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Featured researches published by Jun Niki.


Interventional Neuroradiology | 2011

Outcomes analysis of ruptured distal anterior cerebral artery aneurysms treated by endosaccular embolization and surgical clipping.

Sachio Suzuki; Akira Kurata; Masaru Yamada; Kazuhisa Iwamoto; K. Nakahara; K. Sato; Jun Niki; M. Sasaki; Takao Kitahara; K. Fujii; S. Kan

Although endovascular surgery is now widely used to treat intracranial aneurysms, no comparative studies of clipping versus endovascular surgery to address distal ACA aneurysms at the same institution are available. We compared the results of these treatment modalities to address distal ACA aneurysms at our institution. We treated 68 patients with ruptured distal ACA aneurysms (endovascular surgery, n=13; clipping surgery, n=55). We performed a retrospective comparison of the treatment outcomes. To study the efficacy of endovascular surgery we classified all our cases into three types: type A were small-necked aneurysms, type B were wide-necked aneurysms on the parent artery, and type C were aneurysms in which the A3 portion of the ACA arose from the aneurysmal dome near the neck. Intraoperative hemorrhage occurred in 7.7% of aneurysms treated by endovascular surgery and in 34.5% treated by clipping surgery. In 7.7% of the endovascularly-treated aneurysms we noted coil migration during embolization surgery; venous infarction due to cortical vein injury occurred in 7.3% of clipped aneurysms. Of the endovascularly-treated aneurysms, 7.7% manifested post-embolization hemorrhage; 23.1% manifested coil compaction. In clipping surgery, postoperative rerupture occurred in 1.8% of the aneurysms; one patient presented with postoperative acute epidural hematoma. Clip dislocation was noted in 1.8% of aneurysms. Angiography was indicative of post-treatment vasospasm in 7.7% of aneurysms treated endovascularly and in 50.9% of the clipped aneurysms. The clinical outcome showed no significant difference between endovascular surgery and clipping surgery.


Neuroradiology | 2009

Direct-puncture approach to the extraconal portion of the superior ophthalmic vein for carotid cavernous fistulae

Akira Kurata; Sachio Suzuki; Kazuhisa Iwamoto; Tomoko Miyazaki; Madoka Inukai; Katsutoshi Abe; Jun Niki; Masaru Yamada; Kiyotaka Fujii; S. Kan

IntroductionThe transvenous approach via the superior ophthalmic vein (SOV) is an available approach for carotid cavernous fistula (CCF), especially in the event that there is no other suitable approach route to the fistula. Surgical exposure of the peripheral roots of the SOV is commonly used; however, often, the SOV is often not accessible because of anatomical problems and/or complications. In this paper, we present and discuss our original direct-puncture approach to the extraconal portion of the SOV.MethodsAn attempt on three patients with traumatic CCF failed with the transarterial approach and the conventional venous approach via the inferior petrosal sinus; therefore, the patients were treated with the direct-puncture approach to the extraconal portion of the SOV using two-dimensional digital subtraction angiography with local anesthesia.ResultsAll cases that had tortuous and partially stenotic division of the SOV were treated successfully with this approach and without complications.ConclusionThis approach will become an alternate approach, especially when the peripheral roots of the SOV are focally narrowed and tortuous, making it impossible to insert a catheter.


International Scholarly Research Notices | 2011

Dural Arteriovenous Fistulas in the Cavernous Sinus: Clinical Research and Treatment

Akira Kurata; Sachio Suzuki; Kazuhisa Iwamoto; Kuniaki Nakahara; Makoto Sasaki; Chihiro Kijima; Madoka Inukai; Katsutoshi Abe; Jun Niki; Kimitoshi Satou; Kiyotaka Fujii; Shinichi Kan

Introduction. The purpose of this paper is to clarify the clinical course, with the dural carotid cavernous fistula (CCF), featuring a pallet of symptoms, paying special attention to radiological findings. Methods. Seventy-six consecutive patients with dural CCFs were investigated in detail, all of whom were defined by angiography. Results. The most common initial symptom was diplopia in 47 patients (62%) and the most frequently observed on arrival were type II, featuring cranial nerve palsies followed by the classical triad in 27, and then type I only with cranial nerve palsies. The time until admission with type I (mean: 6.7 W ± 6.0) was significantly shorter than that with type II (mean: 25.1 W ± 23.5). Branches from bilateral carotid arteries widely inflowing into bilateral carotid cavernous sinus were present in 30 (39%), 20 (26%) of which also demonstrated direct inflow into the intercavernous sinus. type I and II had more multiple venous drainage routes as compared with type III (classical triad only on arrival) and IV (initial development of the classical triad followed by cranial nerve palsy). Conclusion. In our series of dural CCF patients, the most common initial symptom was cranial nerve palsy, mostly featuring multiple venous drainage including cortical drainage. Such palsies should be added to the classical triad as indicative symptoms. Bilateral carotid arteries often inflow into cavernous and intercavernous sinuses, which should be taken into account in choice of therapeutic strategy.


Interventional Neuroradiology | 2007

Efficacy of Endovascular Surgery for Unruptured Internal Carotid Artery Aneurysms Presenting with Cranial Nerve Symptoms

Sachio Suzuki; Akira Kurata; S. Kan; Masaru Yamada; Jun Niki; I. Yuzawa; K. Sato; Kazuhisa Iwamoto; Hidehiro Oka; K. Fujii

Whether endovascular surgery is able to reduce the mass effects of unruptured aneurysms is still controversial, although some reports have suggested efficacy in cases of internal carotid artery aneurysms with cranial nerve palsy. Here we assessed outcome in a series of cases. Between April 1992 and April 2005, 18 patients with unruptured internal carotid artery aneurysms presenting with cranial nerve palsy were treated by endovascular surgery. The patients were two males and 16 females aged from 19 to 84 (mean 59.6 years). Aneurysms were located in the cavernous portion in 14, at the origin of the ophthalmic artery in one and at the origin of P-com in three. The aneurysms were all embolized using Guglielmi detachable coils, Interlocking detachable coils, Cooks detachable coils or Trufill DSC and detachable Balloons were applied to occlude the proximal parent artery. We analyzed the efficacy of endovascular surgery for such aneurysms retrospectively. The mean aneurysm size was 21.4 mm and the mean follow-up period was 57.7 months. Palsy of IInd cranial nerve was evident in three patients, of the IIIrd in eight, of the Vth and Vth in one each, and of the VIth in nine. Post embolization occlusion was complete in nine patients and neck remnant in the other seven. Regarding complications of endovascular surgery, one case (5.6%) showed TIA after embolization. Overall 11 (46%) cranial nerve symptoms showed complete resolution, eight (33%) showed some improvement, and five (21%) were unchanged. In three cases (12.5%), the symptoms worsened after treatment. The shorter the duration of symptoms was a factor predisposing to resolution of symptoms. In complete resolution cases, the timing of treatment after symptoms appeared and the time of complete resolution were in proportion. These results showed that there is no difference in reduction of mass effects between surgical clipping and endovascular surgery for unruptured internal carotid artery aneurysms. With endovascular surgery, the rapidity of treatment after symptoms is the most important factor for successful results.


Interventional Neuroradiology | 2010

A case of non-traumatic subgaleal hematoma effectively treated with endovascular surgery.

H. Koizumi; Sachio Suzuki; S. Utsuki; K. Nakahara; Jun Niki; I. Mabuchi; Akira Kurata; K. Fujii

Non-traumatic subgaleal hematoma is very rare. We present a case of refractory non-traumatic subgaleal hematoma occurring in a 15-year-old male patient. The patient was successfully treated by embolization of the superficial temporal artery. This therapeutic approach to refractory non-traumatic subgaleal hematoma is discussed.


Interventional Neuroradiology | 2007

Endovascular Surgery for Ruptured Aneurysms with Vasospasm

Akira Kurata; Sachio Suzuki; Jun Niki; H. Ozawa; Masaru Yamada; K. Fujii; S. Kan; Takao Kitahara; Yoshio Miyasaka; Taketomo Ohmomo

With the existence of vasospasm, it is recommended that direct clipping surgery for a ruptured aneurysm be delayed until its disappearance, but this may be associated with aneurysmal re-rupture resulting in a poor outcome for the patients. Indications for endovascular coil embolization in such cases are discussed. Since November in 2003, we have applied endovascular coil embolization in 11 consecutive patients with ruptured aneurysms and apparent vasospasm of the parent artery from two to 17 days (average: eight days) after initial subarachnoid hemorrhage. Three patients had aneurysmal re-rupture before treatment, but the other eight had only experienced the one episode of subarachnoid hemorrhage. With one exception, all endovascular procedures could be successfully performed, resulting in complete occlusion of aneurysms and remarkable dilatation of inserted spastic vessels without technical complications or aneurysmal re-rupture. For the one case of failure because of a tortuous artery, direct clipping surgery was performed after disappearance of vasospasm. Cerebral infarction occurred in four, but only one correlated with the distribution of catheterization, and neurological deficits had completely disappeared three months after the onset. This preliminary report concerning a small number of patients suggests that endovascular coil embolization is not contra-indicated for aneurysms with vasospasm requiring catheterization. A large study for confirmation is now warranted.


Neurological Research | 2011

Contrast stasis in large and giant internal carotid artery aneurysms as a good prognostic factor for endovascular coil embolization: retrospective study

Sachio Suzuki; Akira Kurata; Masaru Yamada; Kazuhisa Iwamoto; Kuniaki Nakahara; Jun Niki; Kimitoshi Sato; Kiyotaka Fujii; Shinichi Kan

Abstract Objective: Before treatment for large and giant aneurysms, we need some of the predictors to prognose a good result. In this retrospective study, we attempted to determine criteria such as angiographic signs to identify good candidates for effective endovascular surgery. Methods: This study involved 45 patients with large or giant aneurysms treated by endovascular embolization. For angiographic study, we delivered a bolus injection of contrast medium. All aneurysms were confirmed angiographically and the morphology was defined in detail before endovascular embolization. We divided the patients into two groups based on angiographic findings. Group A (n = 16) manifested stasis of the contrast medium in the aneurysm on venous phase. Group B (n = 29) exhibited other findings. We retrospectively evaluated the relationship between stasis of the contrast medium in the aneurysm and results of endovascular embolization. Results and Discussion: There was no significant difference between the two groups with respect to the size of the aneurysm. However, the neck/dome ratio (P = 0·04) and size of the neck (P = 0·003) were significantly different between groups A and B. The morphological outcome was better in group A than group B (P = 0·03). We demonstrate that contrast stasis is a good predictor of outcome in patients with large or giant aneurysms to consider the endovascular embolization. Hemodynamic studies on large patient populations may reveal other factors predictive of a good treatment outcome.


Interventional Neuroradiology | 2008

Relationship between Focal Inflammation and Symptom Exacerbation after Endovascular Coil Embolization for Symptomatic Intracranial Aneurysms.

Sachio Suzuki; Akira Kurata; Kazuhisa Iwamoto; Masaru Yamada; Jun Niki; Tomoko Miyazaki; Oka H; Kiyotaka Fujii; Shinichi Kan

As endovascular surgery (EVS) of symptomatic unruptured aneurysms can result in symptom exacerbation due to intra-aneurysmal thrombosis or lump formation by coils, this treatment remains controversial. We present five women ranging in age from 58 to 76 years (mean 65.6 years) who suffered post-EVS symptom exacerbation attributable to local inflammation. The aneurysms measured from 8 to 25 mm (mean 19 mm) and were located at the cavernous portion in four patients and at the origin of the ophthalmic artery in one. All underwent endosaccular embolization under local anesthesia. Immediately after embolization, 24 h anticoagulation therapy was started via the continuous injection of heparin; they also received anti-platelet therapy. At one to three days post-EVS, all five patients manifested worsening of their cranial nerve symptoms. In three other patients the symptoms were improved after EVS. We posit that inflammation induced by coil embolization may worsen cranial nerve symptoms transiently. Our findings suggest that post-EVS follow-up is necessary and that patients exhibiting an inflammatory reaction be treated with anti-inflammatory drugs.


Interventional Neuroradiology | 2008

Efficacy of Selective Transarterial Chemotherapy Using a Port System for Angiosarcomas of the Face and Scalp

Kazuhisa Iwamoto; Sachio Suzuki; Akira Kurata; K. Sato; Jun Niki; Tomoko Miyazaki; S. Utsuki; Hidehiro Oka; K. Fujii; S. Kan; M. Masuzawa

Angiosarcoma is a rare, highly malignant tumor with a poor clinical outcome. From January 2004 to September 2005, we advocated transarterial chemotherapy using a port system for four patients with angiosarcomas of the face and scalp. A heparin coated ANTHRON P-U catheter was introduced into the feeding artery. The proximal part of the P-U catheter was connected to the port system and buried in subcutaneous tissue. The amount of chemotherapeutic drug applied using the port system was almost the same as the conventional intravenous dose. Paclitaxel was the standard agent, at 50–100mg/diluted in 15–30 ml of physiological saline fluid slowly injected over 0.5–1 hour. For immunotherapy where appropriate, r-IL2 was mainly used at a dose of 70.000U/diluted in 5ml of physiological saline fluid injected into the port system over 30 seconds. This was continued for two to three weeks (five days/week) until recognition of a disappearance of the tumor. Macroscopic size reduction of the tumor was achieved in three out of the four cases. One case could not be evaluated because of eruptions induced by immunotherapy. Unfortunately two patients died after placement of port system, but the other two are still alive and are enjoying useful lives. Transarterial infusion chemotherapy using such a port system may be particularly effective for angiosarcoma in the early stages because small lesions with limited invasion mean a small territory of blood supply to be covered, and useful life was possible because the port system embedded in subcutaneous tissue allows treatment in an out-patient clinic.


Journal of Neurosurgery | 2006

Endovascular surgery for very small ruptured intracranial aneurysms

Sachio Suzuki; Akira Kurata; Taketomo Ohmomo; Takao Sagiuchi; Jun Niki; Masaru Yamada; Hidehiro Oka; Kiyotaka Fujii; Shinichi Kan

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S. Kan

Kitasato University

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