Traditional Radiofrequency Ablation Research Articles

Traditional versus cooled-radiofrequency neurotomy for the treatment of chronic lumbar facet (zygapophyseal) joint pain.

Aim: Traditional radiofrequency ablation (TRFA) effectively treats facet joint-related pain, while water-cooled radiofrequency ablation (CRFA) may offer benefits like larger lesions and easier nerve access. Our goal is to assess the effectiveness of TRFA and CRFA for facet joint-related pain. Materials & methods: This retrospective study included an evaluation of 346 RFA interventions performed on 190 patients suffering from long-term low-back pain. The primary outcome was defined as a decrease of ≥50% of the mean numeric rating scale. Results: The primary outcome was achieved at the first follow-up (FU) for both TRFA and CRFA, with pain relief of 55.2and 60.5%, respectively. At the second FU, the primary outcome was achieved only in the CRFA group (54.1%), although the TRFA group also showed a good improvement (48.6%). In both groups, pain relief was under 50% during the third FU. Conclusion: Our study indicates that both CRFA and TRFA modalities are effective and safe treatments.

Pulsed-field ablation: An alternative ablative method for gastric electrophysiological intervention.

Pulsed-field ablation (PFA) is an emerging ablative technology that has been used successfully to eliminate cardiac arrhythmias. As a non-thermal technique it has significant benefits over traditional radio-frequency ablation with improved target tissue specificity and reduced risk of adverse events during cardiac applications. We investigated whether PFA is safe for use in the stomach and whether it could modulate gastric slow waves. Female weaner pigs were fasted overnight before anesthesia was induced using tiletamine hydrochloride (50 mg mL-1) and zolazepam hydrochloride (50 mg mL-1) and maintained with propofol (Diprivan 2%, 0.2‑0.4 mg kg‑1 min‑1). Pulsed-field ablation was performed on their gastric serosa in vivo. Adjacent point lesions (n=2-4) were used to create a linear injury using bipolar pulsed-field ablation consisting of 40 pulses (10 Hz frequency, 0.1 ms pulse width, 1000 V amplitude). High-resolution electrical mapping defined baseline and post-ablation gastric slow-wave patterns. A validated five-point scale was used to evaluate tissue damage in hematoxylin and eosin stained images. Results indicated that PFA successfully induced complete conduction blocks in all cases, with lesions through the entire thickness of the gastric muscle layers. Consistent post-ablation slow-wave patterns emerged immediately following ablation and persisted over the study period. Pulsed-field ablation induces rapid conduction blocks as a tool to modulate slow-wave patterns, indicating it may be suitable as an alternative to radio-frequency ablation.

Research progress and clinical application of cooled radiofrequency ablation

Radiofrequency ablation (RFA) is a minimally invasive clinical treatment that uses radiofrequency energy to generate heat, resulting in the thermal necrosis of targeted tissues. To enhance the therapeutic benefits of traditional RFA, cooled RFA (CRFA) technology has been developed. CRFA incorporates cooling technology to prevent thermal damage and rapid impedance changes caused by tissue overheating. This review article provides a comprehensive overview of various types of cooling electrode needles used in CRFA, as well as an evaluation of their efficacy and clinical applications. We discuss the advantages of CRFA, including its minimally invasive nature, improved safety profile, and highly effective treatment outcomes. Nevertheless, certain problems and limitations are also addressed to optimize the potential of CRFA as a clinical treatment option. Overall, CRFA has promising prospects. With continued advancements in technology and further research, this innovative treatment modality is expected to significantly impact the treatment of a wide range of medical conditions.

Pulsed Field Ablation for the Treatment of Atrial Fibrillation: A Review and a Look into its Future

Pulsed field ablation (PFA) is a novel technology to treat atrial fibrillation (AF) utilizing electric fields to induce nonthermal irreversible electroporation of electrically active cardiac tissue to induce cardiac cell death. PFA offers improved safety benefits compared to traditional radiofrequency ablation (RFA) and cryoablation by specifically ablating only cardiac tissue. However, there are avenues for further optimization including neurological risk associated with microbubble formation and left atrial function post ablation. Various PFA devices with different electric pulse waveforms have been studied and tested in human trials, with the majority utilizing microsecond duration pulses. Shorter nanosecond duration pulses, or nanosecond PFA, is beginning to be studied for AF ablation. In this review we will delve into current waveforms used for PFA, areas for improvement, mechanisms behind nanosecond PFA, and its clinical impact for cardiac ablation.

High-Power Short-Duration Ablation of Paroxysmal and Persistent Atrial Fibrillation.

Catheter ablation has become a cornerstone in atrial fibrillation (AF) therapy, improving freedom from all-atrial arrhythmias, as well as outperforming antiarrhythmic drugs in alleviating AF-related symptoms, reducing hospitalizations, and enhancing quality of life. Nevertheless, the success rate of traditional radiofrequency ablation (RFA) methods remains less than ideal. To address these issues, refinement in RFA strategies has been developed to improve efficacy and laboratory efficiency during pulmonary vein isolation (PVI). High-power short-duration (HPSD) RFA has emerged as a safe strategy to reduce the time required to produce durable lesions. This article reviews critical aspects of HPSD ablation in the management of both paroxysmal and persistent AF, covering aspects such as effectiveness, safety, procedural intricacies, and the underlying biophysics.

Endoscopic Rhizotomy in Management of Facetogenic Chronic Lumbar Pain

Background Facet Arthritis causing Chronic Low Back Pain (CLBP) is an increasingly controversial field. The diagnosis of Facetogenic pain is still deemed difficult by many physicians, and its pathophysiology, as well as its management are still not quite understood. From the available literature, we can conclude that Lumbo-sacral Facet Arthritis is attributed to a degenerative process affecting the facet joint, which is described as the articulation between the superior articular process of one vertebrae and the inferior articular process of a vertebrae above. This degenerative process is commonly attributed to the „wear-and-tear' theory coming with age, highly comparative to the same degenerative process affecting any other joint. Aim of the Work to evaluate its effectiveness in controlling short term and long term pain caused by lumbar facet arthritis resulting in Chronic Low Back Pain (CLBP), and its effectiveness in decreasing disabilities caused by the debilitating symptoms of progressive arthritis in the lumbar facet joints. Patients and Methods was done to evaluate a novel technique, the Endoscopic Rhizotomy, as one of the minimally invasive procedures that is implemented in the management of Lumbar Facet Arthritis. All the available papers in literature describing this intervention from May 2000 to December 2020 were included. Results The initial search resulted in 468 articles from five databases including PubMed, Science Direct, Cochrane Library, Scopus, and Google Scholar. 16 studies are retrieved from additional databases. The total number before duplicates removal is 484 records. Conclusion that Endoscopic Rhizotomy is a very safe procedure, with a very low complication rate. We also concluded that Endoscopic Rhizotomy significantly relieves Facetogenic CLBP, with up to 3 years of pain relief. The procedure improved the subjective and objective quality of the patients. With comparison to the traditional Radiofrequency Ablation (RFA), Endoscopic Rhizotomy does not use radiation and allows direct visualization, in addition to being superior to RFA considering improving both pain and disability post-operative. It is considered a single day procedure, and the patient can return to work the 2nd day, fully-functioning. Without doubt, several factors, however, have to be taken into account when offering the patient such a procedure, as the presence of spinal deformities, instabilities, hypermobility, and the overall assessment of the patient‟s condition.

Radiofrequency ablation prior to total knee arthroplasty does not improve post-surgical pain or recovery: a double-blinded, multi-center, randomized clinical trial.

Radiofrequency ablation (RFA) targeting the genicular nerves is an effective treatment for knee pain due to osteoarthritis. The aim of this study was to determine the effects of two RFA interventions delivered preoperatively on early postoperative pain management and subjective outcomes after total knee arthroplasty (TKA). One hundred forty-three participants were enrolled in this double blinded, sham-controlled prospective randomized trial. Participants assigned at random to traditional RFA (t-RFA) (n=50), cooled RFA (c-RFA) (n=49), or sham (n=44) procedures prior to TKA. Outcomes were recorded at postoperative day 3, week 1, week 2, week 12, month 6, and month 12 following TKA. Primary outcomes included hospital length of stay (LOS), opioid consumption (reported as MEQ, or daily morphine equivalents), time to narcotic cessation (reported in days), and pain scores (reported as NRS, or Numeric Rating Scale). Secondary outcomes included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) measures. All side effects and complications were reported. Participants were followed for a year to detect any unexpected side effects. Compared with sham controls, t-RFA and c-RFA did not affect inpatient LOS, pain scores, or opioid consumption. There were no reductions in time to opioid cessation, pain scores, or WOMAC scores at any time point post-TKA. RFA of the genicular nerves prior to TKA did not affect opioid use or time to cessation, pain, or WOMAC scores, following TKA. Current techniques of t-RFA and c-RFA of these specific geniculate nerves preoperatively are not indicated as routine interventions to improve short-term surgical recovery after TKA. The trial was registered on ClinicalTrials.gov (NCT02925442).

Cooled Radiofrequency Ablation Provides Prolonged Pain Relief Compared to Traditional Radiofrequency Ablation: A Real-World, Large Retrospective Clinical Comparison from a Single Practice.

BackgroundGenicular radiofrequency ablation is an established therapy for chronic knee pain. An analysis comparing different probe sizes and technologies has not yet been undertaken for this indication. This large retrospective, comparison study from a single-center comprehensive pain management practice aims to do that.MethodsOutcomes of 170 patients who underwent traditional radiofrequency ablation (tRFA) for chronic knee pain were compared to 170 consecutive patients who received cooled radiofrequency ablation (CRFA) with similar (p=0.5) pre-procedural pain scores.ResultsThe VAS pain score at the first post-procedure visit at 4–6 weeks decreased to 5.07±2.8 cm for tRFA and to 4.26 ± 3.2 cm for CRFA (p<0.001 for both from baseline). The difference was profound and significantly better in the favor of CRFA (p<0.001) as the duration of reduction of pain scores by greater than 50% was 2.6 months for tRFA and 11.1 months for CRFA. There were only 15 patients (8.8%) who continued to receive >50% of pain relief in tRFA at 12 months, as opposed to 78 (46%) at 12 months for CRFA. We compared the initial outcomes and long-term pain relief. Long-term outcomes were better for the bigger lesion size treatment group patients.ConclusionWe conclude that the duration and intensity of pain relief were of a greater magnitude after the larger diameter probe cooled RFA.

Comparison of traditional radiofrequency ablation and high-power short-duration ablation in the treatment of atrial tachyarrhythmias

Atrial tachyarrhythmias are becoming more common in the population. The prevalence increases with age. Often, these arrhythmias lead to disability and reduced life expectancy (indirectly through strokes). Drug therapy of atrial tachyarrhythmias reduces symptoms but does not completely resolve issue of treatment. In this regard, surgical treatment (catheter ablation) is preferable. One of the methods of catheter ablation is ablation using radio frequency energy. The key parameters of radiofrequency catheter ablation are the energy delivered to the endocardium and the time of this energy delivery. According to the traditional method, it is customary to use energy of 30 Watts for 30 s at one point. This technique has a disadvantage – in 30 s the electrode can be displaced, and the application of energy has to be repeated. A new strategy was proposed – reducing the application time by increasing the energy to respond to the challenge of high probability of electrode displacement. The aim of this work was to determine the effectiveness of the рhigh-power short-duration protocol. Materials and methods. To carry out this work, we analyzed the surgical treatment of atrial fibrillation with the help of radiofrequency catheter ablation – isolation of the pulmonary veins. In patient group 1, ablation was performed using an irrigated ablation electrode with an energy of 30 Watts and an application time of 30 s, in group 2 – using the irrigated electrode with the energy of 70 Watts and the application time of 5 s. Ablations were performed under the control of radiography and electroanatomical mapping system. Full electrical isolation of the four pulmonary veins with confirmation of the entrance and exit block were considered as the criteria of efficiency. Results. When comparing the groups by the number of required application cycles during the procedure needed to achieve the clinical effect and time to the first recurrence in all positions of the electrode, group 2 showed a lower number of applications and shorter time to the first recurrence. Reducing the time to pulmonary vein isolation, the number of relapses and restarting the control time, as well as shortening the time spent on the need to rebuild the electroanatomical map have resulted in a significant decrease in the duration of the radiofrequency ablation procedure. Conclusions. The work has shown that the use of the new protocol is more effective and allows to achieve the criteria of success faster than the traditional technique; the number of the procedure complications was not higher compared to traditional methods. When using the ablation protocol with higher energy, a lower incidence of atrial fibrillation recurrence was recorded.

Multi-functional sensor array on the cryoablation balloon for atrial fibrillation

A new treatment of cryoablation for atrial fibrillation shows advantages over traditional radiofrequency ablation, including lower re-ablation rate, fewer thrombus, higher efficiency, and increased safety. However, for the commercial cryoablation balloon, physical signs are monitored by an extra guide wire and thermocouples inside the cryoballoon, which is complex and results in errors. Here, we propose a stretchable and flexible array with electrodes and temperature sensors attached to the surface of the cryoballoon for in-situ cardiac electrocardiograph mapping and ablation feedback. The influence of inflation degrees, electrode size, and temperature on electrodes is investigated and the optimized diameter of electrodes is chosen as 400 µm. The sensitivity, stability, repeatability, resolution, and response time of temperature sensors are tested, showing its ability of accurate monitoring. Furthermore, in-vitro experiments on a swine heart are performed. The proposed device attached to the cryoballoon contributes to the monitoring of the cryoablation process and feedback to the operator, simplifying the catheter and easing the interventional operation.

Cooled-radiofrequency neurotomy for the treatment of chronic lumbar facet (zygapophyseal) joint pain: A retrospective study.

Cooled-radiofrequency (CRFA) is a newer technique and may have some theoretical advantages over traditional radiofrequency ablation (TRFA). In this study, we aimed to investigate the efficacy and safety of CRFA for the treatment of lumbar facet joint-mediated pain. In this retrospective study, we evaluated 185 CRFA performed on 105 patients. All patients with axial lower back who received the preliminary diagnosis of lumbar facet joint-mediated pain and refractory to conservative therapy underwent diagnostic medial branch blocks. CRFA was recommended to those patients who responded favorably to two sets of diagnostic medial branch blocks. Pain scores in numeric rating scale (NRS) were recorded pre-treatment and post-treatment at different time-points. The primary outcome measure was to report descriptive NRS score and average % improvement from baseline at each time point. A significant pain relief was determined by a decrease of ≥50% of mean NRS. Secondary outcome measure was the time to repeat treatment with subsequent CRFA. Adverse events were also recorded.Primary outcome measure determined as the improvement in NRS, for at least 50% or more, was achieved in both 1st (4–8 weeks) and 2nd (>2–6 months) follow-up (FU) with 60.5% and 53.6% reduction in NRS respectively. Our subgroup analysis comparing the younger (<50) and older (≥50) age groups showed superior pain relief with CRFA in the older (≥50) age group, both in the 1st (4–8 weeks) and 2nd (>2–6 months) FU time points (63.4% and 58.4% reduction in NRS, respectively). Cooled-radiofrequency ablation is an effective and safe procedure for the treatment of chronic lumbar facet joint related pain. The duration of pain relief was comparable to traditional radiofrequency ablation as reported in the literature.

B-IN02-03 USING PULSED ELECTRIC FIELDS TO CAUSE FOCAL FIBROSIS IN THE INTERVENTRICULAR SEPTUM

Pulse electric fields (PEF) are being investigated as an alternative ablation modality to traditional radiofrequency ablation for modification of myocardial substrate. Assess the extent and time course of myocardial scar formation caused by application of PEF at the interventricular septum. Four-week survival experiments were performed in 8 canines. Energy was delivered using ablation catheters in bipolar configuration to apply PEF to the septum. Two animals were administered pulses at microsecond pulse widths and six received nanosecond pulses for a total 75-189 J delivered per animal. MRI studies were performed in 4 of the 8 animals. Scar formation was assessed by measuring late gadolinium enhancement (LGE) and confirmed by histology. Sites of PEF delivery exhibited myocardial edema on triple inversion recovery and early scar with some LGE visible after 7 days. Lesion volumes were larger for transmural configurations vs. bipolar PEF delivered in a single cardiac chamber (10.7 ± 2.3 cm3 vs. 2.9 ± 1.1 cm3). At 30 days, lesions predominantly exhibited LGE and total lesion volumes were similar for both groups (5.3 ± 2.4 cm3 vs. 4.0 ± 0.2 cm3). Transmural MRI lesions were achieved when bipolar electrodes were placed on either side of the septum, and total lesion volume was dose-dependent. Myocardial fibrosis was identified on histology. Bipolar configurations entirely within a chamber produced superficial lesions, even with delivery of higher energy. Application of PEF to the myocardium can cause substrate modification, including transmural fibrosis. Lesion volume is dose-dependent for transmural electrode configurations.

Towards quantitative and intuitive percutaneous tumor puncture via augmented virtual reality.

In recent years, the radiofrequency ablation (RFA) therapy has become a widely accepted minimal invasive treatment for liver tumor patients. However, it is challenging for doctors to precisely and efficiently perform the percutaneous tumor punctures under free-breathing conditions. This is because the traditional RFA is based on the 2D CT Image information, the missing spatial and dynamic information is dependent on surgeons' experience. This paper presents a novel quantitative and intuitive surgical navigation modality for percutaneous respiratory tumor puncture via augmented virtual reality, which is to achieve the augmented visualization of the pre-operative virtual planning information precisely being overlaid on intra-operative surgical scenario. In the pre-operation stage, we first combine the signed distance field of feasible structures (like liver and tumor) where the puncture path can go through and unfeasible structures (like large vessels and ribs) where the needle is not allowed to go through to quantitatively generate the 3D feasible region for percutaneous puncture. Then we design three constraints according to the RFA specialists consensus to automatically determine the optimal puncture trajectory. In the intra-operative stage, we first propose a virtual-real alignment method to precisely superimpose the virtual information on surgical scenario. Then, a user-friendly collaborative holographic interface is designed for real-time 3D respiratory tumor puncture navigation, which can effectively assist surgeons fast and accurately locating the target step-by step. The validation of our system is performed on static abdominal phantom and in vivo beagle dogs with artificial lesion. Experimental results demonstrate that the accuracy of the proposed planning strategy is better than the manual planning sketched by experienced doctors. Besides, the proposed holographic navigation modality can effectively reduce the needle adjustment for precise puncture as well. Our system shows its clinical feasibility to provide the quantitative planning of optimal needle path and intuitive in situ holographic navigation for percutaneous tumor ablation without surgeons' experience-dependence and reduce the times of needle adjustment. The proposed augmented virtual reality navigation system can effectively improve the precision and reliability in percutaneous tumor ablation and has the potential to be used for other surgical navigation tasks.

Physiological and functional responses of water-cooled versus traditional radiofrequency ablation of peripheral nerves in rats

Background and objectivesSeveral clinical studies have focused on assessing the effectiveness of different radiofrequency ablation (RFA) modalities in pain management. While a direct head-to-head clinical study is needed, results from...

Endoscopic rhizotomy for chronic lumbar zygapophysial joint pain

BackgroundChronic lumbar zygapophysial joint pain is a common cause of chronic low back pain. Percutaneous radiofrequency ablation (RFA) is one of the effective management options; however, the results from the traditional RFA need to be improved in certain cases. The aim of this study is to investigate the effect of percutaneous radiofrequency ablation under endoscopic guidance (ERFA) for chronic low back pain secondary to facet joint arthritis.MethodsThis is a prospective study enrolled 60 patients. The cases were randomized into two groups: 30 patients in the control group underwent traditional percutaneous radiofrequency ablation, others underwent ERFA. The lumbar visual analog scale (VAS), MacNab score, and postoperative complications were used to evaluate the outcomes. All outcome assessments were performed at postoperative 1 day, 1 month, 3 months, 6 months, and 12 months.ResultsThere was no difference between the two groups in preoperative VAS (P > 0.05). VAS scores, except the postoperative first day, in all other postoperative time points were significantly lower than preoperative values each in both groups (P < 0.05). There was no significant difference between the two groups in VAS at 1 day, 1 month, and 3 months after surgery (P > 0.05). However, the EFRA demonstrated significant benefits at the time points of 3 months and 6 months (P > 0.05). The MacNab scores of 1-year follow-up in the ERFA group were higher than that in the control group (P < 0.05). The incidence of complications in the ERFA group was significantly less than that in the control group (P < 0.05).ConclusionsERFA may achieve more accurate and definite denervation on the nerves, which leads to longer lasting pain relief.

Tumor-related HSP70 released after cryo-thermal therapy targeted innate immune initiation in the antitumor immune response

Purpose In our previous study, a novel cryo-thermal therapy that could stimulate the maturation of innate immune cells to subsequently activate the CD4+Th1 cell-dominated antitumor response was developed. However, why cryo-thermal therapy can induce the maturation of innate immunity remains unknown. Methods In this study, western blot and ELISA were used to analyze the levels of damage-associated molecular patterns (DAMPs, including heat shock protein 70 (HSP70), calreticulin and high-mobility group box protein 1) in situ and in the peripheral blood at different times after cryo-thermal therapy or traditional radiofrequency ablation. The effects of these three DAMPs on myeloid-derived suppressor cells (MDSCs), dendritic cells (DCs) and macrophages were investigated by antibody neutralization in vitro. The phenotypic and functional changes in MDSCs, DCs and macrophages were analyzed using FACS and qRT-PCR. An anti-HSP70 antibody was injected intravenously at 6 h after cryo-thermal therapy on days 1 and 2 and mouse survival was monitored. Results Cryo-thermal therapy could trigger the release of DAMPs in situ and in the peripheral circulation, which could downregulate the proportion and suppressive signature of MDSCs, and promote the M1 macrophages polarization and DCs maturation. Among three DAMPs, HSP70 played the most evident role in M1 macrophage polarization. In vivo neutralization of HSP70 in the early stage of treatment could significantly decrease the survival rate of cryo-thermal therapy treated mice. Conclusions Local cryo-thermal therapy not only destroyed solid tumors thermally and mechanically but also induced the release of a large amount of DAMPs to effectively trigger a systemic antitumor response.

Poster 101: A Randomized Comparative Trial of Medial Branch Nerve Cooled Versus Traditional Radiofrequency Ablation for the Treatment of Zygaphophyseal Joint Pain; 6-Month Outcomes

Poster 101: A Randomized Comparative Trial of Medial Branch Nerve Cooled Versus Traditional Radiofrequency Ablation for the Treatment of Zygaphophyseal Joint Pain; 6-Month Outcomes

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P50. A randomized prospective comparative trial of water-cooled versus traditional radiofrequency ablation of the median branch nerve in the treatment of zygapophyseal joint pain: six-month outcomes

BACKGROUND CONTEXT No study has compared the effectiveness of water-cooled radiofrequency ablation (WC-RFA) and traditional RFA (T-RFA) of the medial branch nerves (MBNs) for lumbar zygapophyseal joint (Z-joint) pain. PURPOSE Evaluate six-month pain, functional, psychometric, and medication usage outcomes of MBN WC-RFA versus T-RFA for lumbar Z-joint pain. STUDY DESIGN/SETTING Randomized comparative trial at an urban, tertiary, academic spine or pain center. PATIENT SAMPLE Individuals with Z-joint pain diagnosed by clinical evaluation and positive diagnostic MBN blocks (>50% relief) were randomized to WC-RFA or T-RFA. OUTCOME MEASURES The primary outcome was the proportion of “responders” (≥50% NRS reduction) at 6-months. Secondary outcomes included the NRS, ODI, Patient Anxiety Symptom Scale (PASS-20), McGill Pain Inventory (MPI), Center for Epidemiologic Studies Depression scale (CESD-10), daily morphine equivalents (DME), and Patient Global Impression of Change (PGIC). METHODS Six-month clinical outcomes were compared in the the group that was randomized to WC-RFA and the group that was randomized to T-RFA. Data were analyzed by descriptive statistics, chi-square tests, one-sample t-tests, independent t-tests, and Mann-Whitney-Wilcoxon tests RESULTS Forty participants (mean age=55.9, 24 females, mean BMI 30.2 kg/m2) underwent MBN WC-RFA (n=21) or T-RFA (n=19). There were no differences in demographic variables (p>.05). A ≥50% NRS reduction was observed in 52% (95% CI 31%–74%) and 47% (95% CI 26%–71%) of participants undergoing WC-RFA and T-RFA, respectively, at 6 months (p=.75). A ≥15-point or ≥30% reduction 6 months was observed in 62% (95% CI 39%–80%) and 42% (95% CI 22%–66%) of participants in the WC-RFA and T-RFA groups, respectively (p=.21). Significant reductions in mean NRS and ODI scores were observed in both groups: WC-RFA (NRS 7.4–3.6; ODI 29–18) and T-RFA (NRS 7.1–4.2; ODI 26–19) (NRS p 0.05). CONCLUSIONS Approximately half of participants reported clinically meaningful improvements in pain and function with MBN WC-RFA and T-RFA at 6 months, with no intergroup differences observed. These results are representative of a selection protocol with a high false-positive rate; use of dual comparative MBN blocks for patient selection would likely result in a higher success rate regardless of RFA modality.

Abstract 21364: Multicenter Prospective Study Comparing Phased Multipolar versus Traditional Radiofrequency Ablation

Background: Multipolar, phased radiofrequency (RF) catheter ablation (PVAC) has been associated with reduced procedural times compared to traditional RF. We performed a multicenter study to assess the efficacy and efficiency of using this catheter. Methods: This is a multicenter, sequential, prospective, cohort study between 2012 to 2016 in 6 tertiary care centers (NCT01562912). Patients were enrolled if they had symptomatic, paroxysmal AF (less than 7 days) refractory to at least one antiarrhythmic medication. Patients were enrolled in a 2:1 ratio of PVAC (group A) to control point-by-point RF with 3D mapping (group B). ECG and 48 hour Holter monitor were used to assess patients at 3, 6, 9 and 12 months post-ablation follow up. Recurrence was defined as any atrial arrhythmia &gt;30 seconds excluding an initial 3 month blanking period. Results: Overall, 230 patients consisting of 162 males (70.4%) with mean age 57±11 years were analyzed. By Kaplan-Meier analysis, freedom from any atrial arrhythmia at 12 months was 49% and 69.2% in group A and B respectively (p=0.033) (Figure1). Among patients with recurrence, 14.7% (21) in group A and 7.7% (6) in group B had redo procedure within 12 month post procedure(p=0.12). Procedure time was significantly lower in Group A than Group B (P&lt;0.0001). There was no significant difference in fluoroscopy time between the two groups (p=0.49). Stroke was not reported in any of the patients. Pulmonary Embolism, occurred in 1.3% of patients in group B. Pericardial effusion occurred in 1.4% in group A and 2.6% in group B. Tamponade occurred in 3.8% of patients in group B. Conclusion: This study demonstrated that the PVAC catheter is associated with significantly reduced procedure times for AF ablation, however, AF recurrence rates may be higher than contemporary point-by-point RF ablation with 3D mapping technology.

84 - Non-inferiority of Cooled vs Traditional Radiofrequency Ablation of the Lumbar Medial Branch Nerves in the Treatment of Axial Low Back Pain

84 - Non-inferiority of Cooled vs Traditional Radiofrequency Ablation of the Lumbar Medial Branch Nerves in the Treatment of Axial Low Back Pain