EUS-guided radiofrequency ablation with a prototype electrode array system in an animal model (with video)

Assessing EUS-guided radiofrequency ablation in unresectable pancreatic ductal adenocarcinoma: a single-center historic cohort study

BACKGROUND AND AIMS

EUS-guided radiofrequency ablation (EUS-RFA) has emerged as an alternative for the local treatment of unresectable pancreatic ductal adenocarcinoma (PDAC). We assessed the feasibility and safety of EUS-RFA in patients with unresectable PDAC.

METHODS

This study followed an historic cohort compounded by locally advanced (LA-) and metastatic (m)PDAC-naïve patients who underwent EUS-RFA between October 2019 and March 2022. EUS-RFA was performed with a 19-gauge needle electrode with a 10-mm active tip for energy delivery. Study primary endpoints were feasibility, safety, and clinical follow-up, whereas secondary endpoints were performance status (PS), local control, and overall survival (OS).

RESULTS

Twenty-six patients were selected: 15 with locally advanced pancreatic duct adenocarcinoma (LA-PDAC) and 11 with metastatic pancreatic duct adenocarcinoma (mPDAC). Technical success was achieved in all patients with no major adverse events. Six months after EUS-RFA, OS was seen in 11 of 26 patients (42.3%), with significant PS improvement (P = .03). Local control was achieved, with tumor reduction from 39.5 mm to 26 mm (P = .04). A post-treatment hypodense necrotic area was observed at the 6-month follow-up in 11 of 11 patients who were still alive. Metastatic disease was a significant factor for worsening OS (hazard ratio, 5.021; 95% confidence interval, 1.589-15.87; P = .004).

CONCLUSIONS

EUS-RFA for the treatment of pancreatic adenocarcinoma is a minimally invasive and safe technique that may have an important role as targeted therapy for local treatment of unresectable cases and as an alternative for poor surgical candidates. Also, RFA may play a role in downstaging cancer with a potential increase in OS in nonmetastatic cases. Large prospective cohorts are required to evaluate this technique in clinical practice.

EUS-guided radiofrequency ablation of solid pancreatic lesions: An updated review

Recent years have brought to light newly developed therapeutic modalities for the treatment of premalignant and malignant pancreatic lesions. The role of EUS-guided radiofrequency ablation (EUS-RFA) as a treatment modality for malignant pancreatic lesions is still under evaluation. Several animal studies and human studies have demonstrated the safety and efficacy of EUS-RFA in the management of premalignant and malignant pancreatic lesions. EUS-RFA therapy can potentially ablate these lesions safely and with minimally invasive techniques. In this article, we provide an updated review of the application of EUS-RFA of pancreatic lesions. We also review the clinical efficacy and safety of this technique and future directions.

Interventional Endoscopic Ultrasound: Current Status and Future Frontiers

Interventional endoscopic ultrasound has fueled remarkable advancements in the field of therapeutic procedures, revolutionizing minimally invasive interventions for a diverse range of conditions. This review highlights the latest breakthroughs and advancements in therapeutic endoscopic ultrasound, showcasing its potential to transform patient care.

Efficacy and Safety of Endoscopic Ultrasound-Guided Radiofrequency Ablation for Pancreatic Neuroendocrine Tumors: A Systematic Review and Metanalysis

Introduction: The development of dedicated endoscopes and the technical evolution of endoscopic ultrasound (EUS) have allowed a direct approach to pancreatic neoplastic lesions both for diagnosis and treatment. Among the more promising targets are pancreatic neuroendocrine tumors (Pan-NETs). Aim: to describe the evolution of endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) with particular attention to the treatment of PanNETs, focusing on safety and clinical efficacy of the technique. Methods: MEDLINE, Scopus, and Cochrane Library databases were searched for studies reporting about EUS-RFA for the treatment of PanNETs. Studies with outcomes of interest were selected and results were reported to describe clinical success, complications, fol-low-ups, and electrodes used. Clinical success was defined as the disappearance of clinical symp-toms for functional (F-) PanNETs and as complete ablation per nonfunctional (NF)-PanNETs. The pooled data were analyzed by a random-effects model. Results: Nineteen studies were selected, including 183 patients (82 males, 44.8%) with 196 lesions (101 F-PanNETs and 95 NF-PanNETs). Pooled estimates for the overall AE rates for the clinical efficacy were 17.8% (95% CI 9.1-26.4%) and 95.1% (95% CI 91.2-98.9%) for F-PanNETs and 24.6% (95% CI 7.4-41.8%) and 93.4% (95% CI 88.4-98.4%) for NF-PanNETs. Conclusions: EUS-RFA appears to be a mini-invasive technique with a good safety and efficacy profile for the treatment of F- and NF-PanNETs. EUS-RFA could be of-fered as possible alternative to surgery for the treatment of low-grade NF- or F-PanNETs, especially for those patients that are not eligible or are at high-risk for surgery.

Fiber-Optic Distributed Sensing Network for Thermal Mapping of Gold Nanoparticles-Mediated Radiofrequency Ablation

In this work, we report the design of an optical fiber distributed sensing network for the 2-dimensional (2D) in situ thermal mapping of advanced methods for radiofrequency thermal ablation. The sensing system is based on six high-scattering MgO-doped optical fibers, interleaved by a scattering-level spatial multiplexing approach that allows simultaneous detection of each fiber location, in a 40 × 20 mm grid (7.8 mm² pixel size). Radiofrequency ablation (RFA) was performed on bovine phantom, using a pristine approach and methods mediated by agarose and gold nanoparticles in order to enhance the ablation properties. The 2D sensors allow the detection of spatiotemporal patterns, evaluating the heating properties and investigating the repeatability. We observe that agarose-based ablation yields the widest ablated area in the best-case scenario, while gold nanoparticles-mediated ablation provides the best trade-off between the ablated area (53.0–65.1 mm², 61.5 mm² mean value) and repeatability.

Role of endoscopic ultrasound in anticancer therapy: Current evidence and future perspectives

The digestive system is one of the most common sites of malignancies in humans. Since gastrointestinal tumors represent a massive global health burden both in terms of morbidity and health care expenditures, scientists continuously develop novel diagnostic and therapeutic methods to ameliorate the detrimental effects of this group of diseases. Apart from the well-established role of the endoscopic ultrasound (EUS) in the diagnostic course of gastrointestinal and hepatobiliary malignancies, we have recently become acquainted with a vast array of its therapeutic possibilities. A multitude of previously established, evidence-based methods that might now be guided by the EUS emerged: Radiofrequency ablation, brachytherapy, fine needle injection, celiac plexus neurolysis, and endoscopic submucosal dissection. In this review we endeavored to provide a comprehensive overview of the role of these methods in different malignancies of the digestive system, primarily in the treatment and symptom control in pancreatic cancer, and additionally in the management of hepatic, gastrointestinal tumors, and pancreatic cysts.

The Role of Interventional Endoscopic Ultrasound in Liver Diseases: What Have We Learnt?

Chronic liver disease (CLD) is still a major problem, where the disease progression will lead to liver cirrhosis (LC) or hepatocellular carcinoma (HCC). Portal hypertension (PH) management and loco-regional therapy for HCC have become the cornerstones in advanced liver disease management. Recently, there are studies looking at the potential role of interventional endoscopic ultrasound (EUS) in liver diseases. EUS may be useful in vascular changes of the digestive wall evaluation, performing dynamic assessment of hemodynamic changes, predicting variceal bleeding and rebleeding risk, and assessing the pharmacological effects. In PH management, EUS-guided vascular therapy-which revolves around glue injection, endovascular coil placement/embolization, and combination of both-has shown promising results. As a diagnostic modality for liver cancer, the implementation of EUS in liver diseases is currently not only limited to liver biopsy (EUS-LB) but also in shear-wave elastography (SWE) and portal pressure gradient measurement, as well as portal vein sampling. The application of EUS-guided radiofrequency ablation (EUS-RFA) and tumor injection can also overcome the limitations shown by both modalities without EUS. Nevertheless, establishing EUS as a firm diagnostic and therapeutic modality is still challenging since the performance of interventional EUS requires high expertise and adequate facilities.

[Large Animal Models in Pancreas and Biliary Disease]

Rodent models, which have played important roles in preclinical research of pancreas and biliary diseases, have some limitations to translating data from rodent models to human diseases. Large animal models have recently been developed to overcome these limitations and perform translational research of medical devices and drugs in pancreas and biliary diseases. Preclinical studies using large animal models are necessary before clinical application, especially for the research and development of equipment, instrumentation, and techniques in pancreato-biliary diseases. As long as the endoscope used in humans can enter an organ, there appears to be no limitation in terms of species or organ for endoscopic experiments of large animal models. Investigators have mainly used swine for pancreas and biliary endoscopic experiments. Until now, unique swine models that investigators have been established include the normal bile duct model, bile duct dilation model, bile duct dilation+direct peroral cholangioscopy model, benign biliary stricture model, hilar biliary obstruction model, and acute pancreatitis (post-ERCP pancreatitis) model. Many preclinical studies have been performed using these established endoscopy-based large animal models to develop novel medical devices. Furthermore, porcine pancreatic cancer models induced by a transgenic or orthotopic method are currently under development. These models appear to be available for general use in the future and will have multiple potential preclinical and clinical applications.

Fully laparoscopic thermo-ablation of liver malignancies with or without liver resection: tumor location is an independent local recurrence risk factor

BACKGROUND

The aim of this study was to analyze risk factors of local recurrence (LR) after exclusive laparoscopic thermo-ablation (TA) with or without associated liver resection.

METHODS

Between 2012 and 2017, among 385 patients who underwent 820 TA in our department, 65 (17%) patients (HCC = 11, LM = 54) had exclusive laparoscopic TA representing 112 lesions (HCC = 17, LM = 95). TA was associated with other procedures in 57% of cases (liver resection 81%). All TA were done without liver clamping. Median tumor size was 1.8 cm [ranges from 0.3 to 4.5], 18% of the lesions were larger than 3 cm in size and 11% close to major liver vessels. Tumors locations were 77.5% in right liver, 36% in S7&S8, and 46% in S7&S8&S4a.

RESULTS

Mortality was nil and morbidity rate 15.4% including Dindo-Clavien > II grade 3%. The median follow-up was 24 months [0.77-75]. Per lesion LR rate after TA was 18% (n = 19 patients) with a mean time of 7.6 months. Among patients with LR, 18 (95%) could have been re-treated successfully (new resection = 11, re-TA = 7). Multivariate analyses revealed that tumor location in S7 alone, S7&S8 and/or S7, S8, or S4a were independent risk factors of LR after TA.

CONCLUSIONS

Exclusive laparoscopic TA is a safe and an effective tool to treat liver malignancies with or without liver resection. Other than classical risk factors, tumor location in upper segments of the liver, are independent risk factors for LR.

The role of EUS in diagnosis and treatment of liver disorders

Background and aim  Transabdominal ultrasound (US), computed tomographic scanning (CT) and magnetic resonance imaging (MRI) are established diagnostic tools for liver diseases. Percutaneous transhepatic cholangiography is used to perform hepatic interventional procedures including biopsy, biliary drainage procedures, and radiofrequency ablation. Despite their widespread use, these techniques have limitations. Endoscopic ultrasound (EUS), a tool that has proven useful for evaluating the mediastinum, esophagus, stomach, pancreas, and biliary tract, has an expanding role in the field of hepatology complementing the traditional investigational modalities. This review aimed to assess the current scientific evidence regarding diagnostic and therapeutic applications of EUS for hepatic diseases.

Optimization of an Endoscopic Radiofrequency Ablation Electrode

Radiofrequency ablation (RFA) is an increasingly used, minimally invasive, cancer treatment modality for patients who are unwilling or unable to undergo a major resective surgery. There is a need for RFA electrodes that generate thermal ablation zones that closely match the geometry of typical tumors, especially for endoscopic ultrasound-guided (EUS) RFA. In this paper, the procedure for optimization of an RFA electrode is presented. First, a novel compliant electrode design is proposed. Next, a thermal ablation model is developed to predict the ablation zone produced by an RFA electrode in biological tissue. Then, a multi-objective genetic algorithm is used to optimize two cases of the electrode geometry to match the region of destructed tissue to a spherical tumor of a specified diameter. This optimization procedure is then applied to EUS-RFA ablation of pancreatic tissue. For a target 2.5 cm spherical tumor, the optimal design parameters of the compliant electrode design are found for two cases. Cases 1 and 2 optimal solutions filled 70.9% and 87.0% of the target volume as compared to only 25.1% for a standard straight electrode. The results of the optimization demonstrate how computational models combined with optimization can be used for systematic design of ablation electrodes. The optimization procedure may be applied to RFA of various tissue types for systematic design of electrodes for a specific target shape.

New Indications for Endoscopic Radiofrequency Ablation

Radiofrequency ablation (RFA) is a well-established treatment for several benign, premalignant, and malignant disorders. Although the role of RFA has been clearly defined, new indications for luminal and extraluminal applications of endoscopic RFA-directed therapies have emerged. RFA has recently produced promising results in patients with a variety of gastrointestinal and hepatopancreatobiliary pathologies. For example, endoscopic RFA has been used to treat patients with gastric antral vascular ectasia, chronic radiation proctitis, malignant biliary strictures, and ampullary adenomas with intraductal extension. Furthermore, endoscopic ultrasound-guided RFA appears to be an effective, minimally invasive treatment for ablation of solid and cystic lesions-particularly in the pancreas. We review the newer indications for RFA and discuss potential limitations of endoscopic RFA.

Technique, safety, and feasibility of EUS-guided radiofrequency ablation in unresectable pancreatic cancer

BACKGROUND AND AIMS

Radiofrequency ablation (RFA) is a well-recognized local ablative technique applied in the treatment of different solid tumors. Intraoperative RFA has been used for non-metastatic unresectable pancreatic ductal adenocarcinoma (PDAC), showing increased overall survival in retrospective studies. A novel RFA probe has recently been developed, allowing RFA under endoscopic ultrasound (EUS) guidance. Aim of the present study was to assess the feasibility and safety of EUS-guided RFA for unresectable PDACs.

METHODS

Patients with unresectable non-metastatic PDAC were included in the study following neoadjuvant chemotherapy. EUS-guided RFA was performed using a novel monopolar 18-gauge electrode with a sharp conical 1 cm tip for energy delivery. Pre- and post-procedural clinical and radiological data were prospectively collected.

RESULTS

Ten consecutive patients with unresectable PDAC were enrolled. The procedure was successful in all cases and no major adverse events were observed. A delineated hypodense ablated area within the tumor was observed at the 30-day CT scan in all cases.

CONCLUSIONS

EUS-guided RFA is a feasible and safe minimally invasive procedure for patients with unresectable PDAC. Further studies are warranted to demonstrate the impact of EUS-guided RFA on disease progression and overall survival.

Evaluation of Effects of Radiofrequency Ablation of Ex vivo Liver Using the 1-Fr Wire Electrode

BACKGROUND AND STUDY AIMS

Percutaneous and intraoperative radiofrequency ablation (RFA) has become a valued tool in the management of primary and secondary hepatic lesions. A recent FDA-approved endoscopic ultrasound (EUS)-guided RFA probe now offers promise to help manage such lesions. However, there are no data to determine the ideal power setting and duration of ablation needed to effectively treat hepatic masses. The aim of the study was to evaluate the macroscopic zone of hepatic injury for EUS-RFA using a variety of settings within a fresh porcine hepatic specimen.

METHODS

RFA was performed using the Habib EUS-RFA needle (EMcision Ltd, London, UK) which is a 1-Fr wire (0.33 mm, 0.013 inch) with a working length of 190 cm. A step by step approach to deliver radiofrequency energy at 5, 10, 15, 20, and 50 W of power and 10, 30, 60, 90, 120, and 300 seconds, respectively, was followed. Macroscopic and microscopic findings of the ablation zone were evaluated at each setting.

RESULTS

The maximal zone (diameter, 8.2±0.14 mm; length, 20.85±0.21 mm) of coagulative necrosis was achieved using an ablation power of 10 W for duration of 90 seconds. Notably, increased power settings resulted in an unexpected and diminished effect on tissue destruction.

CONCLUSIONS

Our findings support the use of 10 W power for 90 seconds for maximum ablation in the liver. Our data also provide initial guidance and alternate settings to be considered when performing EUS-RFA to adjust the ablation power and duration to match the lesion size, shape, and risk of injury to adjacent structures.

EUS dating with laser ablation against the caudate lobe or left liver tumors: a win-win proposition?

Endoscopic ultrasound (EUS) have been not only a diagnostic tool, but also available in interventional therapy, which often previously needed surgical approaches to achieve. The study aimed to evaluate the effectiveness and safety of EUS-guided Nd:YAG laser ablation in unresectable tumors of the caudate lobe and left liver. We discussed ten cases of the caudate lobe and left liver tumors underwent laser ablation with EUS guidance. And we also have reviewed previous publication of EUS-guided thermal ablation for liver tumors in several decade years. EUS-guided Nd:YAG laser ablation (LA) of these tumors were successfully completed in ten patients, who had favourable prognosis with no complications in two-month follow-up. Based on our early observations, this suggested that EUS-guided LA might be technically feasible in selected patients with tumors of the caudate lobe and left liver. However, the safety of this technique need to be further confirmed in the future and if possible larger, prospective trials.

Recent Advances in Therapeutic Endosonography for Cancer Treatment

Therapeutic endosonography (EUS) may play an important role in the management of cancers. EUS-guided fiducial placement has a high success rate and can aid in stereotactic radiotherapy. EUS-guided tumor ablation therapies can help in palliation of locally advanced tumors. EUS-guided antitumor injection seems to be feasible and safe in animals; initial human studies suffer from small sample size and lack of controls. Randomized, controlled trials have not shown benefit over conventional therapy. EUS celiac plexus neurolysis has gained popularity and is performed by interventional endosonographers. Large trials are needed to determine the most appropriate indications and overall usefulness of these therapies.

Endoscopic ultrasonography-guided tumor ablation

Real-time guidance of needle advancement has transformed endoscopic ultrasound (EUS) from a diagnostic to an interventional procedure. EUS-guided fine-needle puncture has application in various interventional procedures (drainage of pseudocyst, biliary intervention, and injection of drugs). Celiac plexus or ganglion neurolysis for pain control is the major current EUS-guided fine-needle injection procedure. Feasibility and safety to accurately position needle devices and/or inject under real-time EUS imaging with precise delivery of interventional agent have expanded the use of EUS to ablate tumors. These include radiofrequency ablation, or delivery of fiducial markers, potential antitumor agents, or radioactive seeds, in the cancer mass. Minimally invasive EUS-guided antitumor therapy is primarily used for pancreatic cancer because of better anatomic access (vs other imaging modality) and the dismal prognosis (despite improvements in surgery and chemoradiation). Also, the response to parenteral chemotherapy in pancreatic cancer is poor because of suboptimal drug delivery resulting from hypovascularity and abundant desmoplasia. Other targets for EUS-guided tumor ablation are pancreatic neuroendocrine tumor and pancreatic cyst lesion, which are less aggressive and curable by resection. However, patients non-eligible for surgery may benefit from local EUS-guided ablation.

Review of endoscopic radiofrequency in biliopancreatic tumours with emphasis on clinical benefits, controversies and safety

Most pancreatic cancers and extrahepatic cholangiocarcinomas are unresectable at the time of diagnosis, and even in case of a resectable cancer, for elderly or patients with coexistent comorbidities, surgery is not an option. Current treatment alternatives in these scenarios are very limited. Biliary stenting with self-expanding metal stents (SEMS) is the mainstay palliative treatment of biliary obstruction due to unresectable pancreatic cancer or cholangiocarcinoma. Nevertheless, more than 50% of SEMS become occluded after 6 mo due to tumour over- and ingrowth, leading to hospital readmissions and reinterventions that significantly impair quality of life. Regimes of chemotherapy or chemoradiotherapy also provide minimal survival benefits. Therefore, novel therapies are eagerly awaited. Radiofrequency (RF) energy causes coagulative necrosis leading to local destruction of the accessed malignant tissue and has an established role in the treatment of malignancies in several solid organs, especially liver cancers. However, pancreatic and extrahepatic biliary cancers are not easily accessed by a percutaneous route, making the procedure dangerous. Over the past five years, the development of dedicated devices compatible with endoscopic instruments has offered a minimally invasive option for RF energy delivery in biliopancreatic cancers. Emerging experience with endoscopic RF ablation (RFA) in this setting has been reported in the literature, but little is known about its feasibility, efficacy and safety. A literature review makes it clear that RFA in biliopancreatic tumours is feasible with high rates of technical success and acceptable safety profile. Although available data suggest a benefit of survival with RFA, there is not enough evidence to draw a firm conclusion about its efficacy. For this reason, prospective randomized trials comparing RFA with standard palliative treatments with quality-of-life and survival endpoints are required. Anecdotal reports have also highlighted a potential curative role of RFA in small pancreatic tumours and benign conditions, such as ductal extension of ampullomas, intrahepatic adenomas or non-tumoural biliary strictures. These newest indications also deserve further examination in larger series of studies.

Endoscopic Ultrasound-Guided Radiofrequency Ablation of the Pancreatic Tumors: A Promising Tool in Management of Pancreatic Tumors

Objective. Radiofrequency ablation is a well-established antitumor treatment and is recognized as one of the least invasive therapeutic modalities for pancreatic neoplasm. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) delivery can be used to treat both pancreatic cancer and asymptomatic premalignant pancreatic neoplasms and may serve as a less invasive alternative to surgical resection. This is an appealing option that may result in less morbidity and mortality. The aim of this review was to summarize and evaluate the clinical and technical effectiveness of EUS-guided RFA of pancreatic neoplasms. Methods. A through literature review was performed to identify the studies describing this novel technique. In this review article, we have summarized human case series. The indications, techniques, limitations, and complications reported are discussed. Results. A total of six studies were included. Overall, a 100% technical success rate was reported in human studies. Complications related to endoscopic ultrasound-guided radiofrequency ablation delivery have been described; however, few cases have presented life-threatening outcomes. Conclusion. We believe that this novel technique can be a safe and effective alternative approach in the management of selected patients.

New semi-spherical radiofrequency energy device for liver resection: an experimental study in pigs

The aim of this experimental study was to verify a new semi-spherical surgical tool for bipolar radiofrequency liver ablation, which can solve some of the disadvantages of the commonly used device, such as the long duration of ablation. A total of 12 pigs which were randomly divided into two groups were used. Each pig underwent resection of the two liver lobes. In group 1, pigs were treated with the commonly used device; in group 2 the newly developed semi-spherical device was used. During surgery and the post-surgical period, many categories were observed and later analyzed. The blood count and biochemistry were monitored on days 0, 14 and 30 from the operation. On day 14 since the liver resection, pigs underwent diagnostic laparoscopy to evaluate their condition focusing on the site of the liver lobe resection. On day 30 after operation, all pigs were euthanized and subjected to histopathological examination. Histopathological evaluation of thermal changes at the resection margin showed strong thermal alteration in both groups. Data between both groups were compared using median test for continuous variables and Fisher’s exact test for categorical variables. Statistical analyses were performed with IBM SPSS software version 18.0. Statistical analysis of collected data did not prove any significant (P < 0.05) differences between the commonly used device and the newly designed surgical tool.

[Endoscopic Ultrasound-guided Local Therapy of Pancreatic Tumors]

The development of curvilinear EUS has enabled EUS-guided fine-needle aspiration of intra-abdominal mass lesions. With the introduction of interventional EUS, this technology has undergone several modifications in order to be applied to clinical medicine. One of the potential uses of interventional EUS is the EUS-guided local therapy of pancreatic tumors. Various treatment modalities such as fine-needle injection, radiofrequency ablation, photodynamic therapy, laser ablation, and brachytherapy have been tried under EUS guidance. Some of these modalities are being applied clinically. These methods for EUS-guided local therapy of pancreatic tumors will be reviewed in this article.

Endoscopic ultrasound and pancreatic cystic lesions-diagnostic and therapeutic applications

Pancreatic cystic lesions are being detected with an increasing frequency. Endoscopic ultrasound (EUS) provides both diagnostic and therapeutic means for pancreatic cystic lesions. Detailed imaging and EUS-guided fine-needle aspiration provide additional information on pancreatic cystic lesions. EUS-guided pseudocyst drainage has advantages over conventional drainage modalities. EUS-guided cyst ablation is a promising therapeutic modality.

Technical development of a new semispherical radiofrequency bipolar device (RONJA): ex vivo and in vivo studies

The aim of this study is to inform about the development of a new semispherical surgical instrument for the bipolar multielectrode radiofrequency liver ablation. Present tools are universal; however they have several disadvantages such as ablation of healthy tissue, numerous needle punctures, and, therefore, longer operating procedure. Our newly designed and tested semispherical surgical tool can solve some of these disadvantages. By conducting an in vivo study on a set of 12 pigs, randomly divided into two groups, we have compared efficiency of the newly developed instrument with the commonly used device. Statistical analysis showed that there were no significant differences between the groups. On average, the tested instrument RONJA had shorter ablation time in both liver lobes and reduced the total operating time. The depth of the thermal alteration was on average 4 mm larger using the newly tested instrument. The new radiofrequency method described in this study could be used in open liver surgery for the treatment of small liver malignancies (up to 2 cm) in a single application with the aim of saving healthy liver parenchyma. Further experimental studies are needed to confirm these results before clinical application of the method in the treatment of human liver malignancies.

Endoscopic ultrasound and fine needle aspiration in pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer mortality for both men and women in the United States. Overall 5-year survival from time of diagnosis is less than 5%. The only meaningful chance for cure results from early detection while the tumor remains resectable without locoregional extension or metastasis. Endoscopic ultrasound (EUS) is uniquely suited to the examination and treatment of the pancreas. Endoscopic ultrasound can provide important information with regard to disease stage including involvement of the mesenteric vasculature, adjacent organ invasion, and regional lymph node metastasis. In addition, EUS is considered the procedure of choice for tissue diagnosis of pancreatic cancer. More recently, EUS has developed therapeutic roles in an array of other clinical situations including EUS-guided fine needle injection, EUS-guided biliary drainage, celiac plexus neurolysis, brachytherapy, fiducial placement, and emerging antitumor agents delivered directly into the tumor.

Endoscopic Ultrasound-Guided Radiofrequency Ablation (EUS-RFA) of the Pancreas in a Porcine Model

Backgrounds. Limited effective palliative treatments exist for pancreatic cancer which includes surgery or chemotherapy. Radiofrequency ablation (RFA) uses high frequency alternating current to ablate diseased tissue and has been used to treat various tumors. In this study, we evaluated a prototype probe adjusted to the EUS-needle to perform EUS-RFA to permit coagulative necrosis in the pancreas. Methods. Five Yucatan pigs underwent EUS-guided radiofrequency ablation of the head of their pancreas. Using an EUS-needle, RFA was applied with 6 mm and then 10 mm of the probe exposed at specific wattage for preset durations. Results. Only one pig showed moderate levels of pancreatitis (20% proximal pancreatitis). The other animals showed much lower areas of tissue damage. In 3 of the 5 pigs, the proximal pancreas showed greater levels of tissue injury than the distal pancreas, consistent with the proximity of the tissue to the procedure site. In 1 pig, both proximal and distal pancreas showed minimal pancreatitis (1%). There was minimal evidence of fat necrosis in intra-pancreatic and/or extra-pancreatic adipose tissue. Conclusion. EUS-guided RFA of the pancreatic head with the monopolar probe through a 19-gauge needle was well tolerated in 5 Yucatan pigs and with minimal amount of pancreatitis.

Endoscopic ultrasonography-guided tumor ablation

With the introduction of curvilinear endosonoscopes, endoscopic ultrasonography (EUS) has achieved the role of a therapeutic modality as well as diagnostic procedure. EUS-guided tumor ablation is one such therapeutic modality. Various techniques of EUS-guided tumor ablation have been described, including radiofrequency ablation, photodynamic therapy, laser ablation, and ethanol injection. Most of the currently described techniques are experimental. Development and continuous improvement of devices, as well as establishment of indications for EUS-guided tumor ablations, are mandatory.

Endo-hepatology: a new paradigm

Recent advances in hepatology have included a new and effective treatment of viral hepatitis, with an increased need for the assessment of liver function and histology. At the same time, there have been a growing number of endoscopic procedures that are pertinent to patients with liver disease. It would be ideal if the assessment and treatment of liver disease and portal hypertension could be performed and assimilated by the liver/gastrointestinal specialist. The authors like to consider this area of integration or overlap of endoscopic procedures within the practice of hepatology as endo-hepatology.

Endoscopic ultrasonography-guided ablation therapy

Endoscopic ultrasonography (EUS) imaging has undergone extensive technological advancement since its development in the 1980s, including improvement of echoendoscopes with larger channels and accessories.These advancements enable not only tissue procurement for diagnosis but also therapeutic interventions that hitherto would have required surgery, with its attendant risks. A wide array of interventional procedures are performed under EUS guidance, including celiac plexus neurolysis, drainage of pancreatic and pelvic fluid collections, drainage of obstructive pancreatic-biliary ducts, ablation of cyst neoplasms in the pancreas, and implantation of fiducial markers and radioactive seeds into gastrointestinal tumors. Various experimental procedures are also underway to evaluate the role of EUS in radiofrequency ablation, vascular therapy, and natural orifice transluminal endoscopic surgery. In this review, we examine the various EUS-guided ablation therapies currently undertaken in humans.

Interventional EUS

The American Society for Gastrointestinal Endoscopy (ASGE) Technology Committee provides reviews of new or emerging endoscopic technologies that have the potential to have an impact on the practice of GI endoscopy. Evidence-based methodology is used by performing a MEDLINE literature search to identify pertinent preclinical and clinical studies on the topic and a MAUDE (U.S. Food and Drug Administration Center for Devices and Radiological Health) database search to identify the reported complications of a given technology. Both are supplemented by accessing the "related articles" feature of PubMed and by scrutinizing pertinent references cited by the identified studies. Controlled clinical trials are emphasized, but, in many cases, data from randomized, controlled trials are lacking. In such cases, large case series, preliminary clinical studies, and expert opinions are used. Technical data are gathered from traditional and Web-based publications, proprietary publications, and informal communications with pertinent vendors. For this review, the MEDLINE database was searched through August 2009 by using the keywords "interventional endoscopic ultrasound," "EUS," and "interventional endoscopy." Reports on Emerging Technologies are drafted by 1 or 2 members of the ASGE Technology Committee, reviewed and edited by the committee as a whole, and approved by the Governing Board of the ASGE. These reports are scientific reviews provided solely for educational and informational purposes. Reports on Emerging Technologies are not rules and should not be construed as establishing a legal standard of care or as encouraging, advocating, requiring, or discouraging any particular treatment or payment for such treatment.