Takeo Kuwabara

Estimation of rate of growth of malignant brain tumors by computed tomography scanning

The growth rate of malignant gliomas was estimated by serial computed tomography scanning. The actual tumor doubling time was determined by calculating the change in tumor volume on the scans. Eleven malignant gliomas were assessed by this method. The actual tumor doubling times of malignant gliomas ranged from 15.0 to 21.1 days, averaged 19.5 +/- 1.9 days, and showed no significant variation according to histopathologic differences. By determining the tumor doubling time in this manner, the growth rate of a tumor can be assessed. The efficacy of treatment and subsequent prognosis in malignant brain tumors can be predicted more accurately by estimation of the growth rate. The clinical application of the growth rate of malignant gliomas is presented.

Orbitocraniobasal Approach for Anterior Communicating Artery Aneurysms

We describe an orbitofrontotemporobasal craniotomy technique that allows excellent access to anterior communicating artery aneurysms. This orbitocraniobasal approach is particularly useful for the surgical treatment of ruptured aneurysms in the acute stage of subarachnoid hemorrhage, when retraction of the brain needs to be kept to a minimum. With this approach, retraction of the orbital contents decreases the amount of retraction of the brain to such an extent that a brain spatula is not necessary for access to the anterior communicating artery complex. The procedure is described, as is a modification of the approach for removal of large tumors on the skull base.

Traumatic Intraventricular Hemorrhage: Report of Twenty-six Cases and Consideration of the Pathogenic Mechanism

A series of 26 patients suffering traumatic intraventricular hemorrhage (IVH) after closed head injury is reviewed, and the pathogenic mechanism of the traumatic IVH is discussed considering the site of origin of the IVH. Computed tomographic detection of the origin of the IVH was possible in 15 patients (Group 1): 6 had frontal or temporal contusional intracerebral hemorrhage spreading into the ventricle (Subgroup A), 5 had the original hemorrhage in the caudate nucleus (Subgroup B), and 4 originally bled in the thalamus (Subgroup C). The origin of the IVH was not determined in 11 patients (Group 2): 6 had concomitant hemorrhage around the brain stem (Subgroup D), and 5 had small IVH with or without small intracerebral hemorrhage (Subgroup E). The site of impact was not uniform in Subgroup A, whereas the other four subgroups usually had frontal or occipital impact. In Subgroup A, the IVH was discovered more than several hours after trauma. In the other four subgroups, however, the IVH was detected in as short a time as 0.5 to 1.5 hours after trauma. In Subgroups B and C, the impact along the long axis of the skull and the early occurrence of hemorrhage in the basal ganglia suggest that shear injury between the perforating vessels and the basal ganglia may be the responsible mechanism. The several other possible mechanisms in Subgroups D and E are reviewed and discussed in relation to diffuse brain injury.

Thrombotic occlusion of the middle cerebral artery

Background and Purpose: Epidemiological study of middle cerebral artery occlusion is important because the indication for extracranial-intracranial arterial bypass remains in dispute. To help clarify this issue, we investigated the prognosis of thrombotic middle cerebral artery occlusion in Japanese patients. Methods: We studied 40 patients with thrombotic middle cerebral artery occlusion who were selected on the basis of clinical features, computed tomographic findings, and angiographic findings. Patients with causes of embolism (i.e., cardiomyopathy, valvular heart disease, cardiac arrhythmia, and carotid ulceration) were excluded. The 40 patients were classified into three groups according to the site of middle cerebral artery occlusion: there were 13 patients with occlusion of the proximal portion of the Ml segment, 13 with distal Ml segment occlusion, and 14 with occlusion of the M2 segment. Results: Good collateral circulation was associated with improved outcomes both clinically and by computed tomography in patients with occlusion of the proximal and distal portions of the Ml segment but not in those with M2 occlusion. Conclusions: It is reasonable to assume that not only collateral circulation but also the site of occlusion plays an important role in the outcome of middle cerebral artery occlusion. Our finding that good collateral circulation improves the outcome for thrombotic occlusion of the proximal and distal Ml segments supports the possible benefits of such surgery.

Telecanthal Approach for Meningiomas in the Ethmoid and Sphenoid Sinuses

In three cases involving meningiomas in the ethmoid and sphenoid sinuses, transbasal spreading of the interocular distance (telecanthal approach) was used for tumor removal and reconstruction of the skull base. This telecanthal approach involves 1) bilateral en bloc removal of the superior lateral rim of the orbit, the nasal bone, and the posterior lateral wall of the orbit; 2) detachment of the medial canthal ligaments; and 3) spreading of the interocular distance. This approach provides a wide working space beneath the anterior half of the midline skull base, and needs neither a facial incision nor significant retraction of the brain. The surgical technique and its modification are described. The discussion focuses not only on comparisons with other techniques, but on the indications for this approach. Meningiomas originating in the paranasal sinuses are rare; a brief review of the literature concerning the clinicopathological features and pathogenesis is also given.

Thermosensitive Determination of Patency in Lumboperitoneal Shunts: Technical note

Surface cooling and thermistor recording over shunt tubing was used in 23 studies of cerebrospinal fluid shunt patency in 19 patients with lumboperitoneal shunts and normal-pressure hydrocephalus. Shunt patency was shown by downward reflection of the recording trace similar to that obtained for ventriculoperitoneal shunts. Obstruction was demonstrated by a flat-line recording or an upward deflection.