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Kiyohiro Houkin, Hiroshi Abe, Tetsuyuki Yoshimoto, and Akihiro Takahashi

✓ Whether a diagnosis of moyamoya disease is justified in patients with typical angiographic evidence of moyamoya disease unilaterally and normal angiographic findings contralaterally remains controversial. In this study the authors analyzed longitudinal angiographic change, familial occurrence, and basic fibroblast growth factor (bFGF) concentration in the cerebrospinal fluid (CSF) of patients with “unilateral” moyamoya disease. Over a 10-year period, 10 cases of unilateral moyamoya disease were followed using conventional angiography or magnetic resonance angiography. Basic FGF in CSF, obtained from the subarachnoid space of the cerebral cortex during revascularization surgery, was measured in five cases. Among the 10 cases of unilateral moyamoya disease, only one pediatric case showed obvious signs of progression to typical bilateral disease. The other nine cases (including six adults and three children) remained stable throughout follow-up radiological examinations (magnetic resonance angiography) with a mean observation period of 3.5 years. There was no familial occurrence in these cases of unilateral moyamoya disease. Levels of bFGF, which are high in typical moyamoya disease, were low in these patients. The progression from unilateral moyamoya disease to the typical bilateral form of the disease appears to be infrequent. The low levels of bFGF in the CSF of these patients and the lack of familial occurrence strongly suggest that most cases of unilateral moyamoya disease, especially those found in adults, are distinct from typical bilateral moyamoya disease.

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Hiroshi Takahashi, Shozo Nakazawa, and Toshiro Shimura

✓ Total excision is the treatment of choice in preventing the relapse of craniopharyngioma, but for tumors involving an extensive area, it is often associated with increased risks of complications. The efficacy of postoperative radiotherapy has not yet been established. The authors have performed minimal tumor excision followed by intensive injection of bleomycin into the remaining tumor as postoperative adjuvant therapy in seven children with craniopharyngioma. Long-term outcome in the children with cystic-type tumors containing little or no solid tissue has proven the regimen to be more advantageous than total excision.

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Experimental spinal cord injury produced by slow, graded compression

Alterations of cortical and spinal evoked potentials

Johannes Schramm, Keizo Hashizume, Takanori Fukushima, and Hiroshi Takahashi

✓ A new model of experimental spinal cord injury produced by slow, graded compression in cats is described. The extent of cord compression was evaluated by monitoring somatosensory evoked potentials (SEP's). The compression was exerted by means of a special screw-plate assembly with stepwise advancement of the compression plate at different time intervals and was completed when cortical SEP had disappeared. Every stage in the total course of gradual compression was expressed as a percentage of the total. Cortical and spinal SEP's were recorded at each increment. The SEP pattern was analyzed in terms of latency, amplitude, and wave form. It was noteworthy that SEP's were remarkably resistant to gradual compression. The amplitude of cortical SEP's began decreasing at a late stage of compression, usually at about 80% of total compression, and that of spinal SEP's some time earlier, at about 60% of total compression. They both then rapidly fell to zero. Cortical SEP's showed a slight increase in latency concurrent with the reduction of amplitude, while the latency of spinal SEP's was constant. Mid-thoracic SEP's showed considerable individual variation in wave form. Their changes were similar to those of cortical SEP. Thoracolumbar SEP's, recorded immediately rostral to the compression, showed little individual variation, and did not show flat recordings even with maximum compression. A small monophasic positive wave was present in all animals even after the cortical SEP's became flat. This “final potential” was assumed to be caused by electrotonic volume conduction from the activities of the dorsal white matter caudal to the compression site. The reversibility of SEP's after the release of compression was remarkable. Both cortical and spinal SEP's could show complete recovery even when histological examination demonstrated hemorrhagic necrosis. The present data show no linear correlation between SEP changes and degree of compression. There are no changes with slight or moderate degree of compression. Alterations of SEP's in slow compression models should suggest the presence of a severe degree of compression.

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Hiroshi Takahashi, Shinya Manaka, and Keiji Sano

✓ A high potassium concentration ([K+]o) in brain tissue impedes neuronal activity, as observed in spreading cortical depression. Experimental studies were performed on mice and rats to determine the role of changes of [K+]o in cerebral concussion. In the first experiment, a 600 gm-cm impact was delivered to the vertex of the mouse skull. This impact induced arrest of spontaneous movement for 465 ± 55.9 seconds (mean ± SD), accompanied by apnea, bradycardia, and low-voltage electroencephalographic recordings (EEG). The injury was also frequently followed immediately by epilepsy. This impact induced an increase of cortical [K+]o from the control level of 4.1 ± 1.8 mM to 20–30 mM, with gradual recovery within 30 minutes to the control level.

In the second experiment, an impact of 9000 gm-cm was delivered to the midline parieto-occipital area of the rat and produced concussion-like phenomena similar to those elicited in mice. This level of trauma induced a significant increase of cortical [K+]o from the control level of 4.2 ± 0.8 mM to 20–50 mM in all of the rats, and also a significant increase of brain-stem [K+]o from 3.9 ± 0.6 to 20–30 mM in 73% of the rats. In these latter rats, the impact also induced apnea and a transient elevation of blood pressure, and resulted in low-voltage EEG recordings. In 23% of the rats in which [K+]o changes in the brain stem were not significant, the impact caused a transient reduction of blood pressure. The present study disclosed that an increase of [K+]o in the cerebral cortex and also in the brain stem is an important element in the phenomenon of concussion.

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Phyo Kim, Buichi Ishijima, Hiroshi Takahashi, Hiroyuki Shimizu, and Masayuki Yokochi

✓ The case is reported of a patient with progressive left hemiparesis due to vascular compression of the medulla oblongata. Metrizamide computerized tomography cisternography revealed that the left vertebral artery was compressing and distorting the left lateral surface of the medulla. Compression was surgically relieved and symptoms improved postoperatively. Neurological and symptomatic considerations are discussed in relation to the topographical anatomy of the lateral corticospinal tract.

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Michihiro Kohno, Hiroshi Takahashi, Katsuhisa Ide, Buichi Ishijima, Katsuhiro Yamada, and Shigeru Nemoto

✓ A 51-year-old man presenting with radiculopathy with a rare cervical dural arteriovenous fistula (AVF) is reported. Angiography revealed that the cervical dural AVF was fed mainly by the left C-3 and C-4 radicular arteries and drained into the internal vertebral venous plexus with no communication with intradural structures. The dural AVF was treated surgically after embolization therapy. Although the AVF showed mass effect on computerized tomography (CT) scanning, abnormal vessels, which were suspected to drain the AVF, were observed intraoperatively to compress the left C-4 and C-5 nerve root sleeves. After resection of these abnormal epidural vessels, monoparesis of the left proximal upper extremity was markedly improved. In this patient, dynamic CT scanning was useful in the initial diagnosis, and the preoperative embolization therapy was very effective.

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Tohru Terao, Hiroshi Takahashi, Fusako Yokochi, Makoto Taniguchi, Ryouichi Okiyama, and Ikuma Hamada

Object. Small, asymptomatic hemorrhages are easier to detect during stereotactic surgery when magnetic resonance (MR) imaging is used for targeting rather than when traditional approaches, such as ventriculography, are performed with contrast material. In the present study the authors examined the actual incidence of intraoperative hemorrhages in patients with movement disorders who had undergone MR imaging—targeted surgery, microelectrode recording (MER)-guided implantation of deep brain stimulation (DBS) electrodes, or radiofrequency-induced coagulation surgery performed.

Methods. Ninety-six consecutive patients underwent a total of 116 stereotactic operations for movement disorders (57 operations for radiofrequency-induced coagulation and 59 for DBS electrode implantation) between January 1998 and November 2002. The authors investigated the correlation between hemorrhages and other factors including the location of the hemorrhage and the type of surgery performed.

Postoperative computerized tomography scans demonstrated the occurrence of intraoperative hemorrhages at 12 locations during 11 procedures (9.5% of all procedures). Nine hemorrhages occurred during 57 coagulation operations (15.8%). Within this group, the frequency of hemorrhages was highest during thalamotomy (five [21.7%] of 23 procedures) and lower during pallidotomy (four [11.8%] of 34 procedures). In contrast, only two intraventricular hemorrhages developed during 59 operations in which DBS electrodes were implanted (3.4%). In no case was hemorrhage detected in the main DBS target, that is, the subthalamic nucleus.

Conclusions. When small, asymptomatic hemorrhages were included in the estimation, the actual rate of hemorrhage was higher than that previously reported. Judging from the incidence of hemorrhage during coagulation and DBS surgeries, the authors suggest that the heat induced by coagulation may play a larger role than microelectrode penetration in the development of hemorrhage.

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Shigeru Hoshino, Hiroshi Takahashi, Toshiro Shimura, Shozo Nakazawa, Zenya Naito, and Goro Asano

✓ The case of a 5-month-old boy with a left retromastoid melanotic neuroectodermal tumor of infancy is presented. The tumor extended from the subcutaneous tissue of the occiput to the cerebellar hemisphere. Histologically, the epidural part of the tumor was composed of undifferentiated neuroblasts, dense connective tissue, and glandular structures lined by melanin-containing cuboidal cells, whereas the subdural part contained differentiated neuroblasts and melanin-containing cells. The preoperative high serum levels of adrenaline, noradrenaline, vanillylmandelic acid, and neuron-specific enolase returned to normal after two operations and two cycles of chemotherapy; however, the dopamine level was mildly elevated. These data and immunohistochemical and ultrastructural findings strongly suggest that melanotic neuroectodermal tumor of infancy is derived from the neural crest.

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Hiroshi Takahashi, Akira Sasaki, Toshimoto Arai, Yasushi Tsukamoto, Osamu Sato, and Keiji Sano

✓ This paper reports the first case of chromoblastomycosis affecting the cisterna magna and the spinal subarachnoid space. Suboccipital craniectomy and laminectomy of T-8, 9, and 10 revealed arachnoiditis and multiple granulomas caused by Hormodendrum pedrosi.