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Temporal lobe epilepsy (TLE) is the most common form of intractable partial epilepsy in adults. Surgery (lobectomy or amygdalohippocampectomy) is effective in most patients. However, some complications can occur and brain shift, hematoma into the post operative cavity and occulomotor nerve palsy have been reported due to the surgical technic. We report the technique, safety and efficacy of temporal disconnection in nonlesional TLE. Forty-seven patients (18 males, 29 females; handedness: 12 left, 33 right; aged 35 years+/-10; mean duration of epilepsy: 24+/-10 years) underwent temporal disconnection (20 left, 27 right) guided by neuronavigation. Sixteen patients (35 %) underwent additional presurgical evaluation with SEEG. The outcome was assessed using Engel's classification. At the two-year follow-up, 85 % of the patients were seizure-free (Engel I), 26 (58 %) of whom were Ia. Postoperative persistent morbidity included mild hemiparesis (n=1), mild facial paresis (n=1), quadranopsia (n=23) and hemianopia (n=1). Verbal memory worsened in 13 % of cases when the disconnection was performed in the dominant lobe. MRI follow-up showed two cases of nonsymptomatic thalamic or pallidal limited ischemias, two cases of temporal horn-cystic dilatation, one requiring surgical reintervention without sequelae. There was one case of postoperative phlebitis. In the seizure-free patient group, postoperative EEG showed interictal temporal spikes at three months, one year and two years located in the anterior temporal region. Temporal disconnection is effective, prevents the occurrence of subdural cyst and hematomas in the temporal cavity, prevents the occurrence of oculomotor palsy, and limits the occurrence of quadranopsia. However, comparative studies are required to evaluate temporal disconnection as an alternative to lobectomy in nonlesional TLE.

The surgical treatment of intractable epilepsies involving eloquent areas of the cortex is still challenging. Deep-brain stimulation could be an alternative to resective surgery because it can modulate the remote control systems of epilepsy, such as the thalamus and basal ganglia. The surgical experience acquired in the field of movement disorder surgery and the low morbidity of this technic could allow one to apply DBS to intractable epilepsies, such as generalized, motor and bitemporal epilepsies. Here we discuss the main experimental and clinical data reported so far in the literature and taken from our own experience.

Authors describe the SEEG technique which is routinely used during stereotactic investigations of brain tumors. By the way of the Talairach's stereoencephalographic electrodes, the brain tissue impedance is measured along the probe trajectory with a four electrode impedancemeter (0.25 mA; 5 KHz). The impedance profile provides a good pattern of the brain structures which are crossed; in pathological areas, the impedance significantly decreases as well in gliomas as in edema; cysts and CSF spaces also decrease the recorded impedance. As a contrary, metastases and meningiomas increase the impedance. SEEG appears to be a sharp method for stereotactic delineation of the brain tumors; a larger series as well as the real-imaginary decomposition of the impedance are needed for a best selectivity of the method.

Electrical stimulation of rat habenular complex induces analgesia, evaluated by the tail-flick test, dependent on intensity of stimulation with a long post-effect, that is reversible by naloxone and without behavior effects at less that 400 mA. Bilateral destruction of habenula fails to provoke hyperesthesia but causes more marked long-term tolerance effects than in controls. Anatomy suggests that the habenula activates an inhibitory descending system in the spinal cord with a probable relay in the dorsal raphe and involving an endogenous opioid-dependent stage.

From the study of 65 severe traumatic comas, the authors describe the syndrome of mesodiencephalic dysfunction, because of its frequency and its particular clinical signs. This peculiar level of loss of consciousness is characterized by a coma without mimic and without awakening after painful stimulation, by a stereotyped motor pattern in extension, by a perseverance of the photomotor reflex, while fronto-orbicular and vertical oculo-vestibular reflexes are lacking. This level of deterioration appears to be a critical point in the natural history of comatose patients. If this level is not surpassed, the probability of early death due to evolutive neurological lesion is low (18%). One half of these patients have a good prognosis, more than 75% have an excellent recovery. This high probability of recovery is decreased by a half when the level of mesencephalic dysfunction is reached.

Authors study the neurological evolution of 50 cases of traumatic coma and recognize 5 misfunction levels corresponding to five steps of rostrocaudal deterioration. The level 1 (cortico-sub-cortical) is defined by the persistence of the mimic and flexion response to painful stimulation. The level 2 (diencephalic) is characterized by stereotypic responses to pain and lack of mimic. At these two levels, the fronto-orbicular and vertical oculo-vestibular reflexes are persistent. These reflexes disappear when the status impair caudodal to the level 3 (meso-diencephalix junction). The photomotor reflex disappear at the level 4 (mesencephalic), where the motor response to pain may be very poor, or may be a bilateral extension. The horizontal oculo-vestibular reflex is always persistent, except for the level 5 corresponding to a pontine lesion. The meso-diencephalic level 3 appears to be a critical impairment point: as long as the level is not overpassed, the half of the patients do improve and 10% only die. More than 75% of those who improve from this level have an excellent recovery. The restructuration probability is diminished by the half when the level of mesencephalic misfunction is reached.

Two cases of papilloma of the choroid plexus in children, one in the fourth ventricle and the other in the central part of the left lateral ventricle, are reported. Hyperproduction of CSF could be suspected in the first case by the productive character of pre-operative external ventricular drainage and demonstrated in the second by measurement of pre and post-operative flow rates through a ventriculo-peritoneal bypass which had been installed previously. The origin of this over-production of CSF is discussed, in the pathogenesis of hydrocephalus, in comparison with other factors such as subarachnoid haemorrhage, hyperproteinorachia impairing the resorption of CSF.