Anatomy of Trigeminal Neuromodulation Targets: From Periphery to the Brain.

The trigeminal nerve complex is a very important and somewhat unique component of the nervous system. It is responsible for the sensory signals that arise from the most part of the face, mouth, nose, meninges, and facial muscles, and also for the motor commands carried to the masticatory muscles. These signals travel through a very complex set of structures: dermal receptors, trigeminal branches, Gasserian ganglion, central nuclei, and thalamus, finally reaching the cerebral cortex. Other neural structures participate, directly or indirectly, in the transmission and modulation of the signals, especially the nociceptive ones; these include vagus nerve, sphenopalatine ganglion, occipital nerves, cervical spinal cord, periaqueductal gray matter, hypothalamus, and motor cortex. But not all stimuli transmitted through the trigeminal system are perceivable. There is a constant selection and modulation of the signals, with either suppression or potentiation of the impulses. As a result, either normal sensory perceptions are elicited or erratic painful sensations are created. Electrical neuromodulation refers to adjustable manipulation of the central or peripheral pain pathways using electrical current for the purpose of reversible modification of the function of the nociceptive system through the use of implantable devices. Here, we discuss not only the distal components, the nerve itself, but also the sensory receptors and the main central connections of the brain, paying attention to the possible neuromodulation targets.

Timing of early and late seizure recurrence after temporal lobe epilepsy surgery.

PURPOSE: Seizure recurrence after epilepsy surgery has been classified as either early or late depending on the recurrence time after operation. However, time of recurrence is variable and has been arbitrarily defined in the literature. We established a mathematical model for discriminating patients with early or late seizure recurrence, and examined differences between these two groups. METHODS: A historical cohort of 247 consecutive patients treated surgically for temporal lobe epilepsy was identified. In patients who recurred, postoperative time until seizure recurrence was examined using an receiver-operating characteristic (ROC) curve to determine the best cutoff for predicting long-term prognosis, dividing patients in those with early and those with late seizure recurrence. We then compared the groups in terms of a number of clinical, electrophysiologic, and radiologic variables. KEY FINDINGS: Seizures recurred in 107 patients (48.9%). The ROC curve demonstrated that 6 months was the ideal time for predicting long-term surgical outcome with best accuracy, (area under the curve [AUC] = 0.761; sensitivity = 78.8%; specificity = 72.1%). We observed that patients with seizure recurrence during the first 6 months started having seizures at younger age (odds ratio [OR] = 6.03; 95% confidence interval [CI] = 1.06-11.01; p = 0.018), had a worse outcome (OR = 6.85; 95% CI = 2.54-18.52; p = 0.001), needed a higher number of antiepileptic medications (OR = 2.07; 95% CI = 1.16-9.34; p = 0.013), and more frequently had repeat surgery (OR = 9.59; 95% CI = 1.18-77.88; p = 0.021). Patients with late relapse more frequently had seizures associated with trigger events (OR = 9.61; 95% CI = 3.52-26.31; p < 0.01). SIGNIFICANCE: Patients with early or late recurrence of seizures have different characteristics that might reflect diversity in the epileptogenic zone and epileptogenicity itself. These disparities might help explain variable patterns of seizure recurrence after epilepsy surgery.

Use of transparent plastic tubular retractor in surgery for deep brain lesions: a case series.

Brain tissue retraction is frequently required to reach deep intra-axial lesions, and the quest for an ideal retractor that would protect the underlying brain tissue continues. Despite the availability of multiple retractors, the incidence of brain retraction injury remains high and has been reported to be 5% to 10%. A recently developed transparent tubular retractor appears to provide several advantages in surgery for deep intra-axial tumors and intracerebral hematomas. We used a new commercially available transparent tubular retractor in 16 craniotomies. Fourteen of these patients were operated upon for deep tumors and cysts, including two intraventricular tumors and two for deep intracerebral hemorrhages. In all patients, the tubular retractor was directed toward the lesion through a small corticotomy and guided by a navigation system. Each lesion was completely removed through the retractor's lumen. In all cases, the tubular retractors provided excellent visualization of the underlying pathology and facilitated its surgical removal, dissection, and hemostasis. The tubular nature of the retractor allowed the rotation and changing the angle of approach without putting extra pressure on the brain tissue, which inevitably occurs when malleable or other ribbon-type retractors are used. There were no hematomas on routine postoperative CT scans in this series. Transparent tubular retractors provide a unique means of deep visualization and even force distribution at the retracted brain tissue. Although these retractors were originally designed for the removal of deep subcortical tumors, they may be used to access and evacuate intracerebral hematomas. In our experience, the use of tubular retractors allows one to achieve safe access to deep intracerebral lesions and decreases the rate of retraction-related complications.

Cervical spinal cord stimulation may prevent cerebral vasospasm by modulating sympathetic activity of the superior cervical ganglion at lower cervical spinal level.

Cervical spinal cord stimulation (SCS) has been for many years hypothesized to be of use in treatment of cerebral vasospasm after subarachnoid hemorrhage. Experiments in animals and research in humans have demonstrated increase in cerebral blood flow (CBF), and different theories have been tried to explain these observations. Although there are many claims of circulatory improvements in these circumstances, no clinical application has yet been established. A complete understanding of physiological and anatomic correlation between CBF modulation and SCS remain unclear. We strongly believe that the main objective is not to treat vasospasm by increasing blood flow but to prevent vasoconstriction of the cerebral arteries by a functional sympathectomy. SCS may, at least theoretically, work in different ways at the same time: (1) preventing vasoconstriction of cerebral arteries by functional sympathectomy, acting at the lower cervical levels; and (2) increasing CBF through central pathways, perhaps involving brainstem connections, at the upper cervical levels. One of the practical implications of this hypothesis would be differential placement of cervical spinal cord stimulation electrodes in patients with subarachnoid hemorrhage depending on the timing of electrode insertion and presence or absence of vasospasm at the time of initial intervention.

Benign fasciculations responsive to gabapentin.

Fasciculations are symptoms present in a broad spectrum of conditions, ranging from normal manifestations to motor neuron diseases. They also represent the main picture of benign fasciculation syndrome. We report a case of such syndrome: a 48-years-old woman complaining about fasciculations for three decades who remained with the symptoms even after the compensation of a disclosed hyperthyroidism. The introduction of gabapentin rendered control of her fasciculations. The available data in the literature about the therapeutic approaches for fasciculations are revised, as long as the rare reports of evolution from patients with "benign" fasciculations to cases of amyotrophic lateral sclerosis, underlining the importance of following the patients with fasciculations.

Benign fasciculations responsive to gabapentin

Fasciculations are symptoms present in a broad spectrum of conditions, ranging from normal manifestations to motor neuron diseases. They also represent the main picture of benign fasciculation syndrome. We report a case of such syndrome: a 48-years-old woman complaining about fasciculations for three decades who remained with the symptoms even after the compensation of a disclosed hyperthyroidism. The introduction of gabapentin rendered control of her fasciculations. The available data in the literature about the therapeutic approaches for fasciculations are revised, as long as the rare reports of evolution from patients with "benign" fasciculations to cases of amyotrophic lateral sclerosis, underlining the importance of following the patients with fasciculations.

Fasciculações são sintomas presentes em um amplo espectro de condições, desde manifestações normais até doenças do neurônio motor. Elas representam também o principal aspecto da síndrome de fasciculações benignas. Relatamos um caso desta síndrome: uma paciente de 48 anos com queixas de fasciculações por três décadas que, mesmo após a compensação de um quadro de hipertireoidismo, permaneceu com os sintomas. A introdução de gabapentina levou a controle das fasciculações. Os dados disponíveis na literatura sobre as abordagens terapêuticas para fasciculações são revisados, assim como os raros relatos de evolução de pacientes com fasciculações "benignas" para casos de esclerose lateral amiotrófica, salientando a importância do seguimento dos pacientes com fasciculações.

Down syndrome with congenital hydrocephalus: case report.

Down syndrome is the most frequent genetic cause of mental retardation. Although usually presenting dysmorphic features and organ malformations, it is rarely associated with congenital hydrocephalus. The case of a male neonate whose hydrocephalus was detected since the pregnancy and was discovered to have the syndrome at birth is reported. Chromosomal analysis confirmed the genetic disorder, and hydrocephalus was treated with ventriculoperitoneal shunt because of abnormal increase of head circumference. The patient has been accompanied and his development is considered normal when compared to the expected for those affected by the syndrome.

Down syndrome with congenital hydrocephalus: case report / Síndrome de Down associada a hidrocefalia congênita: relato de caso

Down syndrome is the most frequent genetic cause of mental retardation. Although usually presenting dysmorphic features and organ malformations, it is rarely associated with congenital hydrocephalus. The case of male neonate whose hydrocephalus was detected since the pregnancy and was discovered to have the syndrome at birth is reported. Chromosomal analysis confirmed the genetic disorder, and hydrocephalus was treated with ventriculoperitoneal shunt because of abnormal increase of head circumference. The patient has been accompanied and his development is considered normal when compared to the expected for those affected by the syndrome.

A síndrome de Down é a causa genética mais freqüente de retardo mental. Embora comumente apresentando dismorfias e malformações de órgãos, raramente está associada à hidrocefalia congênita. O caso de um recém-nascido masculino cuja hidrocefalia foi detectada desde a gravidez e que se descobriu ser portadora da síndrome ao nascimento é relatado. O cariótipo confirmou a anormalidade genética, e a hidrocefalia foi tratada com derivação ventriculoperitoneal devido ao aumento anormal do perímetro cefálico. O paciente está sendo acompanhado e seu desenvolvimento é considerado normal quando comparado ao esperado para os portadores da síndrome.

Metastatic prolactinoma: case report with immunohistochemical assessment for p53 and Ki-67 antigens.

Pituitary carcinomas are rare neoplasms characterized by craniospinal and/or systemic metastases originated from the pituitary. Their histopathology is frequently indistinguishable from that of benign adenomas. The development of markers that better reflect their behavior is desirable. We present the case of a 47 year-old man with a prolactin-secreting macroadenoma who was submitted to surgeries, cranial radiation therapy, and bromocriptine treatment, but evolved to a fatal outcome after the disclosure of intracranial metastases. Tumor samples underwent p53 and Ki-67 immunohistochemical assessment. p53 was absent in all samples, a rare finding among pituitary carcinomas. Ki-67 proliferative index was 2.80% in the original tumor, 4.40% in the relapse, and 4.45% in the metastasis. The figure in the relapse is higher than the expected for a noninvasive adenoma. In conclusion, p53 staining is not positive in all pituitary carcinomas. A high Ki-67 proliferative index in a pituitary adenoma might indicate a more aggressive behavior.