Steerable needles for radio-frequency ablation in cirrhotic livers.

Accurate needle placement in deep-seated liver tumours can be difficult. In this work, we disclose two new manually controlled steerable needles for 17G radio-frequency ablation probe placement. The needles contain stylets with embedded compliant joints for active tip articulations, and concentric tubes for (curved-path) guidance. Needle steering was evaluated sequentially by intended users and in intended-use tissue types. Six interventional radiologists evaluated the needle in repeated ultrasound-guided steering tasks in liver-mimicking phantoms. Targets were located at a 100 mm depth and 20 mm lateral offset from the initial insertion line. The resulting mean absolute tip placement error was 1.0 ± 1.0 mm. Subsequently, steering-induced tissue damage was evaluated in fresh cirrhotic human liver explants. The surface area of puncture holes was estimated in scanned histology slides, using a connected-components analysis. The mean surface area was 0.26 ± 0.16 mm2 after steering with a median radius of curvature of 0.7 × 103 mm, versus 0.35 ± 0.15 mm2 after straight-path insertions with the steerable needle and 0.15 ± 0.09 mm2 after straight-path RFA probe insertions. The steering mechanisms proposed enable clinically relevant path corrections for 17G needles. Radiologists were quickly adept in curved-path RFA probe placement and the evaluation of histological tissue damage demonstrated a potentially safe use during liver interventions.

Laparoscopic transperitoneal adrenalectomy: a comparative study of different techniques for vessel sealing.

BACKGROUND: Laparoscopic adrenalectomy is the standard surgical approach to adrenal lesions. Adrenal vessel sealing is the critical surgical phase of laparoscopic adrenalectomy. This study aimed at comparing perioperative outcomes of laparoscopic transperitoneal adrenalectomy by means of radiofrequency energy-based device (LARFD) to those performed with traditional clipping device (LACD), while focusing on the different adrenal vessel control techniques. METHODS: Patients who underwent adrenalectomy for adrenal disease between January 1994 and April 2019 at the Surgical Clinic, Polytechnic University of Marche were included in the study. Overall, 414 patients met inclusion criteria for study eligibility: 211 and 203 patients underwent LARFD and LACD, respectively. Multiple models of quantile regression, logistic regression and Poisson finite mixture regression were used to assess the relationship between operative time, conversion to open procedure, length of stay (LoS), surgical procedure and patient characteristics, respectively. RESULTS: LARFD reduced operative time of about 12 min compared to LACD. Additional operative time-related factors were surgery side, surgery approach, conversion to open procedure and trocar number. The probability of conversion to open procedure decreased by about 76% for each added trocar, whereas it increased by about 49% for each added centimeter of adrenal lesion and by about 25% for each added year of surgery. Two patient clusters were identified based on the LoS: long-stay and short-stay. In the long-stay cluster, LoS decreased of about 30% in LARFD group and it was significantly associated with conversion to open procedure and postoperative complications, whereas in short-stay cluster only postoperative complications had a significant effect on LoS. CONCLUSION: Laparoscopic transperitoneal adrenalectomy performed by means of radiofrequency energy-based device for the sealing of adrenal vessels is an effective procedure reducing operative time with potentially improved postoperative outcomes.

Prospective comparative study of different endovenous thermal ablation systems for treatment of great saphenous vein reflux.

OBJECTIVE: The aim of our study was to compare three different endovenous thermal ablation (EVTA) modalities in the treatment of great saphenous vein (GSV) incompetence. METHODS: We performed a single-center, prospective, comparative cohort study that included consecutive patients undergoing EVTA of the GSV. Patients were treated with either segmental radiofrequency ablation (sRFA) or endovenous laser ablation (EVLA) with a 1470-nm dual radial fiber or with a 1470-nm jacket-tip fiber. The clinical classification CEAP (clinical, etiologic, anatomic, pathophysiologic), 10-cm visual analog scale scores for pain, Venous Clinical Severity Scores (VCSSs), and chronic venous insufficiency quality-of-life questionnaire (CIVIQ-20) scores were recorded. The primary outcome was clinical success, which was defined as the absence of reflux or recanalization of the GSV and procedure-related complications, assessed at 7 and 30 days and 1 year postoperatively. The secondary outcomes were the assessment of postoperative pain using the VAS and improvement in the VCSSs and CIVIQ-20 scores. RESULTS: A total of 153 patients (160 limbs) had undergone sRFA (sRFA group; n = 53 limbs), 1470-nm radial fiber EVLA (EVLA-R group; n = 55 limbs), or 1470-nm jacket-tip fiber EVLA (EVLA-J group; n = 52 limbs). The patient demographics, CEAP clinical class, and intraoperative details were comparable among the three groups. The GSV occlusion rate at 1 year was 93% in the sRFA group, 93% in the EVLA-R group, and 95% in the EVLA-J group. No major complications were observed postoperatively. Endothermal heat-induced thrombosis was observed in 2 (4.4%), 1 (2.2%), and 2 (4.4%) patients in the sRFA, EVLA-R, and EVLA-J groups, respectively (P > .5). The VCSS showed greater improvement in the EVLA-R group at 1 week compared with that in the sRFA (P = .05) and EVLA-J (P = .002) groups. Changes in the CIVIQ-20 score were in favor of the EVLA-R group at 7 days (-14.3 ± 10.3 vs -7.9 ± 5.9; adjusted difference, 6.06; 95% confidence interval [CI], 1.57-10.55; P = .01) and 30 days (-12 ± 8 vs -11.2 ± 7; adjusted difference, 5.5; 95% CI, 1.21-9.81; P = .02) postoperatively compared with the sRFA group and at 7 days compared with the EVLA-J group (-14.3 ± 10.3 vs -9.6 ± 7.9; adjusted difference, -4.4; 95% CI, -9.06 to 0.22; P = .05). Analyzing the different components of the CIVIQ-20, pain, and physical scores showed a greater reduction in the EVLA-R group in the early postoperative period compared with that in the sRFA and EVLA-J groups. CONCLUSIONS: All three EVTA modalities showed equal effectiveness and safety for the treatment of GSV reflux. EVLA with the 1470-nm radial fiber showed better outcomes in terms of early postoperative VCSSs and pain and physical CIVIQ scores. The clinical and quality of life benefits were similar for all modalities at 1 year postoperatively.

Efficacy and safety of palliative endobiliary radiofrequency ablation using a novel temperature-controlled catheter for malignant biliary stricture: a single-center prospective randomized phase II TRIAL.

BACKGROUND: Endobiliary radiofrequency ablation (EB-RFA) has emerged as a palliative treatment for malignant biliary strictures (MBSs); however, concerns about complications related to thermal injury remain. In this study, we evaluated the efficacy and safety of EB-RFA with a novel catheter for MBS. METHODS: Patients with inoperable cancer causing MBS were randomly assigned to either the radiofrequency ablation (RFA) group or the non-RFA group. The RFA group underwent EB-RFA at the stricture site with a temperature-controlled catheter (ELRA™; STARmed Co., Goyang, Korea) followed by deployment of a self-expanding metal stent (SEMS). For the non-RFA group, only SEMS placement was performed. The duration of stent patency, overall survival (OS), and 30-day complication rate were evaluated. This trial was registered at ClinicalTrials.gov (number NCT02646514). RESULTS: A total of 48 patients were enrolled (24 in each group). During a median follow-up period of 135.0 days (RFA group) and 119.5 days (non-RFA group), the 90-day stent patency rate, median duration of stent patency, and median OS were not different between the groups (58.3% vs. 45.8% [P = 0.386], 132.0 days vs. 116.0 days [P = 0.440], and 244.0 days vs. 180.0 days [P = 0.281], respectively). In the RFA group, procedure-related complications including thermal injury-related complications, such as bile duct perforation or hemobilia, were not reported. The early complication (< 7 days) rates were not different between the groups (4.2% vs. 12.5%, P = 0.609), and there were no late complications (7-30 days) in both groups. CONCLUSION: EB-RFA with a temperature-controlled catheter followed by SEMS placement for patients with inoperable MBS can be safe and feasible with acceptable biliary patency.

Plume Effect of Fractional Radiofrequency Verus Laser Resurfacing: Considerations in the COVID-19 Pandemic.

INTRODUCTION: The COVID-19 pandemic requires us all to re-evaluate aesthetic practices to ensure optimal patient safety during elective procedures. Specifically, energy-based devices and lasers require special consideration, as they may emit plume which has been shown to contain tissue debris and aerosolized biological materials. Prior studies have shown transmission of viruses and bacteria via plume (i.e., HIV and papillomavirus). The purpose of this study was to evaluate plume characteristics of the Er:YAG resurfacing laser (Sciton; Palo Alto, CA) and compare it to the Morpheus8 fractional radiofrequency device (InMode; Lake Forest, CA). METHODS: Five patients who underwent aesthetic resurfacing and/or skin tightening of the face and neck were treated with the Er:YAG (Sciton Joule, Palo Alto, CA) and/or fractional radiofrequency (Morpheus8, Lake Forest, CA) between April 1 and May 11, 2020. Data collected included patient demographics, past medical history, treatment parameters, adverse events, particle counter data, as well as high magnification video equiptment. Patients were evaluated during treatment with a calibrated particle meter (PCE; Jupiter, FL). The particle meter was used at a consistent focal distance (6-12 inches) to sample the surrounding environment during treatment at 2.83 L/min to a counting efficiency of 50% at 0.3 µm and 100% at >0.45 µm. Recordings were obtained with and without a smoke evacuator. RESULTS: Of our cohort (n = 5), average age was 58 years old (STD ±7.2). Average Fitzpatrick type was between 2 and 3. Two patients received Er:YAG fractional resurfacing in addition to fractional radiofrequency during the same treatment session. Two patients had fractional radiofrequency only, and one patient had laser treatment with the Er:YAG only. There were no adverse events recorded. The particle counter demonstrated ambient baseline particles/second (pps) at 8 (STD ±6). During fractional radiofrequency treatment at 1-mm depth, the mean recording was 8 pps (STD ±8). At the more superficial depth of 0.5 mm, recordings showed 10 pps (STD ±6). The Er:YAG laser resurfacing laser had mean readings of 44 pps (STD ±11). When the particle sizes were broken down by size, the fractional radiofrequency device had overall smaller particle sizes with a count of 251 for 0.3 µm (STD ±147) compared with Er:YAG laser with a count of 112 for 0.3 µm (STD ±84). The fractional radiofrequency did not appear to emit particles >5 µm throughout the treatment, however, the Er:YAG laser consistently recorded majority of particles in the range of 5-10 µm. The addition of the smoke evacuator demonstrated a 50% reduction in both particles per second recorded as well as all particle sizes. CONCLUSION: Re-evaluation of the plume effect from aesthetic devices has become important during the COVID-19 pandemic. Further studies are required to characterize viability of COVID-19 viability and transmissibility in plume specimens. Based on this pilot study, we recommend that devices that generate little to no plume such as fractional radiofrequency devices be used in Phase I reopening of practice while devices that generate a visible plume such as Er:YAG laser resurfacing devices be avoided and only used with appropriate personal protective equipment in addition to a smoke evacuator in Phase IV reopening.

Prostate Radiofrequency Focal Ablation (ProRAFT) Trial: A Prospective Development Study Evaluating a Bipolar Radiofrequency Device to Treat Prostate Cancer.

PURPOSE: We determined the early efficacy of bipolar radiofrequency ablation with a coil design for focal ablation of clinically significant localized prostate cancer visible at multiparametric magnetic resonance imaging. MATERIALS AND METHODS: A prospective IDEAL phase 2 development study (Focal Prostate Radiofrequency Ablation, NCT02294903) recruited treatment-naïve patients with a single focus of significant localized prostate cancer (Gleason 7 or 4 mm or more of Gleason 6) concordant with a lesion visible on multiparametric magnetic resonance imaging. Intervention was a focal ablation with a bipolar radiofrequency system (Encage™) encompassing the lesion and a predefined margin using nonrigid magnetic resonance imaging-ultrasound fusion. Primary outcome was the proportion of men with absence of significant localized disease on biopsy at 6 months. Trial followup consisted of serum prostate specific antigen, multiparametric magnetic resonance imaging at 1 week, and 6 and 12 months post-ablation. Validated patient reported outcome measures for urinary, erectile and bowel functions, and adverse events monitoring system were used. Analyses were done on a per-protocol basis. RESULTS: Of 21 patients recruited 20 received the intervention. Baseline characteristics were median age 66 years (IQR 63-69) and preoperative median prostate specific antigen 7.9 ng/ml (5.3-9.6). A total of 18 patients (90%) had Gleason 7 disease with median maximum cancer 7 mm (IQR 5-10), for a median of 2.8 cc multiparametric magnetic resonance imaging lesions (IQR 1.4-4.8). Targeted biopsy of the treated area (median number of cores 6, IQR 5-8) showed absence of significant localized prostate cancer in 16/20 men (80%), concordant with multiparametric magnetic resonance imaging. There was a low profile of side effects at patient reported outcome measures analysis and there were no serious adverse events. CONCLUSIONS: Focal therapy of significant localized prostate cancer associated with a magnetic resonance imaging lesion using bipolar radiofrequency showed early efficacy to ablate cancer with low rates of genitourinary and rectal side effects.

Oclusión de la vena safena con cianocrilato, una alternativa para el tratamiento de insuficiencia venosa crónica. Experiencia inicial en el Instituto Guatemalteco de Seguridad Social ­ IGSS / Occlusion of the saphenous vein with cyanoacrylate, an alternative for the treatment of chronic venous insufficiency. Initial experience at the Guatemalan Social Security Institute - IGSS

Las técnicas de termo ablación han revolucionado el tratamiento de la insuficiencia venosa crónica, siendo actualmente el estándar de tratamiento. Con el avance tecnológico han surgido nuevas técnicas quirúrgicas, no térmicas, no tumescentes; como el uso de cianocrilato para la oclusión venosa, el cual ha demostrado ser seguro y eficaz en el tratamiento, y tener menos complicaciones posoperatorias. Objetivo: Describir la experiencia en nuestro hospital con el uso de cianocrilato para la oclusión de vena safena mayor para el tratamiento de insuficiencia venosa crónica. Describir la eficacia a corto y mediano plazo del cierre, las complicaciones y la mejoría de la sintomatología utilizando el cuestionario CIVIQ-20 y EVA. Material y métodos: Estudio retrospectivo observacional. Entre enero y diciembre de 2019 que incluye a pacientes con insuficiencia de unión safeno femoral, sintomáticos. Con diagnóstico mediante clasificación CEAP y ultrasonido Doppler. Seguimiento clínico y ecográfico valorando oclusión de los segmentos tratados y presencia de venas varicosas a los 3 y 6 meses. Se trataron 5 pacientes con oclusión venosa con cianocrilato (100% mujeres). Valoramos la calidad de vida mediante cuestionario CIVIQ-20 y EVA (Escala Analógica Visual) previo y un mes después del procedimiento. También se describe la tasa de éxito y complicaciones inmediatas y tardías. Resultados: La totalidad de los procedimientos se realizaron con anestesia local, siendo bien tolerados. Con un éxito inmediato del 100 % sin necesidad de conversión. Solo se presentó como complicación urticaria en un paciente en el trayecto de la vena tratada con cianocrilato, la cual se trató con esteroides y resolvió. El CIVIQ-20 mostró mejoría global pasando de 35 a 29 puntos en promedio; siendo el parámetro de actividad física el que mostró una mejoría mayor. EVA demostró que la pesadez (principal síntoma) se redujo un 67%. Durante el seguimiento, ningún caso presento repermeabilización o recanalizaciones segmentarias. Conclusiones: El tratamiento endovenoso de la insuficiencia venosa crónica con las nuevas técnicas no térmicas, no tumescentes es seguro y efectivo. A corto-mediano plazo ofrecen resultados similares a las técnicas termoablativas obviando el inconveniente de la tumescencia y el uso de medias compresivas en el posoperatorio, evitando lesiones térmicas y observándose mejoría en la sintomatología. (AU)

Thermo ablation techniques have revolutionized the treatment of chronic venous insufficiency, being currently the standard of treatment. With technological advancement, new non-thermal, non-tumescent surgical techniques have emerged; such as the use of cyanoacrylate for venous occlusion, which has been shown to be safe and effective in treatment, and have fewer postoperative complications. Objective: To describe the experience in our hospital with the use of cyanoacrylate for occlusion of the greater saphenous vein for the treatment of chronic venous insufficiency. Describe the shortand medium-term efficacy of closure, complications, and symptom improvement using the CIVIQ-20 questionnaire and VAS. Material and methods: Retrospective observational study. Between January and December 2019 that includes patients with symptomatic saphenous femoral junction insufficiency. With diagnosis by CEAP classification and Doppler ultrasound. Clinical and ultrasound follow-up evaluating occlusion of the treated segments and the presence of varicose veins at 3 and 6 months. 5 patients with venous occlusion were treated with cyanoacrylate (100% women). We assessed the quality of life using the CIVIQ-20 questionnaire and VAS (Visual Analogue Scale) before and one month after the procedure. The immediate and late success rate and complications are also described. Results: All the procedures were performed under local anesthesia, being well tolerated. With immediate 100% success without the need for conversion. Urticaria only presented as a complication in a patient in the path of the vein treated with cyanoacrylate, which was treated with steroids and resolved. The CIVIQ-20 showed global improvement, going from 35 to 29 points on average; being the physical activity parameter the one that showed the greatest improvement. VAS showed that heaviness (main symptom) was reduced by 67%. During follow-up, no case presented segmental recanalization or recanalization. Conclusions: Endovenous treatment of chronic venous insufficiency with new non-thermal, non-tumescent techniques is safe and effective. In the short-medium term, they offer results similar to thermoablative techniques, avoiding the inconvenience of tumescence and the use of compression stockings in the postoperative period, avoiding thermal injuries and observing improvement in symptoms. (AU)

A Systematic Review of Nonsurgical Vulvovaginal Restoration Devices: An Evidence-Based Examination of Safety and Efficacy.

BACKGROUND: The efficacy and safety of vulvovaginal restoration devices were called into question in a U.S. Food and Drug Administration statement on July 30, 2018, claiming that women are being harmed by laser and other energy-based devices. The goal of this systematic literature review was to assess existing data, determine gaps in evidence, and propose opportunities for continued investigation pertaining to laser and energy-based vaginal restoration techniques. METHODS: A review of literature using PubMed, Cochrane Library databases, Embase, MEDLINE, and the Cumulative Index to Nursing and Allied Health Literature was conducted on January 9, 2019, and articles up to this point were considered. For inclusion, studies had to be available or translated in English and relate to clinical medicine, direct patient care, and nonsurgical energy-based vulvovaginal procedures. RESULTS: The authors found five level I studies, 19 level II studies, four level III studies, and 46 level IV studies that used 15 different devices. Various degrees of improvement of symptoms were reported in all studies. Adverse events/side effects were noted in two of the 13 radiofrequency device studies, 15 of the 23 erbium:yttrium-aluminum-garnet device studies, and 17 of the 37 carbon dioxide device studies. The majority of adverse events were considered mild. CONCLUSIONS: The majority of studies resulted in mild to no adverse side effects. However, there is a large gap in level I evidence. As a result, the authors emphasize the necessity of supplemental data surrounding this subject and suggest that additional randomized sham-controlled studies be conducted to further investigate vulvovaginal restoration devices in an effort to address women's health issues.

Endoscopic Ultrasound-Guided Antegrade Radiofrequency Ablation and Metal Stenting With Hepaticoenterostomy for Malignant Biliary Obstruction: A Prospective Preliminary Study.

OBJECTIVES: Endobiliary radiofrequency ablation (RFA) for malignant biliary obstruction is a promising option for improving biliary stent patency, but its efficacy and safety with endoscopic ultrasound (EUS)-guided biliary drainage are uncertain. We examined the feasibility of EUS-guided hepaticoenterostomy with antegrade stenting (EUS-HEAS) and RFA in patients with unresectable malignant biliary obstruction. METHODS: This was a prospective, single-center, single-arm, preliminary study. Twenty patients who met the eligibility criteria for inclusion between August 2018 and January 2020 were enrolled. We evaluated the technical success, functional success, recurrent biliary obstruction (RBO), and adverse events other than RBO associated with EUS-HEAS with RFA. RESULTS: The technical and functional success rates were both 80% (16/20). The procedure was unsuccessful in a total of 4 patients due to failure to insert the RFA catheter through the fistula (2 patients) or failure to pass the RFA catheter through the stricture (2 patients). Early and late adverse events other than RBO occurred in 10% (2/20) and 13% (2/16) of subjects, respectively. The RBO rate was 25% (4/16), and the median time to RBO was 276 days. The success rate of endoscopic reintervention using hepaticoenterostomy was 100% (4/4). DISCUSSION: This preliminary study showed that EUS-HEAS with RFA achieves good results but RFA catheter insertion can be difficult. Further evaluation and device improvements are warranted.

Transjugular Intrahepatic Portosystemic Shunt Creation Using a Radiofrequency Wire: Prospective Clinical Safety and Feasibility Trial in Cirrhosis.

PURPOSE: To assess the safety and feasibility of using a radiofrequency (RF) wire for portosystemic shunt creation. MATERIALS AND METHODS: Ten patients undergoing elective creation of a transjugular intrahepatic portosystemic shunt (TIPS) or a direct intrahepatic portosystemic shunt (DIPS) were prospectively enrolled. Primary outcomes were the safety and feasibility of RF wire used for the creation of TIPS and DIPS. Median age was 66.5 ± 6.1 years. Causes of liver disease included alcohol (n = 5), nonalcoholic steatohepatitis (n = 2), hepatitis C virus (n = 1), primary biliary cirrhosis (n = 1), autoimmune hepatitis (n = 1). The median score for model for end-stage liver disease was 11 ± 4.3. The Rosch-Uchida TIPS set was used with intravascular ultrasonography guidance in all cases. A 0.035-inch RF wire was used in lieu of the trocar needle through the 5-F TIPS set catheter to create a track between the hepatic vein and the portal vein. All shunts were created using stent grafts. RESULTS: Technical success rate was 100%. In 7 of 10 patients, portal vein access was achieved with a single pass. A DIPS was created in 2 patients based on anatomic favorability. Median fluoroscopy time was 13.3 ± 3.8 min, and median total procedure time was 102 ± 19 min. The wire passed through parenchyma without subjective deflection. There was 1 case of extracapsular puncture with no clinical consequence. The RF wire was too stiff to curve into the main portal vein, requiring wire exchange in all but 1 case. Mean portosystemic gradient decreased from 13.9 ± 3.3 to 5.9 ± 2.1 mm Hg. No immediate complications were encountered. Shunt patency was 100% at 30 days. CONCLUSIONS: Creation of TIPS and DIPS using an RF wire was safe and feasible, enabling creation of an intrahepatic track without subjective deflection in cirrhotic patients.

Characterization of the ablation zones produced by three commercially available systems from a single vendor for radiofrequency thermoablation in an ex vivo swine liver model.

BACKGROUND: Radiofrequency Ablation (RFA) is rarely performed in veterinary medicine. A rationale exists for its use in selected cases of canine liver tumours. RFA induces ablation zones of variable size and geometry depending on the technique used and on the impedance of the targeted organ. OBJECTIVES: (a) to describe the geometry and reproducibility of the ablation zones produced by three commercially available systems from a single company, using isolated swine liver parenchyma as a model for future veterinary applications in vivo; (b) to study the effects of local saline perfusion into the ablated parenchyma through the electrode tip and of single versus double passage of the electrode on size, geometry and reproducibility of the ablation zones produced. METHODS: Size, and geometry of ablation zones reproduced in six livers with one cooled and perfused (saline) and two cooled and non-perfused systems, after single or double passage (n = 6/condition), were assessed macroscopically on digitalized images by a blinded operator. Longitudinal and transverse diameters, equivalent diameter, estimated volume and roundness index were measured. Reproducibility was assessed as coefficient of variation. RESULTS AND CONCLUSIONS: Ablation zone reproducibility was higher when expressed in terms of ablation zone diameters than estimated volume. Local saline perfusion of the parenchyma through the electrode tip during RFA increased the ablation zone longitudinal diameter. Ablation zone estimated volume increased with saline perfusion only when double passage was performed. These data may provide useful information for those clinicians who intend to include RFA as an additive tool in veterinary interventional radiology.

Radiofrequency combined with immunomodulation for hepatocellular carcinoma: State of the art and innovations.

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and has been considered a very immunogenic tumor. The treatment with radiofrequency ablation (RFA) has been established as the standard ablative therapy for early HCC, and is currently recognized as the main ablative tool for HCC tumors < 5 cm in size; however, progression and local recurrence remain the main disadvantages of this approach. To solve this clinical problem, recent efforts were concentrated on multimodal treatment, combining different strategies, including the combination of RFA and immunotherapy. This article reviewed the combination treatment of RFA with immunotherapy and found that this treatment strategy leads to an increased response of anti-tumor T cells, significantly reduces the risk of recurrence and improves survival rates compared to RFA alone. This review highlighted scientific evidence that supports the current recommendations for pre-clinical studies, and discuss the need for further research on this topic.

Radiofrequency ablation with four electrodes as a building block for matrix radiofrequency ablation: Ex vivo liver experiments and finite element method modelling. Influence of electric and activation mode on coagulation size and geometry.

PURPOSE: Radiofrequency ablation (RFA) is increasingly being used to treat unresectable liver tumors. Complete ablation of the tumor and a safety margin is necessary to prevent local recurrence. With current electrodes, size and shape of the ablation zone are highly variable leading to unsatisfactory local recurrence rates, especially for tumors >3 cm. In order to improve predictability, we recently developed a system with four simple electrodes with complete ablation in between the electrodes. This rather small but reliable ablation zone is considered as a building block for matrix radiofrequency ablation (MRFA). In the current study we explored the influence of the electric mode (monopolar or bipolar) and the activation mode (consecutive, simultaneous or switching) on the size and geometry of the ablation zone. MATERIALS AND METHODS: The four electrode system was applied in ex vivo bovine liver. The electric and the activation mode were changed one by one, using constant power of 50 W in all experiments. Size and geometry of the ablation zone were measured. Finite element method (FEM) modelling of the experiment was performed. RESULTS: In ex vivo liver, a complete and predictable coagulation zone of a 3 × 2 × 2 cm block was obtained most efficiently in the bipolar simultaneous mode due to the combination of the higher heating efficacy of the bipolar mode and the lower impedance by the simultaneous activation of four electrodes, as supported by the FEM simulation. CONCLUSIONS: In ex vivo liver, the four electrode system used in a bipolar simultaneous mode offers the best perspectives as building block for MRFA. These results should be confirmed by in vivo experiments.

Spinal Tumor Ablation: Indications, Techniques, and Clinical Management.

Percutaneous thermal ablation has proven to be safe and effective in the management of patients with spinal tumors. Such treatment is currently proposed following the decision of a multidisciplinary tumor board to patients with small painful benign tumors such as osteoid osteoma or osteoblastoma, as well as carefully selected patients presenting with spinal metastases. In both scenarios, in order to provide a clinically effective procedure, ablation is often tailored to the specific patients' clinical needs and features of the target tumor. In this review, we present the most common clinical contexts in which spine ablation may be proposed. We scrutinize technical aspects and challenges that may be encountered during the procedure, as well as offering insight on follow-up and expected outcomes.

Ablation of Small Renal Masses.

Renal cell carcinoma is most commonly diagnosed in the sixth or seventh decade of life. Historically, surgical extirpation was the gold standard treatment option for small renal masses. However, given the comorbidities in this elderly population, not all patients are candidates for surgery. The development of minimally invasive ablative therapies has solved the surgical dilemma in this patient population. Furthermore, the 2017 American Urological Association guidelines recommends consideration of percutaneous image guided thermal ablation as a treatment option for masses smaller than 3 cm even in healthy individuals. Percutaneous image guided thermal ablation is an attractive treatment option providing excellent local tumor control, fewer complications, better preservation of the renal functions, faster recovery and shorter hospital stay. Various ablative modalities are available in clinical practice. This includes radiofrequency ablation, cryoablation, microwave ablation, irreversible electroporation, high intensity focused ultrasound, and laser ablation. In this review, we focus on the most commonly used modalities including radiofrequency ablation and cryoablation and to a lesser extent microwave ablation and irreversible electroporation.

Low-temperature radiofrequency coblation reduces treatment interval and post-operative pain of laryngotracheal recurrent respiratory papillomatosis.

Laryngeal papillomatosis is a benign disease in the larynx but with the potential to develop into significant complications as a result of its high recurrence rate. CO2 laser and radiofrequency controlled ablation (coblation) have been used to treat recurrent respiratory papillomatosis, but detailed comparisons of their respective treatment outcomes are not fully investigated. This retrospective study examines the procedure time, time interval between interventions, blood loss during operation, post-operative complications and pain scores among patients who received either CO2 laser or radiofrequency coblation interventions for laryngotracheal recurrent respiratory papillomatosis. Compared with CO2 laser intervention, radiofrequency coblation significantly reduced operation time, time interval between interventions, blood loss during operation and number of times bipolar electrocoagulation needed in each procedure. Post-operatively, pain scores after radiofrequency coblation were significantly lower than those after CO2 laser intervention. Incidence rates of post-operative complications, in terms of palate pharyngeal mucosa damage, bleeding and subcutaneous emphysema, were also significantly reduced after radiofrequency coblation. Low-temperature radiofrequency coblation is a superior intervention compared with CO2 laser against laryngotracheal recurrent respiratory papillomatosis.

Risk assessment of neuromuscular stimulation by energy-based transurethral resection devices: an ex vivo test standard.

BACKGROUND: During transurethral resection of bladder tumours (TURB), radio-frequency (RF) currents can lead to adverse neuromuscular stimulation (NMS). Here we present a novel ex vivo method to determine the risk of RF generators and their bipolar TURB modes to cause NMS. We aimed to develop an experimental platform for safety evaluation of new RF generators and their modes with a newly established test standard, suitable for replacement or reduction of animal testing. METHODS: We tested four contemporary RF generators with their bipolar modes for TURB in saline. A two-stage ex vivo approach was pursued: First, we recorded voltages at possible positions of the obturator nerve behind a porcine bladder wall in a TURB model using 18 RF applications per generator. Second, these voltage records were used as stimuli to evoke nerve compound action potentials (CAPs) in isolated porcine axillary nerves. The NMS potential was defined as the ratio between the observed area under the CAPs and the theoretical CAP area at maximum response and a firing rate of 250 Hz, which would reliably induce tetanic muscle responses in most human subjects. The measurement protocol was tailored to optimise reproducibility of the obtained NMS potentials and longevity of the nerve specimens. RESULTS: As prerequisite for the clinical translation of our results, the robustness of our test method and reproducibility of the NMS potential are demonstrated with an excellent correlation (r = 0.93) between two sets of identical stimuli (n = 72 each) obtained from 16 nerve segments with similar diameters (4.2 ± 0.37 mm) in the nerve model. The RF generators differed significantly (p < 0.0001) regarding NMS potential (medians: 0-3%). CONCLUSIONS: Our test method is suitable for quantifying the NMS potential of different electrosurgical systems ex vivo with high selectivity at a reasonable degree of standardization and with justifiable effort. Our results suggest that the clinical incidence of NMS is considerably influenced by the type of RF generator. Future generations of RF generators take advantage from the proposed test standard through higher safety and less animal testing. Health professionals and treated patients will benefit most from improved RF surgery using generators with a low NMS risk.