Morphological Analysis of the Sylvian Fissure Stem to Guide a Safe Trans-sylvian Fissure Approach.

The sylvian fissure stem and its deep cisternal part (SDCP) consist mainly of the orbital gyrus (OG) and anterior medial portion of the temporal lobe. SDCP's adhesion has been found to make a trans-sylvian approach difficult due to the various patterns of adhesion. Thus, in this study, we aim to clarify the morphological features of the SDCP, and to guide a safe trans-sylvian approach. We retrospectively classified the morphology of the SDCP in 81 patients into 3 types (tight, moderate, loose type) according to the degree of adhesion of the arachnoid membrane and analyzed the morphological features of the OG and the temporal lobe using intraoperative video images. In addition, we have retrospectively measured each width of the SDCP's subarachnoid space at the three points (Point A, lateral superior portion; Point B, downward portion; Point C, medial inferior portion of SDCP) and analyzed their relationship to the degree of adhesion using the preoperative coronal three-dimensional computed tomography angiography (3D-CTA) images of 44 patients. As per the results, SDCP's adhesions were determined to be significantly tighter in cases with large OG and young cases. The temporal lobe had four surfaces (posterior, middle, anterior, and medial) that adhered to the OG in various patterns. The tighter the adhesion between the OG and each of the three distal surfaces of the temporal lobe, the narrower the width of the subarachnoid space at each point (A, B, C). Understanding of the morphological features of the SDCP, and estimating its adhesion preoperatively are useful in developing a surgical strategy and obtaining correct intraoperative orientation in the trans-sylvian approach.

A Simple Method to Estimate the Trajectory to the Genu of the Corpus Callosum in the Interhemispheric Approach for Distal Anterior Cerebral Artery Aneurysms.

In the interhemispheric approach (IHA) for the distal anterior cerebral artery (DACA) aneurysms, the surgical trajectory to a DACA aneurysm is very important because surgeons sometimes encounter the intraoperative disorientation and the premature rupture. The purpose of this study was to clarify the anatomical landmarks indicating the trajectory to the genu of the corpus callosum (GCC) at the early stage of dissection for the correct intraoperative orientation. "Point A" was defined as the crossing point between the frontal bone and the line connecting the projected external acoustic opening (EAO) and the GCC on the midline slice of the sagittal three-dimensional computed tomography angiography (3D-CTA) images. We measured the distance from the nasion to Point A using midline sagittal slice images from 50 patients who underwent 3D-CTA at our institution. The average distance was 7.0 cm (±0.3 cm). Therefore, the direction of the spatula inserted in the direction of the EAO from Point A (7 cm above the nasion) corresponds to the trajectory to the GCC. In DACA aneurysms of the A3 segment, the pericallosal artery distal to the aneurysm can be safely identified by dissecting the interhemispheric fissure distal to the trajectory to the GCC. In DACA aneurysms of the A4 or A5 segment, the parent artery of the aneurysm can be safely identified by dissection along the trajectory to the GCC. Point A and the EAO can be used as landmarks indicating the trajectory to the GCC for the correct intraoperative orientation in the IHA for DACA aneurysms.

Dissection of the Sylvian Fissure in the Trans-sylvian Approach Based on the Morphological Classification of the Superficial Middle Cerebral Vein.

The superficial middle cerebral vein (SMCV) is one of the main factors that can impede a wide opening of the sylvian fissure. To reveal the most efficient SMCV dissection for a wide operative field while preserving the veins in the trans-sylvian approach, we retrospectively investigated the SMCVs through intraoperative video images. We characterized the SMCV as composed of the frontosylvian trunk (FST; receiving frontosylvian veins [FSVs] or parietosylvian veins [PSVs]), the temporosylvian trunk (TST; receiving temporosylvian veins [TSVs]), and the superficial middle cerebral common trunk (SMCCT; receiving both FSV/PSV and TSV), and classified the SMCVs of the 116 patients into 5 types based on the morphological classification of the SMCV. Type A SMCV (60.4%) with the SMCCT anastomosed to the frontal side had few bridging veins (BVs) between the SMCCT and the temporal side during dissection. Type B (7.8%) had the SMCCT with no anastomoses to the frontal side. In Type C (17.2%) consisting of the FST and TST and Type D (12.9%) with a merging of the vein of Trolard and Labbé posteriorly and the SMCVs dividing into the FST and the TST again proximally, there were few BVs between the FST and the TST during dissection. Finally, in Type E (1.7%) showing an undeveloped SMCV, there were no BVs between the frontal and the temporal lobes. Postoperative venous infarction occurred in 2.6%. Morphological classification of the SMCV can inform appropriate dissection line to create a wide operative field while preserving the veins in the trans-sylvian approach.

Morphological Classification of the Medial Frontal Cortex Based on Cadaver Dissections: A Guide for Interhemispheric Approach.

The medial frontal cortex (MFC) is a part of the medial surface of the frontal lobe situated in the rostral portion of the corpus callosum (CC). In a surgical interhemispheric approach (IHA), the MFC covers the anterior communicating artery (Aco) complex until the final stage of dissection. To clarify the anatomical relationship between the MFC and the Aco complex, and to facilitate orientation in IHA, we analyzed the morphological features of the MFC in number, size, and pattern of gyri from the medial surface of the hemisphere in the subcallosal portion using 53 adult cadaveric hemispheres. The mean width of the MFC excluding cingulate gyrus (MFCexcg) was 20.6 ± as mm in the subcallosal portion. MFCexcg consisting of 2, 3, 4, or 5 gyri were observed in 7.5%, 56.6%, 32.1%, or 3.8% of the hemispheres, respectively. Bilateral MFCexcg consisting of >2 gyri were observed in approximately 85% of the hemispheres. Therefore, in many cases, the dissection performed at 2 cm upward from the base of the straight gyrus (SG) or 3-4 gyri of the MFC is sufficient to safely reach the upper portion of the cistern of lamina terminalis located distal to the Aco complex in IHA. The MFC is a good landmark for intraoperative orientation in IHA.

Morphological Pattern and Classification of the Superficial Middle Cerebral Vein by Cadaver Dissections: An Embryological Viewpoint.

In this study, we used 45 adult cadaveric cerebral hemispheres to investigate the anatomical classification of the superficial middle cerebral vein (SMCV) based on the number of stems, course, and anastomosis at the distal portion. We classified the SMCVs into five types based on embryological concept. Type A (18 cases, 40.0%) is that the frontosylvian veins (FSVs) merge with the vein of Trolard (VT) and the vein of Labbé (VL) at the distal portion of the sylvian fissure. Type B (5 cases, 11.1%) is that the temporosylvian veins (TSVs) merge with the VT and the VL at the distal portion. Type C (13 cases, 28.9%) is that no vein merge with the VT and the VL at the distal portion. The VT merges with the SMCV from the FSV and the VL merges with the SMCV from the TSV. They course along the sylvian fissure and merge at the proximal portion. In Type D (eight cases: 17.8%), the VT and the VL merge at the distal portion, and the SMCV from the FSV and the SMCV from the TSV join their confluence without merging. Type E (one case, 2.2%) show an undeveloped SMCV. Formation rate of intravenous anastomoses or bridging veins(BVs) at the distal portion between the frontosylvian trunk (FST) and the temporosylvian trunk (TST), between the FST and the temporal lobe, and between the TST and the frontal lobe was very low, because these formation may be difficult to occur during the embryological process in which the SMCV is formed from the telencephalic vein.

The Effect of Irrigation Solutions on Recurrence of Chronic Subdural Hematoma: A Consecutive Cohort Study of 234 Patients.

Chronic subdural hematomas (CSDHs) occur often in elderly persons and can occur with mild head trauma. With burr-hole irrigation as standard treatment, symptoms usually improve and can be cured, and outcomes are good, but postoperative recurrences are a common problem. This study investigated the effectiveness and recurrence rates when using artificial cerebrospinal fluid (ACF) instead of normal saline (NS) as an irrigation solution for burr-hole irrigation in patients with CSDH. This prospective study included 234 consecutive patients who underwent initial surgical treatment by burr-hole irrigation for a CSDH between April 2008 and June 2015. The irrigation solution used was changed from NS to ACF in June 2011. Factors examined with regard to recurrence included age, sex, unilateral or bilateral surgery, computed tomography (CT) findings, antiplatelet or anticoagulant drug use, past history, and irrigation solution (NS or ACF). These were analyzed by univariate and multivariate analyses. Univariate analyses (chi-square test) with a significance level <5% showed that recurrence rates were significantly lower in the ACF group than in the NS group (P = 0.003). Multivariate analysis (multiple logistic regression analysis) showed that the risk of recurrence was reduced 3.14-fold in the ACF group compared to the NS group (odds ratio, 3.143; 95% confidence interval, 0.1504-0.6733; P = 0.0028). None of the other factors were significantly different. In burr-hole irrigation for CSDH, the use of ACF instead of NS as an irrigation solution significantly reduces recurrence rates.

A Japanese pedigree of familial cerebral cavernous malformations--a case report.

Familial cerebral cavernous malformations (FCCM) are autosomal-dominant vascular malformations. At present, 3 cerebral cavernous malformation genes (KRIT1/CCM1, MGC4607/CCM2, and PDCD10/CCM3) have been identified. Few genetic analyses of Japanese FCCM have been reported. A Japanese pedigree of 4 patients with FCCM has been reported that includes the genetic analysis of one of the patients. All 4 patients showed multiple lesions in the brain. Surgical removal was performed at our hospital due to enlargement or hemorrhage of the intracranial lesions in a 21-year-old female (Case 1) and a 30-year-old male (Case 2). The histological diagnoses were cavernous malformations. A 62-year-old female (Case 4), the mother of Cases 1, 2, and 3, suffered from intramedullary hemorrhage at T6-7 and surgical removal was performed at another hospital. Only one patient, a 32-year-old female (Case 3), did not show symptoms. The genetic analysis of Case 2 demonstrated heterozygous partial deletions of exons 12-15 of the KRIT1 gene.

Differences between middle cerebral artery bifurcations with normal anatomy and those with aneurysms.

The objectives of this study were to elucidate the normal anatomy of middle cerebral artery (MCA) bifurcations and to analyze the differences in patients with MCA aneurysms. In the present study, 62 patients underwent three-dimensional magnetic resonance angiography, and no intracranial lesions were noted. The widths of M1 and the superior and inferior M2 branches, as well as their respective lateral angles, were measured. These values were used to calculate the daughter artery ratio (DA ratio; width of larger M2/width of smaller M2) and the lateral angle ratio (LA ratio; lateral angle between M1 and larger M2/lateral angle between M1 and smaller M2). The DA and LA ratios of 54 MCA aneurysm patients (34 with ruptured aneurysms, 20 with unruptured aneurysms) were also calculated, using three-dimensional digital subtraction angiography, and compared with the normal values. In normal patients, the widths of M1 and the branches of M2, the lateral angles, and the LA and DA ratios were not significantly different between the right and left sides. The bilateral superior and inferior lateral angles of normal MCAs were significantly wider than those of MCAs with aneurysms. The DA ratio was 1.5 ± 0.4 in normal MCAs and 1.7 ± 0.7 in MCAs with aneurysms; this difference was significant (p < 0.05). The LA ratio was 1.3 ± 0.4 in normal MCAs and 2.1 ± 1.4 in MCAs with aneurysms; these values were also significantly different (p < 0.01). Normal cerebral artery bifurcations show close to symmetric structure in the M2 branches and the lateral angles, whereas aneurysmal MCAs do not show this symmetry.

Two-step surgical treatment using miniature Ommaya's reservoirs for a neonate with multiple large arachnoid cysts.

METHOD: We followed a two-step surgical strategy using miniature Ommaya's reservoirs in an early neonate with multiple large arachnoid cysts. CONCLUSION: Percutaneous fluid aspiration through the reservoirs placed during the first operation permitted the infant to develop sufficiently to withstand the second, more radical cyst wall excision.

[A case of petrotentorial meningioma presented as an acute subdural hemorrhage].

The authors report a rare case of petrotentorial meningioma presenting as acute subdural hematoma. A 60-year-old female was introduced to our hospital complaining of sudden headache and gait disturbance. CT and MRI demonstrated a petrotentorial tumor with a subdural hematoma in the posterior fossa. The tumor was enhanced intensively on MRI and showed the dural tail sign. The patient developed progressive impairment of consciousness along with hydrocephalus. After ventricular drainage, emergency intracranial decompression through hematoma evacuation and partial tumor resection was performed. One month later, she improved clinically and the tumor resected totally in the second craniotomy. Histological examination showed a meningothelial meningioma with high vascularity in part. She recovered uneventfully and was discharged on foot. We discussed the etiology of an acute subdural hematoma caused by intratumoral hemorrhage and reviewed past literatures.

[Symptomatic Rathke's cleft cyst mimicking suprasellar arachnoid cyst].

The authors report an atypical case of symptomatic entirely suprasellar Rathke's cleft cyst mimicking suprasellar arachnoid cyst. A 55-year-old male was introduced to our hospital complaining of bitemporal hemianopsia. CT and MRI demonstrated a cystic mass located entirely in the suprasellar cistern and to compress the optic nerve and mammillary body. The cystic wall was not enhanced in MRI. CT cisternography showed the suprasellar non-communicating cyst with cistern. The hormonal function was slightly disturbed by the pituitary compression. Under the diagnosis of suprasellar arachnoid cyst, a left front temporal craniotomy was performed to resect the suprasellar mass. The surgical specimen consisted ciliated epithelium and was diagnosed Rathke's cleft cyst. After operation, he recovered completely free.

[Hemangioendothelioma of the brain presenting with intracerebral hemorrhage: a case report].

Hemangioendothelioma (HE) is an uncommon vascular tumor that is intermediate in histological appearance between a hemangioma and an angiosarcoma. Presently, it is regarded as endothelial tumors of low-grade or intermediate malignancy. It has been reported in the liver, lung, heart, mediastinum, lymph nodes, extremity, and bone. The occurrence in the brain is extremely rare; only 16 cases have so far been reported. We report a 51-year-old woman who presented with transient visual disturbance and weakness of the left upper limb on April 12th 2003. Computed tomography (CT) revealed a high density mass in the right parietal lobe. In magnetic resonance imaging (MRI), the lesion is hyperintense on TIWI, isointense on T2WI, and no enhancement with gadopentetate dimegliumine. Intratumoral hemorrhage was indicated and preoperative diagnosis was cavernous angioma. The tumor was excised completely on April 28th 2003. Pathologically, the tumor cells resembled endothelial cells, positive immunoreactivity for Factor VIII, and grew in small nests or cords. Postoperative MRI showed complete removal of the tumor. There has been no recurrence for 8 months after the surgery, but we have to follow MRI up for a long time. We discussed intracerebral HE clinically and neuroradiologically.

[Flow reverse therapy for ruptured dissecting aneurysm of basilar trunk: case report].

Treatment of ruptured dissecting aneurysm of basilar trunk (BADAN) has been controversial yet. We report a case of ruptured BADAN successfully treated with endovascular occlusion of the bilateral vertebral artery (VA) proximal to posterior inferior cerebellar artery (PICA), allowing retrograde flow via the posterior communicating arteries to basilar artery. A 58-year-old woman who had subarachnoid hemorrhage was treated with endovascular occlusion of the right VA in acute stage after ballon occlusion test (BOT) of the right VA. Because following BOT of the left VA showed conscious level down, left VA could not be occluded. Follow-up angiography after 26 days revealed regrowth of BADAN. So left VA occlusion was tolerable by BOT after 1 month, we performed endovascular occlusion of the left VA proximal to PICA. She discharged with no neurological deficit after 3 months. Postoperative angiograms 3 months after onset showed complete healing of the aneurysm. The follow-up MRA at 19 months showed no recurrence. We discussed the therapeutic strategy of ruptured BADAN. Flow reverse therapy of bilateral VA occlusion by endovascular method for ruptured BADAN is one of the effective therapy.

[Ruptured aneurysm arising from the anterior medullary segment of the posterior inferior cerebellar artery: report of two cases].

In the distal posterior inferior cerebellar artery (PICA), saccular aneurysms originating at the first proximal segment, anterior medullary segment (AMS), are unusual but important due to the presence of critical perforators that branch off the PICA and supply the lower brainstem. Because the anatomy of the PICA varies, no standard treatment strategy has been agreed upon to date. We successfully treated 2 patients with open surgery. One was a 53-year-old man who presented with Hunt-Hess grade 2 subarachnoid hemorrhage (SAH). Cerebral angiography revealed an irregular fusiform AMS aneurysm extending to the lateral medullary segment. Intraoperative inspection showed some perforators to the brain stem branching from just proximal and distal to the aneurysm. The patient underwent aneurysmal trapping and occipital artery-PICA anastomosis to preserve perforators flow, and was discharged without any neurological deficits. Another patient, a 74-year-old woman, was transferred to our institute because she suddenly became comatose. She was found to have a ruptured saccular AMS aneurysm. On the 15th day after the event, she underwent successful aneurysmal clipping preserving perforators by surgical inspection. As both patients manifested intra-aneurysmal thrombosis, we suggest that patients presenting with AMS aneurysms that display unusual features require careful management and judicious choice of treatment. Based on our experience we suggest that direct surgery, which facilitates the identification of perforators and allows for revascularization, is the appropriate treatment choice in patients who present with this entity.

[Case of painful tic convulsif: discussion of the underlying mechanisms and review of the literature].

The combination of trigeminal neuralgia and ipsilateral hemifacial spasm, known as painful tic convulsif (PTC), is a relatively rare entity in neurovascular compression syndrome. A case of PTC attributable to different offending arteries is described, the mechanisms and characteristics of PTC are discussed, and a review of the literature is presented. This 80-year-old woman had a 10-year history of left trigeminal neuralgia and ipsilateral hemifacial spasm. She presented with intermittent left facial twitching and pain, especially upon swallowing. MRI revealed compression of the left trigeminal nerve by the left anterior inferior cerebellar artery and of the ipsilateral facial nerve by the posterior inferior cerebellar artery. Microvascular decompression of the lesions via left lateral suboccipital craniotomy resulted in immediate and complete symptom improvement. Our case demonstrates that different arteries can affect the trigeminal and facial nerve at a stage that precedes compression by a tortuous vertebrobasilar artery. We suggest that the presence of PTC should be considered in patients with a tortuous vertebrobasilar artery, irrespective of the offending arteries.

Analysis of subarachnoid hemorrhage according to the Japanese Standard Stroke Registry Study--incidence, outcome, and comparison with the International Subarachnoid Aneurysm Trial.

The data for subarachnoid hemorrhage (SAH) from the Japanese Standard Stroke Registry Study (JSSRS) were analyzed to evaluate the incidence of SAH according to age, neurological grading and outcome, and outcome of surgical clipping, for comparison with the International Subarachnoid Aneurysm Trial (ISAT). From the ISSRS data, the peak incidence of SAH was the sixth decade in males and the eighth decade in females. The overall mortality was 22%, and good outcome, better than 2 on the modified Rankin Scale (mRS), at discharge was achieved in 58% of cases. Radical treatment was performed in 62.6% of all SAH cases, 58.7% with surgical clipping and 3.2% with endovascular coiling. Poor outcome, worse than 3 on the mRS, occurred in 26.6% of patients under 60 years, 47.3% between 60-69 years, 54.2% between 70-79 years, and 72.9% 80 years or over. From the ISAT data, 88% of patients were in grades 1-2 of the World Federation of Neurological Surgeons (WFNS) grading system in both surgical clipping and endovascular coiling groups, 94% in grades 1-3, and 98% in grades 1-4. Poor outcome, worse than 3 on the mRS, at 2 months occurred in 25.4% and 36.4% of patients with endovascular coiling and surgical clipping, respectively. Limiting the patients in the JSSRS to WFNS grades 1-2 showed poor outcome, worse than 3 on the mRS, occurred in 12.8%, and in grades 1-3 and 1-4 occurred in only 16.3% and 23.0%, respectively.

[Usefulness of diffusion-weighted magnetic resonance imaging in diagnosis and therapeutic strategy of deep cerebral venous thrombosis: a case report].

We present the usefulness of Diffusion-weighted magnetic resonance images (DWI) in diagnosis and therapeutic strategy of deep cerebral venous thrombosis (VT). We report a 37-year-old man who suffered general convulsion and deep coma. Magnetic resonance imaging (MRI) showed high intensity in the right caudate nuclei and bilateral thalamus on T2-weighted images. DWI showed slightly high intensity in the same area and apparent diffusion coefficient (ADC) is normal or slightly high (0.748-1.100 x 10(-3) mm2/s). Cerebral angiography showed occlusion of straight sinus from basal veins and internal cerebral veins bilaterally. We treated by anticoagulation, ventricle drainage, barubiturate and normothermia therapy with intracranial pressure (ICP) monitoring. We considered endovascular thrombolysis to be dangerous in this case because of hemorrhage and didn't it. ICP was more than 40 mmHg and consciousness was comatose in acute stage, however, ICP gradually got to be normal, consciousness became almost clear and he recovered. Follow-up Cerebral angiography showed recanalization of deep venous thrombosis. Follow-up MRI showed disappearance of high intensity in the right caudate nuclei and bilateral thalamus on T2-weighted images and DWI. In this case, we could predict reversible vasogenic edema by DWI and ADC in VT.

[A case of subacute subarachnoid hemorrhage without xanthochromic cerebrospinal fluid--usefulness of emergent MRI].

We reported a case of subacute subarachnoid hemorrhage with watery clear cerebrospinal fluid. Emergent magnetic resonance image was useful not only for diagnosis by fluid attenuated inversion recovery image but also for evaluation of cerebral ischemia and vasospasm by magnetic resonance angiography, diffusion weighted image and perfusion weighted image. A 50-year-old man presented disturbance of consciousness and dysarthria. Neither computed tomographic scan nor cerebrospinal fluid study could diagnose subarachnoid hemorrhage clearly. However, emergent fluid attenuated inversion recovery image showed the show subarachnoid hemorrhage as high signal intensity. Diffusion weighted image showed multiple, round hypersignals both in the white and gray matter. In the area with diffusion hypersignal, the apparent diffusion coefficient value was 0.57 x 10(3) mm2/sec. Perfusion weighted image showed normal cerebral blood volume but prolonged mean transit time in the territory of the right middle cerebral artery. Magnetic resonance angiography revealed an aneurysm at the anterior communicating artery and severe vasospasm on the bilateral anterior cerebral artery, the right middle cerebral artery. Thus we are able to diagnose subarachnoid hemorrhage due to a ruptured anterior communicating artery aneurysm. The hyperintensity of the diffusion weighted image and the fluid attenuated inversion recovery image was caused by cerebral ischemia from vasospasm. After conservative therapy during the period of vasospasm, successful surgical clipping was performed with full clinical recovery.

[A case of subcutaneous malignant lymphoma with dura mater lesion].

A 63-year-old male was admitted to our hospital, complaining of a scalp mass located at the frontoparietal area of his head. He noticed that it had been growing for 2 months. The mass was elastic hard and non-moving. Computed tomography demonstrated a subcutaneous mass with low density and which was enhanced homogeneously. The skull just below the mass was slightly destroyed, but the structure remained. Magnetic resonance imaging (MRI) demonstrated a mass with low signal intensity on both the T1 weighted image and the T2 weighted image. Gd-DTPA study showed homogeneous enhancement and showed also that the dura just below the mass was enhanced. At this point we couldn't diagnose it confidently, but suspected this lesion to be a malignant lymphoma. We made a general examination, but no other lesion was found. A biopsy of the subcutaneous mass was performed under local anesthesia. The histological diagnosis was large-cell type B-Cell lymphoma. The tumor was treated with chemotherapy, CHOP (cyclophosphamid, doxorubicin, vincristin predonisolone). It responded to this chemotherapy and disappeared. We treated this lesion without radiation therapy. We report a case of subcutaneous malignant lymphoma treated successfully with a minimum invasive method.

[An intradiploic epidermoid cyst of the skull in infancy: case report].

An intradiploic epidermoid cyst of the skull in infancy is rare. We report a case of a 7-month-old girl with an intradiploic epidermoid cyst of the left parietal bone. The patient was admitted to the department of pediatrics in, our hospital in March, 2000, complaining of a lump in the scalp with a diameter of 1.5 cm. The pediatrician doubted that it was a case of Langerhans cell histiocytosis (LCH). In addition, as a result of further tests there were no systemic findings to suggest LCH. The skull x-ray showed round radiolucency of the left parietal bone. CT scans showed an iso density intradiploic mass with destruction of the outer table. Because of the fact that the mass was enlarging, the patient was admitted to our neurosurgical service in April, 2000. We excised the lesion to confirm the histological findings. The histological diagnosis was epidermoid cyst. We discuss the clinical feature and treatment strategy for intradiploic epidermoid cyst in infancy.