The Thalamic Arteriovenous Malformations Have Better Prognosis than Basal Ganglia Malformations Regarding Obliteration: Prognostic Factors Analysis.

BACKGROUND: Arteriovenous malformations (AVMs) are rare vascular congenital lesions that affect mainly patients during their productive years of life. In order to obtain a better quality of life for patients with this disease, a multidisciplinary approach is recommended. Radiosurgery is one of the treatment modalities available for AVMs, but many factors may influence the effectiveness of this strategy. Classically, it has been said that deep-seated lesions have a particular behavior compared with AVMs in other regions, but a differentiation between thalamic lesions and those located in the basal ganglia has not been made. METHODS: Institutional records for central core AVMs treated with radiosurgery between January 2004 and January 2014 were retrospectively analyzed. Brainstem lesions were excluded from the analysis. RESULTS: Forty-nine patients with deep-seated AVMs were included. Forty-three (87.8%) were located in the thalamus and 6 (12.2%) in the area of basal ganglia. The nidus mean volume was 4.1 cm3 (SD: 4.1), the maximum diameter mean was of 19.5 mm (SD: 8.0). The prescription dose was 18.2 Gy (SD: 2.1), and the follow-up time was 75.8 months (SD: 32.5). There was a greater obliteration rate in thalamic AVMs compared with those located in the basal ganglia: 81.4% versus 33.3% (P = 0.026), respectively. There was no association between categorical variables and obliteration rate. CONCLUSIONS: Stereotactic radiosurgery is a good option for patients with thalamic and basal ganglia AVMs, but a multidisciplinary approach to decision-making is mandatory in order to achieve the best results.

INFLUENCE OF TYPE OF ANESTHESIA ON HEMODYNAMIC PARAMETERS AND OUTCOME OF DIALYSIS ARTERIOVENOUS FISTULA OPERATIONS.

The goal of the study was to compare effectiveness of regional and local anesthesia in dialysis arterio-venous fistula (AVF) operations. It was a prospective, randomized study. 103 patients with end stage renal disease underwent AVF operations on upper limb. The patients have been randomly divided in two groups. Group I: 49 patients in whom the operations have been done under the local anesthesia; and Group II: 54 patients in whom the operation has been performed under the vertical infraclavicular block. Duplex sonography evaluation of upper arm vessels was performed pre-operatively and at 1, 3 and 6 months postoperatively. Following parameters were measured on duplex scan: vessel diameter, blood flow rates (PSV and EDV), resistive index (RI) and pulsatility index (PI). Significantly less number of patients with regional anesthesia required additional perioperative analgesics as compared with the local anesthesia group. Time to postoperative pain initiation, need for postoperative pain killers was significantly better in Group II as compared with the Group I. Duration of operation was significantly less in regional as compared with local anesthesia. Postoperative PSV and EDVs were negatively correlated with patient age. The fistula maturation time was positively correlated with age. The vein diameter, postoperative PSV and EDV have been significantly increased in Group I as compared with Group II. The postoperative PI has significantly increased and RI has significantly decreased in Group I as compared with Group II. The total number of dialysis punctures was higher in regional as compared with the local anesthesia. Regional anesthesia provides significantly better analgesia as compared with the local anesthesia in AVF operations. It significantly improves the duplex sonography parameters after AVF formation. It can be a method of choice for some forms of fistulas.

[A case of dural arteriovenous fistula associated with bilateral thalamic lesions].

We report a 51-year-old man with a dural arteriovenous fistula (DAVF) associated with bilateral thalamic lesions. He was admitted to our hospital because of cognitive disorder. T2-weighted MRI and fluid-attenuated inversion recovery (FLAIR) sequence of the brain revealed symmetric hyperintense lesions of bilateral thalamus and abnormal flow void that represents the enlarged veins. Cerebral angiography demonstrated DAVF in the superior petrosal sinus (SPS). It was mainly supplied by the internal carotid arteries. The strait sinus was not revealed, and the venous drainage was retrograde into the internal cerebral vein. Therefore the mechanism of cognitive disorder in this case was considered to be vasogenic edema of the bilateral thalamus due to DAVF of SPS. We decided to treat the DAVF by embolization via the feeding arteries approach, because strait sinus was not revealed and venous approach was difficult. After embolization, the size of DAVF was remarkably reduced. His cognitive disorder was markedly improved and the hyperintense area on T2-weighted MRI and FLAIR sequence had disappeared. Cognitive disorder due to DAVF of SPS is very rare. It is also difficult to diagnose bilateral thalamic lesions as DAVF, but it may be reversible by DAVF treatment. Thus, early diagnosis and treatment is important. Like this case, abnormal flow void that represents the enlarged veins could help to diagnose bilateral thalamic lesions due to DAVF.

Spinal arteriovenous fistulae with a concomitant cauda equina schwannoma.

BACKGROUND: Perimedullary spinal arteriovenous malformations or direct spinal arteriovenous fistulaes (AVFs) may be associated with other vascular abnormalities, such as arteriovenous malformations, venous ectasis, and aneurysms, but rarely have been reported with intraspinal intradural tumors. PURPOSE: The authors present an interesting case of type IV-A spinal AVF concomitant with a cauda equina schwannoma. STUDY DESIGN: The diagnostic procedures and surgical outcome were described. METHODS: The patient underwent surgery, the vessel feeding the AVFs was identified and cauterized, and the spinal tumor was removed. The fistula was small and located inside the tumor. The pathology revealed AVF and schwannoma, respectively. RESULTS: After surgery, the patient's symptoms began to improve and subside. Two years after surgery, follow-up magnetic resonance imaging showed no vascular lesion and tumor in the spinal canal. CONCLUSIONS: The association of spinal AVFs and cauda equina schwannoma has not been reported previously in any literature. The patient presents the symptoms of myelopathy associated with a spinal vascular lesion; it has to be noted that a concomitant and related intradural spinal tumor may exist.

Evidence of calcium phosphate depositions in stenotic arteriovenous fistulas.

This study investigates vascular samples from patients with and without end-stage renal disease (ESRD) to determine the occurrence of calcium depositions. Findings in stenotic arteriovenous (AV)-fistula veins were compared with those of nonstenotic AV-fistula veins, non-AV-fistula veins, and atherosclerotic vessels. Calcium and phosphorus content was measured by means of scanning electron microscopy and its built-in method of energy-dispersive spectrometry (EDS) X-ray analysis. We found calcium and phosphorus in samples from AV fistulas with stenotic areas with a calcium/phosphorus molar ratio of 1. Based on EDS analysis and crystal shape comparison, we conclude that calcium phosphate precipitations in stenotic AV fistulas are brushites with the composition CaHPO(4)*2H(2)O. This specific calcium phosphate deposition was found solely in stenotic AV fistulas, not in nonstenotic AV-fistula veins or non-AV-fistula veins regardless of whether the patient had ESRD. Moreover, this calcium phosphate deposition was different from calcium compounds found in atherosclerotic samples. Whether the precipitation of brushite is primarily involved in the development of vascular-access stenosis or represents a secondary consequence cannot be determined from the present study.

Venous hypertension associated with a posterior fossa dural arteriovenous fistula: another cause of bithalamic lesions on MR images.

We report a case of a posterior fossa arteriovenous fistula (AVF) with bithalamic hyperintensity of MR images. The thalamic abnormality improved after surgery, suggesting reversible venous hypertension as the pathogenesis of the finding, as opposed to infarction. This manifestation of a posterior fossa AVF should be considered in the differential diagnosis of bilateral thalamic disease.

Hypothalamic hamartoma associated with dural arteriovenous fistula of the transverse-sigmoid sinus--case report.

A 32-year-old female presented with a hypothalamic hamartoma associated with a dural arteriovenous fistula (DAVF) of the left transverse-sigmoid sinus. She complained of pulsatile tinnitus in the left retroauricular region and infertility. Endocrinological examination revealed that the luteinizing hormone reaction to luteinizing hormone-releasing hormone was exceedingly high. Magnetic resonance imaging demonstrated a distinct mass occupying the suprasellar cistern and protruding into the third ventricle. Left carotid angiography demonstrated a DAVF of the left transverse-sigmoid sinus, which was treated by embolization. Histological examination of a biopsy specimen of the tumor revealed a hamartoma. She was free from pulsatile tinnitus after treatment for the DAVF.

Spinal dural arteriovenous fistulas: evaluation with MR angiography.

PURPOSE: To show that postgadolinium three-dimensional time-of-flight MR angiography shows abnormal intradural vessels associated with spinal dural arteriovenous fistula better than routine MR imaging and provides screening information useful for subsequent diagnostic conventional angiography and/or posttreatment evaluation. METHODS: Precontrast and postcontrast MR imaging and MR angiograms, as well as subsequent digital subtraction angiograms, were obtained for eight patients with dural arteriovenous fistulas, diagnosed with digital subtraction angiography and verified with surgery. In four patients, MR studies also were obtained after surgery. RESULTS: All patients had cord hyperintensity of T2-weighted images and postgadolinium enhancement on T1-weighted images. Five had vessellike signal abnormalities in the subarachnoid space on MR. Abnormal intradural vessels were detected in all eight patients with MR angiography. Comparison with digital subtraction angiography revealed these vessels to be primarily enlarged veins of the coronal venous plexus on the cord surface. In six patients, the medullary vein draining the fistula was demonstrated, indicating the level of the fistula, later identified by digital subtraction angiography. After surgical obliteration of the fistula, the draining medullary vein and most or all of the abnormal coronal veins were no longer demonstrated, with decrease or resolution of cord hyperintensity on T2-weighted images. CONCLUSION: Postgadolinium, spinal MR angiography in cases of suspected dural arteriovenous fistula provides information about intradural veins that supplements the diagnostic value of the MR imaging results, facilitates the subsequent digital subtraction angiography study, and, in treated cases, reflects the success of surgery and/or embolization.

Consideraciones clínico-quirúrgicas de los aneurismas arteriovenosos cerebrales en el Hospital Regional Honorio Delgado de Arequipa en los años de 1961 a 1994

El presente trabajo se trata de un estudio retrolectivo en pacientes con el diagnóstico de Aneurisma Arteriovenoso Cerebral, también denominados Malformaciones arteriovenosas congénitas cerebrales hospitalizados en el Servicio de Neurocirugía del Hospital Regional Honorio Delgado de Arequipa en los años de 1961 a 1994; se registraron 20 casos, que guarda relación con otros estudios. También en este estudio se realizó con respecto al tema. Se utilizó el método estadístico descriptivo. La edad de aparición de la sintomatología varió desde los 30 años. No se encontró diferencia por sexo. En cuanto a la forma clínica de presentación preponderante se tiene a la cefálea en un 70 por ciento de casos, luego se presentó la hemorragía en un 65 por ciento de casos. En relación al procedimiento diagnóstico de mayor uso se tiene a la arteriografía cerebral, y por medio de ello se evidenció que el vaso arterial de mayor compromiso fue la cerebral anterior y luego la cerebral media, que en conjunto abarcan el 70 por ciento del total de los casos. El tratamiento quirúrgico más empleado lo constituyó la excéresis total, se realizó en seis pacientes, de ellos todos tuvieron una buena evolución, tal es así que al momento del alta mostraron una recuperación total