Bilateral Anterior Thalamic Nucleus Lesions Are Not Protective against Seizures in Chronic Pilocarpine Epileptic Rats

Aims: To investigate whether anterior thalamic nucleus (AN) lesions are protective against spontaneous recurrent seizures in the chronic phase of the pilocarpine model of epilepsy. Methods: Two groups of rats were treated with bilateral AN radiofrequency thalamotomies or sham surgery 2 weeks after pilocarpine-induced status epilepticus. After the lesions, animals were videotaped from the 2nd to the 8th week after status epilepticus (total 180 h). Results: During the 6 weeks of observation, no differences in the frequency of spontaneous seizures were found between animals that had bilateral AN lesions (n = 26; 3.1 +/- 0.6 seizures per animal) and controls (n = 25; 3.0 +/- 0.6 seizures per animal; p = 0.8). Conclusions: We conclude that AN thalamotomies were not effective in reducing the frequency of seizures during the chronic phase of the pilocarpine model of epilepsy. Copyright (C) 2009 S. Karger AG, Basel

Stereotactic disconnection of hypothalamic hamartoma to control seizure and behavior disturbance: case report and literature review

An 18-year-old boy with refractory epilepsy and aggressiveness associated to a hypothalamic hamartoma was submitted to a stereotactically guided lesion by thermocoagulation. The target was based on magnetic resonance (MR) images merged with computed tomography scan images taken on the day of surgery while patient was on a stereotactic frame. In order to reveal structures not discernible in MR images, the Schaltenbrand digital brain atlas was merged onto the patient`s images. Target and trajectory of the depth electrode were chosen based on three-dimensional imaging reconstructions. A surgical plan was devised to disconnect the hypothalamic hamartoma from the hypothalamus, medial forebrain bundle, fasciculus princeps, and dorsal longitudinal fasciculus. Our target was placed at the inferior portion of the posterolateral component of the hamartoma, bordering the normal hypothalamus. The patient evolved with marked lessening of aggressiveness. Seizure frequency was reduced from several seizures per day to less than one tonic-clonic seizure during sleep per month and only two episodes suggestive of partial complex seizures during daytime. These results have remained consistent over a 24-month postoperative follow-up. Functional neuroanatomy of hypothalamic connections involved in seizure propagation and aggressive behavior was reviewed.

Gastric hypomotility following epicardial vagal denervation ablation to treat atrial fibrillation

Gastric Palsy Following AF Vagal Ablation. We report a case of a 55-year-old man with vagal paroxysmal atrial fibrillation (AF) who was submitted to selective epicardial and endocardial atrial vagal denervation with the objective of treating AF. Radiofrequency pulses were applied on epicardial and endocardial surface of the left atrium close to right pulmonary veins (PVs) and also on epicardial surface close to left inferior PV. Following the procedure, patient presented with symptoms of gastroparesis, which was documented on CT scan and gastric emptying scintigraphy. Symptoms were transient and the patient recovered completely.

Atrial Coronary Arteries in Areas Involved in Atrial Fibrillation Catheter Ablation

Background-The proximity to vascular structures is a limiting factor during radiofrequency ablation. However, little or no attention has been given to the atrial arterial circulation during the development of atrial fibrillation (AF) catheter ablation techniques. Methods and Results-We examined the atrial arterial circulation in areas involved in AF ablation in 24 heart specimens by colored resin injection and careful dissection. The sinus node artery (SNA) arose from the circumflex artery in 42% of case; proximal to the LA appendage in 29%, crossing the left atrium (LA) anterior wall; and after the LA appendage in the remaining 13%, crossing the mitral isthmus and passing close to the left pulmonary veins (PVs), the LA roof, and the right superior PV. In 58%, the SNA arose from the right coronary artery. Major arteries (>= 1 mm in external diameter) were found in the mitral isthmus in 54%, at the LA roof in 54%, and at the LA anterior wall in 29%. Around the left PV ostia, there were areas with major arteries in up to 37% (at the roof and inferior segments) and around the right PV ostia in up to 29% (at the roof segment). Conclusions-Major atrial coronary arteries, including the SNA, were commonly found in the areas involved in AF ablation and could cause difficulties in obtaining transmural lesions and electric isolation or even lead to ischemic sinus node or atrial dysfunction. (Circ Arrhythm Electrophysiol. 2010;3:600-605.)

Two-stage laparoscopic liver resection for bilateral colorectal liver metastasis

Hepatectomy may prolong the survival of colorectal cancer patients with liver metastases. Two-stage liver surgery is a valid option for the treatment of bilobar colorectal liver metastasis. This video demonstrates technical aspects of a two-stage pure laparoscopic hepatectomy for bilateral liver metastasis. To the authors` knowledge, this is the first description of a two-stage laparoscopic liver resection in the English literature. A 54-year-old man with right colon cancer and synchronous bilobar colorectal liver metastasis underwent laparoscopic right colon resection followed by oxaliplatin-based chemotherapy. The patient then was referred for surgical treatment of liver metastasis. Liver volumetry showed a small left liver remnant. Surgical planning was for a totally laparoscopic two-stage liver resection. The first stage involved laparoscopic resection of segment 3 and ligature of the right portal vein. The postoperative pathology showed high-grade liver steatosis. After 4 weeks, the left liver had regenerated, and volumetry of left liver was 43%. The second stage involved laparoscopic right hepatectomy using the intrahepatic Glissonian approach. Intrahepatic access to the main right Glissonian pedicle was achieved with two small incisions, and an endoscopic vascular stapling device was inserted between these incisions and fired. The line of liver transection was marked following the ischemic area. Liver transection was accomplished with the Harmonic scalpel and an endoscopic stapling device. The specimen was extracted through a suprapubic incision. The falciform ligament was fixed to maintain the left liver in its original anatomic position, avoiding hepatic vein kinking and outflow syndrome. The operative time was 90 min for stage 1 and 240 min for stage 2 of the procedure. The recoveries after the first and second operations were uneventful, and the patient was discharged on postoperative days 2 and 7, respectively. Two-stage liver resections can be performed safely using laparoscopy. The intrahepatic Glissonian approach is a useful tool for pedicle control of the right liver, especially after previous dissection of the hilar plate.

Electrophysiological characteristics of the Marshall bundle in humans

BACKGROUND Marshall bundles (MBs) are the muscle bundles within the ligament of Marshall. OBJECTIVE This trial sought to the electrophysiological characteristics of the MB and the anatomical connections between MB and left atrium (LA) in patients with persistent atrial fibrillation (AF). METHODS We enrolled 72 patients (male: female 59: 13, age 59.9 +/- 9.4 years) who underwent MB mapping and ablation for AF. MB mapping was done via an endocardial or epicardial approach during sinus rhythm and AF. RESULTS Recordings were successful in 64 of 72 patients (89%). A single connection was noted in 11 of 64 patients between the MB and the coronary sinus (CS) muscle sleeves. The MB recordings showed distinct MB potentials with a proximal-to-distal activation pattern during sinus rhythm. During AF, organized passive activations and dissociated slow MB ectopic activities were commonly observed in this type of connection. Double connections to both CS and LA around left pulmonary veins were noted in 23 of 64 patients (36%). After the ablation of the distal connection, MB recording showed typical double potentials as in single connection. Multiple connections were noted in 30 of 64 patients (47%). During sinus rhythm, the earliest activation was in the middle of the MB. The activation patterns were irregular and variable in each patient. During AF, rapid and fractionated complex activations were noted in all patients of this group. CONCLUSION We documented 3 different types of MB-LA connections. Rapid and fractionated activations were most commonly observed in the MB that had multiple LA connections.

A methodology for current density calculations in high-frequency RF resonators

As nuclear magnetic resonance imaging and spectroscopy move inexorably toward higher field-strength magnets in search of improved signal-to-noise ratio, spectral resolution, and spatial resolution, the way in which radiofrequency (RF) probes are designed changes. At higher frequencies, resonant cavities become the favored RF ''coil'' type and may be built using streamline elements to reduce the inductance of the system. In modeling such systems, the quasi-static approach of assuming that current flows evenly in all conductor cross sections and that adjacent conductors do not affect each other becomes less reasonable. The proximity of RF conductors in resonators typically causes RF eddy currents to flow, whereby the current density in each rung is altered by the RF fields generated by nearby conductors. The proper understanding and prediction of how resonators will perform require a model of the current densities flowing in conducting sections, including all RF eddy current effects. Very few models of this type have been presented in the literature. This article presents an overview of one such model and of how it may be applied to a variety of resonators, both shielded and unshielded, circular, and elliptical, in cross section. Results are presented from a shielded head coil operating at 2 tesla. (C) 1997 John Wiley & Sons, Inc.

Treatment of advanced hepatocellular carcinoma with very low levels of amplitude-modulated electromagnetic fields

BACKGROUND: Therapeutic options for patients with advanced hepatocellular carcinoma (HCC) are limited. There is emerging evidence that the growth of cancer cells may be altered by very low levels of electromagnetic fields modulated at specific frequencies. METHODS: A single-group, open-label, phase I/II study was performed to assess the safety and effectiveness of the intrabuccal administration of very low levels of electromagnetic fields amplitude modulated at HCC-specific frequencies in 41 patients with advanced HCC and limited therapeutic options. Three-daily 60-min outpatient treatments were administered until disease progression or death. Imaging studies were performed every 8 weeks. The primary efficacy end point was progression-free survival >= 6 months. Secondary efficacy end points were progression-free survival and overall survival. RESULTS: Treatment was well tolerated and there were no NCI grade 2, 3 or 4 toxicities. In all, 14 patients (34.1%) had stable disease for more than 6 months. Median progression-free survival was 4.4 months (95% CI 2.1-5.3) and median overall survival was 6.7 months (95% CI 3.0-10.2). There were three partial and one near complete responses. CONCLUSION: Treatment with intrabuccally administered amplitude-modulated electromagnetic fields is safe, well tolerated, and shows evidence of antitumour effects in patients with advanced HCC. British Journal of Cancer (2011) 105, 640-648. doi:10.1038/bjc.2011.292 www.bjcancer.com Published online 9 August 2011 (C) 2011 Cancer Research UK

Catheter ablation of severe neurally meditated reflex (neurocardiogenic or vasovagal) syncope: cardioneuroablation long-term results

Aims Neurally meditated reflex or neurocardiogenic or vasovagal syncope (NMS) is usually mediated by a massive vagal reflex. This study reports the long-term outcome of NMS therapy based on endocardial radiofrequency (RF) catheter ablation of the cardiac vagal nervous system aiming permanent attenuation or elimination of the cardioinhibitory reflex (cardioneuroablation). Methods and results A total of 43 patients (18F/25M, 32.9+/-15 years) without apparent cardiopathy (left ventricular ejection fraction=68.6+/-5%) were included. All had recurrent NMS (4.7+/-2 syncope/patient) with important cardioinhibition (pauses=13.5+/-13 s) at head-up tilt test (HUT), normal electrocardiogram (ECG), and normal atropine test (AT). The patients underwent atrial endocardial RF ablation using spectral mapping to track the neurocardiac interface (AF Nest Mapping). The follow-up (FU) consisted of clinical evaluation, ECG (1 month/every 6 months/or symptoms), Holter (every 6 months/or symptoms), HUT (>= 4 months/or symptoms), and AT (end of ablation and >= 6 months). A total of 44 ablations (48+/-9 points/patient) were performed. Merely three cases of spontaneous syncope occurred in 45.1+/-22 months (two vasodepressor, one undefined). Only four partial cardioinhibitory responses occurred in post-ablation HUT without pauses or asystole (sinus bradycardia). Long-term AT (21.7+/-11 months post) was negative in 33 (76.7%, P<0.01), partially positive in 7(16.3%), and normal in three patients only (6.9%) reflecting long-term vagal denervation (AT-Delta% HR pre 79.4% x 23.2% post). The post-ablation stress test and Holter showed no abnormalities. No major complications occurred. Conclusion Endocardial RF catheter ablation of severe neurally meditated reflex syncope prevented pacemaker implantation and showed excellent long-term results in well selected patients. Despite no action in vasodepression it seems to cause enough long-term vagal reflex attenuation, eliminating the cardioinhibition, and keeping most patients asymptomatic. Indication was based on clinical symptoms, reproduction of severe cardioinhibitory syncope, and normal atropine response.

Percutaneous Transatrial Access to the Pericardial Space for Epicardial Mapping and Ablation

Background-Puncture of the atrial appendage may provide access to the pericardial space. The aim of this study was to evaluate the feasibility of epicardial mapping and ablation through an endocardial transatrial access in a swine model. Methods and Results-An 8-F Mullins sheath was used to perforate the right (n=16) or left (n=1) atrial appendage in 17 pigs (median weight, 27.5 kg; first and third quartiles [Q1, Q3], 25.2, 30.0 kg). A 7-F ablation catheter was introduced into the pericardial space to perform epicardial mapping and deliver radiofrequency pulses on the atria. The pericardial space was entered in all 17 animals. In 15 (88%) animals, there was no hemodynamic instability (mean blood pressure monitoring, initial median, 80 mm Hg; Q1, Q3, 70, 86 mm Hg; final median, 88 mm Hg; Q1, Q3, 80, 96 mm Hg; P=0.426). In these 15, a mild hemorrhagic pericardial effusion was identified and aspirated (median, 20 mL; Q1, Q3, 15, 30 mL) during the procedure, and postmortem gross analysis revealed that the atrial perforation was closed in these animals. In 2 (12%) of the 17 animals, there was major pericardial bleeding with hemodynamic collapse. On gross examination, it was found that pericardial space was accessed through right ventricular perforation in 1 animal and the tricuspid annulus in the other. After the initial study, we used an occlusion device in 3 other animals to attempt to seal the puncture (2 at the right atrial appendage and 1 at the right ventricle). These 3 animals had no significant pericardial bleeding. Conclusions-Transatrial endovascular right atrial appendage puncture may provide a potential alternative route for pericardial access. Further studies are needed to evaluate its safety with longer and more-complex procedures before being applied in clinical settings. (Circ Arrhythm Electrophysiol. 2011;4:331-336.)

Focal and linear endocardial and epicardial catheter-based cryoablation of normal and infarcted ventricular tissue

Background: This study of a chronic porcine postinfarction model examined whether linear epicardial cryoablation was capable of creating large, homogenous lesions in regions of the myocardium including scarred ventricle. Endocardial and epicardial focal cryolesions were also compared to determine if there were significant differences in lesion characteristics. Methods: Eighty focal endocardial and 28 focal epicardial cryoapplications were delivered to eight normal caprine and four normal porcine ventricular myocardium, and 21 linear cryolesions were applied along the border of infarcted epicardial tissue in a chronic porcine infarct model in six swines. Results: Focal endocardial cryolesions in normal animals measured 9.7 +/- 0.4 mm (length) by 7.3 +/- 1.4 mm (width) by 4.8 +/- 0.2 mm (depth), while epicardial lesions measured 10.2 +/- 1.4 mm (length) by 7.7 +/- 2 mm (width) by 4.6 +/- 0.9 mm (depth); P > 0.05. Linear epicardial cryolesions in the chronic porcine infarct model measured 36.5 +/- 7.8 mm (length) by 8.2 +/- 1.3 mm (width) by 6.0 +/- 1.2 mm (depth). The mean depth of linear cryolesions applied to the border of the infarct scar was 7 +/- 0.7 mm, as measured by magnetic resonance imaging. Conclusions:Cryoablation can create deep lesions when delivered to the ventricular epicardium. Endocardial and epicardial cryolesions created by a focal cryoablation catheter are similar in size and depth. The ability to rapidly create deep linear cryolesions may prove to be beneficial in substrate-based catheter ablation of ventricular arrhythmias.

Incidence, morphology and morphometry of the foramen of Vesalius: complementary study for a safer planning and execution of the trigeminal rhizotomy technique

The foramen of Vesalius (FV) is located in the greater wing of the sphenoid bone between the foramen ovale (FO) and the foramen rotundum in an intracranial view. The FO allows the passage of the mandibular branch of trigeminal nerve, which is the target of the trigeminal radiofrequency rhizotomy. We analyzed its location, morphology, morphometry and interrelation among other foramina. 400 macerated adult human skulls were examined. A digital microscope (Dino-Lite plus(A (R))) was used to capture images from the FV. A digital caliper was used to perform the measurements of the distance between the FV and other foramina (FO, foramen spinosum and the carotid canal) in an extracranial view of the skull base. In the 400 analyzed skulls, the FV was identified in 135 skulls (33.75%) and absent on both sides in 265 skulls (66.25%). The FV was observed present bilaterally in 15.5% of the skulls. The incidence of unilateral foramen was 18.25% of the skulls of which 7.75% on right side and 10.5% on left side. The diameter of the FV was measured and we found an average value of 0.65 mm, on right side 0.63 mm and on the left side 0.67 mm. We verified that positive correlations were statistically significant among the three analyzed distances. This study intends to offer specific anatomical data with morphological patterns (macroscopic and mesoscopic) to increase the understanding of the FV features as frequency, incidence and important distances among adjacent foramina.

A genetic algorithm/method of moments approach to the optimization of an RF coil for MRI applications - Theoretical considerations - Abstract

A Combined Genetic Algorithm and Method of Moments design methods is presented for the design of unusual near-field antennas for use in Magnetic Resonance Imaging systems. The method is successfully applied to the design of an asymmetric coil structure for use at 190MHz and demonstrates excellent radiofrequency field homogeneity.

Hand-held robotic device for laparoscopic surgery and training

Laparoscopic surgery (LS) has revolutionized traditional surgical techniques introducing minimally invasive procedures for diagnosis and local therapies. LSs have undeniable advantages, such as small patient incisions, reduced postoperative pain and faster recovery. On the other hand, restricted vision of the anatomical target, difficult handling of the surgical instruments, restricted mobility inside the human body, need of dexterity to hand-eye coordination and inadequate and non-ergonomic surgical instruments may restrict LS only to more specialized surgeons. To overcome the referred limitations, this work presents a new robotic surgical handheld system – the EndoRobot. The EndoRobot was designed to be used in clinical practice or even as a surgical simulator. It integrates an electromechanical system with 3 degrees of freedom. Each degree can be manipulated independently and combined with different levels of sensitivity allowing fast and slow movements. As other features, the EndoRobot has battery power or external power supply, enables the use of bipolar radiofrequency to prevent bleeding while cutting and allows plug-and-play of the laparoscopic forceps for rapid exchange. As a surgical simulator, the system was also instrumented to measure and transmit, in real time, its position and orientation for a training software able to monitor and assist the trainee’s surgical movements.