Solitonic Windkessel Model for Intracranial Aneurysm.

The Windkessel model, which is known as a successful model for explaining the hemodynamic circulation, is a mathematical model with a direct correspondence with the electric circuit. We propose a theoretical model for the intracranial aneurysm based on the Windkessel-type steady blood flow. Intracranial aneurysms are well known vascular lesions, which cause subarachnoid hemorrhages. Since an aneurysm is an end-sack formed on the blood vessel, it functions as an unusual blood path that has characteristic features such as a reservoir and bottle neck orifice. We simulate an aneurysm by an electric circuit consisting of three different impedances, resistance, capacitance and inductance. A dumbbell-shaped aneurysm is the most dangerous aneurysm to easily rupture. Our aneurysmal model is created as a two-story aneurysm model for this point, thus namely the five-element Windkessel. Then, the mathematical formula was solved in numerical simulations by changing the size of the aneurysm and the elasticity of the aneurysm wall. An analysis of this model provided that the presence of the daughter aneurysm and the thinning of the aneurysm wall are positively correlated with a sharp increase in blood pressure in the aneurysm dome. Our mathematic aneurysm model proposes a good analogue to the real aneurysm and proved that this model includes soliton that is a non-decreasing wave propagation.

RNA sequencing analysis revealed the induction of CCL3 expression in human intracranial aneurysms.

Intracranial aneurysm (IA) is a socially important disease as a major cause of subarachnoid hemorrhage. Recent experimental studies mainly using animal models have revealed a crucial role of macrophage-mediated chronic inflammatory responses in its pathogenesis. However, as findings from comprehensive analysis of unruptured human IAs are limited, factors regulating progression and rupture of IAs in humans remain unclear. Using surgically dissected human unruptured IA lesions and control arterial walls, gene expression profiles were obtained by RNA sequence analysis. RNA sequencing analysis was done with read count about 60~100 million which yielded 6~10 billion bases per sample. 79 over-expressed and 329 under-expressed genes in IA lesions were identified. Through Gene Ontology analysis, 'chemokine activity', 'defense response' and 'extracellular region' were picked up as over-represented terms which included CCL3 and CCL4 in common. Among these genes, quantitative RT-PCR analysis using another set of samples reproduced the above result. Finally, increase of CCL3 protein compared with that in control arterial walls was clarified in IA lesions. Findings of the present study again highlight importance of macrophage recruitment via CCL3 in the pathogenesis of IA progression.

[A Case of a Solitary Plasmacytoma Extending into the Extradural Space].

Plasmacytomas are characterized by a monoclonal proliferation of plasma cells, and constitute the bulk of multiple myeloma. A solitary plasmacytoma is a rare entity, and is even more unlikely to occur intracranially. Here we present a 62-year-old man with an intracranial tumor. Magnetic resonance imaging revealed a large mass on the surface of the right fronto-parieto-temporal region, with extradurally directed growth. The tumor was enhanced homogenously by gadolinium, with dural tail-like findings, which resembled a meningioma. Head computed tomography scan showed osteolytic changes of the calvarium. Tumor removal following intravascular embolization was performed. The tumor seemed to have developed from the dura mater because it was firmly adhered to the dura but not to the calvarium. Histopathological analysis revealed monoclonal proliferation of plasma cells, which were positive for CD56, CD138, and lambda chain, on immunostaining. Since a systemic examination showed no evidence of other lesions, we diagnosed the tumor as a solitary dural plasmacytoma. There was no recurrence after postoperative radiotherapy. Rare entities, such as a solitary plasmacytoma, should be considered when an intracranial lesion with atypical radiological features is observed. If the lesion is anatomically resectable, histopathological evaluation is essential.

Application of Ion-beam Implanted Expanded Polytetrafluoroethylene to Microvascular Decompression and the Surgical Outcome.

Accurate and long-term transposition of offending vessels is required in microvascular decompression (MVD) for the treatment of hemifacial spasm (HFS) and trigeminal neuralgia (TN). We created ion-beam implanted of an expanded-polytetrafluoroethylene (i-ePTFE) surface to transpose offending vessels in MVD. In 13 patients with MVD, we concealed and transposed offending vessels with tape-shaped i-ePTFE, and relieved facial and trigeminal nerve compression by attaching the i-ePTFE to the dura with fibrin glue. After surgery, none of the patients reported further symptoms or experienced recurrence of symptoms up to 12 months post-surgery. Favorable surgical outcomes are obtainable, since i-ePTFE has high tissue affinity and is easy to manipulate, even under a narrow and deep operative field. Our results suggested that i-ePTFE is very useful for transposition in MVD.

[A Case of Bilateral Traumatic Carotid-Cavernous Fistula].

Bilateral traumatic carotid-cavernous fistula(CCF)is rare. It is most commonly caused by a direct head or face injury involving the cavernous sinus and develops immediately after trauma. We report a case of bilateral traumatic CCF that occurred as an intracerebral hematoma(ICH)mimicking apoplexy 5 months later. We treated the patient with point occlusion of venous reflux causing an ICH using coil embolization to remove the hematoma. Three days after we performed trans-venous occlusion of the intercavernous connection and right cavernous sinus using coil embolization through the right inferior petrosal vein, it was identified that the left CCF was occluded after first embolization into the left sylvian vein. The mechanism of delayed development of traumatic CCF and spontaneous disappearance of CCF after occlusion of venous reflux are discussed.

Repression of wall shear stress inside cerebral aneurysm at bifurcation of anterior cerebral artery by stents.

The effect of a simple bare metal stent on repression of wall shear stress inside a model cerebral aneurysm was experimentally investigated by two-dimensional particle image velocimetry in vitro. The flow model simulated a cerebral aneurysm induced at the apex of bifurcation between the anterior cerebral artery and the anterior communicating artery. Wall shear stress was investigated using both stented and non-stented models to assess the simple stent characteristics. The flow behavior inside the stented aneurysm sac was unusual and wall shear stress was much smaller inside the aneurysm sac. Stent placement effectively repressed the temporal and spatial variations and the magnitude of wall shear stress. Hence, there is an effective possibility that would retard the progress of cerebral aneurysms by even simple stent.

Brain metastasis from a lung mucoepidermoid carcinoma mimicking a brain abscess.

BACKGROUND: Mucoepidermoid carcinoma (MEC) is a rare tumor of the lung that accounts for 0.1-0.2% of all pulmonary tumors. To the best of our knowledge, brain metastasis from lung MEC is rare and magnetic resonance imaging (MRI) findings of this lesion have not been documented. CASE DESCRIPTION: We herein report the case of a 72-year-old male. MRI revealed a left parietal tumor showing ring enhancement with medium gadolinium contrast and an evident high intensity area in the nonenhanced central portion on diffusion-weighted images (DWI) mimicking a brain abscess. Histologically, MEC is composed of a mixture of different cell types including mucin-secreting glandular cells and squamous cells. Accordingly, we suggest that the high DWI signal can be explained by the development of intracellular and intraluminal mucin, which have a high viscosity. CONCLUSION: Further accumulation of cases with brain metastasis from MEC is needed to establish the characteristic image findings, which would lead to prompt and adequate treatment.

[A synovial cyst accompanied by asymptomatic lumbar vertebral fracture requiring differentiation from spinal metastasis].

We experienced a case with a synovial cyst accompanied by asymptomatic lumbar vertebral fracture that required differentiation from spinal metastasis. An 82-year-old man suffered from right leg and anal pain. Computed tomography (CT) showed L5 spondylolysis. Magnetic resonance images (MRI) revealed an intra spinal cyst and acute lumbar vertebral fracture of L5 vertebral body. The surrounding area of the cyst presented contrast enhancement, and the extradural mass compressed the dural sac. Bone scintigraphy with 99m technetium-MDP demonstrated intense uptake on the right first, fourth, fifth, and seventh ribs and L2, L3, and L5 vertebra. The F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) image demonstrated an increased radiotracer uptake in the L5 vertebra(standardized uptake value(SUV) max=3.5). Spinal metastasis was suspected. Because of the cauda equina compression syndrome, it was surgically removed. Intraoperatively, a well-demarcated extradural cyst was found and compressed the dural sac markedly. The cyst capsule was thin and contained clear, thin fluid with no signs of bleeding. The histological diagnosis was a synovial cyst. His neurological symptoms improved after the surgery. The synovial cyst may enlarge after asymptomatic vertebral fractures.

Sensitivity and specificity in transcranial motor-evoked potential monitoring during neurosurgical operations.

BACKGROUND: Intraoperative transcranial motor-evoked potential (TCMEP) monitoring is widely performed during neurosurgical operations. Sensitivity and specificity in TCMEP during neurosurgical operations were examined according to the type of operation. METHODS: TCMEP monitoring was performed during 283 neurosurgical operations for patients without preoperative motor palsy, including 121 spinal operations, 84 cerebral aneurysmal operations, and 31 brain tumor operations. Transcranial stimulation at 100-600 V was applied by screw electrodes placed in the scalp and electromyographic responses were recorded with surface electrodes placed on the affected muscles. To exclude the effects of muscle relaxants on TCMEP, compound muscle action potential (CMAP) by supramaximal stimulation of the peripheral nerve immediately after transcranial stimulation was used for compensation of TCMEP. RESULTS: In spinal operations, with an 80% reduction in amplitude as the threshold for motor palsy, the sensitivity and specificity with CMAP compensation were 100% and 96.4%, respectively. In aneurysmal operations, with a 70% reduction in amplitude as the threshold for motor palsy, the sensitivity and specificity with CMAP compensation were 100% and 94.8%, respectively. Compensation by CMAP was especially useful in aneurysmal operations. In all neurosurgical operations, with a 70% reduction in amplitude as the threshold for motor palsy, the sensitivity and specificity with CMAP compensation were 95.0% and 90.9%, respectively. CONCLUSIONS: Intraoperative TCMEP monitoring is a significantly reliable method for preventing postoperative motor palsy in both cranial and spinal surgery. A 70% reduction in the compensated amplitude is considered to be a suitable alarm point in all neurological operations.

Cervical unilateral open-door laminoplasty with titanium miniplates through newly designed hydroxyapatite spacers.

A newly designed hydroxyapatite (HA) spacer for cervical laminoplasty is provided with a hole through which the titanium miniplate is passed. A new method of unilateral open-door laminoplasty with titanium miniscrew and miniplate through this HA spacer is described. Twenty-two patients with cervical stenotic disorders were treated by this procedure. Only the predominantly affected side of the laminae is exposed. The supraspinous and interspinous ligaments and the deep muscle layer in the contralateral side are left intact. A 4-mm wide gutter near the intervertebral joint is made and contralateral hinges are made under the deep muscle layer with minimum detachment of these muscles. The opened lamina is fixed with the titanium miniplate passed through the hole in the newly designed HA spacer. Mean operative time for the 22 operations was 193.5 minutes. Mean enlargement of the minimum spinal canal diameter was 50.9%. Neurological outcomes after 3 months were evaluated according to the Japanese Orthopaedic Association (JOA) scoring. Mean recovery rate of JOA score by Hirabayashi's method was 49.5%. Only 2 patients reported postoperative axial neck pain. Our method for unilateral open-door laminoplasty provides adequate decompression and tight fixation of laminae, and is less invasive to the posterior supporting elements of cervical spine.

[Hypertrophic pachymeningitis associated with autoimmune pancreatitis examined for IgG4 related disease: a case report].

Hypertrophic pachymeningitis is a rare disease, and the fibrosing inflammatory process causes a thickening of the dura mater. A 62-year-old male undergoing corticosteroid therapy for autoimmune pancreatitis presented with headache and right facial numbness. Brain CT and MRI revealed thickened mass lesion around the tentorium. The specimen obtained by biopsy showed a small number of immunostain areas positive for IgG and IgG4. Systemic IgG4 related disease entity is proposed and analyzed from Japan, and pachymeningitis is also included in the examination. Some autoimmune mechanism is related to pachymeningitis, however, it is necessary to consider well if only the IgG4 has responsibility for the disease.

[Radiation-induced fibrosarcomas rapidly appeared more than 20 years after radiation therapy for germ cell tumors: report of two cases].

Radiation-induced brain tumor is a rare but serious and potentially fatal complication. We report two cases of radiation-induced fibrosarcomas which occurred more than 20 years after whole brain radiation therapy (60 Gy) for intracranial germinomas. Although both of them underwent imaging examination every year, the symptomatic sarcomas developed rapidly within a year. Eight months after total removal, the tumor recurred in the one case. Second surgery and gamma knife surgery could not prevent the tumor progression. In the other case, tumor regrowth was not observed during the five months follow-up after total removal surgery. It is important to keep in mind the possibility of a postradiation sarcoma that might have developed very aggressively after a long latent period.

Inflammatory myofibroblastic tumor of the cerebellar hemisphere--case report.

A 60-year-old man presented with a rare cerebellar inflammatory myofibroblastic tumor (IMT) manifesting as gait disturbance and dysarthria. Brain magnetic resonance imaging demonstrated an intra-axial round-shaped isointense mass homogeneously enhanced with gadolinium in the right cerebellar hemisphere, as well as perifocal edema extending to the brain stem and right thalamus. The tumor was elastic hard and was resected en bloc with a clear margin. Histological examination revealed IMT with spindle cells and collagen, but negative for anaplastic lymphoma kinase expression. IMT most commonly affects the lung, but may involve many other parts of the body. There is some debate regarding the disease entity of IMT in the central nervous system (IMT-CNS) because of its rarity and high frequency of recurrence. IMT-CNS is an important differential diagnosis among tumor-like intracranial lesions and total resection is required.

Subarachnoid hemorrhage caused by pilocytic astrocytoma--case report.

A 20-year-old woman presented with subarachnoid hemorrhage (SAH) in the frontal interhemispheric fissure, and a cystic lesion in the left frontal lobe. Cerebral angiography demonstrated no aneurysm or vascular abnormalities. T(1)-weighted magnetic resonance imaging with contrast medium revealed an enhanced lesion along the falx. The lesion and cyst were removed, and histological examination revealed a pilocytic astrocytoma. Spontaneous intracranial hemorrhage from pilocytic astrocytoma is rare, with only 15 reported cases mostly involving intratumoral hemorrhage in the parenchyma of hypothalamic and cerebellar tumors. SAH caused by cerebral hemisphere pilocytic astrocytoma is extremely rare. This case suggests that interhemispheric fissure SAH, not associated with aneurysm or abnormal vascularity, could originate from small, low-grade glioma in the superficial cerebral hemisphere.

Clinical presentation of intracranial epidermoids: a surgical series of 20 initial and four recurred cases.

Epidermoids are generally recognized as benign tumors; however, total resection is often difficult. The recurrence from the residual capsule, dissemination of the tumor, and aseptic meningitis are common problems. The aim of the present study was to analyze and report on the clinical characteristics of intracranial epidermoids, particularly complications and cases with a poor clinical outcome. 24 patients with intracranial epidermoids who were treated surgically at Tokyo Women's Medical University Hospital between 1997 and 2007 were examined. The location and size of the tumor, pre-and postoperative symptoms, adherence of the tumor to cranial nerves, and proliferative capacity were determined. The most frequent site of the tumor was the cerebello-pontine (C-P) angle (16/24); eight of these patients presented with hearing loss and six presented with trigeminal neuralgia. In many cases, hearing loss and diplopia persisted after surgery. All epidermoids located in the C-P angle were attached to and/or compressed the trigeminal nerves, therefore, the origin is suggested to be the dura mafer of petrous bone around the trigeminal nerve. Of all 24 patients, the tumor recurred in four (after 3, 5, 10 and 20 years). One patient had a poor prognosis, with dissemination and brain stem infarction. Epidermoids can recur from residual capsule adhering to the brain stem or cranial nerves up to 10-20 years after the initial surgery. Long-term follow-up imaging studies are required when complete resection of the tumor capsule is not possible. In rare cases, spontaneous cyst rupture, dissemination, and brain stem infarction result in a poor prognosis.

Basilar artery trunk saccular aneurysms: morphological characteristics and management.

The purpose of this retrospective study was to report the morphological characteristics and results of surgical and endovascular treatment of basilar artery (BA) trunk saccular aneurysms. Twenty-two patients with 22 BA trunk saccular aneurysms underwent surgery including endovascular intervention. In this series, BA trunk aneurysms showed characteristic features such as so-called lateral aneurysm (41%), multiple aneurysms (32%), including two de novo aneurysms, and various vascular anomalies. Eleven craniotomies for neck clipping were performed for 11 ruptured aneurysms. However, in one of these cases, we abandoned neck clipping, because of concern for neck tearing, and embolized it later. Five ruptured and five unruptured aneurysms were successfully treated by endovascular surgery. Another one incompletely embolized aneurysm had grown to a huge size, and the patient underwent a Hunterian ligation with a flow reconstruction. The unusually high incidence of various associated vascular anomalies suggests that focal wall weakness must be based on the mechanism of aneurysm initiation. Most patients presented with subarachnoid hemorrhage. The pretreatment neurological state was predictive for clinical outcome. And, clinical outcomes in this series were not affected by the choice of treatment. However, considering that three of 11 surgical cases needed subsequent treatment, endovascular surgery should be considered as a first choice.

Intracranial epidermoid tumor after subcutaneous lipoma excision.

A 66-year-old man presented with complaints of numbness for the past 5 years and progressive motor weakness of the right leg for the previous 2 months. Magnetic resonance imaging revealed large intra- and extracranial tumors in the frontoparietal region. Physical examination suggested the extracranial lesion was a subcutaneous lipoma, which had been partially resected 60 years before, connected to the intracranial lesion via a defect of the skull. Gross total removal of the tumors was performed. Histological examination showed the intracranial lesion was epidermoid tumor, and connected to the extracranial lipoma by a lipoma bridge. The symptoms improved remarkably following surgery. This case of intracranial epidermoid tumor associated with intra-extracranial lipoma indicates that implantation of skin tissue in childhood carries the risk of epidermoid tumor even after several decades. Neuroimaging screening is recommended to detect the development of any intracranial components.

Individual adjuvant therapy for malignant gliomas based on O6-methylguanine-DNA methyltransferase messenger RNA quantitation by real-time reverse-transcription polymerase chain-reaction.

A new adjuvant therapy, individual adjuvant therapy (IAT), which is individualized according to the results of real-time reverse-transcription polymerase chain-reaction (RT-PCR) for O6-methylguanine-DNA methyltransferase (MGMT), was used to treat malignant gliomas. Immediately after the operation, mRNA expression for drug-resistance genes was investigated in frozen samples of malignant gliomas from 55 patients (30 glioblastoma multiformes, 20 anaplastic astrocytomas and 5 anaplastic oligodendroglial tumors) by real-time quantitative RT-PCR with specific primers for MGMT. Forty-two patients were treated with 1-(4-amino-2-methyl-5-pyrimidynyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU)-based chemotherapies since the relative quantitation value (RQV) of MGMT in real-time RT-PCR with SYBR-Green I was <1.0 or the absolute value of MGMT mRNA as measured by Taq Man probe methods normalized to the level of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was <6.0x10(3) copies/microg RNA. Thirteen patients, whose tumors had an RQV of >1.0 or who had an absolute value of MGMT of >6.0x10(3) copies/microg RNA, were treated by platinum-based chemotherapy using cisplatin or carboplatin. The response rate was 40.9% for glioblastoma multiformes, 60.0% for anaplastic astrocytomas and 80.0% for anaplastic oligodendroglial tumors. The median survival period of 30 patients with glioblastoma treated by IAT was 21.7 months. The 2-year survival rate of glioblastoma patients treated by IAT was 70.9%. Our IAT, based on the results of real-time RT-PCR, may lead to a beneficial glioma therapy.

Velocity profile and wall shear stress of saccular aneurysms at the anterior communicating artery.

It has recently been shown that the aspect ratio (dome/neck) of an aneurysm correlates well with intraaneurysmal blood flow. Aneurysms with an aspect ratio larger than 1.6 carry a higher risk of rupture. We examined the effect of aspect ratio (AR) on intra-aneurysmal flow using experimental models. Flow visualization with particle imaging velocimetry and measurement of wall shear stress using laser Doppler anemometry were performed on three different aneurysm models: AR 0.5, 1.0, and 2.0. Intraaneurysmal flow consists of inflow, circulation, and outflow. Rapid inflow impinged on the distal neck creating a stagnant point. Rapid flow and maximum wall shear stress were observed in the vicinity of the stagnant point. By changing the Reynold's number, the stagnant point moved. By increasing the AR of the aneurysm, vortices inside the aneurysm sac closed and very slow flow was observed, resulting in very low shear stress markedly at a Reynold's number of 250, compatible with the diastolic phase. In the aneurysm model AR 2.0, both rapid flow at the neck and vortices inside the aneurysm are sufficient to activate platelets, making a thrombus that may anchor on the dome where very slow flow takes place. Hemodynamics in aneurysms larger than AR 2.0 definitely contribute to thrombus formation.