Neuroanestesia (I) Dra.Neus Fàbregas 18/Mayo/2004 1991-2004

Dr. Ricard Valero Dr. Enrique Carrero Dra. Lydia Salvador Dra. Amalia Alcón Dr. Pedro Gambús

Cirugía de la Epilepsia Cualquier intervención neuroquirúrgica con el objetivo de solucionar la epilepsia intratable

Valoración previa a la cirugía de la epilepsia The European Federation of Neurological Societies task force was established in November 1997. It was the aim of the Task Force to produce a report on the state of pre-surgical evaluation for epilepsy surgery across Europe and to recommend standards. European Standards. European Federation of Neurological Societies Task Force Eur J Neurol 2000;7:119-122

ANATOMÍA Esclerosis del hipocampo Resonancia magnética (RM) T2 T1 T2 Tomografía axial computarizada (TC) Resonancia magnética (RM) T2 T1 T2 Imaging studies to define structural abnormalities High quality MRI is nowadays the investigation of choice: demonstrates an abnormality within the epileptogenic lobe in the majority of cases Definition of the clinical syndrome of mesial TLE has allowed surgeons to select patients in whom the epileptogenic zone is confined to the medial structures of the temporal lobe. Selective removal of these structures is equally effective in controlling seizures and, unlike standard temporal lobectomy, may avoid postoperative memory deficits The outcome of temporal resections is a function of presurgical selection criteria, topography and extent of resection MRI has changed dramatically knowledge of Esclerosis del hipocampo La RM de alta resolución objetiva los patrones de surcos individuales y facilita la identificación de los márgenes intraoperatorios de resección

RM Funcional: Información fisiológica dinámica Astrocitoma derecho Área del lenguaje (zurdo) Visualization of rapid changes in regional venous oxygenation to detect cortical activation during seizures Measurement of N-acetyl-aspartate concentration (a biochemical marker of neuronal integrity), with magnetic resonance spectroscopy shows great promise in improving the evaluation of the candidate for surgery Mapping of eloquent areas Actividad motora Izda FISIOLOGÍA

Tomografía por emisión de positrones FISIOLOGÍA PET Tomografía por emisión de positrones Metabolismo cerebral de glucosa (18F-FDG), para identificar las áreas epileptógenas PET and hihg resolution magnetic resonance imaging may obviate the need for intracranial recording in many patients 18F-fluorodeoxyglucose positron emission tomographyHelpful in localizing seizure foci and evaluating the metabolic effects of seizure focus resection Interictally there is hypometabolism in the region of seizure foci. Hipometabolismo interictal

PHYSIOLOGICAL IMAGING SPECT Tomografía por emisión de un único fotón Estudios de FSC estático Interictal e ictal (123I-IMP, 99TcHMPAO). Localiza el foco durante las convulsiones 99Tc HMPAO 99Tc HMPAO 131I-iodoamphetamine single photon emission tomographyEvaluation of CBF changes with interictal and ictal SPET Hipoactividad interictal lóbulo temporal Izqdo Hipoactividad interictal lóbulo temporal Dcho

A Randomized, Controlled Trial on Surgery for Temporal-Lobe Epilepsy Wiebe et al. N Engl J Med 2001;345:311-8 80 p. con epilepsia temporal se distribuyeron aleatoriamente cirugía (40p) Tratamiento antiepiléptico durante 1 año (40p)

A Randomized, Controlled Trial on Surgery for Temporal-Lobe Epilepsy Wiebe et al. N Engl J Med 2001;345:311-8 At one year, the cumulative proportion of patients free of seizures impairing awareness was: 58% in the surgical group and 8% in the medical group. (P<0.001)

La amígdala y el control cardiovascular Relación entre el sistema límbico y el SNA Bradicardia severa en 6 pacientes al manipular la amígdala o el hipocampo 29 pacientes lobectomía temporal anterior (23 amígdalo-hipocampectomías) Anestesia mantenida con N2O-fentanilo-droperidol si ECoG intraoperatorio, Sevoflurane-fentanilo o propofol-fentanilo si no ECoG In 74 temporal lobe resections (+ amygadalo hyppocampectomy) we have had 5 episodes of bradycardia (6.75%), unpublished data Sato et al. J Neurosurg Anesthesiol 2001;13.329-332

5 episodios de bradicardia en 74 RTAM Hemisferio afectado Administración de atropina Atropina en inducción Mantenimiento anestesia Relajante muscular Analgesia Hipotensión Paciente 1 Derecho No Si Propofol Vecuronio Fentanilo Paciente 2 Mivacurio Remifent Paciente 3 Paciente 4 Izquierdo Sevofluorane Paciente 5 Sanchez-Etayo et al, Rev Esp Anestesiol Reanim 2003; 50:267-273

Electrodos subdurales Electrocorticografía

Electrodos en foramen oval Bilateral foramen ovale electrods with four contact electrodes in both

Electrodos en foramen oval Monitorización video-EEG . In EEG video monitoring bilateral seizures origin was confirmed. Intervention was refused do to risk of postoperative memory deficit, other groups operted on these patients with acdeptable results.

Callosotomía (completa o parcial) Cirugía de la epilepsia (origen multifocal) Interrumpir una vía de crisis (procedimientos paliativos) Hemisferectomía “Funcional” Hemicorticectomía Kanev et al J Neurosurg 1997;86:762-7 When the seizure onset zone is in or overlap eloquent cortex (that is brain areas of immoprtant funciton such as language or miotor), multiple subpial transections are frequently used as an alternative to corticla resection. This vertical columnar organization of the gray matter is preserved at the same time the neuronal network is disconnected and the epileptogenic critical mass reduced by this surgical procedure. Brian function is preserved yet horizontal seizure propagation is reduced. The postoperative deficits generally resolve over several weeks and seizure control improves in perhaps 70% of patients. Callosotomía (completa o parcial) Múltiples transecciones subpiales Schramm et al. J Neurosurg 2002;97:39-47

SyO2 Rasmussen Hemisferectomía funcional (Matta et al Anesth Analg 1994;79:745-750)

SyO2

Estimulación del N. Vago izquierdo Alternativas quirúrgicas para la epilepsia Estimulación neural crónica Estimulación del N. Vago izquierdo (Landy et al. J Neurosurg 1993;78:26-31) The substantia nigra act as a gating mechanisn to modulate, via GABAergic efferents, excitation in other brain structures. VNS works by delivering balanced electrical pulses to the left vagus nerve through two platinum electrodes (a common stimulation train lasts 30 sec (frequency 30Hz) and is given at 5-min intervals. The current intensity is adjusted according to the effect and patient’s tolerance) Kalkanis J Neurosurg 2002;96:949-51 FDA approval in 1997 for treatment of medically intractable multifocal epilepsy Adverse effects encountered during pulse delivery of VNS Intermittent hoarseness (37% of patieCough Throat discomfort Shortness of breath Nausea Vocal cord paralysis (rarely reported) nts) Estimulación del núcleo Subtalámico (Benabid et al. Neurosurgery 2002;50:1385-92)

Craneotomía con el paciente despierto (“awake craniotomy”) Requisitos: Paciente colaborador Infiltración adecuada de la calota Sedación consciente Asegurar el control de la vía aérea

Mapping área lenguaje

Monitored anesthesia care using remifentanil and propofol for awake craniotomy H Berkenstadt et al. J Neurosurg Anesthesiol 2001;13:246-9 Curva de aprendizaje Incidencia de complicaciones respiratorias en cinco grupos consecutivos de 5 pacientes cada uno Remifentanilo: 0,01-0,05 g Kg-1 min-1 Propofol: 15-100 g Kg-1 min-1

FIS:PI 020582 Farmacocinética farmacodinámica del bromuro de rocuronio en los pacientes tratados de forma crónica con difenilhidantoína