[Hemispheric transcranial electrical stimulation: clinical results]. / Estimulación eléctrica transcraneal hemisférica en cirugía supratentorial: resultados clínicos.

INTRODUCTION: Transcranial electrical stimulation (TES) is a technique widely used in intraoperative neurophysiological monitoring. However, there are theoretical limitations to their use in supratentorial surgery. AIM: To test the usefulness of hemispheric TES (C3/C4-Cz) in supratentorial surgery. PATIENTS AND METHODS: Hemispheric TES was conducted in a group of 15 patients operated on supratentorial region with possible compromise of the inner capsule. In all cases orbicularis oris, extensor digitorum, abductor of V finger, anterior tibialis and abductor hallucis brevis contralateral to stimulation were recorded. We used trains of 4-6 pulses of 50 micro-seconds at 500 Hz. RESULTS: The intensity of the movements induced by hemispheric TES did not interfere with the microsurgical dissection. We have used 78.5 +/- 11.2 trains per patient, with the voltage of 235 +/- 21 V and the equivalent current 370 +/- 37 mA. Stimulation resulted in response in facial region in 80% of cases, 100% in arm/hand and 66.7% in leg/foot. In eight patients, there was no change in latency and/or amplitude during resection. In six patients we observed retardation, decreased amplitude or both in any of the region studied. In these patients no neurologic injury was observed. In one patient a sharp decrease and complete absence of motor response was observed. In this case there was a post-surgical neurologic injury. CONCLUSIONS: The hemispheric TES have high sensitivity and specificity monitoring the inner capsule in supratentorial neurosurgery.

Estimulación eléctrica transcraneal hemisférica en cirugía supratentorial: resultados clínicos / Hemispheric transcranial electrical stimulation: clinical results

Introduction. Transcranial electrical stimulation (TES) is a technique widely used in intraoperative neurophysiological monitoring. However, there are theoretical limitations to their use in supratentorial surgery. Aim. To test the usefulness of hemispheric TES (C3/C4-Cz) in supratentorial surgery. Patients and methods. Hemispheric TES was conducted in a group of 15 patients operated on supratentorial region with possible compromise of the inner capsule. In all cases orbicularis oris, extensor digitorum, abductor of V finger, anterior tibialis and abductor hallucis brevis contralateral to stimulation were recorded. We used trains of 4-6 pulses of 50 microseconds at 500 Hz. Results. The intensity of the movements induced by hemispheric TES did not interfere with the microsurgical dissection. We have used 78.5 ± 11.2 trains per patient, with the voltage of 235 ± 21 V and the equivalent current 370 ± 37 mA. Stimulation resulted in response in facial region in 80% of cases, 100% in arm/hand and 66.7% in leg/foot. In eight patients, there was no change in latency and/or amplitude during resection. In six patients we observed retardation, decreased amplitude or both in any of the region studied. In these patients no neurologic injury was observed. In one patient a sharp decrease and complete absence of motor response was observed. In this case there was a post-surgical neurologic injury. Conclusions. The hemispheric TES have high sensitivity and specificity monitoring the inner capsule in supratentorial neurosurgery (AU)

Introducción. La estimulación eléctrica transcraneal (EET) es una técnica muy utilizada en monitorización neurofisiológica intraoperatoria. Sin embargo, existen limitaciones teóricas a su utilización en cirugía supratentorial. Objetivo. Comprobar la utilidad de la EET hemisférica (C3/C4-Cz) en cirugía supratentorial. Pacientes y métodos. Se realizó una EET hemisférica en un grupo de 15 pacientes intervenidos quirúrgicamente en la región supratentorial con eventual afectación de la cápsula interna. En todos los casos se registraron los músculos orbicular de los labios, extensor común de los dedos, abductor del V dedo, tibial anterior y abductor del primer dedo del pie contralaterales. Se emplearon trenes de 4-6 pulsos de 50 microsegundos, a 500 Hz. Resultados. La intensidad de los movimientos inducidos por la EET hemisférica no dificultó la microdisección quirúrgica. Se han empleado 78,5 ± 11,2 trenes/paciente, siendo el voltaje de 235 ± 21 V y la corriente equivalente de 370 ± 37 mA. La estimulación dio lugar a respuesta en la región facial en el 80% de los casos, en brazo/mano en el 100% y en pierna/ pie en el 66,7%. En ocho pacientes no se observó ninguna modificación de latencia o amplitud durante la resección. En seis pacientes se observó retraso, disminución de amplitud o ambos en alguna región estudiada, con carácter reversible. En una ocasión se observó disminución brusca y completa de la respuesta motora. En este caso se observó una lesión neurológica posquirúrgica. Conclusiones. La EET hemisférica tiene una alta sensibilidad y especificidad para monitorizar la cápsula interna en intervenciones neuroquirúrgicas supratentoriales (AU)