Radiofrequency Ablation Technique Research Articles

Radiation risk reduction in AF ablation procedures through use of a novel visualisation and navigation system

Background: Atrial fibrillation (AF) is the most common form of cardiac arrhythmia afflicting patients presenting to cardiologists and general practitioners in Australia. However, ablation procedures for the treatment of AF are amongst the most complex and time consuming cardiac imaging procedures. This study reviews the adoption of a visualisation and navigation system (MediGuide) and the impact this has on overall procedural radiation risk. Methods: Records for 181 AF ablation procedures performed by an experienced Electrophysiologist between February 2012 and December 2014 using a single imaging system were analysed. These procedures comprised 151 conventional radiofrequency (RF) ablations using 3D mapping (49 grid, 102 gridless) and 30 using the MediGuide system. Radiation measures including Fluoroscopy time (FT) and estimated Effective Dose (E) were compared. Results/Discussion: Use of the MediGuide system markedly reduced FTs by comparison to conventional RF ablation techniques (4.8min vs. 18.5min gridless and 22.5min grid). Median E for MediGuide was 0.11mSv compared with 0.88mSv and 0.40mSv for conventional RF (with and without grid). Median total procedure time for MediGuide was 147min compared with 125 minutes for conventional RF procedures. Prolongation of procedure time was linked to a learning curve and a preference to use MediGuide in complex redo procedures. Conclusion: This study emphasises the need for careful evaluation and optimisation of new technologies to ensure progression in efforts to reduce radiation risks associated with complex imaging procedures. Use of the MediGuide technology has substantially reduced the radiation risks for both patients and clinical staff involved in AF ablation procedures.

Recent advances in radio frequency ablation techniques of atrial fibrillation

Multiple wavelet hypothesis and fibrillatory conduction are believed to be atrial fibrillation’s pathogenesis. Radio frequency ablation (RFA) technique, a therapy for atrial fibrillation (AF), applies radio frequency (RF) energy to targeted tissue to make it transmural. Research on AF ablation has already been conducted in China. Currently, there are single-electrode and dual-electrode ablation electrodes. It is discovered that the latter can reduce the treatment time and maintain the ablation shape of the tissue. Clinical application has shown that it has become the first-line treatment option for part of indications patients with AF.

Combined ultrasonic aspiration and saline-linked radiofrequency precoagulation: a step toward bloodless liver resection without the need of liver inflow occlusion: analysis of 313 consecutive patients.

BackgroundHemorrhage is undoubtedly one of the main factors contributing to morbidity and mortality in liver resections. Vascular occlusion techniques are effective in controlling intraoperative bleeding, but they cause liver damage due to ischemia. We evaluated the effectiveness and safety of using a combined technique for hepatic parenchymal transection without liver inflow occlusion.MethodsThree hundred and thirteen consecutive patients who underwent liver resection in four hepato-pancreato-biliary units. Hepatic parenchymal transection was carried out using a combined technique of saline-linked radiofrequency precoagulation and ultrasonic aspiration without liver inflow occlusion.ResultsDuring the study period 114 minor and 199 major hepatic resections were performed. The mean amount of intraoperative blood loss was 377 ml (SD 335 ml, range 50 to 2,400 ml) and the blood transfusion rate was 10.5%. The median amount of blood loss during parenchymal transection and parenchymal transection time was 222 ml (SD 224 ml, range 40 to 2,100 ml) and 61 minutes (range 12 to 150 minutes) respectively. There were two postoperative deaths (0.6%). Complications occurred in 84 patients (26.8%) and most complications were minor.ConclusionsCombined technique of saline-linked radiofrequency ablation and ultrasonic aspiration for liver resection is a safe method for both major and minor liver resections. The method is associated with decreased blood loss, reduced postoperative morbidity, and minimal mortality rates. We believe that this combined technique is comparable to other techniques and should be considered as an alternative.

Various complications of percutaneous radiofrequency ablation for hepatic tumors: radiologic findings and technical tips

Radiofrequency ablation is a safe and effective treatment for primary and secondary liver malignancies and has a low complication rate; however, there are various radiofrequency ablation-related complications which can occur from the thorax to the pelvis. Although most of these complications are usually minor and self-limited, they may become fatal if diagnosis and treatment are delayed. It is important for radiologists performing radiofrequency ablation to have a perspective regarding the possible radiofrequency ablation-related complications and their risk factors as well as the radiologic findings for their timely detection and increase of the treatment efficacy, and thereby encouraging the use of the radiofrequency ablation technique. This article illustrates the various imaging features of common and rare radiofrequency ablation-related complications as well as offers technical tips in order to avoid these complications.

Cost-effectiveness of navigated radiofrequency ablation for hepatocellular carcinoma in China.

Real-time virtual sonography (RVS) is a promising navigation technique for percutaneous radiofrequency ablation (RFA) treatment, especially in ablating nodules poorly visualized on conventional ultrasonography (US). However, its cost-effectiveness has not been established. The purpose of this study is to evaluate the cost-effectiveness of RVS navigated RFA (RVS-RFA) relative to US guided RFA (US-RFA) in patients with small hepatocellular carcinoma (HCC) in China, from the modified societal perspective. A state-transition Markov model was created using TreeAge Pro™ 2012. The parameters used in the model, including natural history of HCC patients, procedure efficacy and related costs, were obtained from a systematic search of literature through PubMed, EMBASE, and Science Citation Index databases. The simulated cohort was patients with solitary, small HCC (<3 cm in diameter) and Child-Pugh class A or B, whose tumors are poorly visualized in B-mode US but clearly detectable by CT or MRI. In this cohort of difficult cases, RVS-RFA was a preferred strategy saving 2,467 CNY ($392) throughout the patient's life while gaining additional 1.4 QALYs compared with conventional US guidance. The results were sensitive to the efficacy of US-RFA and RVS-RFA including complete ablation rate and local recurrence rate, the median survival for patients with progressive HCC, the probability of performing RFA for recurrent HCC, and the cost of RVS navigation, disposable needle or hospitalization. RVS-RFA is a dominant strategy for patients with small HCC unidentifiable in B-mode US, in terms of cost savings and QALYs gained, relative to the conventional US-guided method.

간세포암에 대한 초음파유도하의 고주파열치료술의 새로운 기법

간세포암에 대한 초음파유도하의 고주파열치료술의 새로운 기법

Sacroiliac joint radiofrequency ablation with a multilesion probe: a case series of 60 patients.

This retrospective case series of patients with refractory sacroiliac joint (SIJ) pain presents our first 77 SIJ radiofrequency ablation (RFA) procedures performed with a multilesion probe. Of these, 16 (20.8%) provided no relief; 55 (71.4%) provided >50% pain relief at 6 weeks; 42 (54.5%, 95% confidence interval, 42.8%-65.8%) provided >50% pain relief at 6 months; and 12 (15.6%) continued to provide >50% pain relief at 1 year. These results compare favorably to those published using other RFA techniques. In conclusion, more than half of our patients with refractory SIJ pain received some pain relief for at least 6 months after RFA.

Efficacy and survival analysis of percutaneous radiofrequency versus microwave ablation for hepatocellular carcinoma: an Egyptian multidisciplinary clinic experience.

Hepatocellular carcinoma (HCC) is a primary tumor of the liver with poor prognosis. For early stage HCC, treatment options include surgical resection, liver transplantation, and percutaneous ablation. Percutaneous ablative techniques (radiofrequency and microwave techniques) emerged as best therapeutic options for nonsurgical patients. We aimed to determine the safety and efficacy of radiofrequency and microwave procedures for ablation of early stage HCC lesions and prospectively follow up our patients for survival analysis. One Hundred and 11 patients with early HCC are managed in our multidisciplinary clinic using either radiofrequency or microwave ablation. Patients are assessed for efficacy and safety. Complete ablation rate, local recurrence, and overall survival analysis are compared between both procedures. Radiofrequency ablation group (n = 45) and microwave ablation group (n = 66) were nearly comparable as regards the tumor and patients characteristics. Complete ablation was achieved in 94.2 and 96.1% of patients managed by radiofrequency and microwave ablation techniques, respectively (p value 0.6) with a low rate of minor complications (11.1 and 3.2, respectively) including subcapsular hematoma, thigh burn, abdominal wall skin burn, and pleural effusion. Ablation rates did not differ between ablated lesions ≤ 3 and 3-5 cm. A lower incidence of local recurrence was observed in microwave group (3.9 vs. 13.5% in radiofrequency group, p value 0.04). No difference between both groups as regards de novo lesions, portal vein thrombosis, and abdominal lymphadenopathy. The overall actuarial probability of survival was 91.6% at 1 year and 86.1% at 2 years with a higher survival rates noticed in microwave group but still without significant difference (p value 0.49). Radiofrequency and microwave ablations led to safe and equivalent ablation and survival rates (with superiority for microwave ablation as regards the incidence of local recurrence).

Complications of image-guided thermal ablation of liver and kidney neoplasms.

Image-guided thermal ablation is a widely accepted tool in the treatment of a variety of solid organ neoplasms. Among the different techniques of ablation, radiofrequency ablation, cryoablation, and microwave ablation have been most commonly used and investigated in the treatment of liver and kidney neoplasms. This article will review complications following thermal ablation of tumors in the liver and kidney, and discuss the risks and clinical presentation of each complication as well as how to treat and potentially avoid complications.

Percutaneous radiofrequency ablation of spinal osteoid osteoma under CT guidance

Osteoid osteoma (OO) accounts for approximately 10-12% of all benign bone tumours and 3% of all bone tumours. Spinal involvement appears in 10-25% of all cases. The purpose of this study was to evaluate the safety and efficacy of CT-guided radiofrequency (RF) ablation in the treatment of spinal OOs and report our experience. 13 patients suffering from spinal OO and treated at the authors' institution using CT-guided RF ablation were retrospectively evaluated. The RF probe was introduced through a 11-G Jamshidi(®) needle, and the lesion was heated at 90°C for 6 min. All procedures were considered technically successful as the correct positioning of the probe was proven by CT. 11 of the 13 patients reported pain relief after RF ablation. In two cases, RF ablation was repeated 1 month after the first procedure. Pain relief was achieved in both cases after the second procedure. No recurrence was reported throughout the follow-up. No complications like skin burn, soft-tissue haematoma, infection, vessel damage or neurological deficit were reported. This study demonstrates that CT-guided percutaneous RF ablation is a safe and effective method for the treatment of spinal OOs. The data of this study support the efficacy and safety of the recently applied CT-guided percutaneous RF ablation technique for the treatment of spinal OOs.

Evaluation of the current radiofrequency ablation systems using axiomatic design theory

This article evaluates current radiofrequency ablation systems using axiomatic design theory. Due to its minimally invasive procedure, short-time hospital stay, low cost, and tumour metastasis treatment, the radiofrequency ablation technique has been playing an important role in tumour treatment in recent decades. Although the radiofrequency ablation technique has many advantages, some issues still need to be addressed. Among these issues, the two most important are as follows: (1) the size of tumours to be removed (has to be larger than 3 cm in diameter) and (2) cleanness of the removal. Many device solutions have been proposed to address the two issues. However, there is a lack of knowledge regarding the systematic evaluation of these solutions. This article evaluates these systems in terms of their solution principles (or simply called conceptual design in general product design theory) using a design theory called axiomatic design theory. In addition, with the axiomatic design theory, a better conceptual design in terms of its feasibility to cope with incomplete target tissue necrosis from the large size of tumours has been found. The detailed analysis and simulation of the new conceptual design are conducted using finite element approach. The results in this article are proved by the information of animal experiments and clinical practices obtained from the literature. This study thus contributes to the current knowledge to further developments in radiofrequency ablation systems and procedure guidelines for physicians to perform the radiofrequency ablation operation more effectively.

Renal Nerve Ablation for Resistant Hypertension

Sympathetic renal denervation, or renal nerve ablation (RNA), has become the new buzz word in hypertension and interventional cardiology. Recent advances in catheter-based approaches have allowed sympathetic fiber interruption through transvascular techniques that are minimally invasive and can be delivered expeditiously and safely. Radiofrequency (RF) energy sources are currently the preferred modalities, but other sources of energy, such as cryoablation, microwave, high-intensity focus ultrasound, and local neurotoxic agent infusion, are under intense investigation. Results thus far have been encouraging and offer promise for the future. The role of the sympathetic nervous system (SNS) in the development of resistant hypertension and cardiovascular disease has long been known, and a great deal of work has been done through the years trying to explore potential interventions to interrupt the sympathetic influence on systemic vasculature and target organs. In this article we attempt an overview of time-dependent interventions on the SNS and examine approaches used in humans and in the many experimental models that offer a better understanding of the role of sympathetic activity in cardiovascular disease. Naturally we focus on methods and techniques addressing sympathetic renal denervation in patients with drug-resistant hypertension, examine the current state of the art, and attempt a look into the future. In 1889, after meticulous experiments on dogs, Bradford1 reported that stimulation of dorsal and splanchnic nerves causes changes in blood pressure (BP) and kidney size measured by plethysmography. Whether BP increased or decreased depended on the anatomic area stimulated, as well as the electric impulse frequency, but outcomes were consistent and reproducible. Neurosurgical treatment of hypertension was independently suggested by researchers in 1923.2 Adson, however, was the first to performed surgical sympathectomy for the treatment of malignant hypertension in 1925.3 During the following years and in the 1930s, Peet in Ann Arbor, Page and …

A fatal case of atrioesophageal fistula following radiofrequency ablation of left atrium and pulmonary veins for atrial fibrillation

Atrial fibrillation (AF) is associated with significant morbidity and mortality. Hemodynamic compromise and formation of thrombi within the fibrillating atrium or atrial appendage can occur. Surgical treatment aims to eliminate dysrhythmia-triggering foci in the pulmonary veins and posterior left atrium by radiofrequency ablation techniques using ohmic heat. As medical treatment may be ineffective, radiofrequency catheter ablation is increasingly being used by interventional cardiac electrophysiologists for AF. Serious complications have been observed among patients who have undergone radiofrequency ablation, atrioesophageal fistula being a very rare example. This case describes a 43-year-old man who died after the development of an atrioesophageal fistula following radiofrequency ablation of the left atrium and pulmonary veins for treatment of AF.

9:12 AM Abstract No. 239 - Long-term efficacy and complication rate of a novel percutaneous CT-guided radiofrequency ablation technique for osteoid osteoma of the lower extremity

9:12 AM Abstract No. 239 - Long-term efficacy and complication rate of a novel percutaneous CT-guided radiofrequency ablation technique for osteoid osteoma of the lower extremity

Percutaneous radiofrequency ablation of renal tumours: 29-month mean follow-up results of 118 patients

Background. Percutaneous radiofrequency ablation (RFA) is a minimally invasive method of treatment based on thermal effects. This retrospective study aimed to clarify percutaneous RFA of kidney tumors – performance, extremeness and 5-year survival in patients with small renal tumors in a single center. Materials and methods. Between September 2003 and December 2012, a total of 118 patients underwent percutaneous RFA of renal tumors. During more than 9 years period 144 RFA procedures were performed. Tumors were verified by biopsy. We used 3 RFA techniques: RFA under ultrasound control only (US), ultrasound guided RFA with CT navigation (US/CT) and ultrasound guided RFA with CT navigation, fiducial markers placed around the kidney tumor before the treatment (US/CT/FM). RFA electrodes were one and three. Patients were followed up regularly by CT with contrast enhancement. Results. The mean patient age was 68.72 years (range 28 to 86). The mean tumor size was 2.8 cm (range 1 to 5.4). The mean follow-up time was 29 months (1–111 months). Radical dependence on technical procedures: only US 39 (66.1%), US/CT 18 (94.7%), US/CT/FM 37 (92.5%), p = 0.001. Radical differences between using one and three electrodes: 39 (66.1%) and 55 (93.2%), p

Cadaveric Study of Sacroiliac Joint Innervation: Implications for Diagnostic Blocks and Radiofrequency Ablation

Background and ObjectivesOptimization of clinical outcomes of lateral branch radiofrequency ablation or blocks for sacroiliac joint (SIJ) pain requires precise nerve localization; however, there is a lack of comprehensive morphological...

Novel Use of Noninvasive High-Intensity Focused Ultrasonography for Intercostal Nerve Neurolysis in a Swine Model

High-intensity focused ultrasound (HIFU) is a noninvasive thermal ablation technique. High-intensity focused ultrasound has been used in small-animal models to lesion neural tissue selectively. This study aimed to evaluate the efficacy of HIFU in a large-animal model for ablation of nerves similar in size to human nerves. Twelve acute magnetic resonance-guided HIFU ablation lesions were created in intercostal nerves in a swine model. In a second pig, as a control, 4 radiofrequency ablation and 4 alcohol lesions were performed on intercostal nerves under ultrasound guidance. Preprocedural and postprocedural magnetic resonance imaging was then performed to evaluate radiologically the lesion size created by HIFU. Animals were euthanized 1 hour postprocedure, and necropsy was performed to collect tissue samples for histopathologic analysis. On gross and histological examination of the intercostal nerve, acute HIFU nerve lesions showed evidence of well-demarcated, acute, focally extensive thermal necrosis. Four intercostal nerves ablated with HIFU were sent for histopathologic analysis, with 2 of 4 lesions showing pathologic damage to the intercostal nerve. Similar results were shown with radiofrequency ablation technique, whereas the intercostal nerves appeared histologically intact with alcohol ablation. High-intensity focused ultrasound may be used as a noninvasive neurolytic technique in swine. High-intensity focused ultrasound may have potential as a neuroablation technique for patients with chronic and cancer pain.

Osteoid Osteoma Treated by Percutaneous Thermal Ablation: When Do We Fail? A Systematic Review and Guidelines for Future Reporting

Osteoid osteoma (OO) is a painful benign bone tumor of the young that is widely treated by percutaneous thermal ablation (PTA) with success rates close to 100%. Nevertheless, some patients have recurrences. We reviewed the literature to understand whether these are true recurrences or incomplete treatments; to analyze safety and efficacy during long-term follow-up in a extremely large cohort of patients; to detail best-practice suggestions from the largest clinical trials as well as report their complications; and to recommend standards for future reporting. This study followed the Cochrane's guidelines for Systematic Reviews of Interventions. Inclusion criteria were as follows: (1) prospective or retrospective cohort study for PTA of OO under computed tomography (CT) guidance; (2) CT or magnetic resonance diagnosis; (3) radiofrequency ablation or interstitial laser ablation technique; (4) English language; (5) population <10 patients; (6) follow-up ≥12 months; and (7) original research. Risk of bias was assessed with a modified Newcastle-Ottawa Scale. Two hundred fourteen articles were initially found. After applying the criteria mentioned previously, 27 PTA articles concerning 1,772 patients were chosen for inclusion. No exclusions were made due to risk of bias. The investigators proved the long-term efficacy and superiority of PTA for OO compared with other techniques. In 5% of patients, however, the technique failed, and the researchers did not offer detailed exhaustive explanations. Future clinical trials for OO ablation should consider reporting essential procedure details and follow-up findings to allow for a meta-analysis. We provide both recommended standards for future reporting and suggestions for the prevention of recurrence.

Multilevel radiofrequency ablation to the soft palate and tongue base: tips and pitfalls

The objective of the study is to increase awareness and understanding of the techniques and safety measures to minimise complications and improve patient outcomes. Literature review using MedLine and keywords snoring; obstructive sleep apnoea; radiofrequency ablation; electrosurgery; palate; tongue base was conducted. There is no accepted gold standard technique for radiofrequency ablation; to date, there is no published literature regarding common tips and pitfalls in radiofrequency application specifically for superficial applications and second-stage surgery. Surgery for snoring and obstructive sleep apnoea is typically multilevel. Pre-operative patient assessment and selection are critical to ensure good outcomes. Radiofrequency is generally safe and efficacious in this subset of patients. However, as with all surgery, it is operator-dependent. In particular, we emphasise the methodology for second-stage surgery, optimising visualisation and avoiding ulceration/fistulation of the soft palate, which are previously undescribed in the literature.

En Bloc Resection of Coracoid Base Osteoid Osteoma in a Child: An Extremely Rare Case

Background:Osteoid osteomas account for approximately 2- 3% of all primary bone neoplasm's sampled for biopsy. 50% of all of them occur in the long bones of the lower extremities, but osteoid osteoma of the coracoid process is rare. We have found only nine previously reported cases of coracoid osteoid osteoma in the international literature. We report a child with coracoid base osteoid osteoma.Case presentation:A twelve-years-old boy with a persistent pain at the right shoulder since 9 months ago, were evaluated. His pain relatively responds to non-steroidal anti-inflammatory drugs (NSAIDs). Imaging studies showed foci of sclerosis at right coracoid base with increased uptake on the Technetium-99m study. Because proximity to the neurovascular bundle we couldn't use radiofrequency ablation technique, so the patient underwent open surgery with a mini- deltopectoral approach and two level osteotomies ; one proximal to coracoid tip and the other at the base of coracoid just distal to subcoracoidphyseal line. Then a segment of coracoid resected. Tip of coracoid securely reattached with a screw.Conclusions:To our knowledge in the literature up to now there are only nine reports of coracoid osteoid osteoma. These cases were treated with different approaches and different techniques. We used en-bloc resection via mini-anterior approach. Our patient 30 months after surgery (October 2012) have full range of motion and became pain free since wound healing with normal control imaging.Definite diagnosis of osteoid osteoma in the uncommon sites may be delayed. En bloc resection of tumor with two osteotomies by an anterior approach has been limited soft tissue injury and is a reliable method of treatment.