Akihiko Wachi

Arachnoid Cysts of the Middle Cranial Fossa: Experience with 77 Patients Who Were Treated with Cystoperitoneal Shunting

OBJECTIVEnOur surgical results of middle fossa arachnoid cysts are presented, and advantages and disadvantages of cystoperitoneal shunting are discussed.nnnMETHODSnSeventy-seven patients with middle fossa arachnoid cysts, including 20 cases of asymptomatic cyst, were treated by cystoperitoneal shunting. In cases associated with subdural hematoma, the cystoperitoneal shunt was preceded by irrigation of the hematoma. Follow-up periods ranged from 8 months to 16 years (mean, 7.7 yr).nnnRESULTSnIn all cases, postoperative computed tomography and magnetic resonance imaging revealed subsequent expansion of the surrounding brain, concomitant with either the disappearance of or a marked decrease in the size of the cyst. Patients who initially presented with headaches, hemiparesis, choked discs, and diplopia were cured postoperatively. Head enlargement presented preoperatively did not progress after shunting. Mental retardation and behavior problems, however, remained unchanged postoperatively, even though the cyst had disappeared. One cystoperitoneal shunt became infected, and shunt malfunction developed in eight patients. Four of the eight patients presented acute signs and symptoms of intracranial hypertension when the shunt malfunctioned, although the concurrent increase in cyst size was slight and ventriculomegaly was not seen. The observed condition in these four patients could be considered shunt dependency.nnnCONCLUSIONnCystoperitoneal shunting is a valid method of achieving obliteration of the cyst and clinical improvement and seems to feature low operative risk and few complications. It should be noted, however, that some patients experience shunt dependency after cystoperitoneal shunting.

Craniosynostosis in the presence of a sinus pericranii: case report.

The case of a 16-month-old baby girl with craniosynostosis associated with venous sinus stenosis and sinus pericranii is reported. Monitoring of intracranial pressure indicated increased cerebrospinal fluid outflow resistance in addition to increased intracranial pressure. Despite intracranial hypertension, however, the pressure-buffering capacity, expressed as pressure-volume index, was remarkably elevated. A similar case has not been reported in the literature. The mechanism of pressure-volume index elevation and the management of this anomaly are discussed.

Cerebral aneurysms in children

Childhood intracranial saccular aneurysms are rare, accounting for only 0.6-4.6% of all aneurysms. This paper presents two such cases. A 12-year-old boy developed sudden severe headaches. CT indicated subarachnoid hemorrhage in the bilateral sylvian fissure. Angiography failed to demonstrate any vascular lesions. Repeat angiography, however, revealed a 2 mm aneurysm on the right A-1. A miniclip was successfully applied to obliterate the aneurysm. The postoperative course was uneventful. In the second case, a 3-year-old boy, CT incidentally revealed a bullet-shaped high density area. Angiography demonstrated a large aneurysm arising from the insular portion of the prefrontal branch of middle cerebral artery. This large aneurysm with a broad-based neck was successfully clipped, employing the angioplastic and/or tandem clipping, despite the fact the prefrontal artery unfortunately was compromised in postoperative angiography. The patient was doing well postoperatively. Spontaneous subarachnoid hemorrhage (SAH) in childhood is uncommon. However, when children with SAH is encountered, angiography should be performed repeatedly even if the first angiogram does not demonstrate any vascular abnormality. Childhood aneurysms are increasingly being found incidentally in CT scans. The differences between child and adult aneurysms in regard to site, size, sex predominance, clinical features, and surgical outcome are discussed.

Characteristics of cerebrospinal fluid circulation in infants as detected with MR velocity imaging

Analysis of cerebrospinal fluid (CSF) flow and motion at the craniospinal junction was conducted by magnetic resonance velocity imaging with phase encoding followed by motion velocity intergration. Thirteen normal subjects classified into two groups were studied: an infant group with open sutures and fontanel, and a noninfant group with closed sutures and fontanel. Predominance in CSF to-and-fro motion was recognized in the ventral subarachnoid space, and a maximum caudad motion velocityof 7.5±2.4 mm/s was recorded in the infant group and one of 14.9±6.2 mm/s in the noninfant group. The average bulk flow velocity in all cases was 86.7±81.6 (means±SD) mm/min. The difference in flow velocity between the infant group (19.7±28.2 mm/min) and the noninfant group (116.5±80 mm/min) suggested that the CSF circulation around the cervical spine may vary at different ages.

Anatomical and biomechanical similarity in intracranial environment in identical twins with external hydrocephalus

Identical twins who both presented with progressively enlarging heads in their first year of life are reported. Neuroimaging demonstrated morphological similarities in the cerebral cortex. The CSF space, including ventricular system, and subarachnoid space were dilated, suggesting external hydrocephalus. Cerebral blood flow velocity in the anterior cerebral artery monitored by Doppler sonogram indicated the two had similar flow patterns and velocities. Simultaneous recording of ICP waves and intracranial biomechanical properties, that is, pressure buffering capacity (pressure volume index: PVI) and CSF outflow resistance (Ro) measured by the bolus saline injection technique, objectively indicated that all these biomechanical factors were also quite similar in the twins. These results indicate that identical twins with external hydrocephalus have very similar intracranial environments, both anatomically and bio-mechanically.

Multiple aneurysms associated with bilateral carotid occlusion and venous angioma: surgical management risk-case report.

A unique case of multiple aneurysms associated with bilateral carotid artery occlusion and venous angioma is described. A 42 year old female presented with subarachnoid haemorrhage. Cerebral angiograms demonstrated(1) a ruptured saccular aneurysm in the right posterior cerebral artery,(2) bilateral occlusion of internal carotid arteries,(3) a rete mirabile in the subtemporal fossa fed by left external carotid artery which connected with the internal carotid artery at the cavernous portion where a saccular aneurysm had formed, and(4) a venous angioma in the posterior fossa. The ruptured aneurysm of the posterior cerebral artery was obliterated preserving the anterior choroidal arteries. However, a left hemiparesis developed and CT scan revealed a small low density area in the right posterior limb of the internal capsule postoperatively. A ruptured aneurysm associated with bilateral extracranial carotid occlusion poses a clinical dilemma and treatment of such cases is challenging and difficult. The non-surgical and surgical outcomes of ruptured cerebral aneurysms associated with internal carotid occlusion are reviewed.

‘Salt and pepper on the face’ pain followed by cardiac and respiratory arrests: The stormy postoperative manifestations after the surgery of posterior fossa arteriovenous malformation

The authors describe salt and pepper on the face pain in a case of medullary arteriovenous malformation (AVM), which was caused by post-operative hemorrhage from a very small residual nidus of AVM left remaining in the left dorsal medulla. The peculiar, sharp, jabbing pain, which has been rarely reported at the onset of intracranial hemorrhage, was followed by acute elevation of blood pressure, arrhythmia, cardiac and respiratory arrests. The patient had been in a comatose state for a month and gradually recovered from the cardiopulmonary and neurological derangements. The pathophysiology of the phenomenon which occurred in this case is discussed.

MRI detection of ruptured malignant teratoma in the third ventricle

We describe a case in which CT and MRI showed evidence of intraventricular fat, which proved to have come from a ruptured malignant teratoma.

Systolic Cerebral Blood Inflow (SCBI) as a CBF-Index Estimated with ICP Wave-Change in CBF and SCBI During Mannitol Infusion

The ICP wave is closely related to the pulsatile intracranial blood flow. The objectives of this study are: n n1. n nto estimate the pulsatile inflow by analyzing pulse wave and pressure-volume relationship in an experimental model using a pulsatile pump and to compare the Estimated Inflow Volume with the Actual Inflow Volume in this system, n n n n n2. n nto compare systolic cerebral blood inflow (SCBI) with cortical CBF during mannitol infusion in patients with subarachnoid hemorrhage.

Chronological Change in Biomechanical Indices of Chronic Subdural Hematoma During and After Closed Drainage — When Should Fluid Drainage Cease?

Patients with chronic subdural hematoma (ages 33–83) were investigated to elucidate the bianechanical status of the homatoma and to determine the time for termination of external hematoma drainage. After trepanation, initial pressure within hematoma was first recorded, followed by pressure-volume measurement. In conclusion, mean initial intrahematoma pressure of 27 mmHg, remarkably higher than in previous reports, was found. Pressure buffering capacity within hematoma after successive drainage of hematoma demonstrated that there were two groups of patients, one in which there was a decrease in PVI and the other with slow increase in PVI. Usually, fluid outflow ceased within few days after surgery in former group, while CSF continuously drains in latter group. External drainage may therefore be terminated when there is normalization of intrahematoma pressure-volume status or fluid outflow disappears.