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Ichiro Nakahara

ichiro@mub.biglobe.ne.jp

Journal articles

2007
 
DOI   
PMID 
M M Taha, I Nakahara, T Higashi, Y Iwamuro, Y Watanabe, W Taki (2007)  Percutaneous angioplasty and stenting of subclavian arteries before surgical coronary revascularization in a patient with an aberrant right subclavian artery.   J Neuroradiol 34: 4. 267-271 Oct  
Abstract: An aberrant right subclavian artery occurs in less than 2% of the population. An associated stenosis of the subclavian artery carries a risk of subclavian-coronary steal in patients who undergo coronary revascularization. We report on the case of a 54-year-old man admitted to our hospital for a coronary artery bypass graft (CABG). Angiographic examination revealed bilateral subclavian-artery stenosis with an aberrant right subclavian artery, anomalous origin of the right vertebral artery from the right common carotid artery, and left vertebral-artery occlusion. The patient underwent successful bilateral subclavian angioplasty and stenting.
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2006
 
DOI   
PMID 
Yasushi Iwamuro, Ichiro Nakahara, Toshio Higashi, Mitsutoshi Iwaasa, Yoshihiko Watanabe, Eishu Hirata, Kenzo Tsunetoshi, Mahmoud Taha (2006)  Tentorial dural arteriovenous fistula presenting symptoms due to mass effect on the dilated draining vein: case report.   Surg Neurol 65: 5. 511-515 May  
Abstract: BACKGROUND: Tentorial dural arteriovenous fistula (AVF) presented symptoms due to mass effect on the dilated draining vein. We report a patient presenting left hemisensory disturbance because of compression of the midbrain by a dilated draining vein of the AVF. The AVF has disappeared completely by drainer clipping after feeder embolization. CASE DESCRIPTION: A 66-year-old woman presented with left hemisensory disturbance due to compression of the midbrain by a dilated draining vein with tentorial dural AVF. On admission, she complained of left hemisensory disturbance. Enhanced computed tomography (CT), magnetic resonance imaging, and magnetic resonance angiogram revealed the midbrain compressed by a mass lesion, which was a draining vein with AVF fed by numerous feeding arteries neighboring the right tentorial edge. The single-photon emission CT (SPECT) did not depict any laterality. CONCLUSION: This is a rare case of a tentorial dural AVF which caused left hemisensory disturbance not by venous congestion, but by a compression of the midbrain by the dilated draining vein, because SPECT showed no laterality. In this case, magnetic resonance angiogram, 3-dimensional CT angiography, and SPECT were useful in the diagnosis and planning the strategy for treatment.
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DOI   
PMID 
Mahmoud M Taha, Ichiro Nakahara, Toshio Higashi, Yasushi Iwamuro, Mitsutoshi Iwaasa, Yoshihiko Watanabe, Kenzo Tsunetoshi, Toshihiro Munemitsu (2006)  Endovascular embolization vs surgical clipping in treatment of cerebral aneurysms: morbidity and mortality with short-term outcome.   Surg Neurol 66: 3. 277-84; discussion 284 Sep  
Abstract: BACKGROUND: Endovascular embolization of cerebral aneurysms has evolved rapidly worldwide within the last years, and has gained more popularity at the expense of surgical clipping; however, both regimens have inherent risks. This study was undertaken to asses the cerebral complications associated with both modalities of cerebral aneurysm treatment. METHODS: We retrospectively reviewed the charts, operative and embolization reports, and imaging of patients who underwent surgical clipping or embolization for cerebral aneurysms at our institution between October 2001 and October 2004. Patients were divided into 2 groups: group A, patients who had confirmed subarachnoid hemorrhage; group B, patients with unruptured cerebral aneurysms. Patients belonging to group A were evaluated according to the Hunt and Hess scale with their computed tomography scan evaluated according to Fisher scale. Short-term outcome was measured with Glasgow Outcome Scale for both groups. RESULTS: One hundred thirty-three patients with 168 aneurysms were treated; 95 (71.4%) were women and 38 (28.6%) men; mean age was 60.28 years. Hypertension (29.6%) was the most commonly encountered risk factor; average size of aneurysms treated was 7.21 mm; 53 patients belonged to group A. Seven patients were Hunt and Hess grade I, 23 grade II, 11 grade III, 7 grade IV, and 5 grade V. Eighty patients belonged to group B; for both groups, the periprocedural technical complication rate associated with coiling was 8.4% vs 19.35% with clipping. Follow-up angiographic results were better with clipping, as total aneurysm occlusion was 81.4% vs 57.5% with coiling. In group A, the incidence of angiographic vasospasm was 17.4% vs 45.4% with coiling vs clipping, whereas the incidence of shunt-dependant hydrocephalus was comparable with embolization and clipping. In group A, excellent outcome was achieved in 62% vs 44% (endovascular vs surgical) of subgroups, whereas in group B, it was 93% vs 81%, respectively. CONCLUSION: With rapidly evolving technology of endovascular embolization, accumulated experience, and good selection of patients with optimum angioanatomical criteria and endovascular accessibility, our results of morbidity and mortality associated with both modalities of cerebral aneurysm treatment with short-term outcome show that endovascular embolization of cerebral aneurysms is a safe alternative to surgical clipping in the treatment of both ruptured and unruptured cerebral aneurysms; however, long-term outcome needs to be evaluated.
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DOI   
PMID 
Ichiro Nakahara, Mahmoud M Taha, Toshio Higashi, Yasushi Iwamuro, Mitsutoshi Iwaasa, Yoshihiko Watanabe, Kenzo Tsunetoshi, Toshihiro Munemitsu (2006)  Different modalities of treatment of intracranial mycotic aneurysms: Report of 4 cases.   Surg Neurol 66: 4. 405-9; discussion 409-10 Oct  
Abstract: BACKGROUND: Intracranial mycotic aneurysms, although rare neurovascular pathology, represented a neurosurgical challenge that required careful stepwise decision making. Different approaches for their management were used. We present our experience with 4 patients treated in terms of indications and efficacy of different treatment modalities. METHODS: Four patients with infective endocarditis and 5 intracranial mycotic aneurysms were treated during the last 5 years. All of the patients were men; their ages ranged between 29 and 62 years (mean, 47.3 years). Distal MCA was the commonest site (3 patients) of aneurysm, 1 was located at the distal PCA, whereas the remaining aneurysm was at the distal ACA. Angiographic studies were done in 2 patients because of neurologic signs and for screening in 2 patients with documented endocarditis. RESULTS: One patient was treated conservatively because of his moribund general condition; 1 patient was treated with direct surgical clipping; 1 patient was treated with surgical trapping and resection of the aneurysm without revascularization; and the remaining patient, harboring 2 distal mycotic aneurysms, was treated with selective embolization for his PCA aneurysm and endovascular trapping for the distal ACA aneurysm. Follow-up angiographic results showed stable occlusion of the aneurysms. No periprocedural technical complications were reported, and none of the patients, including the patient with medical treatment only, has ever experienced new neurologic events after definitive treatment. CONCLUSIONS: Prolonged courses of antibiotics are recommended for all patients with mycotic aneurysms. Selective endovascular embolization or trapping with soft and ultrasoft electrolytically detachable coils seems to be an effective technique that should be considered for treatment of dynamic unruptured mycotic aneurysms, with conventional surgical repair restricted for ruptured aneurysms with associated hematoma and high intracranial pressure.
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PMID 
Yasuhiko Akiyama, Masahito Tanaka, Junya Hayashi, Motoaki Fujimoto, Kei Harada, Ichiro Nakahara, Yoshinori Taniwaki (2006)  Internal carotid artery obstruction derived from persistent arterial wall dissection associated with old trivial trauma.   Neurol Med Chir (Tokyo) 46: 8. 395-397 Aug  
Abstract: A 59-year-old man presented with acute onset of visual loss in his right eye. He was treated under a diagnosis of retinal artery thrombosis. Ultrasonography revealed obstruction of the ipsilateral internal carotid artery (ICA). He had no risk factor for stroke and he denied any history of trauma. Follow-up ultrasonography obtained 6 months later showed spontaneous ICA recanalization. Cerebral angiography demonstrated an arterial wall flap suggesting ICA dissection at the craniocervical junction. He then remembered suffering hemicranial headache and Horner's sign of several days' duration after jumping off a stepladder 1 year earlier. The present case is quite unusual in that persistent carotid arterial wall dissection was thought to proceed to ICA obstruction and manifested as retinal ischemia after a long asymptomatic period.
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2005
 
PMID 
Yasushi Iwamuro, Ichiro Nakahara, Masato Tanaka, Toshio Higashi, Yoshihiko Watanabe, Kei Harada, Motoaki Fujimoto, Takayuki Oku (2005)  Occlusion of the vertebral artery secondary to dissection of the subclavian artery--case report.   Neurol Med Chir (Tokyo) 45: 2. 97-99 Feb  
Abstract: A 34-year-old man presented with occlusion of the left vertebral artery (VA) secondary to dissection of the left subclavian artery manifesting as vertigo, nausea, vomiting, and neck pain. On admission, he was alert with left limb and truncal ataxia. Magnetic resonance (MR) imaging and MR angiography showed left cerebellar infarction and occlusion of the left VA. Conventional angiography and three-dimensional computed tomography (3D-CT) angiography showed stenosis with thrombosed pseudo-lumen of the left subclavian artery, and occlusion of the left VA. Presumably the idiopathic dissection of the left subclavian artery had reached the orifice of the left VA, and an embolism from the dissection had caused occlusion of the VA, leading to cerebellar infarction. After one month, he was discharged without severe neurological deficits. Idiopathic dissection of the subclavian artery is very rare. 3D-CT angiography is very useful for the diagnosis of arterial dissection.
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2004
 
PMID 
Motoaki Fujimoto, Ichiro Nakahara, Masato Tanaka, Yasushi Iwamuro, Yoshihiko Watanabe, Kei Harada (2004)  Multiple intracranial aneurysms and vascular abnormalities associated with neurofibromatosis type 1: a case report   No Shinkei Geka 32: 4. 355-359 Apr  
Abstract: We present an unusual case of multiple intracranial aneurysms, persistent primitive trigeminal artery (PPTA), and fenestration of the middle cerebral artery (MCA), associated with type 1 neurofibromatosis (NF 1). The patient was a 55-year-old woman in a state of semicoma. We observed widespread neurofibromas and café au lait spots on her trunk and limbs. Computed tomography (CT) scan revealed diffuse subarachnoid hemorrhage and right frontal intracerebral hemorrhage (WFNS grade IV, Fisher's classification group 4). Cerebral angiography showed two intracranial aneurysms at the anterior communicating artery, an aneurysm at the cavernous portion of the right carotid artery, a PPTA, and MCA fenestration. The patient remained in an apallic state, even after successful clipping of the anterior communicating artery aneurysms.
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PMID 
Kei Harada, Ichiro Nakahara, Masato Tanaka, Yasushi Iwamuro, Yoshihiko Watanabe, Motoaki Fujimoto (2004)  Comparison of the findings of multislice CT and angiography after stenting for supraaortic arteries   No Shinkei Geka 32: 1. 29-35 Jan  
Abstract: We compared the findings of multislice computed tomography (MSCT) with angiography after stenting for supraaortic arteries. Twelve cases that underwent both MSCT and angiography were evaluated. In 4 cases, stenotic findings were shown by neither MSCT nor angiography. Lumen diameters measured by MSCT tended to be shorter than those measured by angiography. In-stent stenosis evaluated by MSCT was found in 6 cases, and all of them revealed low density areas in the inner stent lumen. In 4 of them, intimal hyperplasia was indicated by angiography, but in 2 of them, unexpectedly, no stenotic findings were found by angiography. In one case, using MSCT the part two stents partially lying over one another revealed severe artifact in the inner stent lumen, but no stenosis was found by angiography. In 2 cases, unevenly spread extra-stent space was found, but that was not revealed by angiography. We conclude that MSCT is useful to evaluate lumen diameter, in-stent intimal hyperplasia, in-stent thrombus, and extra-stent space.
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PMID 
Kei Harada, Ichiro Nakahara, Masato Tanaka, Yasushi Iwamuro, Yoshihiko Watanabe, Motoaki Fujimoto (2004)  Therapeutic strategy and outcome of stenting for subclavian and innominate artery occlusive disease   No Shinkei Geka 32: 2. 151-158 Feb  
Abstract: We performed stenting for the subclavian artery (SA) and innominate artery occlusive disease in 14 patients between April, 2000 and March, 2003. In 13 of 14 patients, good dilatation was obtained with stenting. In one patient with left SA occlusion, true lumen could not be detained from either proximal or distal sides of the occluded lesion, so stent deployment was not performed. From June, 2002, we performed stenting using combined femoral and brachial approaches in 6 of 8 patients. In patients in whom occlusive lesion existed in the proximal portion of the SA, it was useful strategy to create a "pull-through" system to stabilize the guiding catheter position in the aorta or the proximal portion of the SA, and to protect the vertebral artery (VA) with a balloon catheter. Post-operative morbidity was 0%. Restenosis was manifested in one patient (8%) two years after stent placement, and in-stent PTA was carried out. In stenting for the subclavian and innominate arteries, the pull-through system is considered useful for stabilization of the guiding catheter, and protection of the VA for prevention of distal embolism to the VA.
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2003
2002
 
PMID 
Keiji Sugimoto, Ichiro Nakahara, Michio Nishikawa (2002)  Bilateral metachronous germinoma of the basal ganglia occurring long after total removal of a mature pineal teratoma: case report.   Neurosurgery 50: 3. 613-6; discussion 616-7 Mar  
Abstract: OBJECTIVE AND IMPORTANCE: We report the extremely rare occurrence of a second germ cell tumor at a different site and with different histological types long after total removal of a mature pineal teratoma. CLINICAL PRESENTATION: A 10-year-old boy who presented with headache and vomiting was admitted to our hospital. Neuroradiological studies revealed a tumor in the pineal region. The tumor was totally removed. Histologically, the tumor proved to be a mature teratoma. The patient's postoperative course was uneventful. The patient received no adjuvant therapy and was followed in the outpatient clinic. Three years later, he was readmitted with transient left upper limb weakness and vomiting. Neuroradiological studies showed a tumor in the bilateral basal ganglia. INTERVENTION: The second tumor, which was located in the right basal ganglion, was partially removed for biopsy. Histologically, the tumor proved to be a germinoma. The patient received three cycles of combination chemotherapy consisting of carboplatin and etoposide with radiotherapy. After the second course of chemotherapy, magnetic resonance imaging studies revealed no evidence of the tumor. CONCLUSION: The second tumor was considered to be a de novo metachronous neoplasm rather than a recurrence of the original mature teratoma. We think that if primordial germ cell groups exist along the midline of the brain, more than two primordial germ cell groups could give rise to metachronous neoplasms at different sites and with different histological types.
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2001
 
PMID 
K Sugimoto, I Nakahara, M Nishikawa, M Tanaka, T Terashima, H Yanagihara, J Hayashi (2001)  Osteoma originating in the dura: a case report   No Shinkei Geka 29: 10. 993-996 Oct  
Abstract: We report a case of intracranial osteoma attached to the dura. The patient, a 35-year-old man, had suffered several episodes of vertigo over the previous two years. Physical and neurological findings on admission were unremarkable. A plain craniogram showed a dense calcified mass in the right frontal area, and CT revealed a homogeneous high-density mass without significant enhancement. MRI confirmed the dural origin of the lesion, which showed hyperintensity in the T1-weighted image and low intensity in the T2-weighted image. The mass was 5 cm in diameter and 2 cm in thickness. Total resection was performed under a preoperative diagnosis of calcified meningioma. Histopathology revealed the mass to be an osteoma. Osteomas are common benign bone tumors that usually arise from long bones of the extremities. Intracranial osteomas are extremely rare lesions. The literature on intracranial osteoma of dural origin is reviewed.
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2000
 
PMID 
A Morizane, N Sakai, I Nagata, I Nakahara, H Sakai, H Kikuchi (2000)  Combined endovascular stent implantation and coil embolization for the treatment of a vertebro-basilar fusiform aneurysm: technical case report   No Shinkei Geka 28: 9. 811-816 Sep  
Abstract: We describe a case of the combined application of endovascular stent implantation and Guglielmi detachable coil packing for the treatment of a vertebro-basilar fusiform aneurysm and review the literature on stent placement to treat cerebral aneurysms. A 70-year-old female presented with an acute headache from subarachnoid hemorrhage. A fusiform aneurysm with a broad-based neck and dome, measuring 15 mm, involving the union of the vertebral arteries and the proximal basilar artery was demonstrated on cerebral angiography. The aneurysm was judged to be inoperable and treated conservatively. Twelve days later the patient was transferred to our hospital for endovascular therapy. An intravascular stent (MultiLink) was placed across the base of the aneurysm through the right vertebral artery. After this, coil placement in the aneurysm around the stent was performed via a microcatheter guided from the left vertebral artery. After that a microcatheter was guided from the right vertebral artery through the interstices of the stent into the aneurysm, and additional coils were placed. Final angiography showed subtotal occlusion of the aneurysm and excellent blood flow of the parent artery through the stent. There were no new neurological deficits. Neither rerupture nor ischemic event has occurred. The use of stents provides another treatment for managing the difficult entity of intracranial aneurysms.
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1999
 
PMID 
I Nakahara, W Taki, H Kikuchi, N Sakai, F Isaka, H Oowaki, A Kondo, K Iwasaki, S Nishi (1999)  Endovascular treatment of aneurysms on the feeding arteries of intracranial arteriovenous malformations.   Neuroradiology 41: 1. 60-66 Jan  
Abstract: The association between intracranial aneurysms and arteriovenous malformations (AVMs) is well documented. Recent advances in the understanding of the haemodynamics of this association encourage an aggressive approach to these aneurysms. However, the pathophysiology of these aneurysms is not fully understood and a strategy for their management has not been established. We describe seven patients, with eight aneurysms, on the feeding arteries of AVMs. The aneurysms could be divided into those located 1. proximally on the superficial feeding artery (type I; 4 aneurysms); 2. distally on the superficial feeding artery (type II; 3 aneurysms); and 3. on the deep feeding artery (type III; 1 aneurysm). All aneurysms were treated by the endovascular procedure prior to, or simultaneously with, treatment of the AVM, using detachable coils or liquid embolic material. All aneurysms were obliterated successfully, with no adverse events. Each patient further received treatment of the AVM. None of the patients suffered intracranial haemorrhage after treatment for the aneurysms. Based on our experiences, we discuss the indications for this approach for each type of aneurysm. We believe endovascular treatment could be an important alternative for treatment of aneurysms associated with AVMs, thus reducing the risk of haemorrhage.
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PMID 
M Sawada, H Yanamoto, I Nagata, N Hashimoto, I Nakahara, Y Akiyama, H Kikuchi, R L Macdonald (1999)  Prevention of neointimal formation by a serine protease inhibitor, FUT-175, after carotid balloon injury in rats.   Stroke 30: 3. 644-650 Mar  
Abstract: BACKGROUND AND PURPOSE: In vivo and vitro studies revealed the activation of thrombin and the complement system in vascular lesion formation during the process of atherosclerosis, along with pathological proliferation of smooth muscle cells. We examined the effect of the synthetic serine protease inhibitor FUT-175 (developed as a potent inhibitor of thrombin and the complement system) on vascular lesions using balloon dilatation-induced neointimal formation in the carotid artery of rats. METHODS: Sprague-Dawley (SD) rats underwent balloon dilatation injury of the left carotid artery to induce neointimal formation. Three groups of these rats (n=8, each) were treated with daily intraperitoneal injections of 1 of the following doses of FUT-175: 0.5, 1.0, or 2.0 mg/d in 1 mL of saline for 7 consecutive days. The control group (n=8) was similarly treated with 1 mL of saline for 7 days. The injections were started immediately after balloon injury. Two weeks after the injury, the left carotid arteries were perfusion-fixed, and the areas of the neointimal and medial layer were analyzed under a microscope. RESULTS: A morphometric analysis revealed that there were significant differences in the intima-media ratio between the 4 groups treated with vehicle (saline) or a low, medium, or high dose of FUT-175 (1.45+/-0.11, 1.08+/-0.06, 0.71+/-0.04, or 0.32+/-0.04, respectively). This suppression was achieved in a dose-dependent manner by the administration of FUT-175 after balloon injury. In the histological study, it was demonstrated that FUT-175 suppresses the production of platelet-derived growth factor (PDGF)-BB in the neointima and the medial smooth muscle cell layer. CONCLUSIONS: After balloon injury activated proteases that were inhibited by FUT-175 were demonstrated to have an essential role in the development of the pathological thickening of the arterial wall.
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PMID 
S Miyamoto, I Nagata, K Yamada, Y Ueno, I Nakahara, H Toda, I Hattori, H Kikuchi (1999)  Delayed thrombus propagation after parent artery clipping for giant fusiform aneurysms of the circle of Willis.   Surg Neurol 51: 1. 89-93 Jan  
Abstract: BACKGROUND: Obliteration of a giant fusiform aneurysm without significant therapeutic morbidity is extremely difficult. Ischemic complications have been often reported. METHODS: Two patients with giant fusiform aneurysms of the circle of Willis are presented. Both patients underwent proximal parent artery clipping after a bypass procedure. Balloon occlusion tests confirmed both patients' ability to tolerate flow reduction after proximal clipping. RESULTS: Although both patients awoke from anesthesia without neurologic deficit, they developed contralateral hemiparesis several hours after the operation as a result of a small infarct in the basal ganglia. These ischemic events might be attributed to the delayed thrombosis involving the orifice of the distal perforating arteries. CONCLUSIONS: In the treatment for giant fusiform aneurysms of the circle of Willis, special attention should be paid not only to flow reduction, but also to delayed thrombus propagation that may not be predicted by preoperative balloon occlusion testing.
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PMID 
A Morizane, I Nakahara, N Sakai, H Yanamoto, Y Akiyama, H Sakai, T Higashi, S Namura, J Takahashi, J Nishizaki, J Kokuzawa, H Manaka, N Hayashi, I Nagata, H Kikuchi (1999)  Endovascular surgery for untreated ruptured aneurysm with symptomatic vasospasm   No Shinkei Geka 27: 10. 941-946 Oct  
Abstract: It is difficult to treat ruptured aneurysms with symptomatic vasospasm. Although direct surgery for such cases is associated with poor outcomes, conservative therapy has the risk of both rerupture and infarction. In two cases of ruptured aneurysms with symptomatic vasospasm, we performed aneurysmal coil embolization with Guglielmi electrodetatchable coils (GDC). At the same time we performed percutaneous transluminal angioplasty (PTA) with papaverine infusion. In both cases, rerupture did not occur and PTA was effective angiographically. A good outcome was achieved in case 1. However, broad cerebral infarction occurred in case 2, in which the patient had shown severe symptomatic vasospasm on admission. In advanced cases, such as in case 2, the outcome is poor. The aneurysm may not be able to be approached before PTA because of severe vasospasm. In such cases, PTA must be performed carefully to avoid aneurysmal rerupture. Intraarterial papaverine infusion is safer than PTA for severe spasm in distal vessels. However the efficacy of papaverine is known to be transient in many cases. It is often difficult to determine the exact relationship between branches and the aneurysm in the presence of vasospasm. In such cases, we recommend that the rupture point be packed and that the aneurysmal neck remain unpacked. After vasospasm is cured and good general condition has been recovered, direct surgery can be performed. In summary, endovascular surgery is an effective option for treatment of ruptured aneurysm with symptomatic vasospasm.
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PMID 
H Yanamoto, I Nagata, I Nakahara, N Tohnai, Z Zhang, H Kikuchi (1999)  Combination of intraischemic and postischemic hypothermia provides potent and persistent neuroprotection against temporary focal ischemia in rats.   Stroke 30: 12. 2720-6; discussion 2726 Dec  
Abstract: BACKGROUND AND PURPOSE: It is not known whether a combination of intraischemic and postischemic mild hypothermia provides extra neuroprotection and if so, whether the neuroprotection is persistent. METHODS: Sixty-eight Sprague-Dawley rats were used. In group 1, ischemia and reperfusion were performed under normothermic (N) conditions (control, N-N). In group 2, ischemia was induced and maintained under hypothermic conditions (33 degrees C for 2 hours) and reperfusion was performed under normothermic conditions, H-N. In group 3, both ischemia and reperfusion were performed under hypothermic conditions for an additional 21 hours after the surgery, H-22H. In group 4, ischemia was induced and maintained under hypothermic conditions and reperfusion was performed under hypothermic conditions only for the initial 3 hours (H-3H). In group 5, ischemia was induced and maintained under normothermic conditions and reperfusion was performed under hypothermic conditions (33 degrees C) (N-22H). All rats were perfused 48 hours after the induction of ischemia. In addition, the normothermic or hypothermic therapy used for groups 1, 3, and 4 was performed again, and these rats were killed 30 days after the induction of ischemia. Furthermore, neurological deficits were monitored in groups N-N and H-22H for 4 weeks. RESULTS: In the H-3H and H-22H groups, the total infarct volume was significantly reduced by 41% or 66%, respectively, assessed 48 hours after ischemia. The significant reduction in group H-22H was again confirmed 30 days after ischemia, ie, 50% reduction was observed. In contrast, the reduction in group H-3H (31%) was not significant. The neurological deficits were significantly more severe in the N-N group than in the H-22H group during week 4. CONCLUSIONS: The neuroprotective effects against temporary focal ischemia evaluated by infarct volume and neurological functions by the combination therapy with intraischemic and prolonged postischemic mild hypothermia were persistent in rats. Appropriate design of mild hypothermia therapy extending into the late reperfusion period is important to maximize the neuroprotective effects of hypothermia.
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1998
 
PMID 
W Taki, I Nakahara, N Sakai, K Irie, K Murao, N Ohkata, M Tanaka, H Kikuchi (1998)  Large and giant middle to lower basilar trunk aneurysms treated by surgical and interventional neuroradiological methods.   Neurol Med Chir (Tokyo) 38: 12. 826-34; discussion 834-5 Dec  
Abstract: Treatment of large and giant aneurysms of the basilar artery remains difficult and controversial. Three large or giant aneurysms of the lower basilar artery were treated with a combination of surgical and interventional neuroradiological procedures. All patients underwent the balloon occlusion test with hypotensive challenge (blood pressure reduced to 70% of the control value). The third patient did not tolerate the test. In the first patient, both vertebral arteries were occluded through a craniotomy. In the second patient, both the aneurysm and the basilar artery were occluded by detached balloons. In the third patient, one vertebral artery was occluded by surgical clipping and the other by detached helical coils and fiber coils. In spite of anti-coagulation and anti-platelet therapy, postoperative thrombotic or embolic ischemia occurred in the second and third patients. Fibrinolytic therapy promptly corrected the ischemic symptoms, but the second patient developed hemorrhagic complications at the craniotomy area 2 hours later. At follow-up examination, the first patient had only 8th cranial nerve paresis, the second patient who had a hemorrhagic complication was bed-ridden, and the third patient had no deficit. Interventional occlusion requires a longer segment of the parent artery compared to surgical occlusion of the parent artery and might cause occlusion of the perforating arteries. However, selected use of various coils can occlude only a short segment of the parent artery. Thus, the postoperative management of thromboembolic ischemia after the occlusion of the parent artery is easier using the interventional technique.
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PMID 
W Taki, N Sakai, I Nakahara, N Osaka, T Koshiji, K Matsuda, Y Enoki, H Kikuchi (1998)  Circulatory arrest with profound hypothermia during the surgical treatment of large internal carotid artery aneurysm--case report.   Neurol Med Chir (Tokyo) 38: 11. 725-729 Nov  
Abstract: A 43-year-old male presented with a cerebral aneurysm manifesting as right facial paresthesia, without neurological deficit. Angiography revealed a large aneurysm (22 mm) of the left internal carotid artery. Intravascular treatment using placement of a detachable coil was attempted, but the coil did not stay in the aneurysmal cavity and the procedure was abandoned. The patient did not tolerate the transient balloon occlusion test of the left internal carotid artery. Therefore, the aneurysm was clipped through an open craniotomy with profound hypothermia (20 degrees C) with cardiac arrest (24 minutes). The aneurysmal dome was collapsed, allowing easy dissection of the posterior communicating artery. The closed chest method was used during the extracorporeal cardiopulmonary bypass. Postoperative angiography revealed complete neck clipping with preservation of carotid blood flow. The patient recovered well and resumed his employment. Circulatory arrest with hypothermia provides several benefits for the surgical treatment of large and giant aneurysms.
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1997
 
PMID 
H Kikuchi, S Miyamoto, I Nagata, W Taki, I Nakahara (1997)  Surgical extirpation of the posterior hippocampal arteriovenous malformation.   Surg Neurol 47: 3. 251-6; discussion 256-7 Mar  
Abstract: BACKGROUND: Surgical extirpation of medial temporal (AVMs) arteriovenous malformations has been one of the most challenging issues in neurosurgery. YaÅŸargil classified mediobasal AVM into four subtypes: amygdala, anterior hippocampal, middle hippocampal, and posterior hippocampal lesions. The lesions around the trigone extending forward to the temporal horn, and medially adjacent to the midbrain, can be referred to as posterior hippocampal AVMs. The therapeutic indications and operative approaches for these lesions remain controversial. METHODS: Nine patients underwent surgical resection for AVMs of the posterior hippocampus using a laterobasal approach. RESULTS: In four patients, AVMs were located chiefly within the lateral ventricle, and the lesions were resected using a laterobasal approach through the occipitotemporal sulcus, or through a hematoma cavity within the fusiform gyrus. Clinical improvement followed the procedure in three of four patients. In the remaining five patients, the nidi were located chiefly within the ambient cistern, extending upward to the basal ganglia. Contralateral hemiparesis occurred in three patients. Two patients showed marked improvement following an initial decline in neurologic status. CONCLUSIONS: A laterobasal transventricular approach is suitable for ventricular AVMs, whereas only limited exposure can be afforded through a transventricular, transchoroidal fissure route for the AVMs within the ambient cistern. For these lesions, a conventional subtemporal approach to the tentorial incisura is preferable.
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N Mikuni, A Ikeda, K Murao, K Terada, I Nakahara, W Taki, H Kikuchi, H Shibasaki (1997)  "Cavernous sinus EEG": a new method for the preoperative evaluation of temporal lobe epilepsy.   Epilepsia 38: 4. 472-482 Apr  
Abstract: PURPOSE: In presurgical evaluation of temporal lobe epilepsy (TLE), invasive methods are necessary if results of various noninvasive methods are not sufficiently convergent enough to identify the epileptogenic area accurately. To detect the epileptiform discharges originating specifically from the mesial temporal lobe, we applied the cavernous sinus catheterization technique. METHODS: We placed Seeker Lite-10 guide wire electrodes into bilateral cavernous sinus through the internal jugular veins to record EEG (cavernous sinus EEG) in 6 patients with intractable TLE. Scalp EEG was simultaneously recorded in all 6 and electrocorticogram (ECoG) was also recorded in 4. RESULTS: The cavernous sinus EEG demonstrated clear epileptiform discharges, sometimes even when they were absent on the simultaneously recorded scalp EEG. The epileptiform discharges recorded from the cavernous sinus electrodes were specifically associated with those in the mesial temporal region on ECoG. Ictal EEG pattern originating from mesial temporal lobe was also clearly documented on the cavernous sinus EEG. CONCLUSIONS: This new, semi-invasive method of identifying epileptogenic areas can detect the epileptiform discharges specifically arising from the mesial temporal lobe; it is as useful as or complements the invasive techniques such as foramen ovale or depth recording.
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PMID 
K Irie, W Taki, I Nakahara, N Sakai, F Isaka, H Kikuchi (1997)  Endovascular treatment of a partially thrombosed giant basilar tip aneurysm using interlocking detachable coils--case report.   Neurol Med Chir (Tokyo) 37: 9. 681-684 Sep  
Abstract: A 65-year-old female presented with visual acuity loss. Magnetic resonance imaging confirmed the presence of a partially thrombosed giant aneurysm on the basilar tip. Cerebral angiography showed the opacified lumen of the aneurysm was 25 x 15 mm with a broad-based neck. Using a transfemoral approach, a microcatheter was guided through the vertebral artery and placed directly into the aneurysm under local anesthesia. Interlocking detachable coils were deposited into the patent portion of the aneurysm, resulting in 95% obliteration of the aneurysm and preservation of the parent artery. No complication was observed during or after surgery. Follow-up angiography 2 months later demonstrated the aneurysm was 95% occluded. No coil compaction was observed. Endovascular coil embolization therapy provides a therapeutic option for management of basilar tip aneurysms.
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PMID 
K Araki, I Nakahara, W Taki, N Sakai, K Irie, F Isaka, H Ohwaki, H Kikuchi (1997)  A case of cavernous dural arteriovenous fistula resulting in intracerebral extravasation during transvenous embolization   No Shinkei Geka 25: 8. 733-738 Aug  
Abstract: Cortical venous drainage has been described as one of the major risk factors for dural arteriovenous fistula, which may induce venous hypertension leading to venous ischemia or intracerebral hemorrhage. However, it is rather rare to observe cortical venous drainage manifesting in this way in the cavernous sinus region. We report a case of a 55-year-old gentleman with a right cavernous dural arteriovenous fistula, presenting with conjunctival chemosis, exophthalmus and ocular hypertension on the affected side. Magnetic resonance imaging showed a small intracerebral hemorrhage in the right frontal lobe. Cerebral angiography revealed a dural arteriovenous fistula in the right cavernous sinus draining into the right olfactory vein via the uncal vein, as well as into the superior and inferior ophthalmic veins. This unusual cortical venous reflux was thought to be consistent with the intracerebral hemorrhage found on the magnetic resonance imaging. The patient underwent transvenous embolization for the dural arteriovenous fistula using an inferior petrosal catheterization into the uncal vein was difficult, and the cortical venous reflux through the vein seemed to be slight. However, extravasation of the contrast material occurred in the right frontal lobe after obliteration of the ophthalmic veins during the procedure. The cause of the extravasation was suspected to be the same olfactory vein that had been involved in the previous intracerebral hemorrhage. The obliteration of the dural fistula was continued rapidly, and the fistula disappeared after the embolization. Neurologically, the patient had no noticeable troubles, except for a mild headache. The pretreatment symptoms were alleviated within several days, and the patient was discharged in a week. We emphasize the following points from this rare case in order to facilitate a safer procedure during transvenous embolization for cavernous dural arteriovenous fistula. It is important to obliterate the cortical venous drainage as early as possible, even if the reflux is small or the catheterization is difficult. Repeated, careful sinography is useful for the evaluation of the drainage pattern at certain stages during the transvenous embolization procedure.
Notes:
 
PMID 
A Morizane, I Nakahara, J A Takahashi, M Ishikawa, H Kikuchi (1997)  A malignant rhabdoid tumor appearing simultaneously in the kidney and the brain of an infant: case report   No Shinkei Geka 25: 7. 665-669 Jul  
Abstract: A 6-month-old female was admitted to the hospital with bad temper and decreased sucking power. CT scans revealed tumors in her right kidney and left cerebellum. The patient underwent right radical nephrectomy to excise the kidney tumor. The pathological diagnosis was malignant rhabdoid tumor (MRT). Seven days later, the patient underwent left suboccipital craniectomy for total excision of the cerebellar tumor. The cerebellar tumor existed extraaxially, and consisted of a solid mass lesion and a cystic lesion. Histological examination revealed that it was also a malignant rhabdoid tumor. A follow-up CT, 1.5 months after surgery, revealed a recurrence of the kidney tumor and metastasis to the chest wall and lung. The patient received 16.9 Gy radiotherapy to the abdominal tumor and chemotherapy with etoposide, carboplatin, and ifosfamide. However, she died of respiratory insufficiency 4 months after surgery, though neither recurrence nor metastasis was found in the brain. Nor was there evidence of leptomeningeal dissemination. MRT is a highly malignant tumor that occurs most frequently in the kidney. However, it can also occur in other tissues, including the brain. This tumor occurs most commonly in children under 2 years of age. There is a 3:2 male predominance. The median length of overall survival of MRT in the brain is 6 months. MRT contains nests or sheets of rhabdoid cells. A typical rhabdoid cell has an eccentric round nucleus with a prominent nucleolus and a plump cell body. MRT is composed entirely or partly of rhabdoid cells. Many MRTs have other components, such as PNET areas, mesenchymal area, and epithelial areas. For this reason, they are sometimes called atypical teratoid/rhabdoid tumors. MRTs in the brain contain fewer rhabdoid cell areas than MRT in the kidney. This makes diagnosing MRT in the brain more difficult. A careful search of the entire specimen for variations in pattern and cell type, along with application of immunohistochemical methods is the most useful method of obtaining a diagnosis. In our case, the cerebellar tumor consisted of rhabdoid cell areas, mesenchymal areas, and PNET areas. The cerebellar tumor contained fewer rhabdoid cell areas than the kidney tumor. However, the rhabdoid cell areas in the cerebellar tumor were almost the same as those in the kidney tumor. Furthermore, immunohistochemical staining was positive for vimentin and keratin in the rhabdoid cell areas. Therefore, we were able to make a diagnosis of MRT. It is possible that some of the previously reported cases diagnosed as CNS PNET were actually MRT in the brain, especially if the cases were associated with MRT in the kidney.
Notes:
1996
 
PMID 
S Nishi, W Taki, I Nakahara, K Yamashita, A Sadatoh, H Kikuchi, H Hondo, K Matsumoto, H Iwata, Y Shimada (1996)  Embolization of cerebral aneurysms with a liquid embolus, EVAL mixture: report of three cases.   Acta Neurochir (Wien) 138: 3. 294-300  
Abstract: Embolization of three surgically difficult cerebral aneurysms was performed using our newly developed non-adhesive embolic material, EVAL mixture (ethylene vinyl alcohol copolymer). Conventional embolic materials such as detachable balloons or microcoils were not used because of a large or irregular aneurysmal neck. After temporary occlusion of the parent artery with a superselective balloon catheter, the EVAL mixture was slowly injected through a microcatheter placed in the aneurysm or parent artery. The locations of the aneurysms were anterior communicating artery, basilar artery-posterior cerebral artery and basilar artery-anterior inferior cerebellar artery (BA-AICA). One aneurysmal occlusion and 2 parent artery occlusions were performed. Patients had no persistent deficits. The patient with the BA-AICA aneurysm associated with an arteriovenous malformation died of rupture of the residual AVM due to haemodynamic change 2 weeks after embolization. In selected and limited cases, embolization of surgically difficult cerebral aneurysms using EVAL mixture was more effective and safer than embolization using conventional embolic materials such as balloons and microcoils.
Notes:
1995
 
PMID 
I Nakahara, W Taki, M Tanaka, K Matsumoto, H Kikuchi (1995)  Dolichoectasia of the middle cerebral artery--Case report.   Neurol Med Chir (Tokyo) 35: 11. 822-824 Nov  
Abstract: A 59-year-old female with a previous history of head injury presented with mild occipitalgia due to dolichoectasia of the middle cerebral artery (MCA). Initial examination by computed tomography and angiography using the usual projections suggested a terminal internal carotid artery saccular aneurysm. However, angiography by the reverse Waters view excluded a saccular aneurysm. Superselective angiography using a microcatheter revealed the complex tortuous course of the MCA due to dolichoectasia. She was discharged and has remained asymptomatic. Superselective angiography is extremely useful for the diagnosis of dolichoectasia localized in the MCA.
Notes:
 
PMID 
A Sadato, W Taki, Y Ikada, I Nakahara, K Matsumoto, M Tanaka, H Kikuchi (1995)  Immediately detachable coil for aneurysm treatment.   AJNR Am J Neuroradiol 16: 7. 1459-1462 Aug  
Abstract: We developed an endovascular coil that is instantly detached by high-frequency electrical current. By applying the electrical current, a polyvinyl alcohol junction between the coil and the delivery wire is disrupted by heat within a second. This detachment system was shown to be reliable in the treatment of experimental aneurysms.
Notes:
 
PMID 
M Hojo, S Miyamoto, I Nakahara, H Kikuchi, M Ishikawa, W Taki, I Nagata, K Yamamoto, Y Yonekura, S Nishizawa (1995)  A case of arteriovenous malformation successfully treated with functional mapping of the language area by PET activation study   No Shinkei Geka 23: 6. 537-541 Jun  
Abstract: The authors report a case of temporal AVM safely treated by mapping the language area with PET activation study. The patient was a 50-year-old woman with temporal epilepsy as her chief complaint. MRI and angiography revealed a right temporal AVM. Before surgical treatment, we assessed the dominant hemisphere with PET activation study. We performed PET scanning while the patient was playing "capping" (called "Shiritori" in Japanese), from which we subtracted PET images performed when she was in a resting state, and then we superimposed those images upon MRIs. The blood flow increased in the left frontal operculum (Broca's area), the left caudal head, the left putamen and the right cerebellar hemisphere. We were thus able to determine that her left hemisphere was dominant, and that it was safe to undertake embolization and operation for the AVM. Postoperative course was uneventful and higher cortical functions were preserved perfectly. In cases of cerebral AVMs, unusual dominancy of cerebral hemispheres is often encountered, and so, preoperative evaluation of the relation of AVM to the eloquent cortex is essential. In our study, blood flow increased in some areas other than the language area, but they were considered to be areas related to phonation, and we think that we were able to map the language area. Though this method is still in its preliminary stage, we think it gives us useful information for surgical treatment of cerebral AVMs.
Notes:
 
PMID 
F Tanaka, S Nishizawa, Y Yonekura, N Sadato, K Ishizu, H Okazawa, N Tamaki, I Nakahara, W Taki, J Konishi (1995)  Changes in cerebral blood flow induced by balloon test occlusion of the internal carotid artery under hypotension.   Eur J Nucl Med 22: 11. 1268-1273 Nov  
Abstract: Balloon test occlusion (BTO) of the internal carotid artery (ICA) combined with cerebral blood flow (CBF) study has proved to be a sensitive test for prediction of the outcome of permanent vessel occlusion. In this study, we evaluated the acute changes in regional CBF during BTO under hypotension in order to examine the possible risk of cerebral ischaemia after surgical treatment. Eleven patients in whom surgical carotid sacrifice was planned underwent BTO combined with CBF studies using technetium-99m hexamethyl-propylene amine oxime single-photon emission tomography under hypotension by decreasing the systemic blood pressure by about 50 mm Hg using a ganglion blocking agent. All patients showed a mild to severe decrease in CBF in the ipsilateral ICA territory relative to the contralateral side. A decrease in CBF of greater than 20% was observed in nine patients (82%), and two of them showed a decrease exceeding 40%. However, no ischaemic symptoms were demonstrated during scanning with hypotensive BTO. Our results suggest that in many patients with negative normotensive BTO, a considerable reduction in CBF would occur during hypotension. This procedure may predict a possible risk of hypotensive accident during and/or after surgery.
Notes:
1994
 
PMID 
I Nakahara, W Taki, M Tanaka, A Sadatou, K Matsumoto, H Kikuchi (1994)  Perioperative management of coagulation and fibrinolytic activity in endosaccular embolization of cerebral aneurysms   Nippon Geka Hokan 63: 3. 91-98 May  
Abstract: Endosaccular embolization is an innovative and effective treatment for surgically formidable cerebral aneurysms. Platinum microcoils are soft, easily fit to complex configuration of aneurysms, highly thrombogenic, so that suitable for this purpose. Recently developed Guglielmi detachable coils have more advantages in terms of retrievability and electrothrombotic effect. However, distal migration of intraaneurysmal thrombus produces thromboembolism in normal cerebral arteries, leading to neurological deficits. Three cases are presented in which thromboembolic complications occurred during or after embolization of cerebral aneurysms with platinum microcoils. Emergent fibrinolytic treatment resolved neurological deficits in each case without any other complications. From these lessons, a protocol of intra- and postoperative anticoagulation and antiplatelet therapy is presented. In conclusion, perioperative management of fibrinolytic and coagulation activity is extremely important in preventing thromboembolic complication and obtaining successful result.
Notes:
 
PMID 
A Sadato, W Taki, I Nakahara, S Nishi, K Yamashita, K Matsumoto, M Tanaka, H Kikuchi (1994)  Improved provocative test for the embolization of arteriovenous malformations--technical note.   Neurol Med Chir (Tokyo) 34: 3. 187-190 Mar  
Abstract: A modified provocative test to assess the safety of embolization of cerebral and spinal arteriovenous malformations is described. The modified test uses successive amobarbital and lidocaine injections to elicit any possible neurological deficit, both mixed with radiopaque material to visualize the distribution of the anesthetic in the vessels. The modified provocative test caused no false negative results in 11 patients tested, compared to six of 27 patients with the unmodified method.
Notes:
 
PMID 
W Taki, I Nakahara, S Nishi, K Yamashita, A Sadatou, K Matsumoto, M Tanaka, H Kikuchi (1994)  Pathogenetic and therapeutic considerations of carotid-cavernous sinus fistulas.   Acta Neurochir (Wien) 127: 1-2. 6-14  
Abstract: Carotid-cavernous sinus fistula (CCF) is a syndrome in which arteriovenous shunts exist between the carotid artery and the cavernous sinus. These shunts vary widely in pathogenesis, angiogram, haemodynamics and treatment. Several systems of classification in terms of either haemodynamics, aetiology and/or pathogenesis have been reported, but they are not comprehensive. A more comprehensive and simpler nomenclature of classification is now required. Fifty seven cases of CCFs were analyzed and were classified according to their pathogenesis, angiography and treatment modalities. There were 11 traumatic CCFs with direct shunts (T-D group), and 2 traumatic CCFs with indirect shunts (T-I group). Spontaneous CCFs were divided into three groups. There were 37 spontaneous CCFs caused by dural arteriovenous shunts that were naturally classified as being indirect shunts (SD-I group). There were 5 spontaneous CCFs caused by suspected connective tissue disorders, such as fibromuscular dysplasia, Ehlers-Danlos syndrome etc.; these had direct shunts. Care was needed to avoid dissection of the artery or complications due to the fragility of connective tissue (SC-D group). There were 2 spontaneous CCFs caused by the rupture of an inflaclinoid aneurysm without any background of connective tissue disorder; these had direct shunts (SA-D group). By this system of grouping and use of abbreviations, each case of CCF can be clearly delineated in terms of its pathogenesis and selection for appropriate treatment.
Notes:
 
PMID 
I Nakahara, J Pile-Spellman, L Hacein-Bey, R M Crowell, D Gress (1994)  Usefulness of non-detachable balloons in endovascular treatment for cerebral aneurysms.   Neurol Med Chir (Tokyo) 34: 6. 353-359 Jun  
Abstract: An endovascular non-detachable balloon technique was used to treat 14 patients with cerebral aneurysms. Eight patients presented with subarachnoid hemorrhage, and six others presented with headache or mass effect. Six aneurysms were located in the anterior circulation and eight in the posterior circulation. Seven aneurysms were giant, three were large, and four were small. All target aneurysms or vessels were occluded successfully. Parent vessel was successfully spared in seven cases. There were no procedural complications related to the non-detachable nature of the balloon used. Follow-up angiography detected refilling of aneurysms in three of 11 patients, two with small ruptured aneurysms that bled again following partial deflation or balloon movement. The other aneurysms tested remained occluded, as demonstrated on follow-up angiograms, for up to 15 months. Outcomes were good to excellent in 10 patients, poor in one, and three died. Non-detachable balloons might be preferred for treatment of certain types of cerebral aneurysms including those where intraaneurysmal maneuvers might be considered dangerous, for example, with recent bleeding or intraluminal fresh clots; where precise placement of the balloon is required, for example, in the vicinity of perforators or collaterals emerging near the neck; and where detachment could be dangerous or difficult in broad neck and fusiform aneurysms or in tortuous parent vessels.
Notes:
 
PMID 
K Yamashita, W Taki, H Iwata, I Nakahara, S Nishi, A Sadato, K Matsumoto, H Kikuchi (1994)  Characteristics of ethylene vinyl alcohol copolymer (EVAL) mixtures.   AJNR Am J Neuroradiol 15: 6. 1103-1105 Jun  
Abstract: PURPOSE: To determine physical characteristics of mixtures of ethylene vinyl alcohol copolymer (EVAL) and metrizamide dissolved in dimethyl sulfoxide, liquid materials developed for embolization of arteriovenous malformations. METHODS: EVAL and dimethyl sulfoxide were mixed in various proportions and sterilized. The viscosity and density of each mixture was measured. Precipitation times were determined by dropping the mixtures into saline or human blood. The mixtures were filtered and the filtrates weighed. RESULTS: Densities and viscosities of the various mixtures differed significantly, proportionally to the concentration of EVAL. Precipitation times also differed significantly, in inverse proportion to the concentration of EVAL. Temperature and aqueous solution did not affect precipitation times significantly. The weight of the filtrate significantly increased with time but was constant for each precipitation time. Temperature significantly affected filtrate weight; aqueous solution did not. CONCLUSIONS: Because of their different physical properties, the various EVAL mixtures are suited to embolizing different types of arteriovenous malformations.
Notes:
 
PMID 
A Sadato, W Taki, Y Ikada, I Nakahara, K Yamashita, K Matsumoto, M Tanaka, H Kikuchi, Y Doi, T Noguchi (1994)  Experimental study and clinical use of poly(vinyl acetate) emulsion as liquid embolisation material.   Neuroradiology 36: 8. 634-641 Nov  
Abstract: A new material, an emulsion of poly(vinyl acetate) was experimentally developed and clinically used to overcome several disadvantages in currently used liquid embolisation materials. The emulsion microparticles, 0.3-0.7 microns in size, possessed cationic charge on the surface and hence aggregated immediately on contact with fluids containing anions. This inert polymer has the advantage that it does not induce a deleterious reaction in living tissue. Moreover, its medium is water and it is not adhesive, like the cyanoacrylates. Several concentrations of emulsion were injected into the renal arteries of dogs. For the investigation of tissue reactions and the possibility of recanalisation, the emulsion was injected into rats both subcutaneously and into the renal arteries. The renal artery injections in dogs showed adequate radiopacity and consistent complete occlusion. The lower the concentration of the emulsion, the smaller the arteries which could be occluded. Even at very low concentrations, however, venous occlusion did not occur. Histological study of the embolised rat kidney revealed no detectable damage in the vessel wall and no recanalisation for up to 6 months. The subcutaneously injected PVAc emulsion elicited mononuclear cell infiltration and gradual centripetal fibrosis, without any deleterious effect on the surrounding tissue. A cerebral arteriovenous malformation (AVM) was embolised using the material. Histology of the resected nidus showed findings similar to those in the animal experiments.
Notes:
 
PMID 
M Tanaka, W Taki, S Miyamoto, I Nakahara, A Sadato, K Matsumoto, H Kikuchi (1994)  Percutaneous transluminal angioplasty (PTA) for stenosis at the subclavian artery and at the origin of the vertebral artery: therapeutic indication and some adjunctive safe methods during PTA   No Shinkei Geka 22: 10. 939-946 Oct  
Abstract: Percutaneous transluminal angioplasty (PTA) for brachiocephalic occlusive lesions has progressed. In this paper our experiences and results of PTA in dealing with those lesions are described with emphasis on adjunctive procedures during PTA. Recently, twenty-four patients with stenosis of the subclavian artery (SA) and/or stenosis at the origin of the vertebral artery (VA) were included in this study. Among the 24, there were 16 cases with SA stenosis, 6 cases with stenosis at the origin of VA and 3 cases with both SA and stenosis at the origin of VA. The stenosis was due to atherosclerosis in 21 cases and aortitis in 3 cases. Most of the patients presented ischemic symptoms of vertebrobasilar circulation and affected upper extremities. In PTA of brachiocephalic lesions, one of the most formidable complications is an embolism distal to the central nervous system. To prevent this complication, a vascular endoscope was used for visualization of the luminal surface of the stenotic lesions in 7 cases, and a protective balloon was used in 4 recent cases. The protective balloon was used for transient occlusion of the artery to alter the flow direction so that the possible emboli might be forced to flow away to a less critical distal artery. In the distal protective balloon technique, the protective balloon was set so as to occlude the stenotic artery distally. Debris caused by PTA was aspirated and/or washed out to an extracranial artery with heparinized saline. In the proximal protective balloon technique, the protective balloon was set so as to occlude the stenotic artery proximally. Debris was washed out with blood flow caused by the induced steal phenomenon to an extracranial artery.(ABSTRACT TRUNCATED AT 250 WORDS)
Notes:
 
PMID 
M Hojo, I Nakahara, M Tanaka, Y Oda, H Kikuchi (1994)  Surgical treatment of atlanto-axial dislocation in a patient of athetoid cerebral palsy   No Shinkei Geka 22: 9. 887-891 Sep  
Abstract: The authors report a case of successful surgical treatment of atlanto-axial dislocation (AAD) secondary to athetoid cerebral palsy. A 61-year-old woman was admitted to our hospital in July 1993 complaining of progressive weakness in the right upper extremity and gait disturbance. She had been suffering from athetoid movements of her face, neck and arms due to cerebral palsy. Neurological examinations on admission revealed down-beat nystagmus on downward gazing, motor weakness of extremities, pallhypesthesia, hyperreflexia exaggerated in the right side and bilateral positive pathological reflexes. Lateral tomogram of the upper cervical spine demonstrated instability of the atlanto-axial joint, increased atlanto-dental interval (ADI) by 5.5 mm (in flexion), and narrowed canal at C1 level. Myelogram showed narrowed dural sac and angulation of the spinal cord at C1 level. A halo vest was applied two days before operation for reduction of the atlanto-axial junction and external fixation. She underwent posterior internal fixation using a Hartshill Ransford Loop combined with posterior decompression. This loop was secured to the occiput, C1, C2 and C3 by sublaminar wiring, and foramen magnum decompression and laminectomy of C1 were performed. Postoperative course was uneventful. Postoperative plain X-ray film, tomogram and computed tomography demonstrated good fixation (ADI was 2.5 mm) and excellent stability. There has been no problem during 6 months since the operation. It is known that involuntary movements in patients with athetoid cerebral palsy sometimes cause cervical spondylosis (especially at C3/4 and C4/5 level). Recently, AAD due to athetoid cerebral palsy has been reported. Almost every case of AAD secondary to athetoid cerebral palsy is combined with incompetence of the odontoid process.(ABSTRACT TRUNCATED AT 250 WORDS)
Notes:
1993
 
PMID 
I Nakahara, H Handa, M Nishikawa, Y Yamakawa, S Inagawa, T Koide, W Taki, H Iwata (1993)  A midbrain arteriovenous malformation at quadrigeminal plate completely obliterated by embolization   No Shinkei Geka 21: 1. 67-72 Jan  
Abstract: An eighteen year-old boy presented sudden loss of consciousness and tetraparesis. Radiological examinations revealed a ruptured midbrain arteriovenous malformation (AVM) at the right quadrigeminal plate. The patient recovered from symptoms by conservative treatment over 6 months with residual right hemisensory disturbance and mild diplopia during bilateral horizontal gaze. One year later, he was admitted to our institute for radical treatment of the AVM. On the angiography, the AVM was fed by two branches of the right long circumferential artery and a left paramedian penetrating artery of the posterior cerebral artery (PCA), and drained into the straight sinus via a dilated quadrigeminal vein. After much discussion on several strategies, endovascular surgery was chosen as a radical treatment. In the initial session, a medial branch of the right long circumferential artery was catheterized with Tracker-18, and embolized with 1.0 ml of ethylene vinyl alcohol copolymer (EVAL) without any deficits after negative provocative tests using Amytal and Xylocaine. Then, a lateral branch of the same artery was embolized with 0.8 ml of EVAL in the same way without any deficits. In the second session, catheterization into the left paramedian artery was difficult because of its small diameter and steep branching angle, and only a 3 mm hooked tip of Tracker-18 could be canulated into the feeding pedicle. Left oculomotor palsy was induced by provocative Xylocaine test. However, angiographic cure of the AVM was expected to be made possible by the occlusion of this pedicle, and the procedure was continued due to the request of the patient and his family.(ABSTRACT TRUNCATED AT 250 WORDS)
Notes:
 
PMID 
K Yamashita, W Taki, S Nishi, A Sadato, I Nakahara, H Kikuchi, Y Yonekawa (1993)  Transvenous embolization of dural caroticocavernous fistulae: technical considerations.   Neuroradiology 35: 6. 475-479  
Abstract: Sixteen patients with symptomatic dural caroticocavernous fistulae were treated by transvenous embolization, via the jugular vein and inferior petrosal sinus. The fistula was occluded by thrombogenic coils. Complete resolution of symptoms and signs was achieved in 14 patients, and complete angiographic resolution was also obtained in 14 patients. Failures to achieve angiographic cure were attributed to failure to reach the fistula within the cavernous sinus precisely. Factors which make placement of the catheter at the fistula difficult are trabeculae within the cavernous sinus, a specific configuration of the superior ophthalmic vein and venous thrombosis. To improve the efficacy of transvenous embolization, every possible venous route to the cavernous sinus therefore should be tried, to facilitate reaching the fistula and the possibility of transvenous embolization should not be thwarted by venous thrombosis.
Notes:
 
PMID 
H Yamakawa, M Nishikawa, I Nakahara, S Inagawa, T Koide, H Handa (1993)  Congenital subclavian steal syndrome with anomaly of the aortic arch.   Surg Neurol 39: 2. 133-137 Feb  
Abstract: A case of congenital subclavian steal syndrome associated with an anomalous right-sided aorta is reported. A 41-year-old man complaining of vertigo and a loss of consciousness was admitted. Physical examination revealed a blood pressure differential between the arms that was 20 mm Hg less in the left. Aortography showed a right aortic arch from which arose the right subclavian and both common carotid arteries. The left subclavian artery did not opacify. Right vertebral angiography showed retrograde filling of the left vertebral. A left carotid-subclavian bypass was performed. Postoperatively, the patient is symptom free with equalized blood pressure.
Notes:
 
PMID 
I Nakahara, J Pile-Spellman, L Hacein-Bey, R M Crowell, D Gress (1993)  Posterior fossa dural arteriovenous fistula with isolated sinus segment   No To Shinkei 45: 8. 703-709 Aug  
Abstract: Radiological and clinical analysis was performed in 5 patients with posterior fossa dural arteriovenous fistulas (DAVFs) with isolated sinus segment due to sinus thrombosis, and their patho physiological, diagnostic, and therapeutic concerns were discussed. Patients ranged in age from 36 to 73 years old with a mean of 57 years and included 2 males and 3 females. Two patients presented with ataxia, one with ataxia and bruit, one with atypical facial pain, and one with parietal dysfunction. One patient had a history of hemorrhagic event. DAVFs were located at transverse-sigmoid sinus (3 cases), superior petrosal sinus (1 case), and straight sinus (1 case). They were fed by many branches of external carotid artery including middle meningeal artery, ascending pharyngeal artery, posterior auricular artery, occipital artery, meningeal branches of vertebral artery and posterior cerebral artery, and meningohypophyseal trunk of internal carotid artery. Shunt flow drained into contralateral transverse-sigmoid or supratentorial sinuses via the isolated venous segment through markedly dilated cortical and/or deep venous systems, which caused altered normal venous drainage pattern and venous hypertension. Transarterial embolization in multiple stages (mean 3.4) using n-butyl cyanoacrylate (NBCA) could alleviate symptoms in all cases. DAVFs were almost totally obliterated in 3 patients. Further embolization in one case, and surgical excision in one case were planed because of some residual dilated cortical venous drainage. Posterior fossa DAVFs with isolated sinus segment accompany markedly dilated cortical and/or deep venous systems. They could cause cerebellar, brainstem, or cranial nerve dysfunctions, and sometimes present distant supratentorial symptoms or hydrocephalus due to abnormal venous drainage and venous hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
Notes:
 
PMID 
I Nakahara, H Kikuchi, W Taki, S Nishi, K Yamashita, A Sadato, K Matsumoto, K Nojima (1993)  A large vertebrobasilar junction aneurysm grown at the proximal end of basilar artery fenestration--usefulness of balloon occlusion test with 99mTc-HMPAO SPECT under induced hypotension and consideration in therapeutic strategies   No To Shinkei 45: 5. 477-483 May  
Abstract: A 48-year-old lady suffered a transient loss of consciousness. CT and MRI revealed a large vascular lesion compressing the left lower pons. Angiography revealed a large aneurysm at vertebro-basilar junction, dome of which projected anteriorly and left to midline. Her previous vertebral angiogram taken 10 years ago when she suffered a subarachnoid hemorrhage from the left MCA aneurysm, had showed a fenestration of lower basilar artery without apparent aneurysm. Bilateral super-selective vertebral angiograms revealed that the aneurysm arose at the proximal end of the fenestration, and vertebrobasilar junction was incorporated into the aneurysm indicating broad neck aneurysm. The left posterior communicating artery was well developed. Balloon test occlusion (BTO) of bilateral vertebral artery was performed under normotension and induced hypotension. 99mHM-PAO SPECT was used to examine cerebral blood flow (CBF) during hypotensive BTO. The patient tolerated the test and CBF imaging showed insignificant sight decrease in bilateral cerebellar hemispheres. Exploration of the aneurysm was carried out by the right far lateral suboccipital approach. Bilateral vertebral arteries and the right segment of the basilar artery fenestration were identified. Neck clipping of the aneurysm with reconstruction of the parent vessels were tried with fenestrate clip. However, narrow operative field and large dome of the aneurysm made it hard to identify the left segment of the fenestration. Neck clipping was given up and clipping of bilateral vertebral arteries were performed distal to posterior inferior cerebellar artery with three body clippings. The patient showed moderate postoperative left lower nerve palsy, which was gradually improved in several weeks. Follow-up angiography revealed no opacification of the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)
Notes:
1992
 
PMID 
I Nakahara, H Kikuchi, W Taki, S Nishi, M Kito, Y Yonekawa, Y Goto, N Ogata (1992)  Changes in major phospholipids of mitochondria during postischemic reperfusion in rat brain.   J Neurosurg 76: 2. 244-250 Feb  
Abstract: Major mitochondrial phospholipids were examined in rat brain after 30 minutes of reperfusion following 30- or 60-minute periods of ischemia to examine their changes and explore their relationship to mitochondrial dysfunction during postischemic reperfusion. The amount of phospholipids and the percentage of polyunsaturated fatty acid chains, which tended to decrease during 30 minutes of ischemia, recovered after reperfusion. However, after ischemia lasting for 60 minutes, these parameters did not recover but decreased further, suggesting progressive disruption of phospholipids by phospholipase A2 after reperfusion. These changes were particularly notable in cardiolipin, which is contained specifically in mitochondria. The changes were also closely associated with mitochondrial respiration and respiratory enzyme (cytochrome c oxidase and F0F1-adenosine triphosphatase) activities, which have been known to correlate with the amount of cardiolipin. These results suggest that phospholipid metabolism in mitochondrial membranes is an important factor bearing on the integrity of energy metabolism during postischemic reperfusion.
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PMID 
I Nakahara, H Handa, M Nishikawa, T Koide, H Yamakawa, S Inagawa, M Kojima (1992)  Endovascular coil embolization of a recurrent giant internal carotid artery aneurysm via the posterior communicating artery after cervical carotid ligation: case report.   Surg Neurol 38: 1. 57-62 Jul  
Abstract: The case of a 29-year-old man with a giant fusiform aneurysm of the left internal carotid artery (ICA) is presented. The aneurysm, treated by cervical ICA ligation and extracranial-intracranial bypass, recurred 4 years later owing to recruitment of the posterior communicating artery (PCoA). Because of the previous bypass surgery a direct surgical approach was excluded. After an initial failure with balloon embolization, the aneurysm was embolized successfully with occlusive platinum microcoils through the microcatheter navigated into the aneurysm via the enlarged PCoA. Endovascular coil embolization may be useful in the treatment of cerebral aneurysms not amenable to direct surgery or balloon embolization.
Notes:
 
PMID 
W Taki, S Nishi, K Yamashita, A Sadatoh, I Nakahara, H Kikuchi, H Iwata (1992)  Selection and combination of various endovascular techniques in the treatment of giant aneurysms.   J Neurosurg 77: 1. 37-42 Jul  
Abstract: Between April, 1989, and January, 1991, a total of 19 cases of giant aneurysm were treated by the endovascular approach. The patients included seven males and 12 females aged 15 to 72 years. Detachable balloons, occlusion coils, and ethylene vinyl alcohol copolymer liquid were used as embolic materials. In seven cases, thrombosis of the aneurysmal sac and/or base was achieved while sparing the parent arterial flow, complete obliteration of the aneurysm was achieved in four of these. Of these four patients, the thrombotic material was a detachable balloon in two, a combination of a detachable balloon and coils in one, and occlusion liquid in one. In the other three cases, complete occlusion was not achieved; one aneurysm was occluded with a detachable balloon and two with coils. In 11 patients, the parent artery was occluded either by trapping or by proximal arterial occlusion, and all patients showed complete occlusion of the aneurysms. In one patient, a combined bypass procedure and parent artery occlusion was performed. Among the 19 cases in this series there were four transient ischemic attacks, one reversible ischemic neurological deficit, and one death due to aneurysmal rupture during the procedure. Two patients died in the follow-up period, one from pneumonia 2 months postoperatively and the other from acute cardiac failure 2 weeks following surgery. Both deaths were unrelated to the endovascular procedure. It is concluded that the endovascular treatment of giant aneurysms remains difficult because of the large and irregular shape of the aneurysmal base and thrombus in the aneurysmal sac. The proper selection and combination of the available endovascular techniques is therefore of critical importance.
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1991
 
PMID 
I Nakahara, H Kikuchi, W Taki, S Nishi, M Kito, Y Yonekawa, Y Goto, N Ogata (1991)  Degradation of mitochondrial phospholipids during experimental cerebral ischemia in rats.   J Neurochem 57: 3. 839-844 Sep  
Abstract: Changes in content of brain mitochondrial phospholipids were examined in rats after 30 and 60 min of decapitation ischemia compared with controls, to explore the degradation of the mitochondrial membrane and its relation to dysfunction of mitochondria. Activities of respiratory functions and respiratory enzymes (cytochrome c oxidase; F0F1-ATPase) decreased significantly during ischemia. Considerable decreases in cardiolipin and phosphatidylinositol content were observed after 60 min, and other phospholipids showed similar but nonsignificant decreases in content. The amount of polyunsaturated fatty acids chains, such as arachidonic and docosahexaenoic acids, was reduced in each phospholipid, in some cases significantly, after 30 and 60 min of ischemia in time-dependent manners. Degradation of mitochondrial phospholipids during ischemia associated with the deterioration of mitochondrial respiratory functions suggested the significance of such changes in phospholipid content in disintegration of cellular energy metabolism during cerebral ischemia.
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PMID 
M Nishikawa, H Handa, I Nakahara, H Yamakawa, S Inagawa, T Koide (1991)  Association of an epidermoid tumor with a cerebral aneurysm on the contralateral internal carotid artery   No Shinkei Geka 19: 9. 847-850 Sep  
Abstract: A 71-year-old female was evaluated for a sudden loss of consciousness. Initial computed tomography and cerebral angiography revealed a severe subarachnoid hemorrhage, a large cystic lesion in the left occipital region, and an aneurysm at the bifurcation of the internal carotid and the posterior communicating artery on the right side. As the subarachnoid hemorrhage was thought to be due to rupture of the aneurysm, we attempted to clip the aneurysmal neck at first, and 2 weeks later the cystic tumor was removed for the purpose of internal decompression. The extirpated specimen proved to be an epidermoid tumor. Association of a brain tumor and an cerebral aneurysm is very rare, especially a combination of an epidermoid tumor and a cerebral aneurysm, and until now only 2 cases have been reported to the best of our knowledge. Moreover, the epidermoid tumor of our case was located intracerebrally. The phenomenon that the internal carotid aneurysm was on the left side and the tumor on the right side may suggest that these 2 lesions originated quite coincidentally. It is controversial to decide which lesion and when to treat first in a case of association of a tumor and an aneurysm, and we discussed as to the surgical therapy reviewing literature.
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1990
 
PMID 
I Nakahara (1990)  Experimental studies on the changes of mitochondrial membrane phospholipids during cerebral ischemia and recirculation   Nippon Geka Hokan 59: 1. 27-38 Jan  
Abstract: Changes of brain mitochondrial phospholipids during cerebral ischemia and recirculation were experimentally studied in a rat 4-vessel occlusion model, to explore the relation between changes of mitochondrial phospholipids and dysfunction of mitochondria. Respiratory functions, activities of respiratory enzymes (cytochrome c oxidase, F0F1-ATPase) were analyzed after 30 and 60 minutes of ischemia, and after 30 minutes of recirculation following each ischemic period. Activities of respiratory functions and respiratory enzymes decreased progressively during ischemia, which recovered completely after recirculation following 30 minutes of ischemia, while only partial recovery was observed after recirculation following 60 minutes of ischemia. In phospholipid analyses, contents of phospholipid classes tended to decrease time-dependently during ischemia, and compositions of polyunsaturated fatty acids (PUFA) such as arachidonic acid (20:4) and docosahexaenoic acid (22:6) were decreased preferentially. In recirculation, phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cardiolipin (CL) showed recovery of contents of phospholipids and compositions of PUFA after recirculation following 30 minutes of ischemia, while further decrease of contents of phospholipids and compositions of PUFA were observed after recirculation following 60 minutes of ischemia, especially in CL. On the other hand, progressive degradation of phospholipids occurred after recirculation following both 30 and 60 minutes of ischemia in phosphatidylserine and phosphatidylinositol. Changes of major phospholipid classes such as PC, PE, and CL correlated with the changes of mitochondrial respiratory functions and activities of respiratory enzymes. In conclusion, changes of mitochondrial membrane phospholipids appear to affect the integrity of cellular energy metabolism via mitochondrial dysfunction during cerebral ischemia and recirculation.
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1987
 
PMID 
I Nakahara, K Nozaki, J Ishikawa (1987)  A case of cleidocranial dysostosis associated with arachnoid cyst   No Shinkei Geka 15: 11. 1241-1246 Nov  
Abstract: Cleidocranial dysostosis (CCD) is a rare congenital disorder characterized by the heredity, the disturbance of the ossification of the skull and clavicles, and dental anomaly. The entity of CCD was established by Marie and Sainton in 1898. In Japan about 150 cases have been reported since Haneda's first report in 1933. Recently we experienced a rare case of CCD associated with the temporal arachnoid cyst. The patient was a 61-year-old male who had suffered from mild spastic paresis of the left upper extremity since his childhood. One morning he suddenly noticed motor weakness of the left upper and lower extremities and was transferred to our hospital. On admission we observed the left hemiparesis (MMT 3/5), the left central type facial palsy, and the left long tract signs. Physical examination disclosed frontal bossing, depression of the forehead, sloped shoulders, cone-shaped thorax, and thoracic scoliosis. Plain skull radiograph showed persistent metopic suture and frontal fontanelle, many wormian bones around coronal and lambdoid sutures. Plain radiographs of the systemic bones also showed typical features of CCD such as dysplasia of the lateral third of the bilateral clavicles, deformities of the cervical vertebral bodies, thoracic scoliosis, and wide symphysis. CT scan disclosed the right putaminal hemorrhage, the right temporal arachnoid cyst, enlargement of the right middle fossa, thinning of the temporal bone adjacent to the arachnoid cyst. It also showed the atrophy of the right cerebral peduncle and midbrain. Surgical treatment was performed to remove the hematoma and release the cyst. Several neurological disorders associated with CCD have been reported such as epilepsy, mental retardation, spastic paresis etc.(ABSTRACT TRUNCATED AT 250 WORDS)
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1986
1985
 
PMID 
N Hashimoto, S Okamoto, T Yamagami, M Kojima, I Nakahara, H Handa (1985)  Treatment of primary empty sella with intractable headache via the transsphenoidal approach   No Shinkei Geka 13: 7. 791-796 Jul  
Abstract: Two cases of primary empty sella with intractable headache were treated via the transsphenoidal approach. One patient was a fifty-three-year-old female with right upper nasal quadrantanopsia and intractable retrobulbar pain and the other was fourty-six-year-old female with continuous retrobulbar pain with a history of transient right temporal hemianopsia. Both cases were diagnosed by metrizamide CT cisternography. They had normal endocrinological functions. They did not respond to drug therapy and were treated surgically. In each case, the dura mater of the floor of the sella was elevated with lyophilized human dura mater and bone fragments obtained during the procedure. In the former case, significant improvement of visual field defect was not obtained but the retrobulbar pain disappeared completely after the operation. In the latter case which had intractable headache for six months, the symptom disappeared just after the operation. Until now, retroorbital pain has not recurred in both cases for several months. Primary empty sella has been considered to be a benign condition except in some cases with CSF rhinorrhea or with visual disturbance. Headache which is often accompanied to primary empty sella has rarely been treated surgically because it is difficult to know whether the headache is related to the empty sella or not. Another reason may be that there is few available data concerning to the efficacy of surgical treatment. Headache caused by stretching of the dura of the floor of the sella is usually frontal or retrobulbar, continuous, profound and intractable.(ABSTRACT TRUNCATED AT 250 WORDS)
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