

In our population permanent atrial fibrillation (pAF) is a frequent concomitant problem in patients undergoing open heart surgery. A 3-year experience with a treatment strategy using mono- and bipolar radiofrequency (RF) ablation procedures in a heterogeneous group of patients is reported. In a prospective analysis the incidence of pAF among all patients undergoing open heart surgery in our department between February 2001 and July 2004 was evaluated. In a second step a selective group of 106 patients with pAF (primary mitral: n=63; aortic: n=24; CABG: n=16; aortic+mitral: n=3) underwent either monopolar (n=86) or bipolar (n=20) RF ablation procedures creating two encircling isolation lesions around the left and the right pulmonary veins (PVs) and a connection line between both. In addition amiodarone was given for 3 months after surgery. Regular follow-ups were performed 3, 6, 9, 12, 18, 24 and 36 months after surgery. The incidence of pAF in the total group of 4.110 patients was 3.6%. While the rate was low in cases without severe heart valve disease (1.1%), a significantly higher presence of pAF in patients scheduled for heart valve surgery (10.3%) was observed (P<0.0001). The incidence was 30-39% in patients with degenerative and rheumatic mitral valve (MV) disease, and further particularly high in the older aged compared to younger patients (4.2-8.3% at 70-99 years; P<0.001). Hospital mortality after combined open heart and RF ablation surgery was 1.9%. Whereas patients with small left atrial size (LA-diameters <56 mm; n=59) had SR in almost 90% at follow-up, LA enlargement (LA-diameter > or =56 mm; n=47) was associated with a significant risk of persisting pAF after surgery (P=0.033, 0.002 and 0.006 at 3, 6 and 9 months follow-up). The use of RF ablation procedures in combination with amiodarone therapy represents a safe and efficient option to cure pAF during open heart surgery in a selective group of patients. The preoperative LA size was of significant importance for the outcome in this investigation.

Atrial fibrillation ablation surgery in patients with advanced age: A 3-year clinical experience with mono- and bipolar radiofrequency ablation surgery

Atrial fibrillation ablation surgery in patients with advanced age: A 3-year clinical experience with mono- and bipolar radiofrequency ablation surgery

Permanent atrial fibrillation ablation surgery in CABG and aortic valve patients is at least as effective as in mitral valve disease: A 3-year experience with mono- and bipolar radiofrequency ablation surgery

Objectives: Permanent atrial fibrillation (pAF) is a serious concomitant problem in patients undergoing open heart surgery (Table 1). In contrast to mitral valve (MV) surgery, concomitant pAF ablation is not routinely performed in non-MV patients, e.g. CABG and aortic valve replacement (AVR). In this study the conversion rate to stable sinus rhythm (SR) after ablation in CABG and/or AVR cases, compared to MV surgery was evaluated.

Clinical short-term results of radiofrequency ablation in patients with liver metastases from colorectal cancer

The aim of this study was to examine the therapeutic efficacy of radiofrequency tumour ablation in patients with liver metastases from colorectal cancer who are not suitable for hepatic resection. Between April 2002 and January 2004, 18 patients underwent open radiofrequency ablation (RFA) for colorectal liver metastases. Median lesion size was 5.6 cm (range 3.0-8.0 cm). Patient's follow-up included ultrasound and computed tomography imaging at 3, 6 and 18 months postoperatively. Mean total procedure time was 86 min. The average hospital stay was 5 days. There was no treatment-related mortality. Twelve patients (66.7%) experienced mild right hypochondrium discomfort for 3 days and 6 patients (33.4%) low-grade fever for 4 days. Four patients died within 12 months with extrahepatic disease. In 4 patients lesions increased in size or new lesions developed, 7 patients are alive, symptom-free, with stable disease and 4 patients are free of disease. RFA is a safe, well tolerated procedure for the treatment of unresectable colorectal liver metastases.

Monopolar and Bipolar Radiofrequency Ablation Surgery: 3-Year Experience in 90 Patients with Permanent Atrial Fibrillation

In our population, permanent atrial fibrillation (pAF) is a serious concomitant problem in patients scheduled for open heart surgery. The high incidence necessitates reliable methods of treating pAF efficiently. We report our 3-year experience with a safe concept of using monopolar and bipolar radiofrequency (RF) ablation procedures. Ninety patients (mitral, n = 56; aortic, n = 22; aortic and mitral, n = 1; coronary artery bypass grafting, n = 11) underwent either monopolar (n = 77) or, recently, bipolar (n = 13) RF ablation procedures that produced encircling isolation lesions around the left and the right pulmonary veins (PVs) and a connection line between the two. Amiodarone was given for 3 months after surgery. Hospital mortality was 2.2%. At follow-up, 75% of the patients were in stable sinus rhythm (SR). Preoperative pAF duration, etiology of heart disease, and type of RF energy application were not predictive of the risk of persisting pAF after surgery. Whereas patients (50 of 90) with small preoperative left atrial (LA) diameters (<56 mm) had SR in almost 90% of cases, large preoperative LA diameters (>or=56 mm; 40 of 90 patients) were associated with a significant risk of persisting pAF (P < .05). Particularly in cases of small preoperative LA diameters, isolation of the PVs using either monopolar or bipolar RF ablation procedures in combination with amiodarone therapy represents a safe and efficient option for curing pAF in patients undergoing open heart surgery.

THE RADIOGRAPHIC EVOLUTION OF RADIO FREQUENCY ABLATED RENAL TUMORS

Radio frequency ablation (RFA) of renal tumors is a relatively new technology. Few groups are familiar with the posttreatment appearance of these lesions and how they differ from cryoablated renal masses. We describe the evolution of the appearance of these lesions on followup contrast enhanced (CE) computerized tomography (CT). A total of 64 consecutive renal tumors treated with RFA from April 2000 to September 2003 for which posttreatment CE-CT was done were included in this study. CE-CT was reviewed at 6 weeks, 3 months, 6 months and every 6 months thereafter to determine the characteristic features and evolution of these lesions. Renal tumors were treated with CT guided percutaneous (34), laparoscopic (28) or open (2) RFA. At a median followup of 13.7 months (range 6 weeks to 29 months) 62 RFA lesions demonstrated an absence of contrast enhancement on CE-CT. Treated endophytic tumors developed a low density, nonenhancing, wedge-shaped defect with fat infiltration seen between the ablated tissue and normal parenchyma. Treated exophytic tumors retained a configuration similar to that of the original with a lack of contrast enhancement and minimal shrinkage. Percutaneous treated lesions developed a peritumor scar or halo that demarcated ablated and nonablated tissue (perirenal fat). Persistent tumor was marked by contrast enhancement within the ablation borders of the original mass in 1 case, whereas tumor recurred after initial successful ablation with an enhancing nodule in 1. The radiographic features and evolution of radio frequency ablated renal tumors are unique. Successfully treated tumors demonstrated no contrast enhancement, minimal shrinkage and occasional retraction from normal parenchyma by fat infiltration.

Saline infusion markedly reduces impedance and improves efficacy of pulmonary radiofrequency ablation.

Radiofrequency ablation (RFA) is a relatively new technique that has been investigated for the treatment of lung tumors. We evaluated for the first time the in vivo use of saline infusion during radiofrequency ablation of sheep lung. We performed RFA on 5 sheep using open and closed chest RFA and the RITA starburst XL and Xli probes using saline infusion with the Xli probe. The impedance and volume of ablation were compared. A total of 16 ablations were produced, 5 percutaneously and 11 open. The impedance during percutaneous and open RFA without saline infusion was 110 +/- 16.2 and 183.3 +/- 105.8 ohms, respectively. With the saline infusion the impedance was 71.3 +/- 22 ohms and 103.6 +/- 37.5 ohms. The effect of this was significantly larger volume of ablation using the saline infusion during percutaneous RFA (90.6 +/- 23 cm3 vs 10.47 +/- 2.9 cm3, p = 0.01) and open RFA (107.8 +/- 25.8 cm3 vs 24.9 +/- 19.3 cm3, p = 0.0002). Saline infusion during RFA is associated with lower impedance, higher power delivery and larger lesion size.

Early and late complications after radiofrequency ablation of malignant liver tumors in 608 patients.

Radiofrequency ablation (RFA) has become a common treatment of patients with unresectable primary and secondary hepatic malignancies. We performed this prospective analysis to determine early (within 30 days) and late (more than 30 days after) complication rates associated with hepatic tumor RFA. All patients treated between January 1, 1996 and June 30, 2002 with RFA for hepatic malignancies were entered into a prospective database. Patients were evaluated during RFA treatment, throughout the immediate post RFA course, and then every 3 months after RFA to assess for the development of treatment-related complications. A total of 608 patients, 345 men (56.7%) and 263 women (43.3%), with a median age of 58 years (range 18-85 years) underwent RFA of 1225 malignant liver tumors. Open intraoperative RFA was performed in 382 patients (62.8%), while percutaneous RFA was performed in 226 (37.2%). The treatment-related mortality rate was 0.5%. Early complications developed in 43 patients (7.1%). Early complications were more likely to occur in patients treated with open RFA (33 [8.6%] of 382 patients) compared with percutaneous RFA (10 [4.4%] 226 patients, P < 0.01), and in patients with cirrhosis (25 [12.9%] complications in 194 patients) compared with noncirrhotic patients (31 [7.5%] complications in 414 patients, P < 0.05). Late complications arose in 15 patients (2.4%) with no difference in incidence between open and percutaneous RFA treatment. The combined overall early and late complication rate was 9.5%. Hepatic tumor RFA can be performed with low mortality and morbidity rates. Though relatively rare, late complications can develop and physicians performing hepatic RFA must be cognizant of these delayed treatment-related problems.