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  • Author or Editor: Jun-ichiro Hamada x
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Jun-Ichiro Hamada, Nobuo Hashimoto and Tetsuya Tsukahara

✓ Two cases of moyamoya disease associated with repeated intraventricular hemorrhage are reported. The origin of bleeding was thought to be a distal aneurysm of the choroidal artery. The aneurysms were confirmed radiologically and histologically. The relationship between moyamoya disease and aneurysms is discussed, and a treatment proposed.

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Shinji Nagahiro, Jun-ichiro Hamada, Yuji Sakamoto and Yukitaka Ushio

✓ The authors assessed the reliability of magnetic resonance (MR) imaging contrast enhancement for the detection and follow-up evaluation of dissecting aneurysms of the vertebrobasilar circulation. Twenty consecutively admitted patients who underwent both gadolinium-enhanced MR imaging and conventional angiography were reviewed. Enhancement of the dissecting aneurysm was seen in all but one of the 20 patients, including 10 (71%) of 14 patients examined in the chronic phases, when the T1-hyperintensity signal that corresponded to the intramural hematoma was unrecognizable. The enhanced area corresponded to the “pearl sign” or aneurysm dilation noted on the comparable angiogram. On follow-up MR studies enhancement had spontaneously disappeared in four patients at a time when comparable vertebral angiograms revealed disappearance of the aneurysm dilation. The enhancement persisted in five of nine patients examined more than 24 weeks after symptom onset; in all five patients the aneurysm dilation remained on comparable angiograms. Dynamic MR studies showed rapid and remarkable enhancements with their peaks during the immediate dynamic phase after injection of the contrast material. The authors conclude that gadolinium-enhanced MR imaging is useful for the detection and follow-up evaluation of dissecting aneurysms of the vertebrobasilar circulation.

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Yutaka Hayashi, Masashi Kinoshita, Mitsutoshi Nakada and Jun-ichiro Hamada

Object

Disturbance of the arcuate fasciculus in the dominant hemisphere is thought to be associated with language-processing disorders, including conduction aphasia. Although the arcuate fasciculus can be visualized in vivo with diffusion tensor imaging (DTI) tractography, its involvement in functional processes associated with language has not been shown dynamically using DTI tractography. In the present study, to clarify the participation of the arcuate fasciculus in language functions, postoperative changes in the arcuate fasciculus detected by DTI tractography were evaluated chronologically in relation to postoperative changes in language function after brain tumor surgery.

Methods

Preoperative and postoperative arcuate fasciculus area and language function were examined in 7 right-handed patients with a brain tumor in the left hemisphere located in proximity to part of the arcuate fasciculus. The arcuate fasciculus was depicted, and its area was calculated using DTI tractography. Language functions were measured using the Western Aphasia Battery (WAB).

Results

After tumor resection, visualization of the arcuate fasciculus was increased in 5 of the 7 patients, and the total WAB score improved in 6 of the 7 patients. The relative ratio of postoperative visualized area of the arcuate fasciculus to preoperative visualized area of the arcuate fasciculus was increased in association with an improvement in postoperative language function (p = 0.0039).

Conclusions

The role of the left arcuate fasciculus in language functions can be evaluated chronologically in vivo by DTI tractography after brain tumor surgery. Because increased postoperative visualization of the fasciculus was significantly associated with postoperative improvement in language functions, the arcuate fasciculus may play an important role in language function, as previously thought. In addition, postoperative changes in the arcuate fasciculus detected by DTI tractography could represent a predicting factor for postoperative language-dependent functional outcomes in patients with brain tumor.

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Takashi Kamezawa, Jun-Ichiro Hamada, Masaki Niiro, Yutaka Kai, Koichi Ishimaru and Jun-ichi Kuratsu

Object. The authors reviewed angiograms obtained in patients with cavernous malformations to identify and characterize coexisting venous drainage.

Methods. Fifty-seven patients with cavernous malformations treated at the authors' institutions between 1994 and 2002 were classified into three groups according to the venous system adjacent to the malformation on angiography studies. In Group A patients (23 patients) the malformations had no venous drainage; in Group B patients (14 patients) the lesions were associated with typical venous malformations; and in Group C patients (20 patients) the lesions had atypical venous drainage (AVD). The risk of hemorrhage based on the type of associated venous drainage was analyzed, and the usefulness of magnetic resonance (MR) imaging compared with digital subtraction (DS) angiography in demonstrating associated AVD was determined.

Fifty-seven patients harbored 67 cavernous malformations: Group A patients had 29 cavernous malformations with no associated venous drainage; Group B patients had 17 lesions associated with venous malformations; and Group C patients harbored 21 lesions, 20 of which manifested AVD. Symptomatic hemorrhage was present in 10 (43.5%) of 23 Group A patients and in 28 (82.4%) of 34 Groups B and C patients. Although high-resolution MR imaging revealed the presence of associated venous malformations in 11 (78.6%) of 14 Group B patients, such studies demonstrated AVD in only two (10%) of 20 Group C patients.

Conclusions. Patients harboring cavernous malformations plus venous malformations or AVD are more likely to present with symptomatic hemorrhage than are patients with cavernous malformation alone. The actual incidence of associated venous drainage may be underestimated when MR imaging alone is used rather than combined with DS angiography.

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Jun-ichiro Hamada, Tatemi Todaka, Shigetoshi Yano, Yutaka Kai, Motohiro Morioka and Yukitaka Ushio

Object. In patients with aneurysms that require occlusion of the posterior inferior cerebellar artery (PICA), revascularization of this artery should be performed. A novel surgical method for revascularization of the PICA is presented.

Methods. After a segment of the superficial temporal artery (STA) was harvested, the aneurysm was treated by trapping, followed by placement of a vertebral artery (VA)—PICA bypass in which the STA segment was used as a graft. When the length of the proximal PICA was inadequate, the distal end of the STA was anastomosed to the proximal PICA in an end-to-side fashion. When the length of the proximal PICA was adequate, the STA was anastomosed to the proximal PICA in an end-to-end fashion. In either case, the proximal end of the STA was anastomosed to the VA in an end-to-side fashion. This procedure was used in nine patients whose aneurysms involved the PICA. Although partial lateral medullary syndrome developed in one of them, follow-up evaluation revealed graft patency in all patients. There were no instances of recurrent hemorrhage or ischemia.

Conclusions. Although this procedure requires harvesting of an STA graft and two anastomoses, it facilitates anterograde flow to the PICA territory. It also involves minimal mobilization of brainstem perforating vessels and the proximal PICA.

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Yutaka Kai, Jun-ichiro Hamada, Motohiro Morioka, Shigetoshi Yano, Kiyotoshi Hamasaki and Yukitaka Ushio

✓ Dissecting basilar artery (BA) aneurysms in patients presenting with subarachnoid hemorrhage are life threatening, especially in those who experience subsequent bleeding or progressive dissection, and immediate surgical or endovascular intervention may be necessary. The authors report on a 52-year-old woman whose dissecting BA aneurysm was treated successfully with proximal occlusion and flow reversal. Clipping of the proximal BA above the level of the anterior inferior cerebellar arteries facilitated retrograde flow from a radial artery graft placed between the left vertebral artery and the left posterior cerebral artery, thereby providing continuous perfusion of the BA and its branches. Postoperative angiograms obtained 1 year later revealed good retrograde flow through the BA and dilation of the radial arterial graft. There were no episodes of recurrent hemorrhage.

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Jun-ichiro Hamada, Isao Kitamura, Masahito Kurino, Nobuyuki Sueyoshi, Shozaburo Uemura and Yukitaka Ushio

✓ The case of a 64-year-old woman with multiple intracranial aneurysms and abnormal ophthalmic arteries arising from the bifurcation of the internal carotid artery is described. It is believed that this type of anomaly of the ophthalmic artery has not previously been reported. The neuroradiological and operative findings of this case are presented.

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Jun-Ichiro Hamada, Shinji Nagahiro, Chikara Mimata, Takayuki Kaku and Yukitaka Ushio

✓ Two techniques of revascularizing the posterior inferior cerebellar artery (PICA) during aneurysm surgery are presented. One involves transposition of the PICA to the vertebral artery proximal to the aneurysm using a superior temporal artery (STA) as a graft. This is used in cases in which the PICA has branched off from the wall of the giant vertebral artery aneurysm. The other technique involves end-to-end anastomosis of the PICA after excision of a giant distal PICA aneurysm located at the cranial loop near the roof of the fourth ventricle. The reconstructions of the PICA described here are surgical procedures designed to preserve normal blood flow in the PICA in patients treated for giant aneurysms involving that artery.

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Jun-ichiro Hamada, Yutaka Kai, Motohiro Morioka, Shigetoshi Yano, Tatemi Todaka and Yukitaka Ushio

Object. The goal of this study was to implement an algorithm for and assess the multimodal (endovascular and microsurgical) treatment of patients with ruptured dissecting aneurysms of the vertebral artery (VA) during the acute stage.

Methods. During a 4-year period, the authors treated 19 ruptured dissecting aneurysms of the VA during the acute stage, within 3 days after the hemorrhage. Factors guiding management decisions were tolerance of the test occlusion and the site of the dissection. The algorithm takes into account these factors to select among treatment options, that is, trapping of the VA with Guglielmi Detachable Coils (GDCs); trapping of the VA and revascularization of the posterior inferior cerebellar artery (PICA); trapping of the VA and VA—posterior cerebral artery (PCA) anastomosis; and trapping of the VA, VA—PCA anastomosis, and revascularization of the PICA. Of the 15 aneurysms without PICA involvement, 14 were treated by trapping of the VA with GDCs and one by trapping of the VA and a VA—PCA bypass. The other four aneurysms with PICA involvement were treated by VA trapping and PICA revascularization. There was no episode of recurrent hemorrhage or ischemia during the posttreatment follow-up period. Although lateral medullary syndrome developed as a permanent complication in one patient, a good recovery was made by the other 18 patients by 6 months after the ictus.

Conclusions. The factors that determine the appropriate treatment for ruptured dissecting aneurysms of the VA are tolerance of a test occlusion and the site of dissection. Favorable patient outcomes can be achieved when this algorithm is used.