Neuromodulation of the anterior thalamic nucleus as a therapeutic option for difficult-to-control epilepsy.

Deep brain stimulation (DBS) consists of the electrical stimulation of the subcortical structures by implanting electrodes connected to a pulse generator. The thalamus, being a structure that has multiple connections with various parts of the central nervous system, is a suitable target for DBS. The anterior thalamic nucleus (ANT) serves as an important relay site for the limbic system by receiving input from the hippocampus and mammillary bodies, and sending input to the cingulate gyrus; thus forming the Papez circuit. Due to these connections, the ANT constitutes an ideal route for the propagation of epileptogenic activity. ANT-DBS has excellent results in the control of complex partial seizures. The vast majority of patients with ANT-DBS have shown a significant reduction in the frequency of their seizures of more than 50%.

Neuromodulation of the anterior thalamic nucleus as a therapeutic option for difficult-to-control epilepsy. / Neuromodulación del núcleo talámico anterior como opción terapéutica para epilepsia de difícil control.

Deep brain stimulation (DBS) consists of the electrical stimulation of the subcortical structures by implanting electrodes connected to a pulse generator. The thalamus, being a structure that has multiple connections with various parts of the central nervous system, is a suitable target for DBS. The anterior thalamic nucleus (ANT) serves as an important relay site for the limbic system by receiving input from the hippocampus and mammillary bodies, and sending input to the cingulate gyrus; thus forming the Papez circuit. Due to these connections, the ANT constitutes an ideal route for the propagation of epileptogenic activity. ANT-DBS has excellent results in the control of complex partial seizures. The vast majority of patients with ANT-DBS have shown a significant reduction in the frequency of their seizures of more than 50%.

Recurrent Herpes Simplex Virus Encephalitis After Neurologic Surgery.

BACKGROUND: The herpes simplex virus (HSV) is the most common cause of sporadic encephalitis worldwide. Even with proper treatment, this infection is associated with a mortality rate of 19%-30% and with potential neurologic sequelae. Recurrences of encephalitis are rare and limited to a few cases in the literature. Although the mechanism of reactivation has not yet been clarified, in our patient, the surgery might have acted as a precipitating factor. CASE DESCRIPTION: The case involved a female 10-year-old patient with a history of type 1 HSV encephalitis since 24 months of age. Secondarily, the patient developed postherpetic epilepsy in the following years. At 10 years old, she was referred to the epilepsy surgery service, and an elective right temporal lobectomy was performed. After surgery, the patient experienced severe clinical deterioration characterized by fever, severe headache, and altered state of consciousness. Encephalitis was diagnosed based on a positive polymerase chain reaction for HSV in the cerebrospinal fluid. The symptoms remitted after 8 weeks of treatment with acyclovir. The histopathologic diagnosis was a chronic encephalitic process with late secondary parenchymal changes without specific viral cytopathic findings. The only limitation that persisted was related to fine movements of the left hand. One year after surgery, the patient rejoined her school activities and is currently free of seizures. CONCLUSIONS: HSV encephalitis is a rare but serious complication that should be suspected in cases of unexplained postoperative fever with altered consciousness, especially in patients with histories of encephalitic states.

Suprameatal extension of retrosigmoid approach for microvascular decompression of trigeminal nerve: Case report.

INTRODUCTION: Trigeminal neuralgia is produced in a significant number of cases by vascular compression at the level of cisternal segment of the nerve at the entry of the pons. It is common to find superior cerebellar artery (SCA) responsible for this compression. The retrosigmoid approach (RA), with asterional craniectomy, clearly exposes the cisternal portion of the trigeminal nerve (TN). PRESENTATION OF CASE: We describe in this case report how vessels at the trigeminal pore level known as "Meckel's segment" can compress the TN. This situation is unusual. One of the reasons why the compression of this Meckel's segment level could be overlooked is a suprameatal tubercle (ST) prominence that would prevent trigeminal pore visualization through retrosigmoid approach. DISCUSSION: The suprameatal extension of this approach has been described for other purposes, especially in tumors invading Meckel's cave resection. We could not find publications for the use of the resection of the suprameatal tubercle in the retrosigmoid approach for microvascular decompression of the trigeminal neuralgia. CONCLUSION: Microvascular decompression of the TN is an effective treatment for trigeminal neuralgia, however in some cases, in which vascular compression is not evident when exploring the cerebellopontine angle, it is important to note that association of a prominent ST can hide a vascular compression of the nerve in this region.