[Current management of arteriovenous malformations. Retrospective study of 31 cases and literature review]. / Manejo actual de las malformaciones arteriovenosas. Estudio retrospectivo de 31 casos y revisión de la literatura.

OBJECTIVE: To establish some therapeutic criteria about the treatment of AVMs of III, IV and V grade of Spetzler and Martin and to analyse the results in the subgroup of preoperative embolization plus surgery. METHODS: We perform a retrospective analysis of a group of 31 patients with arteriovenous malformations (AVMs) treated in our center between 1999 and 2004. There were 19 women and 12 men, with a mean age of 31.6 years old (range, 1-62a). Their symptoms upon admission were intracranial hemorrhage in 77.4%, seizures in 12.9%, headache, ischemic event and incidental finding in 3.2% each group. Diagnostic angiography was performed in 29 cases and anatomopathologic diagnostic in 2 cases. The malformations were classified with Spetzler and Martin Grading Scale, in 10.3% grade I, 24.1% grade II, 37.9% grade III, 24.1% grade IV and 3.4% grade V. Patients were classified in 6 subgroups of treatment (surgery, embolization, radiosurgery, embolization plus surgery, embolization plus radiosurgery and conservative treatment). RESULTS: AVMs grade III, IV and V (19 patients) were treated with surgery (6 cases), embolization plus surgery (5 cases), but also other kind of treatments (embolization alone, radiosurgery and conservative) were used. Functional results in these groups of patients were 36.8% (7 cases) with no symptoms or slights symptoms (modified Rankin 0-1), 52.6% (10 cases) minor disability (mRankin 2), 5.3% (1 case) moderate disability and 5.3% (1 case) mortality. We observe a high rate of postembolization hemorrhage in the group of patients in which the combination of preoperative embolization plus surgery was used. In these cases, early surgery was performed with a good functional recovery. There was one case of postoperative mortality. CONCLUSION: We should consider some factors like the natural history, clinical presentation (hemorrhage), angiographic features (deep arterial supply, aneurisms), Spetzler and Martin Grading and the clinical condition of the patient before treating a cerebral AVM. In the subgroup of treatment with embolization plus surgery, we recommend to achieve a subtotal preoperative embolization > 50%, not to obliterate more than 50% in one session, to perform staged embolization waiting from 4 to 6 weeks between procedures, and from 1 to 3 weeks between the last embolization and surgery.

[Intraoperative neurophysiological monitoring of brain stem in a case of cavernoma in the pons]. / Monitorización neurofisiológica intraoperatoria del tronco del encéfalo en un caso de cavernoma en protuberancia.

Neurophysiological monitoring during surgery to avoid damaging of eloquent brain areas is a useful tool. We are performing intraoperative neurophysiological test to locate motor, sensitive and speech areas with cortical stimulation and cranial nerves during cerebellopontine cranial base surgery. Neurophysiological monitoring during brain stem surgery has been less described. Brain stem surgery implies a careful selection of patients for surgery given the high risk of morbidity and mortality. For this reason, conservative treatment is usually indicated when an asymptomatic cavernoma is incidentally found. Instead, when bleeding or neurological deficit appear, operative treatment may be indicated and then the goal of surgery is to avoid the disability linked to the natural history. We present the case of a 29 year old woman with diagnosis of multiple cavernomas. She was admitted at our hospital because she presented weakness and sensitive disturbance of left limbs and dizziness. The CT scan and MRI showed a pontine haemorrhage caused by a cavernous hemangioma. We operated her on using neurophysiological monitoring of VII, VIII, X and XII cranial nerves with electromyographic recordings. Postoperative disability could be reduced with a better knowledge of entry zone into the brain stem and early physiotherapy.

Nonhistological diagnosis of human cerebral tumors by 1H magnetic resonance spectroscopy and amino acid analysis.

We describe a multivariate analysis procedure to classify human cerebral tumors nonhistologically in vitro, combining the use of 1H magnetic resonance spectroscopy (MRS) with automatic amino acid analysis of biopsy extracts. Eighty-one biopsies were obtained surgically and classified histologically in eight classes: high-grade astrocytomas (class 1, n = 19), low-grade astrocytomas (class 2, n = 10), normal brain (class 3, n = 9), medulloblastomas (class 4, n = 4), meningiomas (class 5, n = 18), metastases (class 6, n = 8), neurinomas (class 7, n = 9), and oligodendrogliomas (class 8, n = 4). Perchloric acid extracts were prepared from every biopsy and analyzed by high resolution 1H MRS and automatic amino acid analysis by ionic exchange chromatography. Intensities of 27 resonances and ratios of resonances were measured in the 1H MRS spectra, and 17 amino acid concentrations were determined in the chromatograms. Linear discriminant analysis provided the most adequate combination of these variables for binary classifications of a biopsy between any two possible classes and in multiple choice comparisons, involving the eight possible classes considered. Correct diagnosis was obtained when the class selected by the computer matched the histological diagnosis. In binary comparisons, consideration of the amino acid profile increased the percentage of correct classifications, being always higher than 75% and reaching 100% in many cases. In multilateral comparisons, scores were: high-grade astrocytomas, 80%; low-grade astrocytomas, 74%; normal brain, 100%; medulloblastomas, 100%; meningiomas, 94.5%; metastases, 86%; neurinomas, 100%; and oligodendrogliomas, 75%. These results indicate that statistical multivariate procedures, combining 1H MRS and amino acid analysis of tissue extracts, provide a valuable classifier for the nonhistological diagnosis of biopsies from brain tumors in vitro.