Needle Electrode Research Articles

Ultrasound-guided percutaneous high-frequency irreversible electroporation in porcine livers using four electrode needles: A feasibility and safety study.

Malignant liver tumors seriously endanger human health. Among different therapeutic approaches, high-frequency irreversible electroporation (H-FIRE) is a recently emerging tumor ablation technique. The objective of this study was to evaluate the feasibility and safety of ultrasound-guided percutaneous H-FIRE using four electrode needles in porcine livers. Twelve experimental pigs underwent percutaneous H-FIRE ablation using a compound steep-pulse therapeutic device. Liver tissues adjacent to the gallbladder, blood vessels, and bile ducts were selected as the ablation targets. Pigs were randomly divided into three groups: (1) immediately after ablation (N = 4), (2) 2 days after ablation (N = 4), and (3) 7 days after ablation (N = 4). Blood routine, liver and kidney function, and myocardial enzyme levels were measured before and after ablation. Ultrasound, contrast-enhanced ultrasound (CEUS), contrast-enhanced magnetic resonance imaging (MRI), and hematoxylin-eosin staining were performed to evaluate the ablation performance. Ultrasound-guided percutaneous H-FIRE ablations using four electrode needles were successfully performed in all 12 experimental pigs. The general conditions of the pigs, including postoperative activities and feeding behaviors, were normal, with no significant changes compared with the preoperative conditions. The imaging features of ultrasound, CEUS, and MRI demonstrated no significant changes in the gallbladder walls, bile ducts, or blood vessels close to the ablation areas. Laboratory tests showed that liver function indices and myocardial enzymes increased temporarily after H-FIRE ablation, but decreased to normal levels at 7 days after ablation. Histopathological examinations of porcine liver specimens showed that this technique could effectively ablate the target areas without damaging the surrounding or internal vascular systems and gallbladder. This study demonstrated the feasibility and safety of ultrasound-guided percutaneous H-FIRE ablation in porcine livers invivo, and proposed a four-needle method to optimize its clinical application.

Application of remimazolam-0.6% sevoflurane anesthesia for flash visual evoked potential monitoring during pituitary adenoma resection: a non-inferiority randomized controlled trial

BackgroundFlash visual evoked potential (FVEP) is a critical method for monitoring intraoperative visual function during neurosurgery. A new benzodiazepine drug called remimazolam has recently been used for general anesthesia. However, the impact of remimazolam on FVEP remains unclear. Therefore, we aimed to investigate how remimazolam, in comparison to propofol, when combined with 0.6% sevoflurane anesthesia, affects the FVEP waveform during pituitary adenoma resection.MethodsOverall, 36 patients undergoing pituitary adenoma resection under general anesthesia were randomly assigned to either the remimazolam group (Group R) or the propofol group (Group P) in a prospective, randomized, controlled, non-inferiority trial. For anesthesia induction, a bolus of 0.2 mg/kg remimazolam or 2 mg/kg propofol was intravenously infused for approximately one minute. The anesthesia was maintained by continuous infusion of either remimazolam (0.7-1.0 mg/kg/h) or propofol (4–6 mg/kg/h), in combination with 0.6% sevoflurane, aimed at sustaining the bispectral index (BIS) within the range of 40–60. The primary outcome was the N75-P100 amplitude of FVEP recorded at approximately 20 min after intubation (T0). 10% of the amplitude at T0 in group P was defined as the non-inferiority margin (δ). Confidence interval testing was used to evaluate the non-inferiority hypothesis. The secondary outcomes covered the P100 latency of FVEP, electroretinogram (ERG) b wave amplitude, demographic characteristics, hemodynamics, and occurrence of adverse events.ResultsThe BIS index during anesthesia was comparable between the groups at the same measured time points (P > 0.05). The N75-P100 amplitude at T0 in group R was 7.64 ± 1.36 µV, while it was 6.96 ± 0.95 µV in group P (P = 0.09), with a mean difference of 0.68 µV (95% CI, -0.11 µV to 1.48 µV). The δ was set at 0.7 and the lower limit of the 95% CI exceeded the -δ. Both remimazolam and propofol had little effect on ERG b-wave amplitudes. At the designated time points, FVEP amplitude and P100 latency displayed no appreciable variation between the two groups (P > 0.05). Furthermore, there were no significant differences in the incidence of adverse events related to anesthesia, needle electrodes, or surgery between the two groups (P > 0.05).ConclusionOur findings suggest that remimazolam-0.6% sevoflurane is non-inferior to propofol-0.6% sevoflurane for general anesthesia, based on the FVEP N75-P100 amplitude. The electrophysiological data obtained in both groups indicate that reproducible and stable FVEP and ERG waveforms can be acquired at set time points. Therefore, for reliable FVEP monitoring, remimazolam-0.6% sevoflurane appears to be a safe and effective protocol in general anesthesia.Trials registrationThis study was registered on chictr.org.cn (ChiCTR2200056803, 17/02/2022).

Krause approach to pineal tumour with intraoperative oculomotor nerve monitoring

BackgroundThe supra-cerebellar infratentorial approach to pineal region tumours is versatile and safe corridor to lesions located below the deep veins. Monitoring of the extra-ocular muscle pathways using the evoked compound muscle action potential can lead to safer resections. Technical noteTo describe the use of electrooculography and a three handed retractor less method for pineal region tumour surgeries. Material and methodsIntraoperative electrooculography uses recording done from two channels (horizontal and vertical)by inserting disposable subdermal needle electrodes along the periorbital area. The oculomotor nerve is being monitored as it exits the midbrain. Retractor-less three-handed-technique allows for minimal handling of the cerebellum while maximizing the operative corridor. ResultThe oculomotor nerve was stimulated post resection and correspondingly led to improved symptoms post-operatively. Discussion and conclusionWe demonstrate a method for the intraoperative monitoring of the continuity of the oculomotor tracts and a three handed retractor-less method of resection of pineal region tumours. The placement of electrodes and area of stimulation need sound knowledge of anatomy of the region. Haemostasis at every step is absolutely essential to be able to visualize in the narrow corridor.

Investigation of the separation of conductive and insulating objects on a laboratory made electrostatic separator

Electrostatic separators are widely used to separate conductive and insulating objects up to some millimetres in size. Modelling of such equipment has been presented in several studies; laboratory and numerical models have been analysed. However, there are such situations, where larger samples of the order of centimetres have to be separated, as milling them into smaller size particles is not allowed or feasible. It was found that electrostatic separation can be used even in such cases but in a different arrangement than in the “traditional” constructions.This paper is a continuation of a previous study, in which the separation of a constructed laboratory separator was examined. The model was built in a circular plate arrangement with high voltage needle electrodes above the edge of cylinder’s mantle, where the discharges are generated. The slope of the circular plate is steadily decreasing, so the samples on the edge of the plate produce an increasing angle of inclination along the circumference. Charged samples stick to the plate, uncharged ones fall off. Some key parameters as rotation speed, electrode distance, voltage level and position of ionizer electrodes were varied.

Noninvasive monitoring of the vagus nerve during thyroid surgery using cutaneous adhesive and needle electrodes: What is the optimal configuration?

Endotracheal tube (ETT) surface electrodes are used to monitor the vagus nerve (VN), recurrent laryngeal nerve (RLN), and external branch of the superior laryngeal nerve (EBSLN) during thyroid and parathyroid surgery. Alternative nerve monitoring methods are desirable when intubation under general anesthesia is not desirable or possible. In this pilot study, we compared the performance of standard ETT electrodes to four different noninvasive cutaneous recording electrode types (two adhesive electrodes and two needle electrodes) in three different orientations. The VN was stimulated directly during thyroid and parathyroid surgery using a Prass stimulator probe. Electromyographic (EMG) responses for each patient were recorded using an ETT plus one of the following four cutaneous electrode types: large-foot adhesive, small-foot adhesive, long-needle and short-needle. Each of the four electrode types was placed in three orientations: (1) bilateral, (2) ipsilateral mediolateral, and (3) ipsilateral craniocaudal. Four surgical cases were utilized for data collection with the repetitive measures obtained in each subject. Bilateral electrode orientation was superior to ipsilateral craniocaudal and ipsilateral mediolateral orientations. Regardless of electrodes type, all amplitudes in the bilateral orientation were >100 μV. When placed bilaterally, the small-foot adhesive and the long-needle electrodes obtained the highest EMG amplitudes as a percentage of ETT amplitudes. Cutaneous electrodes could potentially be used to monitor the VN during thyroid and parathyroid procedures. Different electrode types vary in their ability to record amplitudes and latencies. Bilateral orientation improves EMG responses in all electrode types. Additional validation of cutaneous electrodes as an alternative noninvasive method to monitor the VN is needed.

Feasibility of Saphenous Nerve Somatosensory-Evoked Potential Intraoperative Monitoring during Lumbar Spine Surgery: Early Results.

Retrospective review. Assess the feasibility of saphenous nerve somatosensory evoked potentials (SN-SSEP) monitoring in lumbar spine surgeries. SN-SSEPs have been proposed for detecting lumbar plexus and femoral nerve injury during lateral lumbar surgery where tibial nerve (TN)SSEPs alone are insufficient. SN-SSEPs may also be useful in other types of lumbar surgery, as stimulation of SN below the knee derives solely from the L4 root and provides a means of L4 monitoring, whereas TN-SSEPs often do not detect single nerve root injury. The feasibility of routine SN-SSEP monitoring has not been established. A total of 563 consecutive cases using both TN and SN-SSEP monitoring were included. Anesthesia was at the discretion of the anesthesiologist, using an inhalant in 97.7% of procedures. SN stimulation was performed using 13mm needle electrodes placed below the knee using 200-400μsec pulses at 15-100mA. Adjustments to stimulation parameters were made by the neurophysiology technician while obtaining baselines. Data were graded retrospectively for monitorability and cortical response amplitudes were measured by two independent reviewers. 98% of TN-SSEPs and 92.5% of SN-SSEPs were monitorable at baseline, with a mean response amplitude of 1.35μV for TN-SSEPs and 0.71μV for SN-SSEPs. A significant difference between the stimulation parameters used to obtain reproducible TN and SN-SSEPs at baseline was observed, with SN-SSEPs requiring greater stimulation intensities. Body mass index (BMI) is not associated with baseline monitorability. Out of 20 signal changes observed, 11 involved SN while TN-SSEPs were unaffected. With adjustments to stimulation parameters, SN-SSEP monitoring is feasible within a large clinical cohort without modifications to the anesthetic plan. Incorporating SN into standard intraoperative neurophysiological monitoring (IONM) protocols for lumbar spine procedures may expand the role of SSEP monitoring to include detecting injury to the lumbar plexus. 3.

Minimally invasive transvaginal single-port laparoscopic vesicovaginal fistula repair: a case report and the point of this technique.

The optimal surgical method of vesicovaginal fistula (VVF) remains uncertain. Minimally invasive surgical approaches have become highly popular in line with technological advancements, namely, laparoscopic, robotic, and transvaginal techniques. However, these techniques still require invasiveness. This is the first case report that described a novel "zero-incision" technique for natural orifice transvaginal single-port laparoscopy used to repair a recurrent and high-position VVF. The patient underwent transvaginal single-port laparoscopic repair of a VVF. Methylene blue was used to locate the VVF, and a needle electrode was used to thoroughly remove the scar tissue of the VVF. In addition, this technique for transvaginal single-port laparoscopy provides more working space to expose and repair fistulas conveniently and adequately. One year after surgery, the patient remained asymptomatic and had no fistula recurrence. Minimally invasive transvaginal single-port laparoscopy provides a clear surgical field, is safe and feasible. This novel technique has promising as an additional personalized treatment option for VVF repair.

Wireless facial biosensing system for monitoring facial palsy with flexible microneedle electrode arrays

Facial palsy (FP) profoundly influences interpersonal communication and emotional expression, necessitating precise diagnostic and monitoring tools for optimal care. However, current electromyography (EMG) systems are limited by their bulky nature, complex setups, and dependence on skilled technicians. Here we report an innovative biosensing approach that utilizes a PEDOT:PSS-modified flexible microneedle electrode array (P-FMNEA) to overcome the limitations of existing EMG devices. Supple system-level mechanics ensure excellent conformality to the facial curvilinear regions, enabling the detection of targeted muscular ensemble movements for facial paralysis assessment. Moreover, our apparatus adeptly captures each electrical impulse in response to real-time direct nerve stimulation during neurosurgical procedures. The wireless conveyance of EMG signals to medical facilities via a server augments access to patient follow-up evaluation data, fostering prompt treatment suggestions and enabling the access of multiple facial EMG datasets during typical 6-month follow-ups. Furthermore, the device’s soft mechanics alleviate issues of spatial intricacy, diminish pain, and minimize soft tissue hematomas associated with traditional needle electrode positioning. This groundbreaking biosensing strategy has the potential to transform FP management by providing an efficient, user-friendly, and less invasive alternative to the prevailing EMG devices. This pioneering technology enables more informed decision-making in FP-management and therapeutic intervention.

Toward Large Ablations With Single-Needle High-Frequency Irreversible Electroporation in Vivo.

Irreversible electroporation (IRE) is a minimally thermal tissue ablation modality used to treat solid tumors adjacent to critical structures. Widespread clinical adoption of IRE has been limited due to complicated anesthetic management requirements and technical demands associated with placing multiple needle electrodes in anatomically challenging environments. High-frequency irreversible electroporation (H-FIRE) delivered using a novel single-insertion bipolar probe system could potentially overcome these limitations, but ablation volumes have remained small using this approach. While H-FIRE is minimally thermal in mode of action, high voltages or multiple pulse trains can lead to unwanted Joule heating. In this work, we improve the H-FIRE waveform design to increase the safe operating voltage using a single-insertion bipolar probe before electrical arcing occurs. By uniformly increasing interphase ( d1) and interpulse ( d2) delays, we achieved higher maximum operating voltages for all pulse lengths. Additionally, increasing pulse length led to higher operating voltages up to a certain delay length ( ∼25 μs), after which shorter pulses enabled higher voltages. We then delivered novel H-FIRE waveforms via an actively cooled single-insertion bipolar probe in swine liver in vivo to determine the upper limits to ablation volume possible using a single-needle H-FIRE device. Ablations up to 4.62 ± 0.12cm x 1.83 ± 0.05cm were generated in 5 minutes without a requirement for cardiac synchronization during treatment. Ablations were minimally thermal, easily visualized with ultrasound, and stimulated an immune response 24 hours post H-FIRE delivery. These data suggest H-FIRE can rapidly produce clinically relevant, minimally thermal ablations with a more user-friendly electrode design.

Using jitter analysis with concentric needle electrodes to assess disease status and treatment responses in myasthenia gravis

ObjectiveThis study assesses the utility of jitter analysis with concentric needles to evaluate disease severity in myasthenia gravis (MG), correlate changes in jitter with clinical status as well as identify reasons for any discordance. MethodsWe performed a retrospective chart review of 82 MG patients and extracted data on demographics, MG subtype, antibody status, clinical scales, electrophysiology, and interventions at baseline and follow-up. ResultsBaseline MGII scores correlated with jitter (r = 0.25, p = 0.024) and abnormal pairs (r = 0.24, p = 0.03). After 28 months, MGII scores correlated with jitter (r = 0.31, p = 0.006), abnormal pairs (r = 0.29, p = 0.009), and pairs with blocks (r = 0.35, p = 0.001). Changes in MGII scores correlated with changes in jitter (r = 0.35, p = 0.002), abnormal pairs (r = 0.27, p = 0.014), and pairs with blocks (r = 0.36, p = 0.001). ConclusionsConcentric needle jitter analysis may have the potential to evaluate baseline and sequential disease severity in MG. SignificanceThis study highlights the potential for improved MG patient care through precise assessment and management using concentric needle jitter analysis to improve the accuracy of MG diagnosis and monitoring of disease activity.

A mesothelin microsensor based on an embedded thionine electronic medium within an imprinted polymer on an acupuncture needle electrode.

An electrochemical microsensor for mesothelin (MSLN) based on an acupuncture needle (AN) was constructed in this work. To prepare the microsensor, MSLN was self-assembled on 4-mercaptophenylboronic acid (4-MPBA) by an interaction force between the external cis-diol and phenylboronic acid. This was followed by the gradual electropolymerization of thionine (TH) and eriochrome black T (EBT) around the anchored protein. The thickness of the surface imprinted layers influenced the sensing performance and needed to be smaller than the height of the anchored protein. The polymerized EBT was not electrically active, but the polymerized TH provided a significant electrochemical signal. Therefore, electron transfer smoothly proceeded through the eluted nanocavities. The imprinted nanocavities were highly selective toward MSLN, and the rebinding of insulating proteins reduced the electrochemical signal of the embedded pTH. The functionalized interface was characterized by SEM and electrochemical methods, and the preparation conditions were studied. After optimization, the sensor showed a linear response in the range of 0.1 to 1000 ng mL-1 with a detection limit of 10 pg mL-1, indicating good performance compared with other reported methods. This microsensor also showed high sensitivity and stability, which can be attributed to the fine complementation of the imprinted organic nanocavities. The sensitivity of this sensor was related to the nanocavities used for electron transport around the AuNPs. In the future, microsensors that can directly provide electrochemical signals are expected to play important roles especially on AN matrices.

An ultrasensitive electrochemical sensor for detecting Cd(II) in aquatic products based on CS/COFs/PEDOT: PSS modified acupuncture needle electrode

The use of low-cost working electrodes is of great importance for the development of sensor industrialization. Acupuncture needles electrode (ANE) was selected as working microelectrode, a sensor was designed based on poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT: PSS) and chitosan (CS) modified covalent organic frameworks (COFs) (CS/COFs) for detection of cadmium (Cd(II)). First, a mixture of PEDOT and PSS was electrodeposited on the surface of the acupuncture needles to synthesize a PEDOT: PSS as conductive polymeric film to support the electron transfer capability and enhance the conductive efficiency of the sensor. Then, CS/COFs was self-assembled and attached to the PEDOT: PSS/ANE surface by π-π stacking intermolecular interaction forces and the viscosity of CS, thus increasing the specific surface area of the electrode. Differential pulse anodic stripping voltammetry (DPASV) was used as the electrochemical method for detection of Cd(II). And the results indicated that the CS/COFs/PEDOT: PSS/ANE was linearly responsive in the range of 400 μg/L to 2400 μg/L, and the LOD was 13.8 ng/L for Cd(II). The constructed sensor also showed great selectivity, reproducibility, and stability. Additionally, the sensor demonstrated outstanding recovery in the detection of Cd(II) in real sample scallops. This sensing construction method based on acupuncture needles as working electrodes is of great significance to the development of sensor industrialization and aquatic product safety detection.

Urinary Bladder Volume Reconstruction Based on Bioimpedance Measurements: Ex Vivo and In Vivo Validation Through Implanted Patch and Needle Electrodes

Urinary Bladder Volume Reconstruction Based on Bioimpedance Measurements: Ex Vivo and In Vivo Validation Through Implanted Patch and Needle Electrodes

Intraoperative cricothyroid muscle electromyography may contribute to the monitorization of the external branch of the superior laryngeal nerve during thyroidectomy.

In thyroid surgery, both the recurrent laryngeal nerve (RLN) and external branch of the superior laryngeal nerve (EBSLN) should be preserved for maintaining the vocal cord functions. We aimed to evaluate whether EMG of the CTM applied after the superior pole dissection provided additional informative data to the IONM via ETT or not, regarding the EBSLN function. The prospectively collected data of the patients, who have undergone thyroidectomy with the use of IONM for the exploration of both the RLN and EBSLN between October 2016 and March 2017, were evaluated retrospectively. Patients over 18 years of age with primary thyroid surgery for malignant or benign thyroid disease, and whom were applied CTM EMG with a needle electrode after the completion of thyroidectomy were included in the study. In the study, each neck side was evaluated as a separate entity considering the EBSLN at risk. The data of 41 patients (32 female, 9 male) (mean age, 46.7+9.1; range, 22-71) were evaluated. Sixty seven EBSLNs out of 26 bilateral and 15 unilateral interventions were evaluated. With EBSLN stimulation after the superior pole dissection, positive glottic EMG waveforms via ETT were obtained in 45 (67.2%) out of 67, and the mean glottic amplitude value was 261+191 μV (min-max: 116-1086 μV). Positive EMG responses via the CTM EMG were achieved from all of the 67 EBSLNs (100%) with stimulation using a monopolar probe at the most cranial portion above the area of divided superior pole vessels. The mean value of CTM amplitudes via CTM EMG obtained with EBSLN stimulation was 5268+3916 μV (min-max:1215 -19726 μV). With EBSLN stimulation, the mean CTM EMG amplitude was detected significantly higher than the mean vocal cord amplitude (p<0.0001). The CTM EMG provided more objective quantifiable data regarding the EBSLN function (100% vs 67,2%, p<0.001). In addition to the IONM via ETT, intraoperative post-dissection CTM EMG via needle electrode is a safe, simple and applicable method that may provide significant additional informative data to IONM with ETT by obtaining and recording objective quantitative data related to the EBSLN function.

The neural control of movement: a century of in vivo motor unit recordings is the legacy of Adrian and Bronk.

In two papers dated 1928 to 1929 in The Journal of Physiology, Edgar Adrian and Detlev Bronk described recordings from motor nerve and muscle fibres. The recordings from motor nerve fibres required progressive dissection of the nerve until a few fibres remained, from which isolated single fibre activity could be detected. The muscle fibre recordings were performed in humans during voluntary contractions with an intramuscular electrode - the concentric needle electrode - that they describe for the first time in the second paper. They recognised that muscle fibres would respond to each impulse sent by the innervating motor neurone and that therefore muscle fibre recordings provided information on the times of activation of the motor nerve fibres which were as accurate as a direct record from the nerve. These observations and the description of the concentric needle electrode opened the era of motor unit recordings in humans, which have continued for almost a century and have provided a comprehensive view of the neural control of movement at the motor unit level. Despite important advances in technology, many of the principles of motor unit behaviour that would be investigated in the subsequent decades were canvassed in the two papers by Adrian and Bronk. For example, they described the concomitant motor neurones' recruitment and rate coding for force modulation, synchronisation of motor unit discharges, and the dependence of discharge rate on motor unit recruitment threshold. Here, we summarise their observations and discuss the impact of their work. We highlight the advent of the concentric needle, and its subsequent influence on motor control research.

갑상선 수술에서 피부 전극을 이용한 신경모니터링의 실제적인 적용

Preservation of the recurrent laryngeal nerve during thyroid surgery is crucial for preserving the patient's quality of life after surgery. It is still considered standard procedure to visually identify the recurrent laryngeal nerve and carefully dissect it in order to preserve the nerve. However, due to the numerous advantages of neuromonitoring, its application in thyroid surgery is gradually increasing. Despite the advantages of neuromonitoring, electromyography tubes could not be used in most thyroid surgeries because they were not covered by insurance. Recently, there has been active research conducted on neuromonitoring using needle electrodes or skin electrodes as alternatives to electromyography (EMG) tubes. In this review, we will examine the practical clinical application of recent neuromonitoring techniques that utilize skin electrodes.

Adipose Tissue Impacts Radiofrequency Ablation Lesion Size: Results of an Ex Vivo Poultry Model

BACKGROUND: Radiofrequency ablation (RFA) is a common treatment in which radiofrequency (RF) is used to heat neural tissue and reduce pain. The impact of adipose content in tissue on the lesion size may impact efficacy, and to date, there is little, if any, data comparing its influence on RFA. OBJECTIVES: We evaluated the influence of adipose tissue on RF lesion size. STUDY DESIGN: Controlled, ex vivo study. SETTING: Academic institution in a procedural setting. METHODS: RF lesions were created using 20-G 10-mm protruding electrode (PE) needles inserted into unbrined chicken breasts and thighs at 21°C. RF current was applied for 90 seconds at 80°C. Chicken breasts were used as the control group and chicken thighs were used as the high adipose variant. Four different groups were examined: 1- Standard 20 g RFA needle, 2- 20 g RFA PE needle, 3- Standard RFA needle with lidocaine 2% injectate, and 4- Standard RFA needle with iohexol 240 mg injectate. There were 12 lesions performed in each group; length, width, and depth were measured. RESULTS: The control group had significantly deeper lesions in all 4 cohorts. Lesions’ lengths were smaller in the fat-rich group. The control and PE cohorts showed a significant difference in width between the 2 fat-rich and nonfatty groups. LIMITATIONS: Radiofrequency ablation was performed at room temperature and not heated to physiological temperature. This was an ex vivo study, thus factors of human anatomy and physiology could not be evaluated. CONCLUSIONS: Adipose tissue content was inversely related to lesion size in all samples. This factor should be considered when assessing methods of enhancing lesion size in human models. KEY WORDS: Radiofrequency, ablation, lesion size, injection, adipose tissue, tissue modeling, interventional pain, education

Intramyocardial Hematoma During Catheter Ablation for Scar-Related Ventricular Tachycardia.

Intramural hematoma during ablation for scar-related ventricular tachycardia (VT) is a rare but life-threatening complication. The goal of this study was to describe the features and outcomes of intramural hematoma during ablation for scar-related VT. From 2010 to 2022, >3,514 ablations for ventricular arrhythmias were performed at 2 institutions. Four cases of intramural hematoma complicating VT ablation for scar-related VT were identified. Intraprocedural details, imaging data, and surgical notes were reviewed to create a recognizable pattern of events highlighting this complication. In 3 of 4 cases, intramural hematoma occurred during catheter ablation with an open irrigated 3.5mm tipped catheter using normal saline for irrigation. In one case, hematoma was noted after ablation using an investigational needle electrode catheter. The occurrence of a steam pop preceded detection of an expanding intramural hematoma in 3 cases. ST-segment elevation on electrocardiography was evident in 3 cases; intracardiac echocardiographic imaging detected the hematoma in all cases. Epicardial rupture and pericardial effusion requiring drainage occurred in 3 cases, whereas 1 hematoma was self-contained and did not require intervention. Surgical intervention was performed in 2 cases, with successful outcomes. One patient who was deemed not a surgical candidate died of progressive cardiogenic shock. Intramural hematoma during ablation for scar-related VT is a rare but potentially catastrophic complication that requires prompt recognition. Steam pops during ablation frequently precede the hematoma formation. Surgical intervention may be life-saving, although contained hematomas can occasionally be managed conservatively.

Combined Ultrasound and Computed Tomography Guidance in Radiofrequency Ablation for Hepatocellular Carcinoma Reduces Local Recurrence Rate

Background/Aim: In radiofrequency ablation (RFA) treatment of hepatocellular carcinoma (HCC), the therapeutic effect depends on the appropriate position of the electrode. To improve the accuracy of the electrode needle position, we currently perform RFA with combined ultrasound sonography (US) and computed tomography (CT) guidance. The purpose of this study was to evaluate the effectiveness of this US/CT-guided RFA method. Patients and Methods: This retrospective study recruited 97 patients with single tumors treated with transcatheter arterial chemoembolization and monopolar RFA between January 2013 and December 2017. Among these, 50 patients were treated with RFA under US/CT guidance (US/CT-guided group) and 47 were treated with RFA under US guidance alone (US-guided group). We analyzed the efficacy of US/CT guidance compared with US guidance alone. Results: The 1-, 2-, and 3-year local recurrence rates for the US/CT-guided and US-guided groups were 4.1%, 6.3%, and 8.6%, and 19.6%, 31.6%, and 41.9%, respectively. The local recurrence rate was lower in the US/CT-guided group (p=0.0030). Cox proportional hazards model for multivariate analysis demonstrated that the independent risk factors associated with local recurrence were tumor size (p=0.0028) and US/CT guidance (p=0.0037). Conclusion: US/CT-guided RFA for HCC reduced the local recurrence rate compared with US-guided RFA alone.

Intradermal DNA vaccine delivery using vacuum-controlled, needle-free electroporation

Intradermal delivery of DNA vaccines via electroporation (ID-EP) has shown clinical promise, but the use of needle electrodes is typically required to achieve consistent results. Here, delivery of a DNA vaccine targeting the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is achieved using noninvasive intradermal vacuum-EP (ID-VEP), which functions by pulling a small volume of skin tissue into a vacuum chamber containing noninvasive electrodes to perform EP at the injection site. Gene expression and immunogenicity correlated with EP parameters and vacuum chamber geometry in guinea pigs. ID-VEP generated potent humoral and cellular immune responses across multiple studies, while vacuum (without EP) greatly enhanced localized transfection but did not improve immunogenicity. Because EP was performed noninvasively, the only treatment site reaction observed was transient redness, and ID-VEP immune responses were comparable to a clinical needle-based ID-EP device. The ID-VEP delivery procedure is straightforward and highly repeatable, without any dependence on operator technique. This work demonstrates a novel, reliable, and needle-free delivery method for DNA vaccines.