Keita Kinoshita

Present epidemiology of chronic subdural hematoma in Japan: analysis of 63,358 cases recorded in a national administrative database

OBJECTIVE Aging of the population may lead to epidemiological changes with respect to chronic subdural hematoma (CSDH). The objectives of this study were to elucidate the current epidemiology and changing trends of CSDH in Japan. The authors analyzed patient information based on reports using a Japanese administrative database associated with the diagnosis procedure combination (DPC) system. METHODS This study included patients with newly diagnosed CSDH who were treated in hospitals participating in the DPC system. The authors collected data from the administrative database on the following clinical and demographic characteristics: patient age, sex, and level of consciousness on admission; treatment procedure; and outcome at discharge. RESULTS A total of 63,358 patients with newly diagnosed CSDH and treated in 1750 DPC participation hospitals were included in this study. Analysis according to patient age showed that the most common age range for these patients was the 9th decade of life (in their 80s). More than half of patients 70 years old or older presented with some kind of disturbance of consciousness. Functional outcomes at discharge were good in 71.6% (modified Rankin Scale [mRS] score 0-2) of cases and poor in 28.4% (mRS score 3-6). The percentage of poor outcomes tended to be higher in elderly patients. Approximately 40% of patients 90 years old or older could not be discharged to home. The overall recurrence rate for CSDH was 13.1%. CONCLUSIONS This study shows a chronological change in the age distribution of CSDH among Japanese patients, which may be affecting the prognosis of this condition. In the aging population of contemporary Japan, patients in their 80s were affected more often than patients in other age categories, and approximately 30% of patients with CSDH required some help at discharge. CSDH thus may no longer have as good a prognosis as had been thought.

Plaque Characteristics of Patients with Symptomatic Mild Carotid Artery Stenosis

BACKGROUND Carotid revascularization may be considered for severe stenosis, but its use for symptomatic mild stenosis (<50%) with vulnerable plaque or ulcer remains uncertain. The characteristics of patients with symptomatic mild stenosis who underwent revascularization are reviewed. METHODS The subjects of this study were 18 patients with symptomatic mild stenosis (<50%) on angiography from among 175 patients who underwent revascularization in our department. The plaques were evaluated by black-blood magnetic resonance imaging (BB-MRI) and ultrasonography (US) and classified into 2 types: type 1 (n = 15), a lesion with an ulcer or mobile plaque or thrombosis on angiography or US; and type 2 (n = 3), a lesion without any of the above. Fourteen patients underwent carotid endarterectomy (CEA), and 4 patients underwent carotid artery stenting. RESULTS The stenosis on angiography was 27.2% ± 10.7 (5%-41%), and the area carotid artery stenosis rate on US was 69.8 ± 14.5% (44.5%-97%). The stenosis rate of these 2 methods was not at all correlated. In type 1 plaque that underwent CEA, 10 of 11 patients had vulnerable plaque by histopathology, and 1 patient had thrombus on the plaque by operative findings. In type 2 plaque that underwent CEA, all patients had vulnerable plaque by histopathology. During the follow-up period, none of the patients had restenosis or stroke. CONCLUSIONS The findings of US and BB-MRI in patients with symptomatic mild stenosis (<50%) on angiography are important for determining treatment. If BB-MRI or US shows the findings of vulnerable plaque in mild stenosis, surgical treatment may be considered for these patients.

Utility of Indocyanine Green Video Angiography for Sylvian Fissure Dissection in Subarachnoid Hemorrhage Patients - Sylvian ICG Technique

Indocyanine green (ICG) emits fluorescence in the far-red domain under light excitation. ICG video angiography (ICG-VA) has been established as a useful method to evaluate blood flow in the operative field. We report the usefulness of ICG-VA for Sylvian fissure dissection in patients with subarachnoid hemorrhage (SAH). Subjects comprised 7 patients who underwent ICG-VA before opening the Sylvian fissure during neck clipping for ruptured cerebral aneurysm. We observed contrasted Sylvian veins before opening the Sylvian fissure using surgical microscopes. This procedure was termed “Sylvian ICG”. We observed ICG fluorescence quickly in all cases. Sylvian veins that appeared unclear in the standard microscopic operative field covered with subarachnoid hemorrhage were extremely clearly depicted. These Sylvian ICG findings were helpful in identifying entry points and the dissecting course of the Sylvian fissure. At the time of clipping, no residual fluorescence from Sylvian ICG was present, and aneurysm clipping was not impeded. Sylvian ICG for SAH patients is a novel technique to facilitate dissection of the Sylvian fissure. We believe that this technique will contribute to improved safety of clipping surgery for ruptured aneurysms.

Bamboo Leaf Sign as a Sensitive Magnetic Resonance Imaging Finding in Spinal Subependymoma: Case Report and Literature Review

Background and Importance. Subependymoma occurs very rarely in the spinal cord. We report another case of spinal subependymoma along with a review of the literature and discussion of a radiological finding that is useful for preoperative diagnosis of this tumor. Clinical Presentation. A 51-year-old man presented with a 2-year history of progressive muscle weakness in the right lower extremity. Sagittal magnetic resonance imaging (MRI) showed spinal cord expansion at the Th7–12 vertebral level. Surgical resection was performed and the tumor was found to involve predominantly subpial growth. Histological diagnosis was subependymoma, classified as Grade I according to criteria of World Health Organization. We made an important discovery of what seems to be a characteristic appearance for spinal subependymoma on sagittal MRI. Swelling of the spinal cord is extremely steep, providing unusually large fusiform dilatation resembling a bamboo leaf. We have termed this characteristic MRI appearance as the “bamboo leaf sign.” This characteristic was apparent in 76.2% of cases of spinal subependymoma for which MRI findings were reported. Conclusion. The bamboo leaf sign on spinal MRI is useful for differentiating between subependymoma and other intramedullary tumors. Neurosurgeons encountering the bamboo leaf sign on spinal MRI should consider the possibility of subependymoma.