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Dive into the research topics where Kazuya Fujii is active.

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Featured researches published by Kazuya Fujii.


BMC Neurology | 2014

Effects of intravenous infusion of hydrogen-rich fluid combined with intra-cisternal infusion of magnesium sulfate in severe aneurysmal subarachnoid hemorrhage: study protocol for a randomized controlled trial

Satoru Takeuchi; Kentaro Mori; Hirohiko Arimoto; Kazuya Fujii; Kimihiro Nagatani; Satoshi Tomura; Naoki Otani; Hideo Osada; Kojiro Wada

BackgroundThe failures of recent studies intended to prevent cerebral vasospasm have moved the focus of research into delayed cerebral ischemia away from cerebral artery constriction towards other mechanisms. Recent accumulating evidence has suggested that early brain injury is also involved in the development of delayed cerebral ischemia, and that hydrogen can prevent early brain injury. Therefore, we have established a combination therapy of intravenous hydrogen infusion and intra-cisternal magnesium sulfate infusion for the treatment of both early brain injury and cerebral vasospasm. The present randomized controlled clinical trial is designed to investigate the effects of this novel therapeutic strategy on the occurrence of cerebral vasospasm, delayed cerebral ischemia, and clinical outcomes after high-grade subarachnoid hemorrhage.MethodsThis study is a randomized, double-blind, placebo-controlled design to be conducted in two hospitals. A total of 450 patients with high-grade subarachnoid hemorrhage will be randomized to one of three arms: (i) Mg + H2 group, (ii) Mg group, and (iii) control group. Patients who are assigned to the Mg + H2 group will receive intra-cisternal magnesium sulfate infusion (2.5 mmol/L) at 20 mL/h for 14 days and intravenous hydrogen-rich fluid infusion (200 mL) twice a day for 14 days. Patients who are assigned to the Mg group will receive intra-cisternal magnesium sulfate infusion (2.5 mmol/L) at 20 mL/h for 14 days and intravenous normal glucose-electrolyte solution (200 mL) without added hydrogen twice a day for 14 days. Patients who are assigned to the control group will receive intra-cisternal Ringer solution without magnesium sulfate at 20 mL/h for 14 days and intravenous normal glucose-electrolyte solution (200 mL) without added hydrogen twice a day for 14 days. Primary outcome measures will be occurrence of delayed cerebral ischemia and cerebral vasospasm. Secondary outcome measures will be modified Rankin scale score at 3, 6, and 12 months and biochemical markers.DiscussionThe present protocol for a randomized, placebo-controlled study of intravenous hydrogen therapy with intra-cisternal magnesium infusion is expected to establish the efficacy and safety of this therapeutic strategy.Trial registrationUMIN-CTR: UMIN000014696


Surgical Neurology International | 2016

Operative surgical nuances of modified extradural temporopolar approach with mini-peeling of dura propria based on cadaveric anatomical study of lateral cavernous structures

Naoki Otani; Kojiro Wada; Terushige Toyooka; Kazuya Fujii; Yasushi Kobayashi; Kentaro Mori

Background: Extradural temporopolar approach (ETA) has been modified as less invasive manner and named as trans-superior orbital fissure (SOF) approach with mini-peeling technique. The present study discusses the operative nuances of this modified technique on the basis of cadaveric study of lateral cavernous structures. Methods: In five consecutive cadaveric specimens, we performed an extradural anterior clinoidectomy with mini-peeling of the dura propria to expose the anterior clinoid process entirely. We also investigated the histological characteristics of the lateral cavernous sinus (CS) between the dura propria and periosteal dura at the SOF, foramen rotundum (FR), and foramen ovale (FO) levels, and of each trigeminal nerve division. Results: Coronal histological examination of the lateral wall of the CS showed invagination of the dura propria and periosteal dura into the SOF. In contrast, no such invagination was observed at the levels of the FR and FO. This finding supports the technical rationale of the only skeletonization of the SOF for peeling of the dura propria but not FR. In addition, our modified ETA method needs only minimal dural incision between the SOF and FR where no cranial nerves are present. Conclusion: Our technical modification of ETA may be recommended for surgical treatment of paraclinoid lesions to reduce the risk of intraoperative neurovascular injury.


Acta neurochirurgica | 2016

Retrograde Suction Decompression Through Direct Puncture of the Common Carotid Artery for Paraclinoid Aneurysm.

Naoki Otani; Kojiro Wada; Terushige Toyooka; Kazuya Fujii; Hideaki Ueno; Satoshi Tomura; Arata Tomiyama; Yasuaki Nakao; Takuji Yamamoto; Kentaro Mori

BACKGROUND Surgical clipping of paraclinoid aneurysm can be very difficult because strong adhesions may hinder the dissection of the perforators and surrounding anatomical structures from the aneurysm dome. We describe our experience with using retrograde suction decompression during the clipping of paraclinoid aneurysms and discuss the relative advantages and pitfalls. MATERIALS AND METHODS This study included 23 patients with large and giant paraclinoid aneurysms who underwent surgical treatment consisting of direct clipping with suction decompression between March 2004 and August 2014. Direct puncture of the common carotid artery (CCA) was performed with a 20-gauge needle. The aneurysm was temporarily trapped by clamping of the CCA and external carotid artery (ECA), followed by temporary clipping of the intracranial internal carotid artery (ICA) distal to the aneurysm neck. Blood was then gently aspirated through a catheter introduced into the cervical ICA, resulting in collapse of the aneurysm. Therefore, safe aneurysm dissection was feasible during interruption of the blood flow, which could be maintained for up to 5 min. This procedure was repeated until dissection and clipping of the aneurysm were completed. RESULTS Seven patients were admitted with SAH, 11 with asymptomatic unruptured aneurysm, and 5 with symptomatic unruptured aneurysm. The aneurysms were located on the paraclinoidal segment of the ICA in 15 cases, on the ICA-posterior communicating artery (PComA) in 6, at the ICA bifurcation in 1, and on the anterior wall of the ICA in 1. None of them suffered complications related to the CCA puncture. Surgical outcome was good recovery in 13 patients, moderate disability in 4, severe disability in 4, and vegetative state in 1. CONCLUSION Retrograde suction decompression through direct puncture of the common carotid artery is a useful adjunct technique for the clipping of paraclinoid ICA aneurysms.


World Neurosurgery | 2017

Flexible Ultrathin Endoscope Integrated with Irrigation Suction Apparatus for Assisting Microneurosurgery

Naoki Otani; Yuji Morimoto; Kazuya Fujii; Terushige Toyooka; Kojiro Wada; Kentaro Mori

BACKGROUND Endoscopy can observe the anatomical components in a deeply located and/or hidden area during neurosurgical procedures under the operating microscope. We have newly developed a flexible ultrathin endoscope integrated with irrigation suction apparatus (FUEISA) to visualize deeply located and/or hidden areas for assisting microneurosurgery. OBJECTIVE The present study investigated the usefulness of the FUEISA system for direct clipping surgery of cerebral aneurysms. METHODS Twenty-one patients underwent microneurosurgery assisted with the FUEISA system for direct clipping of cerebral aneurysms. The flexible ultrathin endoscope (outer diameter 0.75mm) consists of an image guide (6000 dpi) and a light guide, integrated with the irrigation suction apparatus. This endoscopic system was inserted before and after clipping to observe the anatomical conditions surrounding the lesions. RESULTS In all cases, handling and operation of the FUEISA was technically successful during the surgical procedure. The ultrathin endoscope was adequately integrated with the irrigation suction apparatus in all cases. General anatomy visualization including the lenticulostriate arteries, medial striate arteries, and/or internal carotid artery perforators was possible, and the correct clip positioning and vessel conditions were easily checked. The endoscope revealed that the clip had been positioned incorrectly in one case. No complications associated with the endoscopic system occurred. CONCLUSIONS The FUEISA system can be applied with safe manipulation, which was remarkably useful for confirmation of the presence of perforators and cranial nerves behind the lesions, particularly anatomical components located in deep and/or hidden areas during clipping of cerebral aneurysms.


World Neurosurgery | 2016

Usefulness of Extradural Optic Nerve Decompression via Trans–Superior Orbital Fissure Approach for Treatment of Traumatic Optic Nerve Injury: Surgical Procedures and Techniques from Experience with 8 Consecutive Patients

Naoki Otani; Kojiro Wada; Kazuya Fujii; Terushige Toyooka; Kohsuke Kumagai; Hideaki Ueno; Satoshi Tomura; Arata Tomiyama; Yasuaki Nakao; Takuji Yamamoto; Kentaro Mori

OBJECTIVE To describe our experience of extradural optic nerve decompression via the trans-superior orbital fissure approach for traumatic optic neuropathy (TON) and retrospectively analyze its advantages and pitfalls. METHODS Between September 2009 and August 2014, 8 consecutive patients with TON underwent extradural optic canal decompression via the trans-superior orbital fissure approach. We retrospectively reviewed medical charts, radiologic findings, surgical techniques, complications, and final surgical results. RESULTS All 8 patients presented with visual disturbance caused by head injury; 2 patients had no light perception, 6 had light perception, and 2 had ophthalmoplegia. All patients underwent extradural optic canal decompression and high-dose steroid administration within 24 hours after injury. Postoperative visual acuity on discharge was improved in 6 patients and unchanged in 2. The 2 patients with ophthalmoplegia gradually recovered by 3 months after operation. The postoperative outcome was good recovery in 7 patients and moderate disability in 1 patient. There were no complications related to the surgical procedure. CONCLUSIONS Emergent optic canal release has been recommended in patients with TON. The advantage of the extradural optic canal decompression via the trans-superior orbital fissure approach is easy identification of the optic canal after partial removal of the anterior clinoid process, resulting in fewer surgical complications. In addition, this procedure can achieve intraorbital decompression if necessary. We recommend this modified approach with mini-peeling as a safe and reliable procedure in patients with TON.


Acta neurochirurgica | 2015

Canine Double Hemorrhage Model of Experimental Subarachnoid Hemorrhage

Kentaro Mori; Kazuya Fujii; Satosi Tomura; Hideaki Ueno; Kojiro Wada; Naoki Otani; Hideo Osada; Arata Tomiyama

Several animal subarachnoid hemorrhage (SAH) models have been proposed for the investigation of cerebral vasospasm. We describe the experimental procedures of a canine double-SAH model and also examine the model based on the canine physiological parameters and occurrence of angiographic delayed cerebral vasospasm using magnetic resonance (MR) imaging and digital subtraction angiography. Autologous blood was injected twice on days 1 and 3 in 36 beagles. All animals showed delayed angiographic vasospasm in the vertebrobasilar arteries on day 7. The degree of vasospasm was 29-42 % of the arterial caliber. MR imaging did not show any ischemic change. This animal model can produce definite delayed vasospasm without detectable cerebral infarction on MR imaging. The canine SAH model is suitable for the quantitative and chronological study of delayed angiographic vasospasm, but not for investigating early brain injury and delayed cerebral ischemia.


Journal of Neurosurgery | 2017

Validation of effectiveness of keyhole clipping in nonfrail elderly patients with unruptured intracranial aneurysms.

Kentaro Mori; Kojiro Wada; Naoki Otani; Arata Tomiyama; Terushige Toyooka; Kazuya Fujii; Kosuke Kumagai; Satoru Takeuchi; Satoshi Tomura; Takuji Yamamoto; Yasuaki Nakao; Hajime Arai

OBJECTIVE Advanced age is known to be associated with a poor prognosis after surgical clipping of unruptured intracranial aneurysms (UIAs). Keyhole clipping techniques have been introduced for less invasive treatment of UIAs. In this study, the authors compared the complications and clinical and radiological outcomes after keyhole clipping between nonfrail elderly patients (≥ 70 years) and nonelderly patients. METHODS Keyhole clipping (either supraorbital or pterional) was performed to treat 260 cases of relatively small (≤ 10 mm) anterior circulation UIAs. There were 62 cases in the nonfrail elderly group (mean age 72.9 ± 2.6 years [± SD]) and 198 cases in the nonelderly group (mean age 59.5 ± 7.6 years). The authors evaluated mortality and morbidity (modified Rankin Scale score > 2 or Mini-Mental State Examination [MMSE] score < 24) at 3 months and 1 year after the operation, the general cognitive function by MMSE at 3 months and 1 year, anxiety and depression by the Beck Depression Inventory (BDI) and Hamilton Rating Scale for Depression (HAM-D) at 3 months, and radiological abnormalities and recurrence at 1 year. RESULTS Basic characteristics including comorbidities, frailty, and BDI and HAM-D scores were not significantly different between the 2 groups, whereas the MMSE score was slightly but significantly lower in the elderly group. Aneurysm location, largest diameter, type of keyhole surgery, neck clipping rate, and hospitalization period were not significantly different between the 2 groups. The incidence of chronic subdural hematoma was not significantly higher in the elderly group than in the nonelderly group (8.1% vs 4.5%, p = 0.332); rates of other complications including stroke and epilepsy were not significantly different. Lacunar infarction occurred in 3.2% of the elderly group and 3.0% of the nonelderly group. No patient in the elderly group required re-treatment or demonstrated recurrence of clipped aneurysms. The MMSE score at 3 months significantly improved in the nonelderly group but did not change in the elderly group. The BDI and HAM-D scores at 3 months were significantly improved in both groups. No patient died in either group. The morbidity at 3 months and 1 year in the elderly group (1.6% and 4.8%, respectively) was not significantly different from that in the nonelderly group (2.0% and 1.5%, respectively). CONCLUSIONS Keyhole clipping for nonfrail elderly patients with relatively small anterior circulation UIAs did not significantly increase the complication, mortality, or morbidity rate; hospitalization period; or aneurysm recurrence compared with nonelderly patients, and it was associated with improvement in anxiety and depression. Keyhole clipping to treat UIAs in the nonfrail elderly is an effective and long-lasting treatment.


Asian journal of neurosurgery | 2015

Safe fronto-orbito-zygomatic osteotomy using a diamond-coated threadwire saw in orbito-zygomatic craniotomy

Kojiro Wada; Kentaro Mori; Terushige Toyooka; Naoki Otani; Kazuya Fujii; Hideaki Ueno; Satoshi Tomura; Arata Tomiyama

Orbito-zygomatic craniotomy is a widely accepted skull-based technique, but osteotomy at the malar eminence (ME) is complicated. We have developed a safe fronto-orbito-zygomatic (FOZ) osteotomy by creating small guide burr holes in the superior and lateral parts of the orbital wall and cutting the bone using a diamond-coated threadwire saw. This method involves standard two-piece osteotomy by creating small superior and lateral guide orbital burr holes instead of sectioning into the superior and inferior orbital fissures. The guide burr holes are connected using a diamond-coated threadwire saw to create the FOZ bar. This method was applied to the treatment of four patients with skull-based tumors or internal carotid and basilar artery aneurysms. Postoperative three-dimensional bone density computed tomography showed minimum bone gap in the ME. No craniotomy-related complication has occurred. FOZ osteotomy by creating guide burr holes in the orbital wall and cutting the bone using a diamond-coated threadwire saw is safe and results in minimum bone gap in the ME.


World Neurosurgery | 2016

Usefulness of Suction Decompression Method Combined with Extradural Temporopolar Approach During Clipping of Complicated Internal Carotid Artery Aneurysm

Naoki Otani; Kojiro Wada; Terushige Toyooka; Kazuya Fujii; Hideaki Ueno; Satoshi Tomura; Arata Tomiyama; Yasuaki Nakao; Takuji Yamamoto; Kentaro Mori


Journal of Neurosurgery | 2017

Head-up display may facilitate safe keyhole surgery for cerebral aneurysm clipping

Terushige Toyooka; Naoki Otani; Kojiro Wada; Arata Tomiyama; Satoru Takeuchi; Kazuya Fujii; Kosuke Kumagai; Takashi Fujii; Kentaro Mori

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Kentaro Mori

National Defense Medical College

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Kojiro Wada

National Defense Medical College

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Naoki Otani

National Defense Medical College

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Terushige Toyooka

National Defense Medical College

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Arata Tomiyama

National Defense Medical College

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Satoshi Tomura

National Defense Medical College

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Hideo Osada

National Defense Medical College

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