[Hemispheric transcranial electrical stimulation: clinical results].
BACKGROUND
Transcranial electrical stimulation (TES) is a technique widely used in intraoperative neurophysiological monitoring. However, there are theoretical limitations to their use in supratentorial surgery.


OBJECTIVE
To test the usefulness of hemispheric TES (C3/C4-Cz) in supratentorial surgery.


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.
Pastor Gómez
Jesús
J
Servicio de Neurofisiología Clínica, Hospital Universitario de la Princesa, 28006 Madrid, España. jpastor.hlpr@salud.madrid.org
Perla-Perla
Patricia
P
Pulido-Rivas
Paloma
P
Sola
Rafael G
RG
D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D018482:Muscle, Skeletal / Q000502:physiology; D019635:Neurosurgical Procedures; D011930:Reaction Time / Q000502:physiology; D012680:Sensitivity and Specificity; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods; D016896:Treatment Outcome