[Intraoperative identification of the supplementary motor area in neurooncological surgery]. / Identificación intraoperatoria del área motora suplentaria en cirugía neurooncológica.

OBJECTIVES: The main objective of the present work was to identify, by means of intraoperative electrical stimulation, the supplementary motor area (SMA) region which is implicated in complex motor function. The functional prognostic relevance of the surgical preservation of this area was also analyzed. METHOD: Fifteen patients with tumors infiltrating the premotor cortex were selected. All patients were operated under awake conditions. Primary motor cortex was identified with intraoperative electrical stimulation (IES). To identify the SMA, patients were asked to do a finger opposition motor task with their hand contralateral to the lesion, that was blocked by electrically stimulating the premotor cerebral cortex. RESULTS: SMA was identified in all patients with IES. Complete surgical resection was achieved in 13 patients (86.6%) and subtotal in 2 patients (13.3%). SMA function was preserved in 14 patients (93.3%). In only one patient the SMA was partially resected because of tumor infiltration (6.6%). In the immediate postoperative period, 8 patients (53.3%) did not show changes in comparison to their preoperative clinical status, and 2 patients improved. At 6 months follow up, 5 patients (33.3%) were asymptomatic and 10 patients showed permanent deficits. In this last group, five patients (33.3%) showed mild deficits that did not interfere with a normal life. In the other 5 patients (33.3%), permanent deficits interfered with daily life activities: two patients presented severe hemiparesis 3/5 (same similar to their preoperative status with no improvement), one patient had motor aphasia, and two other patients (13.3%) showed permanent left SMA syndrome. In two patients with severe postoperative hemiparesis, tumor infiltration of primary motor cortex and piramidal pathway was observed; severe preoperative motor deficit (KPS <70) was associated with poor functional outcome. CONCLUSIONS: Intraoperative electrical cortical stimulation is useful to identify the SMA. Once identified, SMA preservation decreases the risk of postoperative symptoms and permanent SMA syndrome. When SMA is infiltrated by the tumor, radical resection may cause permanent neurological deficits, specially in the dominant hemisphere. Severe preoperative motor deficit was associated with poor outcome.

Perfusion SPECT, SISCOM and PET (18)F-FDG in the assessment of drug- refractory epilepsy patients candidates for epilepsy surgery.

AIMS: Brain perfusion SPECT (ictal-interictal), SPECT images and subtraction ictal SPECT coregistered to MRI (SISCOM) and (18)F-FDG-PET (interictal), play an important role in the pre-surgical diagnosis of patients with medically refractory epilepsy. This study aimed to establish: the reproducibility of visual ictal-interictal SPECT and SISCOM analysis altogether with the capacity of SPECT, SISCOM and PET to determine the epileptogenic zone. MATERIAL AND METHODS: (99m)Tc-HMPAO SPECT ictal-interictal and SISCOM (Analyze 7.0) were performed on 47 refractory epilepsy patients (24 F, 19-60 yrs). In 13 patients, SISCOM was also performed using a new program (Focus DET). Ictal-interictal SPECT and SISCOM images were analysed independently by two nuclear medicine physicians (observer 1 and 2). Kappa concordance coefficient was used to evaluate the reproducibility. In sixteen patients, SPECT, SISCOM and PET findings were compared with the resected area during the surgery, and surgical outcome using Engel scale or with the stereo EEG-(SEEG). RESULTS: The ictal-interictal SPECT interobserver agreement was 91%, Kappa index 0.86, SISCOM (Analyze 7.0) interobserver agreement percentage was 82%, Kappa index 0.80, Analyze 7.0 showed a higher inconclusive results than visual SPECT analysis. SISCOM FocusDET interobserver agreement was 92%, Kappa index 0.87, with lower inconclusive results than Analyze 7.0. SPECT, SISCOM and PET combined findings identified 87% seizure onset zone: 79% temporal, 26% parieto-temporal and 7% frontal. CONCLUSIONS: Ictal-interictal SPECT and SISCOM showed a high reproducibility in this sample of patients with drug-refractory epilepsy. SPECT,SISCOM and PET combined findings improved detection of epileptogenic zone in comparison with the individual assessment.

Studies with the Golgi method in central gangliogliomas and dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease).

The rapid Golgi method, combined with current optical and electronmicroscopical techniques, was used in three central gangliogliomas and in one dysplastic gangliocytoma of the cerebellum to study the morphology of ganglionic cells. Gangliogliomas were composed of bipolar, fusiform and radiate cells with dense core and clear vesicles in the perikaryon and cellular processes, the number of each cellular type varying from one case to another. These features, together with the fact that isodendritic neurons are considered to be phylogenetically old neurons, suggest that these tumours are composed of "primitive" neurons that are not homogeneous with regard to their morphology. In contrast, ganglionic cells in dysplastic gangliocytoma are huge cells with long, stereotyped neurites that establish unique asymmetric contacts with neighbouring perikarya and neurites by means of claw-shaped processes covered with synaptic buttons. These morphological characteristics are different from those of any other neuron of the CNS.

Clinical application of functional magnetic resonance imaging in presurgical identification of the central sulcus.

OBJECT: The authors sought to evaluate the advantages and limitations of functional magnetic resonance (fMR) imaging when it was used regularly in the clinical context to identify the central sulcus. METHODS: A 1.5-tesla MR system comprising a spoiled gradient recalled acquisition in the steady-state functional sequence and a cross-hand cancellation analysis method were used to evaluate 50 surgical candidates with centrally located space-occupying lesions in the brain. Three-dimensional (3-D) models of the patient's head and brain showing the relative position of the tumor and the eloquent cortex were obtained in each case. A selective and reproducible focal activation was found, indicating the probable central sulcus position in 41 patients (82%). Direct cortical stimulation confirmed the fMR findings in 100% of 22 intraoperatively assessed patients. Failure to identify the central sulcus occurred in 18% of cases and was mainly a consequence of intrinsic damage in the primary sensorimotor region that resulted in severe hand paresis. CONCLUSIONS: Although specific factors were identified that contributed to reduced sensitivity of fMR imaging in the clinical context, the present study supports functional assessment and 3-D representation of specific surgical situations as generally feasible in common practice.

Diagnosis of brain abscess by magnetic resonance spectroscopy. Report of two cases.

Two cases of brain abscess were diagnosed by combining magnetic resonance spectroscopy (MRS) and magnetic resonance (MR) imaging. The resonances observed in vivo were assigned by means of an in vitro MRS study of the exudates extracted during surgical aspiration of the abscesses. The technique of MRS was demonstrated to be very powerful in the differential diagnosis of brain abscesses from other brain pathologies such as neoplasms. Amino acids, probably originating from extracellular proteolysis, and other compounds, such as acetate, arising from bacterial metabolism, were visible in the MRS spectra of the abscess, whereas they are not present in spectra of neoplasms. In this sense, MRS complemented the information provided by MR imaging to achieve a correct diagnosis of brain abscesses and could be added to routine MR examinations with only a small increase in cost and time.

Parvalbumin and calbindin D-28K immunoreactivity in central ganglioglioma and dysplastic gangliocytoma of the cerebellum. Report of two cases.

Calbindin D-28K and parvalbumin immunocytochemistry were used in the study of central ganglionic cell tumors. Most neurons in the ganglioglioma were immunoreactive to calbindin D-28K, but a few cells were labeled with antibodies against parvalbumin. In contrast, most cells in dysplastic gangliocytoma of the cerebellum were parvalbumin immunoreactive, but fewer reacted with anti-calbindin antibodies. These latter cells had two or three dendrites with claw-shaped terminals and axons with recurrent collateral branches and varicose terminals filled with strings and buttons. These observations suggest that central ganglionic cell tumors, including dysplastic gangliocytoma of the cerebellum, are composed of neurons which, on the basis of their calcium-binding protein content, have particular metabolic and electrophysiological properties.

Presurgical identification of the primary sensorimotor cortex by functional magnetic resonance imaging.

The ability of functional magnetic resonance (MR) imaging to detect a selective sensorimotor cortex activation in healthy subjects and the feasibility of motor activation in patients with lesions around the central sulcus were investigated. Twenty-five healthy volunteers performed 100 motor activation trials, using a variety of motor tasks, which were monitored by several image analysis methods. The functional images were obtained using a 1.5-tesla standard MR imaging system magnet with blood oxygenation level-dependent contrast. Four patients were assessed using functional MR imaging and invasive cortical mapping. Rolandic cortex activation was observed in 98% of the trials performed on healthy subjects in which no head motion occurred. Nevertheless, the cortical response was not selective in a task-rest analysis due to concurrent activation of neighboring regions. Across-task comparison analyses were useful in cancelling nonrelevant activity in most cases (86%). In the patient group, the region identified as the sensorimotor cortex by invasive means corresponded accurately to the area that was activated in functional MR imaging. Present data support the feasibility of detecting selective activation of the rolandic cortex, even in the clinical setting, leading the authors to suggest the usefulness of this widely available technique in surgical planning.

Cavernous angiomas of the brain stem.

Cavernous angiomas in contact with the pial or ependymal surfaces of the brain stem can be totally and safely resected. Such an approach is recommended for symptomatic patients. For asymptomatic patients whose lesions are deeply embedded in the parenchyma, close observation without surgical intervention is recommended.

[Intraoperative cortical mapping in the surgical resection of low-grade gliomas located in eloquent areas]. / Estimulación cortical intraoperatoria en el tratamiento quirúrgico de los gliomas de bajo grado situados en áreas elocuentes.

INTRODUCTION: Surgical selection of patients harboring low-grade gliomas based on radiological criteria may be insufficient due to individual variability in eloquent areas location and to the fact that function can be preserved within infiltrated brain tissue. Brain stimulation mapping safety for patients with low-grade gliomas is evaluated, analyzing whether this technique modifies the extent of resection and minimizes postoperative deficits. MATERIAL AND METHODS: Twenty-five patients with lowgrade gliomas (II/IV WHO) located in eloquent areas underwent tumor resection with the aid of intraoperative mapping. Patients underwent surgery under local or general anesthesia depending on the neurological function to be explored. All procedures were performed from an oncological point of view, trying to achieve a radical tumor resection but stopping removal whenever functional tissue was found within or near the lesion. RESULTS: Total or subtotal resection was achieved in 16 patients (64%); in five cases (20%) resection was partial, and in the remaining (16%) only a biopsy was obtained. Tumors located in the supplementary motor area (SMA) or in the operculum were those which could be more often totally resected. Thirteen patients (52%) experienced neurological worsening immediately after surgery but eight of them had almost completely recovered six months after the procedure. CONCLUSIONS: Intraoperative functional mapping can optimize extent of resection minimizing permanent morbidity. Functional tissue can be found within the infiltrated brain and this must be considered in the presurgical planning. SMA and opercular tumors allow radical resection with low morbidity whereas insular tumors remain a challenge even with the aid of this technique.

Breast cancer brain metastases: a review of the literature and a current multidisciplinary management guideline.

Breast cancer represents the second most frequent etiology of brain metastasis (BM). It is estimated that 10-30 % of patients with breast cancer are diagnosed with BM. Breast cancer BM are increasing due to the aging population, detection of subclinical disease, and better control of systemic disease. BM is a major cause of morbidity and mortality affecting neurocognition, speech, coordination, behavior, and quality of life. The therapy of BM remains controversial regarding use and timing of surgical resection, application of whole-brain radiotherapy, stereotactic radiosurgery and systemic drugs in patients with particular tumor subtypes. Despite numerous trials, the range of interpretation of these has resulted in differing treatment perspectives. This paper is a review of the state of the art and a multidisciplinary guideline on strategies to improve the therapeutic index in this situation.

Chronic isolated trochlear nerve palsy produced by intracavernous internal carotid artery aneurysm. Report of a case.

The fourth cranial nerve is rarely affected by intracranial aneurysms, and when this occurs other motor ocular nerves and the trigeminal nerve are almost always involved as well. In the case reported, a middle-aged woman presented with a long-standing selective and stationary palsy of the right superior oblique muscle. Neuroradiologic studies disclosed an aneurysm arising at the C-3 segment of the right internal carotid artery.

[Spontaneous closure of a intracraneal dural arteriovenous fistula by controlled hypotension during a general anesthesia procedure. A case report]. / Cierre espontáneo de fístula arteriovenosa dural intracraneal tras hipotensión controlada bajo anestesia general. A propósito de un caso.

Intracranial dural arteriovenous fistulas (DAVF) are arteriovenous communications within the duramater, which seem to be pathophysiologically related to a venous sinus thrombosis. DAVF may require invasive treatment, although rarely spontaneous occlusion has been reported. The present case is a 48-year-old male with a diagnosed type III DAVF of the right lateral sinus. Complete endovascular embolization was not possible to perform, so he was considered a candidate for surgical treatment. During perioperative management, under general anesthesia, the intraoperative arteriographyc monitoritation showed a spontaneous closure of the DAVF after induced controlled hypotension, resulting in complete cure. We conclude that controlled hypotension could become an alternative for treatment of DAVF in high risk patients or when there is no chance for embolization.patients or when there is no chance for embolization. Neurología 2003;18(10):746-749

Pattern recognition analysis of 1H NMR spectra from perchloric acid extracts of human brain tumor biopsies.

Pattern recognition techniques (factor analysis and neural networks) were used to investigate and classify human brain tumors based on the 1H NMR spectra of chemically extracted biopsies (n = 118). After removing information from lactate (because of variable ischemia times), unsupervised learning suggested that the spectra separated naturally into two groups: meningiomas and other tumors. Principal component analysis reduced the dimensionality of the data. A back-propagation neural network using the first 30 principal components gave 85% correct classification of meningiomas and nonmeningiomas. Simplification by vector rotation gave vectors that could be assigned to various metabolites, making it possible to use or to reject their information for neural network classification. Using scores calculated from the four rotated vectors due to creatine and glutamine gave the best classification into meningiomas and nonmeningiomas (89% correct). Classification of gliomas (n = 47) gave 62% correct within one grade. Only inositol showed a significant correlation with glioma grade.