Bilateral deep brain stimulation of the subthalamic nucleus: Targeting differences between the first and second side / Estimulación cerebral profunda bilateral del núcleo subtalámico: diferencias de posicionamiento entre el primer y el segundo lado

Introduction and objectives Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a recognized treatment for drug-refractory Parkinson's disease (PD). However, the therapeutic success depends on the accuracy of targeting. This study aimed to evaluate potential accuracy differences in the placement of the first and second electrodes implanted, by comparing chosen electrode trajectories, STN activity detected during microelectrode recording (MER), and the mismatch between the initially planned and final electrode positions on each side. Materials and methods In this retrospective cohort study, we analyzed data from 30 patients who underwent one-stage bilateral DBS. For most patients, three arrays of microelectrodes were used to determine the physiological location of the STN. Final target location depended also on the results of intraoperative stimulation. The choice of central versus non-central channels was compared. The Euclidean vector deviation was calculated using the initially planned coordinates and the final position of the tip of the electrode according to a CT scan taken at least a month after the surgery. Results The central channel was chosen in 70% of cases on the first side and 40% of cases on the second side. The mean length of high-quality STN activity recorded in the central channel was longer on the first side than the second (3.07±1.85mm vs. 2.75±1.94mm), while in the anterior channel there were better MER recordings on the second side (1.59±2.07mm on the first side vs. 2.78±2.14mm on the second). Regarding the mismatch between planned versus final electrode position, electrodes on the first side were placed on average 0.178±0.917mm lateral, 0.126±1.10mm posterior and 1.48±1.64mm inferior to the planned target (AU)

Introducción y objetivos La estimulación cerebral profunda (ECP) del núcleo subtalámico (NST) es reconocida como un tratamiento para la enfermedad de Parkinson (EP) refractaria al tratamiento farmacológico. Sin embargo, el éxito de esta intervención depende de la precisión de la colocación de los electrodos. Este estudio tuvo como objetivo evaluar las posibles diferencias de precisión entre la colocación del primer y segundo electrodo, comparando las trayectorias elegidas para cada lado, la actividad del NST detectada durante el microrregistro (MER) y la discrepancia entre las posiciones inicialmente planeadas y las finales. Materiales y métodos En este estudio retrospectivo analizamos datos de 30 pacientes sometidos a ECP bilateral. En la mayoría de los casos se usaron tres conjuntos de microelectrodos para determinar la ubicación fisiológica del NST. El posicionamiento final del electrodo estuvo asimismo condicionado por los resultados de la estimulación intraoperatoria. Se comparó la elección de canales centrales vs. no centrales. El vector euclidiano del desvío se calculó a partir de las coordenadas planeadas inicialmente y la posición final de la punta del electrodo, según una tomografía computarizada realizada al menos un mes después de la cirugía. Resultados La trayectoria central se eligió en 70% de los casos en el primer lado y en el 40% de los casos en el segundo lado. La duración media de la actividad de alta calidad del NST registrada en el canal central fue mayor en el primer lado que en el segundo (3,07±1,85mm vs. 2,75±1,94mm), mientras que en el canal anterior hubo mejores registros de MER en el segundo lado (1,59±2,07mm en el primer lado vs. 2,78±2,14mm en el segundo) (AU)

Bilateral deep brain stimulation of the subthalamic nucleus: Targeting differences between the first and second side.

INTRODUCTION AND OBJECTIVES: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a recognized treatment for drug-refractory Parkinson's disease (PD). However, the therapeutic success depends on the accuracy of targeting. This study aimed to evaluate potential accuracy differences in the placement of the first and second electrodes implanted, by comparing chosen electrode trajectories, STN activity detected during microelectrode recording (MER), and the mismatch between the initially planned and final electrode positions on each side. MATERIALS AND METHODS: In this retrospective cohort study, we analyzed data from 30 patients who underwent one-stage bilateral DBS. For most patients, three arrays of microelectrodes were used to determine the physiological location of the STN. Final target location depended also on the results of intraoperative stimulation. The choice of central versus non-central channels was compared. The Euclidean vector deviation was calculated using the initially planned coordinates and the final position of the tip of the electrode according to a CT scan taken at least a month after the surgery. RESULTS: The central channel was chosen in 70% of cases on the first side and 40% of cases on the second side. The mean length of high-quality STN activity recorded in the central channel was longer on the first side than the second (3.07±1.85mm vs. 2.75±1.94mm), while in the anterior channel there were better MER recordings on the second side (1.59±2.07mm on the first side vs. 2.78±2.14mm on the second). Regarding the mismatch between planned versus final electrode position, electrodes on the first side were placed on average 0.178±0.917mm lateral, 0.126±1.10mm posterior and 1.48±1.64mm inferior to the planned target, while the electrodes placed on the second side were 0.251±1.08mm medial, 0.355±1.29mm anterior and 2.26±1.47mm inferior to the planned target. CONCLUSION: There was a tendency for the anterior trajectory to be chosen more frequently than the central on the second side. There was also a statistically significant deviation of the second electrodes in the anterior and inferior directions, when compared to the electrodes on the first side, suggesting that another cause other than brain shift may be responsible. We should therefore factor this during planning for the second implanted side. It might be useful to plan the second side more anteriorly, possibly reducing the number of MER trajectories tested and the duration of surgery.

Analysis of activity and motor coordination in rats undergoing stereotactic surgery and implantation of a cannula into the dorsal hippocampus. / Análisis de la actividad y coordinación motora en ratas con cirugía estereotáxica e implante de cánula en el hipocampo dorsal.

INTRODUCTION: Stereotactic surgery is used to place electrodes or cannulas in the brain in order to study the function of several brain structures in preclinical research. The hippocampus has been extensively studied with this methodology due to its involvement in a wide range of neurological, cognitive, emotional, and affective disorders. However, the effects of stereotactic surgery on coordination and motor activity should be evaluated in order to determine whether this surgical procedure causes any neurological alterations that may bias the results of studies incorporating this technique. METHODS: We evaluated the effects of stereotactic surgery and implantation of a cannula into the hippocampus of female Wistar rats on the motor activity, forced swim, and rotarod tests. The stage of the oestrous cycle was included in the statistical analysis. RESULTS: Stereotactic surgery had no impact on any of the motor activity variables assessed in the open field (squares crossed, time spent in grooming, and rearing), forced swim (turning behaviour, lateral swimming, latency to first immobility, and time spent immobile), and rotarod (latency to fall) tests, compared with intact rats. Regardless of surgical manipulation, rats in the metestrus and diestrus stages crossed a greater number of squares and displayed longer immobility times than those in the proestrus and estrus stages. CONCLUSION: Stereotactic surgery for cannula placement in the dorsal hippocampus does not affect coordination and motor activity in rats. We can therefore conclude that this procedure has no neurological complications that may interfere in the interpretation of results of studies applying this technique.

Estimulación cerebral profunda bilateral para distonía cervical refractaria en el Hospital Universitario de San Ignacio de Bogotá, Colombia / Bilateral Deep Brain Stimulation for Refractory Cervical Dystonia. Hospital Universitario de San Ignacio in Bogotá, Colombia: A Case Report

La estimulación cerebral profunda (ECP) es una alternativa de manejo para los pacientescon distonía cervical, un síndrome de etiología múltiple, de presentación variada eincapacitante y refractario al manejo médico, que incluye la toxina botulínica. El artículopresenta el caso de una mujer de 56 años de edad con distonía cervical manifiesta conretrócolis e hiperextensión de columna dorsal, de cuatro años de evolución, consideradarefractaria al tratamiento y con indicación de ECP...

Deep brain stimulation (DBS) is a management alternative for patients with cervicaldystonia, syndrome of multiple etiology, presentation varied, disabling and refractoryto medical management, including botulinum toxin. A case of a 56 year old woman withcervical dystonia manifested by retrocollis and hyperextension dorsal spine of 4 yearsof evolution, considered resistant to treatment that is an indication of DBS is presented...

Software para planificación de neurocirugías y su aplicación en una cirugía estereotáxica de aracnoidocele / Neurosurgery planning software and its application in a stereotactic surgery of arachnoidocele

El soporte tecnológico a través de equipos y aplicaciones médicas especializadas se ha convertido en una necesidad en el área de la neurocirugía. Frecuentemente, el neurocirujano utiliza sistemas asistidos por computador y neuronavegadores como herramientas auxiliares durante las fases pre-operatoria e intra-operatoria de la cirugía. Estas herramientas tecnológicas permiten planificar el abordaje quirúrgico de una forma rápida, eficiente e interactiva, facilitando también el uso de técnicas quirúrgicas de mínima invasión, como la cirugía estereotáxica. En este trabajo se presenta la utilización del software para neuronavegación que desarrollamos, en la planificación pre-operatoria de una intervención con marco estereotáxico para remover una lesión de aracnoidocele. El software soporta el manejo de imágenes e información conforme con el estándar DICOM, la visualización directa de datos volumétricos con mapeo de texturas 2D y 3D, el despliegue de imágenes multimodales y la segmentación de estructuras anatómicas, permitiendo al neurocirujano definir la trayectoria y el protocolo del abordaje quirúrgico mientras efectúa la navegación simulada sobre la anatomía del paciente.

In the neurosurgery field, the technological support through specialized equipment and medical applications has become a need. Neurosurgeons often make use of computer assisted systems and neuronavigators as auxiliary tools during the preoperative and intraoperative phases of the surgery. These technological resources allow them to plan the surgical approach in a fast, efficient and interactive way; also, making minimally invasive surgical techniques, such as stereotactic surgery, easier to use. In this work, we present the use of a neuronavigation medical application we developed in the preoperative planning of a frame-based stereotactic procedure to remove an arachnoidocele lesion. This software features support for handling images and information in conformance with the DICOM standard, direct rendering of volumetric data through 2D and 3D texture mapping, displaying of multimodal images and the segmentation of anatomical structures. By using the planning software, neurosurgeons can define the surgical approach protocol and trajectory, while doing the simulated navigation through the patient anatomy.