Predictors of seizure freedom after incomplete resection in children.

OBJECTIVE: Incomplete resection of the epileptogenic zone (EZ) is the most important predictor of poor outcome after resective surgery for intractable epilepsy. We analyzed the contribution of preoperative and perioperative variables including MRI and EEG data as predictors of seizure-free (SF) outcome after incomplete resection. METHODS: We retrospectively reviewed patients <18 years of age with incomplete resection for epilepsy with 2 years of follow-up. Fourteen preoperative and perioperative variables were compared in SF and non-SF (NSF) patients. We compared lesional patients, categorized by reason for incompleteness, to lesional patients with complete resection. We analyzed for effect of complete EEG resection on SF outcome in patients with incompletely resected MRI lesions and vice versa. RESULTS: Eighty-three patients with incomplete resection were included with 41% becoming SF. Forty-eight lesional patients with complete resection were included. Thirty-eight percent (57/151) of patients with incomplete resection and 34% (47/138) with complete resection were excluded secondary to lack of follow-up or incomplete records. Contiguous MRI lesions were predictive of seizure freedom after incomplete resection. Fifty-seven percent of patients incomplete by MRI alone, 52% incomplete by EEG alone, and 24% incomplete by both became SF compared to 77% of patients with complete resection (p = 0.0005). CONCLUSIONS: Complete resection of the MRI- and EEG-defined EZ is the best predictor of seizure freedom, though patients incomplete by EEG or MRI alone have better outcome compared to patients incomplete by both. More than one-third of patients with incomplete resection become SF, with contiguous MRI lesions a predictor of SF outcome.

Incomplete resection of focal cortical dysplasia is the main predictor of poor postsurgical outcome.

BACKGROUND: Focal cortical dysplasia (FCD) is recognized as the major cause of focal intractable epilepsy in childhood. Various factors influencing postsurgical seizure outcome in pediatric patients with FCD have been reported. OBJECTIVE: To analyze different variables in relation to seizure outcome in order to identify prognostic factors for selection of pediatric patients with FCD for epilepsy surgery. METHODS: A cohort of 149 patients with histologically confirmed mild malformations of cortical development or FCD with at least 2 years of postoperative follow-up was retrospectively studied; 113 subjects had at least 5 years of postoperative follow-up. Twenty-eight clinical, EEG, MRI, neuropsychological, surgical, and histopathologic parameters were evaluated. RESULTS: The only significant predictor of surgical success was completeness of surgical resection, defined as complete removal of the structural MRI lesion (if present) and the cortical region exhibiting prominent ictal and interictal abnormalities on intracranial EEG. Unfavorable surgical outcomes are mostly caused by overlap of dysplastic and eloquent cortical regions. There were nonsignificant trends toward better outcomes in patients with normal intelligence, after hemispherectomy and with FCD type II. Other factors such as age at seizure onset, duration of epilepsy, seizure frequency, associated pathologies including hippocampal sclerosis, extent of EEG and MRI abnormalities, as well as extent and localization of resections did not influence outcome. Twenty-five percent of patients changed Engel's class of seizure outcome after the second postoperative year. CONCLUSIONS: The ability to define and fully excise the entire region of dysplastic cortex is the most powerful variable influencing outcome in pediatric patients with focal cortical dysplasia.

[New techniques used to monitor cerebral function in the newborn]. / Nuevas técnicas de monitorización cerebral en el recién nacido.

INTRODUCTION: Continuous display four channels EEG monitoring and near infrared spectroscopy (NIRS) are relatively new and valuable techniques used for continuous brain monitoring in the neonatal period. Supporting the value of continuous display four channels EEG monitoring in the evaluation of neonates with paroxysmal motor events is a study recently conducted at Miami Children s Hospital. DEVELOPMENT: In this study 30 events were captures in 88 hours of simultaneous continuous display four channels EEG monitoring and continuous video EEG telemetry recording in five patients. Fourteen of the events were consider epileptic and 16 were considered non epileptic after evaluation of the continuous display four channels EEG monitoring printed epochs. RESULTS: The continuous video EEG telemetry confirmed the diagnosis for all the events. Several studies attest to the usefulness of NIRS in neonates and in older children with pathologies similar to those seeing in neonates. CONCLUSIONS: 1. NIRS is the best method to monitor regional cerebral oxygen saturation; 2. Regional cerebral oxygen saturation values are primarily those of the venous circulation in the subcortical white matter below the sensor; 3. Values of regional oxygen saturation should be considered not independently but only relative as a change over time; 4. Decreased regional cerebral oxygen saturation may be a sign of impending or established hypoxemia or hypotension, increased cerebral metabolic demands, or a cerebral oxygenation or perfusion problem that involve only brain, and 5. NIRS should be used in conjunction with arterial oxygen saturation and pressure monitoring (to detect hypoxemia and hypotension), with EEG to detect increased cerebral metabolic demands (electroencephalographic seizures) and with anterior cerebral artery Doppler ultrasound to detect perfusion (decreased flow velocity) and oxygenation (constant flow velocity) problems that involve only the brain.

Nuevas técnicas de monitorización cerebral en el recién nacido / New techniques used to monitor cerebral function in the newborn

Objetivo. Este artículo revisa el uso de la monitorización electroencefalográfica continua con cuatro canales (M-EEG-C 4Ca) y la espectroscopía con ondas cercanas al espectro de la luz infrarroja (ECLI) en el recién nacido. Desarrollo. En un estudio realizado con M-EEG-C 4Ca en cinco pacientes, se captaron, en un total de 88 horas, 30 movimientos, 14 fueron epilépticos y 16 no lo fueron. La naturaleza de todos los fenómenos fue confirmada por la VEEGTC. La conclusión de este estudio fue que la M-EEG-C 4Ca es un método eficaz para determinar la naturaleza de los fenómenos motores paroxísticos. Existen varios estudios que utilizan la ECLI para determinar la oxigenación transcraneal en recién nacidos, y en niños y adultos con patología similar a la que ocurre en los recién nacidos. Conclusiones. 1. La ECLI es el mejor método para medir la saturación regional de oxígeno cerebral; 2. Los valores reflejan primordialmente la oxigenación cerebral en la circulación venosa de la sustancia subcortical debajo de la célula receptora; 3. Los valores deben ser considerados no en forma independiente sino de acuerdo con sus cambios en relación con el tiempo (no es posible comparar los valores de un paciente con los de otro paciente); 4. La disminución de la saturación regional de oxígeno cerebral indica hipoxemia o hipotensión inminente o establecida, aumento del metabolismo cerebral, o problemas que afectan la oxigenación o perfusión cerebral exclusivamente; 5. La ECLI debe usarse conjuntamente con la oxigenación y presión arterial sistémica (para detectar hipoxemia e hipotensión), con el EEG para detectar aumentos en el metabolismo cerebral (convulsiones o bajo nivel de anestesia) y con el ultrasonido Doppler para detectar problemas que afectan exclusivamente la oxigenación (no cambios en la velocidad del flujo sanguíneo) y la perfusión (disminución en la velocidad del flujo sanguíneo) cerebral (AU)

Introduction. Continuous display fourchannels EEG monitoring and nearinfrared spectroscopy (NIRS) are relatively new and valuable techniques used for continuous brain monitoring in the neonatal period. Supporting the value of continuous display fourchannels EEG monitoring in the evaluation of neonates with paroxysmal motor events is a study recently conducted at Miami Children’s Hospital. Development. In this study 30 events were captures in 88 hours of simultaneous continuous display fourchannels EEG monitoring and continuous videoEEG telemetry recording in five patients. Fourteen of the events were consider epileptic and 16 were considered non epileptic after evaluation of the continuous display fourchannels EEG monitoring printed epochs. Results. The continuous videoEEG telemetry confirmed the diagnosis for all the events. Several studies attest to the usefulness of NIRS in neonates and in older children with pathologies similar to those seeing in neonates. Conclusions. 1. NIRS is the best method to monitor regional cerebral oxygen saturation; 2. Regional cerebral oxygen saturation values are primarily those of the venous circulation in the subcortical white matter below the sensor; 3. Values of regional oxygen saturation should be considered not independently but only relative as a change over time; 4. Decreased regional cerebral oxygen saturation may be a sign of impending or established hypoxemia or hypotension, increased cerebral metabolic demands, or a cerebral oxygenation or perfusion problem that involve only brain, and 5. NIRS should be used in conjunction with arterial oxygen saturation and pressure monitoring (to detect hypoxemia and hypotension), with EEG to detect increased cerebral metabolic demands (electroencephalographic seizures) and with anterior cerebral artery Doppler ultrasound to detect perfusion (decreased flow velocity) and oxygenation (constant flow velocity) problems that involve only the brain

Epilepsy surgery in children with tuberous sclerosis complex: presurgical evaluation and outcome.

PURPOSE: Children with tuberous sclerosis complex (TSC) benefit from excisional surgery if seizures can be localized to a single tuber. We evaluated the role of noninvasive studies to localize the epileptogenic tuber/region (ET/R) and the outcome of focal resection. METHODS: We identified 21 children with TSC, ages 3 months to 15 years (mean 4.8 years). All had video-(electroencephalogram) EEG and magnetic resonance imaging (MRI) scans, and 18 also had ictal single photon emission-computed tomography (SPECT) studies. An ET/R was localized in 17 patients. Thirteen patients underwent resection guided by intraoperative electrocorticography (n = 7) or subdural monitoring (n = 6). RESULTS: Interictal EEG revealed a principal spike focus (PSF) that corresponded to the ET/R in 14 children. In seven, PSFs occurred in rhythmic runs. PSFs were not observed remote from the ET/R. Focal polymorphic slowing and attenuation occurred in the region of the PSF in 11 patients. Sixteen patients demonstrated an ictal focus corresponding to the ET/R. Ictal SPECT revealed focal hyperperfusion correlating with the ET/R in 10 patients. Although the MRIs in all children revealed multiple tubers, the ET/R corresponded to a large discrete tuber in 8 patients and a calcified tuber in 13 patients. Patchy calcified tubers were also seen elsewhere in six patients. At a mean follow-up of 26 months, 9 of the 13 children who underwent surgery were seizure-free, one had greater than 75% reduction in seizures, two were unchanged, and one was lost to follow-up. New seizures developed in one child from a contralateral tuber. CONCLUSIONS: Surgical resection of an ET/R alleviates seizures in most children with TSC and intractable epilepsy. The scalp EEG and MRI help define the ET/R and improve case selection when ictal SPECT is nonlocalizing.

Intravenous valproate dosing in neonates.

The loading dosage of intravenous valproate required to achieve a desired serum concentration in neonates is not known. Two neonates with seizures received loading doses of intravenous valproate over 30 minutes. Serum valproate concentrations were measured 45 minutes and 3 hours after initiation of the infusion. Both neonates had received phenobarbital and phenytoin before the loading infusions. In the first patient, a loading dose of intravenous valproate of 10 mg/kg increased the 45-minute postinfusion serum valproate concentration to 41 microg/mL with a 3-hour postinfusion serum valproate concentration of 33 microg/mL. In the second patient, a loading dose of 25 mg/kg increased the 45-minute postinfusion serum valproic acid concentration to 100 microg/mL with a 3-hour postinfusion serum valproic acid concentration of 78 microg/mL. We found that each 1 mg/kg of intravenous valproate increased the 45-minute and 3-hour postinfusion serum valproic acid concentrations by approximately 4 microg/mL and 3 microg/mL, respectively. We suggest that these figures be used to calculate the desirable loading dose of intravenous valproate in neonates until larger studies are conducted. The volume of distribution and the serum clearance of valproate were approximately 0.245 L/kg and 25 mL/h/kg, respectively.

[Epilepsy treatment by vagal stimulation]. / Tratamiento de la epilepsia por medio de la estimulación vagal.

INTRODUCTION: Vagal nerve stimulation is the latest therapeutic modality for the treatment of epilepsy. It consists of a lead implanted in the left vagal nerve which is connected to a subcutaneous stimulator implanted in the left axillary or pectorial region. DEVELOPMENT: The stimulator is programmed to intermittently stimulate the vagal nerve throughout the day and a magnet also allows the patient to control the stimulation from the outside. This treatment has been used in patients with intractable partial seizures who are not candidates for epilepsy surgery. The results reported have varied but in general the procedure appears promising with at least 50% of the implanted having over 50% improvement in their seizure frequency and many having complete control without significant side effects. CONCLUSION: Further review of the results are still needed to fully determine the true value of this treatment and to identify the subgroups of patients which will benefit the most.

[Epilepsy centers: classification and basic requirements]. / Centros especializados en epilepsia: clasificación y requisitos básicos.

Over the last two decades the surgical treatment of epilepsies has become a commonly used and effective method for the treatment of intractable epilepsy. However, because of its wide use in various types of centers throughout the world the methodology involved varies significantly throughout the centers. With this article we propose the bases from which a multidisciplinary team of numerous centers can eventually develop an effective and acceptable international protocol for the surgical treatment of the epilepsies and the classifications of the centers.