Kiyonobu Ikeda

Orbitozygomatic temporopolar approach for a high basilar tip aneurysm associated with a short intracranial internal carotid artery: a new surgical approach.

For two cases of a high basilar tip aneurysm accompanied by a short intracranial internal carotid artery, the orbitozygomatic temporopolar approach consisting of an en bloc fronto-orbitozygomatic temporal craniotomy and temporopolar approach was carried out. On angiograms, the height of the bifurcation of an elongated basilar artery and the length of the intracranial internal carotid artery from the interclinoid line between the anterior and posterior clinoid process were 20 mm and 6 mm in Case 1, and 18 mm and 5 mm in Case 2, respectively. The skin flap was separated subfascially to preserve the frontotemporal branch of the facial nerve. The fronto-orbitozygomatic temporal bone flap was made, and a part of the basal bony structures of the orbital roof, the sphenoid ridge, and the temporal bone were removed. The basilar tip aneurysm could be seen and clipped easily by upward and oblique viewing from below through the wide operative space consisting of the less retracted internal carotid and middle cerebral arteries, the oculomotor nerve, the tentorial hiatus, and the emptied anterior temporal fossa obtained by partial division of the temporal bridging veins. The operative procedure is presented in detail and compared with other surgical approaches that have been described previously.

Immunohistochemical localization of tissue-type plasminogen activator in the lining wall of chronic subdural hematoma.

Capsules of chronic subdural hematoma were immunohistochemically stained with monoclonal antibody against tissue-type plasminogen activator. Endothelial cells of sinusoids and capillaries in the outer membrane showed strong immunostaining. Endothelial cells of veins and arteries in the dura mater showed moderate and weak staining. No cells other than the endothelial cells were stained. In the inner membrane, tissue-type plasminogen activator immunoreactivity was not seen. The mean concentration of tissue-type plasminogen activator in the hematoma content was higher than that in the plasma. The more the sinusoids in the outer membrane were developed, the higher the concentration of tissue-type plasminogen activator contained in the hematoma fluid. In chronic subdural hematoma, overproduction and oversecretion of tissue-type plasminogen activator from the sinusoidal and capillary endothelial cells in the outer membrane cause increased fibrinolysis, which in turn impairs hemostasis, and hemorrhage from the capillaries recurs, resulting in enlargement of the chronic subdural hematoma.

Coagulative and fibrinolytic activation in cerebrospinal fluid and plasma after subarachnoid hemorrhage.

OBJECTIVE Intrathecal fibrinolytic therapy has been used as one of the anticerebral vasospasm (VS) preventative therapies in patients with subarachnoid hemorrhage (SAH). However, the changes in coagulation and fibrinolysis in the blood and cerebrospinal fluid (CSF) after SAH remain unknown. METHODS Fifty patients with SAH caused by ruptured cerebral aneurysms were studied postoperatively to detect the serial changes of the thrombin-antithrombin III complex, active plasminogen activator inhibitor (PAI)-1, and tissue plasminogen activator (tPA)-PAI complex (tPA-PAI) activities in the plasma and CSF collected from cisternal drainage catheters. RESULTS The CSF levels of all parameters and plasma PAI-1 levels were significantly higher in patients with severe SAH than in those with mild SAH. There was no relationship between the CSF and plasma levels of these parameters (except the CSF levels of tPA-PAI) and the initial neurological statuses. The CSF PAI-1 levels increased to greater than 20 ng/ml near the time of the occurrence of cerebral VS, whereas they remained below 20 ng/ml in patients without VS. The CSF tPA-PAI levels showed the highest peak near the time of VS remission. The CSF PAI-1 and tPA-PAI levels were significantly lower in patients with good outcomes than in those with poor outcomes. CONCLUSION Both the coagulative and fibrinolytic systems were activated in the CSF and plasma after SAH in correlating to the amount of SAH clot. The intrathecal administration of fibrinolytic agents should be started early after surgery, before CSF PAI-1 levels increase, for patients with severe SAH. Patients with CSF PAI-1 levels greater than 20 ng/ml experienced high incidence of VS and poor outcomes.

Surgical indications and microsurgical anatomy of the transchoroidal fissure approach for lesions in and around the ambient cistern.

OBJECTIVE Opening the temporal part of the choroidal fissure (CF) makes it possible to expose the crural cistern, the ambient cistern, and the medial temporal lobe. We examined the microsurgical anatomy and the surgical indications for use of the trans-CF approach. METHODS The microsurgical anatomy encountered in the trans-CF approach for lesions in and around the ambient cistern was studied in three cadavers. On the basis of these cadaveric studies, the trans-CF approach was used during surgery in three live patients with such lesions. RESULTS The angiographic “plexal point,” which indicates the entrance of the anterior choroidal artery as it enters the temporal horn of the lateral ventricle, was thought to be a key anatomic landmark of the trans-CF approach. A cortical incision for entry into the temporal horn should be made in the inferior temporal gyrus to minimize the potential damage to the optic radiations and to the speech centers. After the CF is opened posteriorly to the plexal point between the tenia fimbria and the choroid plexus, the posterior cerebral artery (PCA) in the ambient cistern can be observed with minimal caudal retraction of the hippocampus. In this study, surgical procedures using the trans-CF approach were successfully performed on patients with high-positioned P2 aneurysms whose PCA ran close to the plexal point or higher, whose medial temporal arteriovenous malformations were fed mainly by the PCA, and whose tentorial hiatus meningiomas protruded into the temporal horn through the CF, with no resulting postoperative visual or memory disturbances. CONCLUSION The trans-CF approach is especially useful in surgery for lesions in and around the ambient cistern.

Three Phases of Cerebral Arteriopathy in Meningitis: Vasospasm and Vasodilatation Followed by Organic Stenosis

A systematic radiological and pathological study of the cerebral arteries was made in an autopsy case of meningitis associated with three phases of cerebral arteriopathy. The latter consisted of vasospasm, vasodilatation, and organic stenosis. A marked change in the caliber of the cerebral arteries was demonstrated 3 times. Vasospasm, the stimulus phenomenon, was produced by the surrounding purulent material. Vasodilatation, the paralytic phenomenon, was presumably due to decreased contractile energy in association with myonecrosis. Organic stenosis, the repair process, was due to the organization of subendothelial edema with resultant intimal thickening. Evidence of increased endothelial permeability, subendothelial proliferation of smooth muscle cells, and necrosis of the latter in the media is presented in both light and electron micrographs.

Thallium-201 accumulation in cerebral candidiasis: unexpected finding on SPECT.

The authors present an unexpected finding of TI-201 uptake in the intracerebral lesions due to candidiasis. SPECT demonstrated the extent of the lesions and a high target-to-background ratio. The regions where abnormal TI-201 accumulation was seen were nearly consistent with CT scans of those enhanced by a contrast agent. After treatment, most of the abnormal TI-201 accumulation disappeared.

Ultrastructural study of calcification process in the ligamentum flavum of the cervical spine

The ultrastructure of the formation of calcified nodules in three cases of symptomatic calcification of the cervical ligamentum flavum were studied. In some areas of the ligament, extracellular plasma membrane-invested matrix vesicles and thick wall-bound matrix giant bodies with or without mineralized deposits were present. These calcified vesicles and bodies were also encountered in the wide mineralized areas among the collagen and elastic fibers in the ligament. The mineralization process of the calcified nodules in the ligamentum flavum implies that matrix vesicles and matrix giant bodies acquire mineralized precipitates; then some gather in clusters. Calcified deposits may spread to collagen and elastic fibers contiguous with the calcified vesicles and bodies, and some eventually coalesce to make a calcified nodule.

CEREBRAL GRANULOMA AND MENINGITIS CAUSED BY CANDIDA ALBICANS : USEFUL MONITORING OF MANNAN ANTIGEN IN CEREBROSPINAL FLUID

The authors report the case of a previously healthy patient who had recurrent cerebral granulomas and meningitis caused by Candida albicans 15 years after the first onset. A combination of external drainage of cerebrospinal fluid (CSF) and intraventricular and intravenous chemotherapy with antifungal agents resulted in a favorable outcome. Investigation of this patient revealed no immunological dysfunction, lymphoproliferative disorder, or candidicidal defect of peripheral blood leukocytes. Sequential measurement of Candida mannan antigen in CSF was useful for establishing the early diagnosis of cerebral candidiasis and for judging the effect of our antifungal chemotherapy. In determining the surgical indications and timing of placement of a ventriculoperitoneal or ventriculoatrial shunt for meningitis subsequent to hydrocephalus after candidal infection, it is better to confirm normal concentrations of the mannan antigen in the CSF repeatedly for more than a week and to determine that cultures of the CSF are negative for Candida albicans.

Immunohistochemical Alterations of Fibronectin During the Formation and Proliferative Repair of Experimental Cerebral Aneurysms in Rats

BACKGROUND AND PURPOSE To determine whether distributional changes of fibronectin, a factor promoting wound healing, occur during the formation and repair of cerebral saccular aneurysms, we performed immunohistochemical analyses in experimental aneurysms. METHODS Cerebral aneurysms were induced in rats by both the ligation of the unilateral common carotid artery and induced hypertension. Intimal proliferation in aneurysmal walls was induced by the ligation of the preserved common carotid artery 3 months after the first operation. The distribution of fibronectin was examined by immunohistochemistry in anterior cerebral artery-olfactory artery bifurcations under the following three conditions: normal bifurcations in control rats, early aneurysmal lesions during the aneurysm induction, and aneurysmal lesions with intimal proliferation. Furthermore, the immunohistochemical distributions of type I and IV collagens were examined to evaluate the specificity of fibronectin immunoreactivity. RESULTS In the normal bifurcations, fibronectin was positive in the subintimal space, the surrounding area of the medial smooth muscle cells, and the adventitial fibrous tissue. In early aneurysmal lesions, linear staining of fibronectin and type I and IV collagens in the subendothelial space disappeared with the loss of the internal elastic lamina. In the intimal proliferation of early aneurysmal lesions, fibronectin was strongly immunostained in the subendothelial space and diffusely immunostained in the widened extracellular space surrounding proliferated cells. In contrast, the stainings of type I and IV collagens were sparse or negative. CONCLUSIONS Although the present findings regarding dynamic changes of fibronectin distribution do not prove any causality in the process of aneurysm formation and repair, these immunohistochemical changes may constitute the crucial sequela of intimal endothelial damage and its subsequent recovery in cerebral aneurysms.

Basic Fibroblast Growth Factor May Repair Experimental Cerebral Aneurysms in Rats

BACKGROUND AND PURPOSE To determine whether basic fibroblast growth factor (FGF) can induce proliferative response of endothelial cells and/or smooth muscle cells in aneurysmal lesions, we investigated the effect of the intravenous administration of basic FGF on experimental cerebral aneurysms. METHODS Cerebral aneurysms were induced in rats by ligation of the unilateral common carotid artery, producing hypertension. Three months later, basic FGF was intravenously injected in two groups of randomly divided rats on days 1, 3, and 5 at two different doses (low dose: 2 micrograms/100 g body wt per day; high dose: 5 micrograms/100 g body wt per day). In a control group, normal saline was similarly injected. The junctions of the anterior cerebral artery (ACA) and the olfactory artery (OA) were examined with a light microscope. Aneurysmal changes were defined as the lesions with discontinuity of the internal elastic lamina in more than half of the outward dilated wall. Depending on whether the smooth muscle cell layer was present in the whole wall, the lesions were divided into two stages: early aneurysmal lesion (whole area) and saccular aneurysm (not totally preserved). RESULTS The control and the low-dose groups presented no obvious intimal thickening in the intact ACA-OA junctions of both nonligated and ligated sides as well as in the aneurysmal changes. In contrast, in the high-dose group, various degrees of intimal thickening in the wall were detected in 7 of 15 early aneurysmal lesions (P = .019, Fishers exact test). Immunohistochemistry showed the proliferated cells to be smooth muscle cells. CONCLUSIONS These results demonstrate that exogenous basic FGF induces the proliferative response of smooth muscle cells in aneurysmal lesions in rats.