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OBJECTIVE Magnetic resonance imaging–guided focused ultrasound (MRgFUS) is a novel and useful treatment for essential tremor (ET); however, the factors impacting treatment outcome are unknown. The authors conducted this study to determine the factors affecting the outcome of MRgFUS. METHODS From May 2016 through August 2017, 15 patients with ET were admitted to Ohnishi Neurological Center and treated with MRgFUS. To determine the factors impacting treatment outcome, the authors retrospectively studied correlations between the Clinical Rating Scale for Tremor (CRST) improvement rate and age, disease duration, baseline CRST score, skull density ratio (SDR), skull volume, maximum delivered energy, or maximum temperature. RESULTS The mean CRST score was 18.5 ± 5.8 at baseline and 4.6 ± 5.7 at 1 year. The rate of improvement in the CRST score was 80% ± 22%. Younger age and lower baseline CRST score were correlated with a higher CRST improvement rate (p = 0.025 and 0.007, respectively). To obtain a CRST improvement rate ≥ 50%, a maximum temperature ≥ 55°C was necessary. There was no correlation between SDR and CRST improvement rate (p = 0.658). A lower SDR and higher skull volume required significantly higher maximum delivered energy (p = 0.014 and 0.016, respectively). A higher maximum temperature was associated with a significantly larger lesion volume (p = 0.026). CONCLUSIONS Younger age and lower baseline CRST score were favorable outcome factors. It is important to assess predictive factors when applying MRgFUS.

OBJECTIVELumbar spinal drainage (LSD) during neurosurgery can have an important effect by facilitating a smooth procedure when needed. However, LSD is quite invasive, and the pathology of brain herniation associated with LSD has become known recently. The objective of this study was to determine the risk of postoperative brain herniation after craniotomy with LSD in neurosurgery overall.METHODSIncluded were 239 patients who underwent craniotomy with LSD for various types of neurological diseases between January 2007 and December 2016. The authors performed propensity score matching to establish a proper control group taken from among 1424 patients who underwent craniotomy and met the inclusion criteria during the same period. The incidences of postoperative brain herniation between the patients who underwent craniotomy with LSD (group A, n = 239) and the matched patients who underwent craniotomy without LSD (group B, n = 239) were compared.RESULTSBrain herniation was observed in 24 patients in group A and 8 patients in group B (OR 3.21, 95% CI 1.36–8.46, p = 0.005), but the rate of favorable outcomes was higher in group A (OR 1.79, 95% CI 1.18–2.76, p = 0.005). Of the 24 patients, 18 had uncal herniation, 5 had central herniation, and 1 had uncal and subfalcine herniation; 8 patients with other than subarachnoid hemorrhage were included. Significant differences in the rates of deep approach (OR 5.12, 95% CI 1.8–14.5, p = 0.002) and temporal craniotomy (OR 10.2, 95% CI 2.3–44.8, p = 0.002) were found between the 2 subgroups (those with and those without herniation) in group A. In 5 patients, brain herniation proceeded even after external decompression (ED). Cox regression analysis revealed that the risk of brain herniation related to LSD increased with ED (hazard ratio 3.326, 95% CI 1.491–7.422, p < 0.001). Among all 1424 patients, ED resulted in progression or deterioration of brain herniation more frequently in those who underwent LSD than it did in those who did not undergo LSD (OR 9.127, 95% CI 1.82–62.1, p = 0.004).CONCLUSIONSBrain herniation downward to the tentorial hiatus is more likely to occur after craniotomy with LSD than after craniotomy without LSD. Using a deep approach and craniotomy involving the temporal areas are risk factors for brain herniation related to LSD. Additional ED would aggravate brain herniation after LSD. The risk of brain herniation after placement of a lumbar spinal drain during neurosurgery must be considered even when LSD is essential.

Object The two-vein occlusion model is known to be useful for ischemic penumbra studies in vivo. It was applied here to examine sequential changes in the expression of Bax and Bcl-2 proteins and in apoptotic cells to assess the relationship between penumbra and apoptosis. Methods Two cortical veins were occluded photochemically by using rose bengal dye in 27 Wistar rats. The animals were killed with perfusion fixation at the following intervals: 4, 12, 24, 48, 96, and 168 hours after vein occlusion (four at each interval; three additional rats were sham-treated). Immunohistochemical analysis for the Bcl-2 family of proteins was performed along with the terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay to examine the relationship to single-cell death. Cells positive for antiapoptotic proteins began to appear in the TUNEL assay for animals killed 24 hours after vein occlusion, with a peak at 48 hours. These cells were localized in the core of infarction. Immunohistochemical staining for Bax protein showed an increased presence around ischemic lesions at 4 hours after vein occlusion, and the amounts continued to rise until 24 hours, when the localization was diffuse around the core of infarction. Negative findings on immunohistochemical studies for Bcl-2 protein were seen at the early phase after two-vein occlusion. Conclusions After vein occlusion, apoptosis appeared sequentially and widely in cortical lesions considered to be the penumbra. Therefore, control of apoptosis would be expected to offer a therapeutic window for treatment of venous infarction.

Object. Although various mechanisms of the development of dural arteriovenous fistula (AVF) have been described, the exact course of its pathogenesis, including molecular processes mediating its genesis, is still unknown. Recently, the importance of sinus thrombosis and venous hypertension has been reported in experimental and clinical studies. Additionally, a role of angiogenic growth factors in the pathogenesis of vascular malformations of the central nervous system has been reported. In this study, the authors investigated the existence of sinus thrombosis in dural AVF and the expression of angiogenic growth factors (basic fibroblast growth factor [bFGF] and vascular endothelial growth factor [VEGF]) in nine patients with dural AVFs that were surgically resected.Methods. The authors examined histological features of dural AVFs that involved the transverse/sigmoid sinus in seven patients and the superior sagittal sinus in two. Sinus thrombosis was verified angiographically in seven cases and histologically in all cases. In surgically resected specimens the angiogenic growth factors bFGF and VEGF were examined immunohistochemically in nine patients with dural AVFs, with five dural sinuses from cadavers with unrelated central nervous system diseases serving as a normal control group. The media and perivascular connective tissues of the arteries in the wall of the normal dural sinuses stained faintly for bFGF; on the other hand, the expression of VEGF was not detected. In all patients with dural AVFs, the thick wall of the dural sinus stained strongly for bFGF, mainly in the subendothelial layer and media of the strongly proliferative vessels in the sinus wall, in addition to the perivascular connective tissues. In all nine cases VEGF was expressed in the endothelium of the sinus and perivascular connective tissues. In two cases, VEGF was expressed in many capillaries proliferating in the granulation-like tissues in sinuses that were obliterated by organized thrombi.Conclusions. It is concluded that the pathogenesis of dural AVF is still unknown, but that angiogenic growth factors, which might be produced by the healing process due to sinus thrombosis, may participate in the genesis of dural AVF. Understanding the mechanism of molecular pathogenesis in the development of dural AVF might aid in the establishment of a new therapeutic strategy for this dynamic vascular disease.

The authors report the rare case of a 58-year-old man with segmental arterial mediolysis (SAM) with associated intracranial and intraabdominal aneurysms, who suffered subarachnoid hemorrhage (SAH) due to rupture of an intracranial aneurysm. This disease primarily involves the intraabdominal arterial system, resulting in intraabdominal and retroperitoneal hemorrhage in most cases. The patient presented with severe headache and vomiting. The CT scans of the head revealed SAH. Cerebral angiography revealed 3 aneurysms: 1 in the right distal anterior cerebral artery (ACA), 1 in the distal portion of the A1 segment of the right ACA, and 1 in the left vertebral artery. The patient had a history of multiple intraabdominal aneurysms involving the splenic, gastroepiploic, gastroduodenal, and bilateral renal arteries. He underwent a right frontotemporal craniotomy and fibrin coating of the dissecting aneurysm in the distal portion of the A1 segment of the right ACA, which was the cause of the hemorrhage. Follow-up revealed no significant changes in the residual intracranial and intraabdominal aneurysms. An SAH due to SAM with associated multiple intraabdominal aneurysms is extremely rare. The authors describe their particular case and review the literature pertaining to SAM with associated intracranial and intraabdominal aneurysms.

Object. To evaluate objectively the visual fields of patients with pediatric epilepsy who are uncooperative with perimetry and in whom postoperative visual field deficits are expected, the authors investigated the usefulness of the multifocal visual evoked potential (VEP) method. Methods. Normal waves in multifocal VEP were determined in 21 healthy children (21 eyes) 6 to 15 years of age (mean 11.4 years). Responses from eight sites in each child were divided into four quadrants (superior and inferior temporal and superior and inferior nasal). In each quadrant, two response waves were grouped and averaged. The peak latency and amplitude at approximately 100 msec were used for assessment. In three cases involving patients with epilepsy, multifocal VEP measurements were also recorded and compared with the peak latency and amplitude in the healthy children. In these children, no significant differences were observed in the peak latency of amplitude among four quadrants using one-way analysis of variance. In each patient, multifocal VEP tests showed abnormal waves in the quadrant corresponding to the lesion demonstrated in neuroradiological images. This result was useful in the treatment of choice and the postoperative evaluation. Conclusions. Multifocal VEP tests can be useful in evaluating the visual field of children objectively. They can also be valuable in assessing preoperative visual field defects and revealing changes in the visual field after treatment.

Object. Mild cerebral venous circulation disturbances (CVCDs) in aged patients are frequently known to cause unexpectedly severe postoperative complications in neurosurgical practice. The object of the present study was to determine whether there are age-related differences involved in vulnerability to CVCDs.Methods. Thirty-eight male Wistar rats were used. A single cortical vein with a 100-µm diameter was occluded photochemically by using rose bengal dye and fiberoptic illumination in young (Group Y, 19 animals aged 10–14 weeks) and aged (Group A, seven animals aged 80–100 weeks) rats. Five young and seven aged animals served as sham-operated controls. Regional cerebral blood flow (rCBF) was determined from local CBF, which was measured at 25 (5 × 5) identical locations, with the occluded vein located central to the scanning field, by using a laser Doppler scanning technique every 15 minutes for 90 minutes after venous occlusion. The cerebral venous flow pattern was examined using fluorescence angiography until 90 minutes after occlusion. Histological specimens were examined 24 hours after occlusion. In Group Y, rCBF did not change significantly after venous occlusion. However, in Group A, rCBF decreased rapidly beginning 15 minutes after occlusion. Significant intergroup differences were observed 30, 60, and 90 minutes after occlusion. Venous flow arrest, which resulted in venous infarct, was observed on angiography 90 minutes after occlusion in two (10.5%) of 19 young and six (85.7%) of seven aged rats. The venous thrombus in Group A rats was significantly larger than that in Group Y rats 90 minutes after occlusion. Venous infarction was seen in all aged rats (100%) and in six young rats (31.6%); the infarct size, expressed as a percentage of the size of the ipsilateral hemisphere, was significantly larger in aged rats than in young rats.Conclusions. This study demonstrated an age-related increase in the rate and size of venous infarct following vein occlusion, suggesting that the greater vulnerability to CVCDs in the aged brain might be attributed to early and extensive hypoperfusion of circumscribed brain areas drained by the occluded vein. The larger thrombus formation in aged animals indicates that a shift in the thrombogenetic/thrombolytic equilibrium is responsible for the observed effect.

This 26-year-old woman presented with amenorrhea and was found to suffer from hyperprolactinemia. Gadolinium-enhanced magnetic resonance (MR) imaging revealed an abnormally enhanced tumor in the left intrasellar region and fenestration of the left internal carotid artery (ICA) adjacent to the lesion (Fig. 1). Angiography demonstrated no tumor blush but did reveal a fenestration of the left ICA at the cavernous portion (Fig. 2). Furthermore, the left persistent otic artery was present. The mass was removed via the transsphenoidal approach. Special care was taken not to injure the fenestrated portion, and surgical manipulation in any portion of the blind operative field was restricted. Histological investigation revealed the tumor to be the diffuse type of pituitary adenoma. The patient’s postoperative course was uneventful except for transient diabetes insipidus. Hemorrhage from the ICA is potentially fatal and the most feared complication of transsphenoidal surgery. 2 The surgeon should be aware of the potential vagaries of the ICA’s location. Magnetic resonance imaging proved to be useful in determining the landmarks for location of the ICA. Fenestration of the intracranial ICA is an extremely rare anomaly. To date only five cases have been reported. 1,3,5 Such an anomaly presumably originated during the 4-mm embryonic stage, in which the primitive ICA divides into cranial and caudal branches. 4 The ob

✓ Research on cerebral venous circulation disturbances (CVCDs) has been limited partly by the paucity of animal models that produce consistent venous infarction. Occlusion of two adjacent cortical veins in rats by means of a photochemical thrombotic technique provides a minimally invasive, clinically relevant, and reproducible model suited to study the pathophysiology of CVCDs. In this study, the effects of venous occlusion on regional cortical blood flow and the brain damage that ensues were evaluated. Cortical vein occlusion was induced by photoactivation of rose bengal via 100-µm fiberoptic illumination. The cerebral venous flow pattern was examined using fluorescence angiography until 90 minutes after venous occlusion, and regional cerebral blood flow (rCBF) was determined at 48 locations by using laser Doppler scanning. Histological damage was assessed 48 hours after vein occlusion. Occlusion of two cortical veins (Group T; seven animals) was compared with single-vein occlusion and its ensuing brain damage (Group S; five animals) and with sham-operated control (five animals). An rCBF reduction occurred 30 minutes after occlusion in Group T and was more extensive than the decrease in Group S after 60 minutes. Observation frequency histograms based on local CBF data obtained in Group T demonstrated that local CBF at some sites decreased to a level below the ischemic threshold within 90 minutes. Six of the seven rats in Group T had a growing venous thrombus with extravasation of fluorescein. The resulting infarction was significantly larger in Group T (9.8 ± 4.5% of the hemispheric area) than in Group S (only 3 ± 1.5% of the hemispheric area). In conclusion, microcirculation perturbations occur early after venous occlusion and result in the formation of a venous thrombus accompanied by local ischemia and severe venous infarction. The extent of vein occlusion determines the resulting brain damage. Based on the results of this study, the authors conclude that CVCDs may be attenuated by prevention of venous thrombus progression together with the use of protective measures against the consequences of ischemia.

✓ In this article, the authors present five cases of dural arteriovenous fistula (AVF) that developed in the transverse—sigmoid sinus 2 to 6 years after sacrifice of the sigmoid sinus because of tumor involvement. The original tumor was meningioma in two patients and neurinoma, glomus jugulare tumor, and ameloblastoma in one patient each. The involved sigmoid sinus was resected along with the tumor and ligated at the normal edge; all that remained of the sigmoid sinus was a small stump on the retrosigmoid portion. Serial angiography performed before and after tumor surgery revealed no abnormal arteriovenous communications or dural AVF in any of the cases. Although many reports have suggested that sinus thrombosis is a precipitating factor in the pathogenesis of dural AVFs, this has been difficult to verify because of the small number of cases in which serial angiography was performed before the development of a dural AVF. In all of the cases presented in this article, surgical resection of a dural AVF and histological examination were performed. Subintimal fibrous thickening was marked, and the sinus wall was found to contain many dural vessels. Organized thrombosis with neovascularization was seen in only two patients. These cases demonstrate that subintimal fibrous thickening and a hypertrophied sinus wall secondary to increased intrasinus pressure or sinus thrombosis occurring after sinus occlusion can provoke the development of a dural AVF within the course of a lifetime. Maintenance of intrasinus blood flow may be very important to prevent this late postoperative complication.

✓ Two patients with intraventricular arachnoid cysts are reported and a brief review of the relevant literature is presented. Arachnoid cysts are usually extracerebral or extraventricular. Intraventricular arachnoid cysts are rare: including the two cases reported here, only five cases have been described. The following characteristics were noted in these five patients: all were young; headache was the initial symptom in four; the cyst was in the trigone of a lateral ventricle in four; and there was dilatation of the inferior horn in three.