Human "memories" can be evoked by stimulation of the lateral temporal cortex after ipsilateral medial temporal lobe resection.

A patient with medically intractable seizures and mesial temporal sclerosis underwent a left anterior temporal lobectomy and amygdalohippocampectomy. After 4 months, his seizures recurred and a left temporal, subdural grid of electrodes was placed to localise his seizure focus. Stimulation through the grid evoked four distinct "memories", or experiential phenomena, despite absence of the ipsilateral medial temporal lobe. To our knowledge, this is the first documented case of experiential phenomena evoked by cortical stimulation in the absence of the ipsilateral medial temporal lobe.

Reversible posterior leukoencephalopathy occurring during resection of a posterior fossa tumor: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: Our goal was to present a clinically and radiographically documented case of reversible posterior leukoencephalopathy (RPL) that occurred during resection of a posterior fossa tumor. Although RPL has been previously described in multiple nonsurgical settings, we hope that this case description makes RPL more clinically and radiographically recognizable to neurosurgeons. CLINICAL PRESENTATION: RPL is the clinical syndrome of headaches, altered mental status, seizures, and visual loss, with radiographic findings of reversible parieto-occipital changes on cerebral computed tomographic and magnetic resonance imaging scans. It has been previously reported in the settings of malignant hypertension, renal disease, eclampsia, and immunosuppression. To our knowledge, the patient presented represents the first clinically and radiographically documented case of RPL occurring during resection of a posterior fossa tumor. The patient intraoperatively exhibited wide fluctuations in blood pressure and awoke with clinical and radiographic findings consistent with RPL. INTERVENTION: Aggressive intraoperative and postoperative management of the patient's blood pressure, supportive intensive care, rehabilitation, and close radiographic follow-up were performed. CONCLUSION: RPL can occur as a result of intraoperative variations in blood pressure, even among young, previously healthy individuals. With the aforementioned interventions, the patient experienced significant clinical and radiographic recovery.

Dynamic nature of cavernous malformations: a prospective magnetic resonance imaging study with volumetric analysis.

OBJECT: Although cavernous malformations (CMs) are not detected in angiographic studies, they have a characteristic appearance on magnetic resonance (MR) images. A number of reports published in the last decade have focused on the behavior of these lesions within the clinical environment. However, little has been published about the evolution of CMs over time, as observed in imaging studies. To understand imaging-documented changes in CMs over time, we analyzed MR images of 114 cavernous malformations in 68 patients who were followed prospectively. METHODS: For each CM the location, volume, and MR imaging signal characteristics were recorded. Volume data were available for 107 lesions from initial images. The mean volume of these 107 CMs was 2779 mm3. The lesions ranged in size from 0.5 to 46,533 mm3 (46.5 cm3). Volume data from a second set of images were available for 76 CMs (mean interval from first imaging session 26 months), and from a third set of images for 24 lesions (mean interval from second imaging session 18 months). Over the first follow-up interval, the mean volume change was -991 mm3 (a decrease of approximately 1 cm3) and over the second interval the mean volume change was -642 mm3. Although these mean volume changes appear modest, volume changes in single lesions during follow-up intervals were more dramatic, with decreases as large as 45,629 mm3 (45.6 cm3) and increases as large as 6,074 mm3 (6 cm3). Serial examinations of the MR imaging signal characteristics of these CMs demonstrate a trend for maturation of blood products from a subacute, to a mixed, and finally to a chronic appearance. Three lesions appeared de novo during the follow-up period. CONCLUSIONS: On the basis of their analysis, the authors conclude that CMs exhibit a range of dynamic behaviors including enlargement, regression, and de novo formation, as well as progression through a series of characteristic MR imaging appearances.

The natural history of cavernous malformations.

This article reviews general information about cavernous malformations, including histology, radiology, epidemiology, and symptomatology. Rates of hemorrhage as reported in the literature are presented. Familial cavernous malformations and their genetic basis are discussed. Finally, the variations in the biological behavior of cavernous malformations in different regions of the central nervous system are discussed and outcomes are assessed.

Surgical obliteration for vein of Galen malformation: a case report.

BACKGROUND: Vein of Galen aneurysm is a relatively rare vascular malformation, often resulting in high morbidity or mortality. Outcome is particularly poor in the neonatal population. METHODS: We report staged surgical treatment of a vein of Galen aneurysm in a neonate who presented in congestive heart failure. RESULTS: Cerebral angiography 6 months following staged surgical treatment revealed complete obliteration of the aneurysm. The patient tolerated surgery well, and at 6 years of age is free of neurologic or cardiovascular impairment. CONCLUSIONS: While the endovascular approach is the procedure of first choice, aggressive medical management followed by staged surgical clipping of aneurysm feeders produced excellent results in this case of neonatal vein of Galen aneurysm. Staged surgical obliteration of arterial feeders should be considered as a therapy when endovascular methods are unsuccessful in safely curing these difficult vascular lesions.