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Image-guided targeted radiofrequency ablation (t-RFA) of spinal tumors using a novel bipolar navigational device: multicenter initial clinical experience
MONDAY: Scientific Sessions
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Monday
Scientific Session
the 1, 2 and 3-year DFS rates were 70%, 41.7% and 37.9% respectively. 29.3% (12/41) of patients were successfully bridged to liver transplant. In TACE-MWA group the 1, 2 and 3-year OS rates were 86.0% (49/57), 73.8% (42/57) and 58.9% (34/57) respectively, and the 1, 2 and 3-year DFS rates were 54.4% , 30.9% and 23.3% respectively. 15.8% (9/57) of patients were successfully bridged to liver transplant. No statistically significant difference in the OS (p¼0.31) and overall DFS (p¼0.08) between TACE-RFA versus TACE-MWA was observed. However, when controlling for tumor size, the RFA cohort had 43% improved DFS compared to MWA cohort (p¼0.033). Univariate and Cox regression analyses indicated that tumor size was unfavorable prognostic factors for OS (po0.001), and DFS (p¼0.015). There were no major complications in both treatment groups. Conclusion: The combined procedures of TACE and percutaneous thermal ablation (MWA and RFA) are both safe and effective for treatment of HCC. While no statistically significant differences in both overall survival and overall disease free survival were observed between the two cohorts, when controlling for tumor size the RFA cohort had a 43% improved disease free survival compared to MWA cohort.
1:46 PM
Abstract No. 83
Radiofrequency (RF) ablation of normal liver increases tumor growth of remote subcutaneous tumors in an animal tumor model M. Ahmed1, G. Kumar1, M. Moussa1, N. Rozenblum2, S. Goldberg1,2; 1Section of Interventional Radiology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA; 2Department of Radiology, Hadassah Hebrew Medical Center, Hadassah, Israel Purpose: To characterize the effect of radiofrequency (RFA) ablation of normal liver on tumor growth of remote tumors. Materials and Methods: R3230 breast tumors were subcutaneously implanted into female Fisher rats (n¼14). When tumors reached 10mm in diameter, animals were randomized (n¼7/arm) to either receive RF to normal liver (21g electrode, 1 cm active tip, standardized to tip temperature of 701C x 5 min via exploratory laparotomy) or to the control group (sham treatment, with needle placement in liver but no RFA). Tumor growth was measured for 7d after treatment, followed by animal sacrifice and tumor harvest to enable immunohistochemistry for proliferative index calculations (% cells positive for Ki-67 staining). Tumor growth curves before and after treatment were also analyzed. Results: While tumors in RFA and sham groups were the same size at the time of treatment (11.0⫾0.7mm vs. 11.3⫾0.3mm, p¼0.48), a significantly greater tumor growth rate was observed in the RFA group such that tumors were significantly larger at 7d compared to sham-treated animals (17.0⫾2.1mm vs. 13.2⫾0.8, p¼0.02), representing an increase in tumor size by 34.8⫾0.1% vs. 13.7⫾0.1% (po0.001). Additionally, subcutaneous tumors at 7d post-RFA demonstrated significantly greater cellular proliferation (Ki-67 % cell positivity) compared to sham treatment (82.7⫾4.5% vs. 25.0⫾3.0%, po0.001). Finally, RFA of normal liver significantly increased the rate of subcutaneous tumor growth compared to before treatment (pre-RFA slope: 0.51⫾0.14, R2¼0.91⫾0.06 vs. post-RFA slope: 0.83⫾0.27, R2¼0.97⫾0.02, p¼0.018) and compared to the growth rate after sham treatment (post-sham slope: 0.32⫾0.13, R2¼0.92⫾0.06, po0.001).
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JVIR
Conclusion: Although RF ablation of normal liver is necessary to achieve an ablative margin, it can stimulate the growth of tumors remote from the ablation site and external to the treated organ in at least one animal model. Additional studies are required to confirm these findings in other tumor types and clinical scenarios and to assess whether this potentially deleterious acceleration of tumor growth can be reversed through pharmacologic therapy.
1:54 PM
Abstract No. 84
Retrospective analysis of percutaneous cryoablation of hepatocellular carcinoma (HCC) in liver J.R. Daniels1M. Katz2, M. Wallman1; 1Oncology, USC, Los Angeles, CA; 2Radiology, USC, Los Angeles, CA Purpose: Percutaneous cryoablation of hepatocellular carcinoma (HCC) was performed with the intention of comparing our experience with published outcomes for radiofrequency ablation (RFA). We hypothesized that our target recurrence rate for cryoablation would be equivalent or superior to RFA due to precise visualization of margins (iceball) during ablation. Materials and Methods: Cryoablation was used to treat 35 lesions in 27 patients with HCC limited to the liver. An average of 2.7 cryoprobes (range 1-5) achieved an estimated margin of at least 0.5 cm after two 10 minute freeze-thaw cycles to -401C. Initial patient and tumor characteristics, initial blood tests, treatment complications, tumor response and time to tumor failure, transplant or death were evaluated. Results: Response was evaluable in 23 patients. Complete response rate was 90.3% after initial treatment and 96.8% after one additional ablation for missed margin in 2 patients. There were no subsequent recurrences in any target lesion. Median follow-up for all patients is 678 days (range 15-1388). Four patients died within 54 days: 2 following intraperitoneal hemorrhage controlled with transarterial embolization, 1 from ischemic liver injury following a TIPS for hydrothorax, and 1 resulting from extra-hepatic abscess. Two patients had recurrent tumor near the ablation tract. Three additional patients had peritoneal hemorrhage not requiring treatment. Risk of bleeding was associated with ascites (P ¼ 0.0129) and albumin level (P¼0.0177). Conclusion: While excellent tumor control was achieved with cryoablation, morbidity and mortality limit use of cryoablation without technique and equipment modification to avoid hemorrhage and needle tract contamination with tumor.
2:02 PM
Abstract No. 85
Image-guided targeted radiofrequency ablation (t-RFA) of spinal tumors using a novel bipolar navigational device: multicenter initial clinical experience J. Jennings1, W. Irving1, B. Georgy2, D. Coldwell3, B. Zablow4, C. DePena5, A. Brook6; 1Washington University, Saint Louis, MO; 2University of California San Diego, San Diego, CA; 3University of Louisville, Louisville, KY; 4Westchester Medical Center, Valhalla, NY; 5Iowa Methodist Medical Center, Des Moines, IA; 6 Montefiore Medical Center, New York, NY
JVIR
’
Scientific Session
Monday
2:10 PM
Abstract No. 86
Characterization of in vivo ablation cavities following percutaneous microwave ablation of the liver R. Winokur, B.B. Pua, A. Talenfeld, D. Madoff; Interventional Radiology, Weill Cornell Medical Center, New York, NY Purpose: Percutaneous microwave ablation is rapidly developing as a minimally invasive technique for treating patients with isolated malignancy in the liver. Currently, pre-procedure planning is relegated to utilization of ablation zones obtained from ex-vivo livers and porcine in vivo models. Recent data suggests that the performance in human tumors can be expected to be somewhere between the performance seen in ex vivo and in vivo normal porcine livers. The goal of the current study is to analyze the experience with microwave ablation in the liver to better estimate the ablation cavity. Materials and Methods: Percutaneous microwave ablations performed on the liver between June 2011 and October 2012 were included. Preprocedure and immediate postablation CT scans were analyzed. The ablation cavities were compared to necrosis tables published by HS Medical and Neuwave Medical. Results: Percutaneous microwave ablation was performed on 22 patients and 27 lesions between June 2011 and October. Fourteen
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patients were diagnosed with hepatocellular carcinoma, three with colorectal carcinoma metastasis, two with gastroesophageal carcinoma metastasis, one with renal cell carcinoma metastasis, one with lung carcinoma metastasis, and one with breast carcinoma metastasis. Four patients were treated with Neuwave Medical ablation probes and 18 patients were treated with HS Medical Amica probes. The size of the ablation cavity was found to be smaller than the reported values in ex vivo room temperature porcine livers regardless of primary diagnosis. The most frequently used settings for ablation was 60 watts for 10 minutes, which resulted in an average ablation cavity of 43.4 x 24.6 mm compared to reported values of 54 x 40 mm. Conclusion: Although necrosis tables were published by the manufacturers of percutaneous microwave ablation equipment, the values are based upon room temperature normal porcine livers, which are highly inaccurate for procedural planning in humans. This study shows that the ablation cavity in patients are smaller than the reported values. A more accurate estimate of ablation cavity size and geometry will allow for better procedural planning and more effective tumor ablation.
2:18 PM
Abstract No. 87
Combined radiofrequency (RF) ablation with nanodrug delivered doxorubicin: effect of liposome composition and ablation strategy on drug delivery and survival in an animal model A.V. Andriyanov1, E. Koren1, M. Ahmed2, Y. Barenholtz1, S. Goldberg1,2; 1Department of Radiology, Hadassah University Hospital, Jerusalem, Israel; 2Radiology, Beth Israel Deaconess Medical Center, Boston, MA Purpose: To determine whether liposomal nanodrug carrier construction and method of delivery influence intratumoral doxorubicin kinetics, tumor growth, and survival when combined with RF ablation. Materials and Methods: Two liposomal doxorubicin preparations: thermally sensitive liposomes (TSL) that rupture at 421C and long-circulating PEG-encapsulated liposomes (Doxil) that slowly accumulate within ablated tumors were prepared and administered at 8mg/kg doxorubicin. 36 Daoy meduloblastoma tumors (12⫾0.9mm) were randomized to 6 groups: (a) no treatment, (b) RF (701C tip, 3min) alone, (c) TSL alone, (d) TSL followed 15min later by RF (to enable maximal immediate doxorubicin deposition), (e) Doxil alone, and (f) RF followed 15min later by Doxil (settings shown to optimize long-term doxorubicin accumulation). Changes in tumor volumes were measured and Kaplan-Meier analysis of defined survival endpoint (time to reach 20mm in maximal dimension) was performed. An additional 18 animals were used to compare intratumoral doxorubicin deposition 15min and 24hr post RF ablation. Results: Whereas tumors treated with Doxil and RF decreased to 4.8⫾4.3% of their initial volume by day 50, the TSLþRF group reduced to 75.9⫾66.8% (po0.01). By contrast, all individual treatment groups progressively increased in tumor growth (104226% at day 50), albeit at a slower rate than controls (372% growth at 50 days; po0.01 ). Likewise, long circulating Doxil in combination with RF demonstrated the greatest endpoint survival (100% survival to 100 days), compared to TSLþRF (57% 100 day survival) or individual therapies alone (40-50% 100 day survival; po0.002 all stated comparison). Finally, although at 15min posttreatment greatest doxorubicin concentrations were seen following
MONDAY: Scientific Sessions
Purpose: Report initial clinical experience and determine the efficacy and safety of targeted radiofrequency ablation (t-RFA) of malignant spinal lesions using a novel bipolar RF ablation system. Demonstrate the use of temperature monitoring of thermocouples (TC) on an articulating electrode to determine ablation size and morphology with use of post-ablation magnetic resonance imaging (MRI) and comparison with pre-clinical thermal distribution curves. Materials and Methods: 101 spinal lesions in 73 procedures were treated at six centers. The STAR Tumor Ablation System includes a robust articulating, navigational bipolar electrode containing two active TCs positioned to permit real time monitoring of the peripheral edge of the ablation zone to determine size of ablation. Treatment was controlled by adjusting power while monitoring TC temperature in-situ. Access and number of ablations were based on lesion size, location and ability to articulate the bipolar electrode. Cement augmentation via the same guiding cannula was performed when required. In some cases, post-procedural MRI was performed. Pain was assessed pre- and postprocedurally. Results: Lesion etiology included a wide variety of metastatic lesions from T2 to S2 and ilium. No complications or thermal injury occurred. Cement augmentation following t-RFA was efficient and resulted in predictable cement filling. Postablation MRIs demonstrated discrete ablation zones with 3:2 length-towidth aspect ratio consistent in size with thermal monitoring by TCs during the ablation. All patients reported pain relief. Conclusion: The STAR device was safely and effectively used in the navigation and t-RFA of spinal malignant lesions. Postablation MRIs confirmed lesions were included in the ablation zone with necrosis of the lesion. The ablation zone was consistent in size with that measured by the TCs and similar in morphology to that extrapolated from thermal distribution curves. The STAR navigational ability allowed for easy access to posterior vertebral body lesions, previously difficult to access with other ablation devices. In many cases, this technique allowed for treatment of individual lesions not controlled by systemic or radiation therapy.
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S44
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Monday
Scientific Session
the 1, 2 and 3-year DFS rates were 70%, 41.7% and 37.9% respectively. 29.3% (12/41) of patients were successfully bridged to liver transplant. In TACE-MWA group the 1, 2 and 3-year OS rates were 86.0% (49/57), 73.8% (42/57) and 58.9% (34/57) respectively, and the 1, 2 and 3-year DFS rates were 54.4% , 30.9% and 23.3% respectively. 15.8% (9/57) of patients were successfully bridged to liver transplant. No statistically significant difference in the OS (p¼0.31) and overall DFS (p¼0.08) between TACE-RFA versus TACE-MWA was observed. However, when controlling for tumor size, the RFA cohort had 43% improved DFS compared to MWA cohort (p¼0.033). Univariate and Cox regression analyses indicated that tumor size was unfavorable prognostic factors for OS (po0.001), and DFS (p¼0.015). There were no major complications in both treatment groups. Conclusion: The combined procedures of TACE and percutaneous thermal ablation (MWA and RFA) are both safe and effective for treatment of HCC. While no statistically significant differences in both overall survival and overall disease free survival were observed between the two cohorts, when controlling for tumor size the RFA cohort had a 43% improved disease free survival compared to MWA cohort.
1:46 PM
Abstract No. 83
Radiofrequency (RF) ablation of normal liver increases tumor growth of remote subcutaneous tumors in an animal tumor model M. Ahmed1, G. Kumar1, M. Moussa1, N. Rozenblum2, S. Goldberg1,2; 1Section of Interventional Radiology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA; 2Department of Radiology, Hadassah Hebrew Medical Center, Hadassah, Israel Purpose: To characterize the effect of radiofrequency (RFA) ablation of normal liver on tumor growth of remote tumors. Materials and Methods: R3230 breast tumors were subcutaneously implanted into female Fisher rats (n¼14). When tumors reached 10mm in diameter, animals were randomized (n¼7/arm) to either receive RF to normal liver (21g electrode, 1 cm active tip, standardized to tip temperature of 701C x 5 min via exploratory laparotomy) or to the control group (sham treatment, with needle placement in liver but no RFA). Tumor growth was measured for 7d after treatment, followed by animal sacrifice and tumor harvest to enable immunohistochemistry for proliferative index calculations (% cells positive for Ki-67 staining). Tumor growth curves before and after treatment were also analyzed. Results: While tumors in RFA and sham groups were the same size at the time of treatment (11.0⫾0.7mm vs. 11.3⫾0.3mm, p¼0.48), a significantly greater tumor growth rate was observed in the RFA group such that tumors were significantly larger at 7d compared to sham-treated animals (17.0⫾2.1mm vs. 13.2⫾0.8, p¼0.02), representing an increase in tumor size by 34.8⫾0.1% vs. 13.7⫾0.1% (po0.001). Additionally, subcutaneous tumors at 7d post-RFA demonstrated significantly greater cellular proliferation (Ki-67 % cell positivity) compared to sham treatment (82.7⫾4.5% vs. 25.0⫾3.0%, po0.001). Finally, RFA of normal liver significantly increased the rate of subcutaneous tumor growth compared to before treatment (pre-RFA slope: 0.51⫾0.14, R2¼0.91⫾0.06 vs. post-RFA slope: 0.83⫾0.27, R2¼0.97⫾0.02, p¼0.018) and compared to the growth rate after sham treatment (post-sham slope: 0.32⫾0.13, R2¼0.92⫾0.06, po0.001).
’
JVIR
Conclusion: Although RF ablation of normal liver is necessary to achieve an ablative margin, it can stimulate the growth of tumors remote from the ablation site and external to the treated organ in at least one animal model. Additional studies are required to confirm these findings in other tumor types and clinical scenarios and to assess whether this potentially deleterious acceleration of tumor growth can be reversed through pharmacologic therapy.
1:54 PM
Abstract No. 84
Retrospective analysis of percutaneous cryoablation of hepatocellular carcinoma (HCC) in liver J.R. Daniels1M. Katz2, M. Wallman1; 1Oncology, USC, Los Angeles, CA; 2Radiology, USC, Los Angeles, CA Purpose: Percutaneous cryoablation of hepatocellular carcinoma (HCC) was performed with the intention of comparing our experience with published outcomes for radiofrequency ablation (RFA). We hypothesized that our target recurrence rate for cryoablation would be equivalent or superior to RFA due to precise visualization of margins (iceball) during ablation. Materials and Methods: Cryoablation was used to treat 35 lesions in 27 patients with HCC limited to the liver. An average of 2.7 cryoprobes (range 1-5) achieved an estimated margin of at least 0.5 cm after two 10 minute freeze-thaw cycles to -401C. Initial patient and tumor characteristics, initial blood tests, treatment complications, tumor response and time to tumor failure, transplant or death were evaluated. Results: Response was evaluable in 23 patients. Complete response rate was 90.3% after initial treatment and 96.8% after one additional ablation for missed margin in 2 patients. There were no subsequent recurrences in any target lesion. Median follow-up for all patients is 678 days (range 15-1388). Four patients died within 54 days: 2 following intraperitoneal hemorrhage controlled with transarterial embolization, 1 from ischemic liver injury following a TIPS for hydrothorax, and 1 resulting from extra-hepatic abscess. Two patients had recurrent tumor near the ablation tract. Three additional patients had peritoneal hemorrhage not requiring treatment. Risk of bleeding was associated with ascites (P ¼ 0.0129) and albumin level (P¼0.0177). Conclusion: While excellent tumor control was achieved with cryoablation, morbidity and mortality limit use of cryoablation without technique and equipment modification to avoid hemorrhage and needle tract contamination with tumor.
2:02 PM
Abstract No. 85
Image-guided targeted radiofrequency ablation (t-RFA) of spinal tumors using a novel bipolar navigational device: multicenter initial clinical experience J. Jennings1, W. Irving1, B. Georgy2, D. Coldwell3, B. Zablow4, C. DePena5, A. Brook6; 1Washington University, Saint Louis, MO; 2University of California San Diego, San Diego, CA; 3University of Louisville, Louisville, KY; 4Westchester Medical Center, Valhalla, NY; 5Iowa Methodist Medical Center, Des Moines, IA; 6 Montefiore Medical Center, New York, NY
JVIR
’
Scientific Session
Monday
2:10 PM
Abstract No. 86
Characterization of in vivo ablation cavities following percutaneous microwave ablation of the liver R. Winokur, B.B. Pua, A. Talenfeld, D. Madoff; Interventional Radiology, Weill Cornell Medical Center, New York, NY Purpose: Percutaneous microwave ablation is rapidly developing as a minimally invasive technique for treating patients with isolated malignancy in the liver. Currently, pre-procedure planning is relegated to utilization of ablation zones obtained from ex-vivo livers and porcine in vivo models. Recent data suggests that the performance in human tumors can be expected to be somewhere between the performance seen in ex vivo and in vivo normal porcine livers. The goal of the current study is to analyze the experience with microwave ablation in the liver to better estimate the ablation cavity. Materials and Methods: Percutaneous microwave ablations performed on the liver between June 2011 and October 2012 were included. Preprocedure and immediate postablation CT scans were analyzed. The ablation cavities were compared to necrosis tables published by HS Medical and Neuwave Medical. Results: Percutaneous microwave ablation was performed on 22 patients and 27 lesions between June 2011 and October. Fourteen
S45
patients were diagnosed with hepatocellular carcinoma, three with colorectal carcinoma metastasis, two with gastroesophageal carcinoma metastasis, one with renal cell carcinoma metastasis, one with lung carcinoma metastasis, and one with breast carcinoma metastasis. Four patients were treated with Neuwave Medical ablation probes and 18 patients were treated with HS Medical Amica probes. The size of the ablation cavity was found to be smaller than the reported values in ex vivo room temperature porcine livers regardless of primary diagnosis. The most frequently used settings for ablation was 60 watts for 10 minutes, which resulted in an average ablation cavity of 43.4 x 24.6 mm compared to reported values of 54 x 40 mm. Conclusion: Although necrosis tables were published by the manufacturers of percutaneous microwave ablation equipment, the values are based upon room temperature normal porcine livers, which are highly inaccurate for procedural planning in humans. This study shows that the ablation cavity in patients are smaller than the reported values. A more accurate estimate of ablation cavity size and geometry will allow for better procedural planning and more effective tumor ablation.
2:18 PM
Abstract No. 87
Combined radiofrequency (RF) ablation with nanodrug delivered doxorubicin: effect of liposome composition and ablation strategy on drug delivery and survival in an animal model A.V. Andriyanov1, E. Koren1, M. Ahmed2, Y. Barenholtz1, S. Goldberg1,2; 1Department of Radiology, Hadassah University Hospital, Jerusalem, Israel; 2Radiology, Beth Israel Deaconess Medical Center, Boston, MA Purpose: To determine whether liposomal nanodrug carrier construction and method of delivery influence intratumoral doxorubicin kinetics, tumor growth, and survival when combined with RF ablation. Materials and Methods: Two liposomal doxorubicin preparations: thermally sensitive liposomes (TSL) that rupture at 421C and long-circulating PEG-encapsulated liposomes (Doxil) that slowly accumulate within ablated tumors were prepared and administered at 8mg/kg doxorubicin. 36 Daoy meduloblastoma tumors (12⫾0.9mm) were randomized to 6 groups: (a) no treatment, (b) RF (701C tip, 3min) alone, (c) TSL alone, (d) TSL followed 15min later by RF (to enable maximal immediate doxorubicin deposition), (e) Doxil alone, and (f) RF followed 15min later by Doxil (settings shown to optimize long-term doxorubicin accumulation). Changes in tumor volumes were measured and Kaplan-Meier analysis of defined survival endpoint (time to reach 20mm in maximal dimension) was performed. An additional 18 animals were used to compare intratumoral doxorubicin deposition 15min and 24hr post RF ablation. Results: Whereas tumors treated with Doxil and RF decreased to 4.8⫾4.3% of their initial volume by day 50, the TSLþRF group reduced to 75.9⫾66.8% (po0.01). By contrast, all individual treatment groups progressively increased in tumor growth (104226% at day 50), albeit at a slower rate than controls (372% growth at 50 days; po0.01 ). Likewise, long circulating Doxil in combination with RF demonstrated the greatest endpoint survival (100% survival to 100 days), compared to TSLþRF (57% 100 day survival) or individual therapies alone (40-50% 100 day survival; po0.002 all stated comparison). Finally, although at 15min posttreatment greatest doxorubicin concentrations were seen following
MONDAY: Scientific Sessions
Purpose: Report initial clinical experience and determine the efficacy and safety of targeted radiofrequency ablation (t-RFA) of malignant spinal lesions using a novel bipolar RF ablation system. Demonstrate the use of temperature monitoring of thermocouples (TC) on an articulating electrode to determine ablation size and morphology with use of post-ablation magnetic resonance imaging (MRI) and comparison with pre-clinical thermal distribution curves. Materials and Methods: 101 spinal lesions in 73 procedures were treated at six centers. The STAR Tumor Ablation System includes a robust articulating, navigational bipolar electrode containing two active TCs positioned to permit real time monitoring of the peripheral edge of the ablation zone to determine size of ablation. Treatment was controlled by adjusting power while monitoring TC temperature in-situ. Access and number of ablations were based on lesion size, location and ability to articulate the bipolar electrode. Cement augmentation via the same guiding cannula was performed when required. In some cases, post-procedural MRI was performed. Pain was assessed pre- and postprocedurally. Results: Lesion etiology included a wide variety of metastatic lesions from T2 to S2 and ilium. No complications or thermal injury occurred. Cement augmentation following t-RFA was efficient and resulted in predictable cement filling. Postablation MRIs demonstrated discrete ablation zones with 3:2 length-towidth aspect ratio consistent in size with thermal monitoring by TCs during the ablation. All patients reported pain relief. Conclusion: The STAR device was safely and effectively used in the navigation and t-RFA of spinal malignant lesions. Postablation MRIs confirmed lesions were included in the ablation zone with necrosis of the lesion. The ablation zone was consistent in size with that measured by the TCs and similar in morphology to that extrapolated from thermal distribution curves. The STAR navigational ability allowed for easy access to posterior vertebral body lesions, previously difficult to access with other ablation devices. In many cases, this technique allowed for treatment of individual lesions not controlled by systemic or radiation therapy.
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