Yasutaka Kurokawa

Pathogenesis of hyponatremia following subarachnoid hemorrhage due to ruptured cerebral aneurysm

BACKGROUND Hyponatremia following subarachnoid hemorrhage (SAH) occurs due to the inappropriate secretion of antidiuretic hormone (SIADH). However, this condition is also sometimes associated with certain dehydration states. METHODS To clarify the pathogenesis, daily values of urine volume, water balance, and sodium balance (Na Bal) were correlated with plasma levels of atrial natriuretic peptide (ANP), antidiuretic hormone (ADH), and plasma renin activity (PRA) in 31 cases of SAH. RESULTS Na Bal was markedly negative on days 2 and 3. Cumulative Na Bal showed continuous negative values until day 10 following SAH. ANP values showed a consistent elevation, while ADH showed only an initial surge. PRA, as the gross indicator of circulatory volume, showed a lack of suppression, indicating no increase in the circulatory volume. CONCLUSION Hyponatremia following SAH therefore appears to be the result of increased natriuresis, due to the inappropriate elevation of ANP rather than SIADH. In this situation, water restriction should not be recommended, since the circulatory volume is decreased.

Characteristics of aneurysms arising from the horizontal portion of the anterior cerebral artery

BACKGROUND Aneurysms arising from the proximal portion of the anterior cerebral artery (A1: horizontal portion) are quite rare and are considered to be unique, because they are usually connected with other vascular anomalies and are sometimes part of a multiple aneurysm occurrence. A1 aneurysm cases experienced over the past seven and a half years are summarized in this paper. METHODS A total of 413 patients were surgically treated including 142 patients with subarachnoid hemorrhage (SAH); the remaining 271 patients had unruptured aneurysms. Among them, nine cases were categorized as constituent A1 aneurysms, three with SAH and six with unruptured aneurysms. RESULTS The shape of the aneurysm was saccular in all nine cases. Three of the nine cases had associated vascular malformations. The average aneurysm diameter in the three cases with SAH was 4.0 mm, which is smaller than other common aneurysms presenting with SAH. Eight aneurysms developed at the takeoff point of perforating arteries-the medial lenticulostriate artery in five cases and the recurrent artery of Heubner in three cases. In the remaining case, the aneurysm originated from the proximal end of the associated A1 fenestration. All nine patients had an excellent outcome after surgery. CONCLUSION A1 aneurysms require surgical elimination even if they are small. We emphasize the importance of preserving the blood flow of these perforating arteries by avoiding compression with either the clip blade or the clip body itself.

Microvascular decompression for hemifacial spasm caused by the vertebral artery: a simple and effective transposition method using surgical glue

BACKGROUND Microvascular decompression for the treatment of trigeminal neuralgia and hemifacial spasm (HFS) has been established and has brought about excellent results. However, recurrence or lack of relief from the symptoms was experienced in some cases in which the nerve root or root exit zone were compressed by the vertebral (VA) and basilar arteries. We experienced a severe HFS case, mainly caused by a compression with the tortuous VA. A more simple transposition technique of the offending VA using surgical glue is reported. METHODS A 64-year-old male had been suffering from HFS for six years. The tortuous right VA with anterior inferior cerebellar arteries (AICA) was considered to be responsible for his vascular compression syndrome. The VA was carefully and slowly dislocated away from the pontomedullary junction toward the cranial base. Then the arteriosclerotic portion of the VA wall was chosen, where a small piece of Surgicel (ETHICON, Inc., Somerville, NJ) is placed beforehand so as to use a minimum amount of glue (Biobond; Mitsubishi Pharma Corp., Osaka, Japan). Until the glue is hardened, the VA is held away from the brain stem. After this procedure, the ordinary transposition of AICA branches was added. RESULTS The annoying HFS completely disappeared immediately after the operation. CONCLUSION The advantage of our method is the simplicity of the procedure. It requires less space and time while the other methods using tapes, strips, and clips need a greater working space and more time.

New Method for Obliterative Treatment of an Anterior Wall Aneurysm in the Internal Carotid Artery: Encircling Silicone Sheet Clip Procedure—Technical Case Report

OBJECTIVE AND IMPORTANCE Aneurysms on the anterior surface of the internal carotid artery (ICA) have been shown to be somewhat different from ordinary berry aneurysms because they are rather small, grow rapidly in a short time, and easily lead to rupture, especially during surgery. The most difficult problem is that this type of aneurysm cannot be eliminated easily by an ordinary clipping procedure without causing apparent arterial stenosis or occlusion. CLINICAL PRESENTATION A 52-year-old man experienced a subarachnoid hemorrhage because of a ruptured aneurysm located on the anterior surface of the ICA. The tiny aneurysmal body, which was covered with a layer of brain tissue, was successfully exposed. The ICA seemed to be atherosclerotic, and the aneurysmal portion was solitary and had a reddish color. TECHNIQUEA large silicone sheet encircling clip (Vascwrap; Mizuho Ikakogyo Co., Ltd., Tokyo, Japan) was selected for this patient. The proximal margin of the silicone sheet was incised with a V-shaped cut, and the middle part of the sheet, which covered the diagonal part of the ICA, was trimmed to make it shorter. The blade of the fenestrated clip was applied to obliterate the aneurysm and was attached to the normal arterial wall together with this modified Vascwrap sheet to create a small space between the normal arterial wall and the surrounding Vascwrap sheet. Then tiny pieces of Teflon fiber (E.I. duPont de Nemours and Co., Wilmington, DE) was inserted from both margins, and the whole Vascwrap sheet was sealed with fibrin glue to ensure good adhesion. CONCLUSIONThis method seemed adequate in treating this difficult aneurysm without causing postoperative regrowth or occlusion of the patient’s ICA.

Regional ischemia in cerebral venous hypertension due to embolic occlusion of the superior sagittal sinus in the rat

To determine the pathophysiological changes in brain tissue that characterize damage following cerebral venous hypertension, a model of cerebral venous hypertension in the rat was devised. This experimental model has the advantage of simultaneously measuring the regional changes in cerebral blood flow as well as the metabolism. The ischemic area demonstrated by the accumulation of NADH is confined to the cerebral cortex and becomes enlarged in proportion to the increase in venous pressure. This metabolic disturbance appears even in the very early period following cerebral venous hypertension. These pathophysiological features are different from those observed in the case of intracranial hypertension.

Hemorrhage into fibrous dysplasia following minor head injury ― Effective decompression for the ophthalmic artery and optic nerve

We performed an effective optic canal decompression in a patient with ethmoid and sphenoid fibrous dysplasia and visual impairment following minor head trauma. On admission, the patients left visual acuity consisted only of light perception, and the left ophthalmic artery was not visible by angiography. A hematoma and fibrous dysplasia tissue in the sphenoid sinus were excised and the left optic canal was decompressed. The vision was markedly improved to an ability to count fingers in the following 2 weeks. The left ophthalmic artery was fully opacified in the postoperative angiogram.

Changes in cerebral microvasculature in congenital hydrocephalus of the inbred rat LEW/Jms: light and electron microscopic examination.

The vascular apparatus in congenitally hydrocephalic rat brains was studied. The characteristic findings were structural changes in the small vessels with formation of an intracerebral cavity in the periventricular white matter. Stenotic or occluded blood vessels were located in an edematous area adjacent to the dilated lateral ventricles. Electron microscopically, the endothelial cells of capillaries and venules in the periventricular edematous region showed an irregular surface with indentations, and contained numerous plasmalemmal vesicles. Occluded capillaries were found in the border zone between the edematous and nonedematous area. These vascular changes indicate the presence of a disturbed microcirculation in the hydrocephalic brain.

The usefulness of 3D-CT angiography for the diagnosis of spontaneous vertebral artery dissection : report of two cases

Spontaneous vertebral artery dissection (VAD) has been recognized as being more common than was first thought, with the growing use of magnetic resonance imaging (MRI). However, simple MRI alone is not always satisfactory for making an accurate diagnosis. We experienced two cases of VAD in our clinic, in which three-dimensional computed tomographic angiography (3D-CTA) was performed. Our scanner has the capability of examining a slice of 1mm thick, 0.5mm reconstruction pitch, and a scan time of 1s/rotation. 3D-CTA clearly demonstrated the stenotic change concomitant with the surrounding thrombus and was thought to be useful for making an accurate diagnosis.

A case of intraventricular arachnoid cyst

A rare case of arachnoid cyst in the trigone of a lateral ventricle is reported. The patient was an 8-year-old boy who had had four episodes of convulsions prior to admission. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated a cystic lesion containing fluid resembling cerebrospinal fluid. Although he received a cyst-peritoneal shunt, the lesion did not decrease in size. Direct removal of the cyst was then scheduled. The entirc cyst was finally removed, although it was firmly attached to the choroid plexus. The enlarged trigone gradually decreased in postoperative CT. The effectiveness of a cyst-peritoneal shunt is not always satisfactory. We recommend total resection of the cyst without use of a shunt system.

Holoprosencephaly with Dandy-Walker cyst

A case of holoprosencephaly associated with Dandy-Walker cyst is reported. The patient was a male baby whose mother had normal serum titers for toxoplasma, syphilis, rubella and hepatitis B. She had no history of dibbetes mellitus, administration of drugs or irradiation during the pregnancy. At the 8th month of gestation, fetal hydrocephalus was diagnosed by ultrasonic imaging. He was delivered by caesarean section at 34 weeks and 4 days, weighing 2,644 g. His head circumference was 42 cm; the anterior fontanel was not distended and its tension was normal. The chromosomal karyotype was a normal 46 XY. X-ray CT showed a large dorsal sac cyst in the supratentorial space and a hypoplastic cerebellum with a large cyst in the posterior fossa. He received a cyst-peritoneal shunt 24 days after birth. After this procedure, his head enlargement was arrested. We discuss the etiology of this rare coexistence of two major malformations.