Anatomical Variations of Vertebrobasilar Artery are Closely Related to the Occurrence of Vertebral Artery Dissection-An MR Angiography Study.

GOAL: Intracranial arterial dissection is a major cause of ischemic stroke and subarachnoid hemorrhage in relatively young patients. We assessed the hypothesis that the tortuosity of the vertebrobasilar artery is associated with the occurrence of vertebral artery (VA) dissection, using MR angiography (MRA). MATERIALS AND METHODS: This study enrolled 43 patients with VA dissection, and 63 age- and sex-matched healthy subjects were used as the controls. MRA was employed to evaluate the presence of dominant VA and the lateral shift of vertebrobasilar junction in both groups. The VA diameters were considered different when the difference was greater than .3 mm. These anatomical variations were divided into 3 types: Type 1 (vertebrobasilar junction within 2 mm from the midline), Type 2 (>2 mm-lateral shift of vertebrobasilar junction to the ipsilateral side of the dominant VA), and Type 3 (>2 mm-lateral shift of vertebrobasilar junction to the contralateral side of the dominant VA). FINDINGS: The presence of dominant VA and the lateral shift of vertebrobasilar junction were more prevalent in patients with VA dissection than in the controls (OR: 3.46, P = .013, and OR: 4.51, P = .001, respectively). The lateral shift of vertebrobasilar junction was classified into Type 1 (n = 6), Type 2 (n = 13), and Type 3 (n = 17) among patients with VA dissection, while into Type 1 (n = 20), Type 2 (n = 8), and Type 3 (n = 7) among the controls. Type 3 predominance was observed in patients with VA dissection (P = .02). CONCLUSIONS: Anatomical variations of the vertebrobasilar artery may play an important role in the occurrence of VA dissection.

Correlation Between Cerebral Microbleeds and Vulnerable Plaque in Patients with Severe Carotid Artery Stenosis; Comparative Magnetic Resonance Imaging Study.

GOAL: There are an increasing idea that the inflammation contributes to vascular diseases in various organs. The pathogenesis of both cerebral small vessel disease such as cerebral microbleeds and carotid plaque may be associated with chronic inflammation. This study was aimed to evaluate the correlation between microbleeds and carotid plaque characteristics. MATERIALS AND METHODS: This study enrolled 85 patients who underwent surgical/endovascular treatments for carotid artery stenosis between January 2009 and July 2016. Their clinical data were precisely analyzed. T2*-weighted magnetic resonance (MR) imaging was performed to detect the cerebral microbleeds. The carotid plaque with high signal intensity on T1-weighted MR imaging was categorized into vulnerable plaque. FINDINGS: The microbleeds was detected in 17 of 85 (20%). The prevalence of vulnerable carotid plaque and previous symptomatic lacunar infarction was significantly greater in the patients with microbleeds than in those without (P = .001 and P = .03, respectively). Multiple logistic regression analysis showed that the vulnerable plaque was significantly associated with the presence of microbleeds when adjusted for age, alcohol intake, antiplatelet drug use, the presence of previous symptomatic lacunar infarction, and coronary artery disease (P = .009, OR = 5.38, 95% CI = 1.51-21.0). CONCLUSIONS: These findings suggest the correlation between microbleeds and vulnerable plaque in patients with severe (>70%) carotid artery stenosis. Systemic, chronic inflammation may play a key role in both small and large arteries' disease of the brain. The knowledge may be valuable to fully understand the entity of cerebrovascular diseases as one of systemic, chronic inflammation.

[Characteristics of Headache and Neck Pain in Spontaneous Vertebral Artery Dissections].

PURPOSE: Sudden onset severe occipital/nuchal pain is believed to be a typical symptom of vertebral artery dissection(VAD). However, recent developments in diagnostic imaging have suggested that VAD is not always associated with such pain. This study aimed to analyze the clinical features of initial symptoms in patients with VAD. METHODS: In total, this study included 29 consecutive patients who were referred to our hospital because of only headache and/or nuchal pain due to VAD between 2011 and 2016. In this study, their clinical features were precisely assessed, including the pain location, onset pattern, duration, intensity, disease period, diagnosis modality, and prognosis. Both MRI and MRA were performed for all subjects. Cerebral angiography and thin-slice T1-weighted MRI were additionally performed in selected cases. RESULTS: Of the 29 patients, 23 presented with occipital headache and/or nuchal pain. The pain was persistent in 26/29 and ipsilateral in 29/29. However, only 16/29 reported a typical sudden onset. Only 12/29 complained of severe pain, while the other 17/29 presented with dull pain. The mean interval between onset and hospitalization was 7.4 days(0 to 30 days)and the mean interval between hospitalization and diagnosis was 3.9 days(0 to 21 days). Intramural hematoma was identified in 21/29 patients using thin-slice T1-weighted MRI. CONCLUSION: Only 55% of patients with VAD demonstrate typical occipital/nuchal pain with sudden onset. Both MRI and MRA should be indicated for patients who complain of persistent, unilateral pain in the occipital/nuchal regions to prevent VAD being missed during diagnosis.

Specific Shrinkage of Carotid Forks in Moyamoya Disease: A Novel Key Finding for Diagnosis.

This study was aimed to analyze the outer diameter of the involved arteries in moyamoya disease, using three-dimensional (3D) constructive interference in steady state (CISS) and direct surgical inspection. Radiological evaluation was performed in 64 patients with moyamoya disease. As the controls, six patients with severe middle cerebral artery (MCA) stenosis and 17 healthy subjects were also recruited. On 3D-CISS, the outer diameter was quantified in the supraclinoid portion of internal carotid artery (C1), the horizontal portions of MCA (M1) and anterior cerebral artery (A1), and basilar artery. The involved carotid fork was directly observed during surgery in another series of three adult patients with moyamoya disease. In 53 adult patients with moyamoya disease, the outer diameters of C1, M1, and A1 segments were 2.3 ± 0.7 mm, 1.3 ± 0.5 mm, and 1.0 ± 0.4 mm in the involved side (n = 91), being significantly smaller than the control (n = 17), severe M1 stenosis (n = 6), and non-involved side in moyamoya disease (n = 15, P < 0.01). There were significant correlations between Suzuki's angiographical stage and the outer diameters of C1, M1, and A1 (P < 0.001). The laterality ratio of C1 and M1 was significantly smaller in unilateral moyamoya disease (n = 20) than the controls and severe MCA stenosis (P < 0.01). Direct observations revealed a marked decrease in the outer diameter of the carotid fork (n = 3). These findings strongly suggest specific shrinkage of the involved arteries in moyamoya disease, which may provide essential information to distinguish moyamoya disease from other intracranial arterial stenosis and shed light on the etiology and novel diagnosis cue of moyamoya disease.

Surgical anatomy and preservation of the middle meningeal artery during bypass surgery for moyamoya disease.

BACKGROUND: The middle meningeal artery (MMA) is known to function as one of the important collateral routes in moyamoya disease. However, the anterior branch frequently courses within the lesser wing of the sphenoid bone and can easily be damaged during craniotomy for bypass surgery. This prospective study aimed to study the surgical anatomy of the MMA and to establish the technique to preserve it during bypass surgery for moyamoya disease. METHODS: Twenty-two patients with moyamoya disease underwent STA-MCA anastomosis combined with indirect bypass on 27 sides. The anatomical relationship between the anterior branch of the MMA and lesser wing was classified into three types: the bridge, monorail, and tunnel types. During surgery, the lesser wing was carefully resected with a rongeur or high-speed diamond drill to preserve the anterior branch of the MMA. RESULTS: The anterior branch of the MMA was classified into the bridge type in 5 sides (18.5 %), monorail type in 10 sides (37.0 %), and tunnel type in 12 sides (44.5 %). Patient age was closely related to the anatomical findings (χ (2) test, p = 0.0168). Careful resection of the lesser wing with a rongeur could preserve bridge- and monorail-type MMAs (100 and 71.4 %, respectively). However, drilling out of the lesser wing under a surgical microscope was essential to preserve the tunnel-type MMA. Intraoperative indocyanine green videoangiography was useful to confirm patency during surgery. CONCLUSIONS: It is essential to understand the surgical anatomy of the MMA around the pterion in order to preserve its anterior branch during bypass surgery for moyamoya disease.

Syringomyelia associated with Paget disease of the skull.

A 38-year-old man presented with a rare case of syringomyelia associated with Paget disease of the skull. Syringosubarachnoid (SS) shunting was performed. We speculate that deformation of the skull secondary to Paget disease caused narrowing of the foramen magnum with progressive impairment of the cerebrospinal fluid circulation, which led to syringomyelia and neurological symptoms. SS shunting is safe, effective, and technically simple, so may be a useful initial treatment for syringomyelia associated with Paget disease of the skull.

Middle cranial fossa arachnoid cyst presenting with subdural effusion and endoscopic detection of tear of the cyst--case report.

A 15-year-old boy presented with a case of middle cranial fossa arachnoid cyst associated with subdural effusion and manifesting as headache and vomiting after minor head injury. Computed tomography disclosed a cystic lesion in the left middle cranial fossa and ipsilateral subdural effusion. Fundoscopic examination revealed papilledema. A small tear of the cyst wall was confirmed endoscopically. Fenestration of the cyst was performed under the operating microscope. Postoperative course was uneventful. The tear in the outer wall of an arachnoid cyst may suggest the mechanism of occurrence of subdural effusion associated with middle cranial fossa arachnoid cyst.

Extracranial-intracranial bypass surgery at high magnification using a new high-resolution operating microscope: technical note.

BACKGROUND: We report a precise technique for EC-IC bypass surgery using a stereoscopic high-resolution microscope at magnifications of 40x and 50x. METHODS: A stereoscopic operating microscope (Mitaka MM50 Surgical Microscope; Mitaka Kohoki Co, Tokyo, Japan) was used in STA-MCA anastomosis. This microscope has 2 optical systems, a standard zooming system, a newly developed high-magnification system, and 4 fixed working distances of 200, 250, 300 and 350 mm, with highest magnifications of 50.4x at 200 mm and 40.3x at 250 mm. High resolution is achieved by a new lens design in the optical system, which makes the image of the object very clear at high magnification. The magnification can be changed depending on the circumstances in a given procedure. The STA-MCA anastomoses were performed using this microscope. RESULTS: Very small vessels were observable, and arterial anastomosis could be performed precisely at high magnification. All anastomoses were patent on postoperative angiograms. CONCLUSIONS: Use of the new microscope allows visualization and manipulation of small vessels at high magnification and high resolution and may be very useful in EC-IC bypass surgery.

Involvement of meteorological factors and sex in the occurrence of subarachnoid hemorrhage in Japan.

The sex difference in the seasonal occurrence of subarachnoid hemorrhage (SAH) and the association of meteorological factors in Japan were analyzed in 1006 consecutive patients with SAH in Toyama, Japan from 1996 to 2000. The study investigated whether these meteorological factors could explain the seasonality of the incidence of SAH in each sex. Seasonal variation of SAH occurrence peaked in spring in men, but peaked in spring and winter in women. The difference between maximum temperature and minimum temperature was the greatest on the day previous to SAH occurrence in multiple individuals in men, whereas mean humidity was the greatest on that day in women. Interestingly, the difference between maximum temperature and minimum temperature peaked in spring and mean humidity in winter from the meteorological data over the 5 years. The relationship between humidity and occurrence of SAH may explain the sex difference of the incidence of aneurysmal SAH. The humidity change may be a specific and additional meteorological factor for the incidence of SAH in women.

Neuroprotective role of transgenic PAF-acetylhydrolase II in mouse models of focal cerebral ischemia.

BACKGROUND AND PURPOSE: Platelet-activating factor (PAF) and oxidized unsaturated free fatty acids have been postulated to aggravate neuronal damage in the postischemic brain. Type II PAF-acetylhydrolase (PAF-AH II) not only terminates signals by PAF by its PAF-hydrolyzing activity but also protects cells against oxidative stress. We examined whether PAF-AH II can rescue cerebral neurons against ischemic insults. METHODS: Transgenic mice overexpressing human PAF-AH II in neurons were generated and enzyme expressions were examined biochemically and histochemically. The mice were subjected to 60 minutes of transient middle cerebral artery occlusion followed by reperfusion for 24 hours. The infarction and apoptosis were estimated by TTC staining and fluorescence TUNEL staining, respectively. RESULTS: Overexpression of PAF-AH II was found in brains of transgenic mice by Western blot and enzymatic activity analyses. In immunohistochemistry, human PAF-AH II expression was found throughout the central nervous system, especially in neurons of neocortex, hippocampus, and basal ganglia. The neurological deficit scores, cerebral edema index, and relative infarction volume were all significantly (P<0.05) lower in transgenic mice (1.30+/-0.72, 1.12+/-0.04, and 14.0+/-7.7%, respectively) than in wild-type mice (2.56+/-0.93, 1.23+/-0.12, and 31.9+/-9.7%, respectively). Percentages of apoptotic cells were also significantly (P<0.001) lower in transgenic mice (cortex, 5.2+/-3.3%; hippocampus, 3.4+/-7.0%) than in wild-type mice (cortex, 41.1+/-16.9%; hippocampus, 58.9+/-15.3%). CONCLUSIONS: These results indicate that PAF-AH II exerts strong neuroprotective effects against ischemic injury and suggest a possibility for clinical use of this enzyme in cerebral ischemia.

Transparent endoscopic sheath and rigid-rod endoscope used in endoscopic third ventriculostomy for hydrocephalus in the presence of deformed ventricular anatomy.

OBJECT: Endoscopic third ventriculostomy (ETV) has been widely performed for the treatment of noncommunicating hydrocephalus. In cases of hydrocephalus in conjunction with deformed and complex ventricular anatomy, it is preferable to use a rigid-rod endoscope for ETV, because the excellent visibility provided by this instrument yields a smooth and correct orientation in the ventricle. The authors report on ETV procedures in which they used a transparent endoscopic sheath that has a common channel in which a rigid-rod endoscope and an instrument can be inserted. METHODS: In 15 cases of noncommunicating hydrocephalus, a transparent endoscopic sheath and a rigid endoscope were used for ETV. In 11 of the 15 patients, the diameter of the foramen of Monro and the width of the third ventricle were greater than 5 mm, and thus a transparent endoscopic sheath and a rigid endoscope could be smoothly introduced through the foramen of Monro and an ETV successfully performed. Four patients had congenital or acquired narrowing of the foramen of Monro and an anatomically deformed ventricular system. In three of the patients, opening of the narrowed foramen and an ETV were successfully performed using the transparent endoscopic sheath under direct visualization through the rigid-rod endoscope. CONCLUSIONS: A transparent endoscopic sheath increases safety by offering a corridor to the third ventricle. It also provides excellent visibility without troublesome bleeding from tissues surrounding the foramen of Monro during endoscopic procedures in which a rigid endoscope is used.

Vidian artery as a collateral channel between the external and occluded internal carotid arteries--case report--.

A 68-year-old man presented with occlusion of the internal carotid artery (ICA) manifesting as a 6-month history of progressive sensory and motor disturbance of the left lower limb. Angiography clearly demonstrated a collateral arterial network between the ICA and external carotid artery (ECA) through the vidian artery, a small branch of both the ICA and ECA. The vidian artery may form an unusual but important ECA-ICA collateral pathway in patients with occlusive lesion of the ICA.

[Selection of surgical approach for quadrigeminal cistern arachnoid cyst].

Preoperative magnetic resonance imaging of 4 cases of quadrigeminal cistern arachnoid cyst were retrospectively reviewed and patterns of extension to surrounding cisterns from the quadrigeminal cistern were examined. Relationship between patterns of extension to surrounding cisterns and selected surgical approach were evaluated. In 2 cases, the cyst extended anteriorly and compressed the quadrigeminal plate. These two cases had hydrocephalus due to aqueductal stenosis. The anteroirly extending cyst was treated with endoscopic ventriculocystocisternostomy via the lateral and third ventricles. In one case, the cyst extended superiorly to the velum interpositum cistern, and was treated with endoscopic ventriculocystocisternostomy via the lateral ventricle. In one case, the cyst extended laterally to the ambient cistern and compressed the posterior horn of the lateral ventricle. This case had loculated hydrocephalus of the inferior horn. The laterally extending cyst was treated with resection of the wall of the arachnoid cyst via an infratentorial supracerebellar approach assisted by endoscope. All cysts were successfully treated. Injury of the foramen of Monro occurred during a procedure using a flexible endoscope in a case with an anterior extending cyst. Exact analysis of the preoperative imaging and selection of appropriate surgical approach are key factors for successful treatment of a quadrigeminal cistern arachnoid cyst.

Duration of cerebrospinal fluid drainage in patients with aneurysmal subarachnoid hemorrhage for prevention of symptomatic vasospasm and late hydrocephalus.

The optimal duration of cerebrospinal fluid (CSF) drainage after acute aneurysm surgery is unclear. The association between the occurrence of symptomatic vasospasm or late hydrocephalus and the duration of CSF drainage was investigated using multiple logistic analysis in 95 consecutive patients with aneurysmal subarachnoid hemorrhage who underwent surgery within 72 hours after onset. The duration of drainage was significantly related to the occurrence of symptomatic vasospasm and late hydrocephalus. The cut-off values of the duration of drainage for preventing symptomatic vasospasm and late hydrocephalus were 11 days (adjusted odds ratio 0.347, 95% confidence interval 0.135-0.889, p = 0.0274) and 6 days (adjusted odds ratio 4.86, 95% confidence interval 1.46-16.2, p = 0.0099), respectively. Prevention of both symptomatic vasospasm and late hydrocephalus is not possible without additional procedures such as cisternal irrigation using fibrinolytic agents.

Isolated third and fourth ventricles associated with neurosarcoidosis successfully treated by neuroendoscopy--case report.

A 48-year-old woman presented with a unique case of isolated third and fourth ventricles associated with neurosarcoidosis, manifesting as upward gaze palsy. She had a past history of surgery for intracranial sarcoid granuloma 10 years previously and placement of a ventriculoperitoneal shunt 3 years later. Magnetic resonance imaging revealed isolated third and fourth ventricles. Endoscopic plasty of the right foramen of Monro, fenestration of the septum pellucidum, and revision of the ventriculoperitoneal shunt were performed. Postoperatively the size of the third and fourth ventricles was reduced, and the upward gaze palsy resolved. Endoscopic treatment is less invasive and effective for the treatment of multiple septum formation in the ventricular system.

Tension pneumocephalus after a neuroendoscopic procedure--case report.

A 60-year-old female presented with gait disturbance, urinary incontinence, and recent memory disturbance. Computed tomography and magnetic resonance imaging revealed a partially calcified mass lesion without enhancement in the left caudate head and mild ventriculomegaly. She underwent endoscopic tumor biopsy. The histological diagnosis was astrocytoma grade 2. After the endoscopic procedure she presented with prolonged consciousness disturbance caused by tension pneumocephalus. Tension pneumocephalus is one of the potential complications of neuroendoscopic procedures.

Supratentorial dynamic computed tomography for the diagnosis of vertebrobasilar ischemic stroke.

Dynamic computed tomography (CT) is an established method for the evaluation of perfusion in acute ischemic stroke, but is not frequently used to assess infratentorial ischemia. Eleven patients with vertebrobasilar ischemia underwent dynamic CT on admission and/or during the follow-up period. The time of appearance (TA) and time to peak (TTP) were mapped and differences in TA (deltaTA) and TTP (deltaTTP) between the bilateral middle cerebral artery and posterior cerebral artery (PCA) territories were calculated. Conventional angiography and brain imaging including CT and magnetic resonance imaging were also performed. The TA and TTP maps obtained within 48 hours after onset exhibited time delay in eight of nine patients in the bilateral PCA territories. deltaTA and deltaTTP were greater in patients with stenosis or occlusion of the bilateral vertebral arteries or the basilar artery, and in patients without collateral circulation via the posterior communicating arteries than in control subjects. Furthermore, TA and TTP normalized dramatically in patients with recanalization of the arteries. deltaTA and deltaTTP were also normalized. deltaTA and deltaTTP were negatively correlated with the time from onset to examination. Dynamic CT can provide important information in patients with vertebrobasilar ischemic stroke, and may allow the diagnosis of acute ischemia and monitoring of the course.

Neuroendoscopic septostomy for isolated lateral ventricle.

The clinical features and endoscopic findings were investigated in 20 patients with isolated lateral ventricle treated by neuroendoscopic septostomy to establish cerebrospinal fluid communication and open an isolated ventricular compartment. The endoscopic procedure was incomplete because of thickened septum pellucidum and insufficient working space in two adults with postmeningitic hydrocephalus. Two children underwent second septostomy. In all other cases, results were good and there were no complications related to endoscopic procedures. Endoscopic septostomy is less invasive and has few complications. Intraoperative navigation and the biportal approach may be required in difficult cases with multiple septum formation and severe postmeningitic hydrocephalus. Adequate stomal size is required in high-risk groups including children under 2 years of age.

Endoscopic ventriculocystostomy through the septum pellucidum via the contralateral anterior horn--technical note.

Paraventricular fluid cysts have recently been treated by endoscopic fenestration performed from the cysts to the ventricular system. However, correct orientation and safe navigation of the endoscope may be difficult in patients with abnormal anatomy. Endoscopic fenestration from the ventricular system to a cyst was performed through penetration of the septum pellucidum via the anterior horn of the contralateral lateral ventricle. The advantage of this approach is correct orientation and introduction of the endoscope to the periventricular lesion because the usual landmarks can be identified in the normal contralateral lateral ventricle.