Yuji Matsumaru

Embolic materials for endovascular treatment of cerebral lesions.

Recently developed soft microcatheters can be maneuvered endovascularly into the brain, permitting treatment of lesions without conventional neurosurgery. Progress in biomaterial science has contributed significantly to the development of this new therapeutic modality termed intravascular neurosurgery or interventional neuroradiology. Although embolic materials play an important role, ideal materials have yet to be devised. Various embolic materials in clinical use are reviewed, such as cyanoacrylates, ethylene-vinyl alcohol copolymer mixtures, Ethibloc, ethanol, estrogen, poly(vinyl acetate), cellulose acetate polymer, poly(vinyl alcohol), gelatin sponges, microfibrillar collagen, surgical silk sutures, detachable balloons, and coils. The materials are reviewed in the context of treatment application for various brain lesions, such as arteriovenous malformations, cerebral aneurysms, and head and neck tumors. Further developments in biomaterial polymer science can bring about progress against brain diseases.

Small unruptured cerebral aneurysms presenting with oculomotor nerve palsy.

OBJECTIVESymptomatic unruptured aneurysms have been considered at relatively high risk for future rupture, and the majority of aneurysms that cause symptoms of mass effect are large. Unruptured aneurysms smaller than 1 cm in diameter sometimes cause neurological symptoms, but their clinical aspects remain obscure. In this article, we review our experience with small unruptured aneurysms presenting with oculomotor nerve palsy. METHODSSixteen patients with unruptured aneurysms smaller than 1 cm presenting with oculomotor nerve palsy were included in this study. The patients’ clinical profiles were reviewed, and factors affecting the recovery of oculomotor function were determined. RESULTSThe mean size of the aneurysms was 5.8 ± 1.4 mm. Eleven patients (68.8%) had preceding retrobulbar pain. Fifteen patients underwent successful microsurgical clipping or intravascular embolization, but one patient died of aneurysm rupture before surgery. Seven patients (43.8%) had a complete recovery of oculomotor function, six (37.5%) had an incomplete recovery, and two (12.5%) remained unchanged after treatment. The mean interval between the onset of oculomotor nerve palsy and treatment was 4.7 ± 3.3 days in patients with complete recovery, 24.2 ± 15.5 days in patients with incomplete recovery, and 41.0 ± 12.7 days in unchanged patients. Early surgery resulted in more complete recovery of neural function (P < 0.01). CONCLUSIONUnruptured aneurysms smaller than 1 cm can cause neurological symptoms of mass effect. We recommend timely surgery, preferably within 5 days, to avoid not only aneurysm rupture but also functional disability even in patients with unruptured aneurysms smaller than 1 cm.

Application of thermosensitive polymers as a new embolic material for intravascular neurosurgery

Application of thermosensitive polymers as an embolic material for intravascular neurosurgery was investigated. We intended to use thermosensitive polymers to occlude vessels by precipitation in response to body temperature. Copolymers of N-isopropylacrylamide (NIPAM) and N-n-propylacrylamide (NPAM) were selected as thermosensitive polymers. To determine the optimal lower critical soluble temperature (LCST) for the embolic material, we developed an in vitro flow model. In this study the copolymers with an LCST of 24-26 degrees C showed appropriate precipitation. To prove the occlusion of vessels in vivo, we injected the copolymers into a rabbit kidney through a microcatheter. The extent of embolization was judged by angiography and histological examination. An acute toxicity test of the copolymer of NIPAM and NPAM was performed in comparison with that of the NIPAM monomer. The copolymer used in this paper showed no acute toxicity in mice. Water solubility, non-adhesiveness, and non-toxicity are the advantages of the use of thermosensitive polymers as an embolic material. By changing the LCST, various embolic materials can be designed. Based on our results, we believe that the application of thermosensitive polymers as a new embolic material is very promising.

Determinants of Poor Outcome After Aneurysmal Subarachnoid Hemorrhage when both Clipping and Coiling Are Available: Prospective Registry of Subarachnoid Aneurysms Treatment (PRESAT) in Japan

OBJECTIVE To examine current determinants of poor outcome after aneurysmal subarachnoid hemorrhage (SAH) when ruptured aneurysms are treated with either microsurgery (clipping) or endovascular treatment (coiling) depending on each patients characteristics. METHODS Between March 2006 and February 2007, 534 patients with SAH were enrolled in the Prospective Registry of Subarachnoid Aneurysms Treatment (PRESAT) project. Patients were treated according to the preference of investigators who were experienced in performing both clipping and coiling. Factors influencing poor outcome (12-month modified Rankin Scale [mRS], 3-6) were determined using multivariate logistic regression analyses. RESULTS In this cohort, 32.4% of patients were World Federation of Neurosurgical Societies (WFNS) grade IV-V, and 28.1% had a poor outcome. Clipping was preferably performed for small aneurysms with a wide neck and for middle cerebral artery (MCA) aneurysms, whereas coiling was preferred for larger, internal carotid artery (ICA) and posterior circulation aneurysms. In addition to increasing age, admission WFNS grade IV-V, preadmission aneurysmal rerupture, vasospasm-induced cerebral infarct, pneumonia, sepsis, shunt-dependent hydrocephalus and seizure, postclipping hemorrhagic complications (odds ratio 4.8, 95% confidence interval 1.5-15.3, P < 0.01), and postcoiling ischemic complications (odds ratio 4.4, 95% confidence interval 1.3-15.2, P < 0.05) significantly caused poor outcomes, although the complications did not affect mortality. Type of treatment modality and size and location of aneurysms did not influence outcome. CONCLUSIONS Introducing an endovascular treatment option has made aneurysm characteristics less important to outcome, but procedural complications are problematic and should be reduced to improve outcome.

Cilostazol reduces restenosis after carotid artery stenting

BACKGROUND Although carotid artery stenting (CAS) has been proposed as an alternative to carotid endarterectomy in cerebral revascularization, restenosis remains an unsolved issue. Cilostazol is a unique antiplatelet drug that has vasodilatory effects and inhibits smooth muscle cell proliferation. We investigated whether cilostazol reduces restenosis after CAS. METHODS A database of 113 consecutive CAS procedures between April 2002 and December 2007 was assessed retrospectively. All patients received aspirin (100 mg/d) and another antiplatelet drug such as cilostazol (200 mg/d), ticlopidine (200 mg/d), or clopidogrel (75 mg/d) at least 3 days before CAS. Two antiplatelet drugs were continued for 2 to 3 months after CAS and reduced to one thereafter. Patients were evaluated at 3 and 6 months and at 6-month intervals thereafter with duplex ultrasound (DUS) imaging. Angiography was used for confirmation when stenosis was suspected as >50% with DUS imaging. RESULTS We were able to monitor 97 patients for a 12-month period. The overall combined rate of stroke, myocardial infarction, and death was 3.1% at 30 days and 4.1% at 1 year. In-stent recurrent stenosis was documented in 11 patients (11%); in 10 patients (9.7%), this occurred <or=12 months of CAS. In-stent restenosis was significantly reduced in the cilostazol (+) group (0% vs 15.7% [11 of 70], P = .03). Patient characteristics were similar between the cilostazol (+) and cilostazol (-) groups. CONCLUSIONS Although this study was retrospective and nonrandomized, the results suggest that cilostazol administration improves long-term patency after CAS due to its inhibitory effect on smooth muscle cell growth.

Multiple dural arteriovenous fistulae involving the cavernous and sphenoparietal sinuses

Abstract A 72-year-old woman who presented with a unilateral oculomotor nerve palsy was shown to have a very rare condition: multiple dural arteriovenous fistulae (DAVF) involving the cavernous and sphenoparietal sinuses. The sphenoparietal DAVF was cured completely by transarterial embolisation. Symptomatic relief was accomplished by this procedure. The cavernous sinus DAVF progressed to acquire cortical venous drainage, and was obliterated completely by transvenous embolisation.

Periprocedural Cilostazol Treatment and Restenosis after Carotid Artery Stenting: The Retrospective Study of In-Stent Restenosis after Carotid Artery Stenting (ReSISteR-CAS)

Restenosis after carotid artery stenting (CAS) is a critical issue. Cilostazol can reduce restenosis after interventions in coronary or femoropopliteal arteries. We investigated whether periprocedural cilostazol treatment was related to the incidence of in-stent restenosis (ISR) or target vessel revascularization (TVR) after CAS. The study group comprised 553 of 580 patients who underwent CAS between April 2003 and August 2006 and were followed for 30 months after the procedure. ISR was defined as stenosis of at least 50% detected on angiography or ultrasonography. TVR was defined as revascularization of the treated carotid artery. During CAS, 207 patients (37.4%) were treated with cilostazol. Over 30 months, ISR occurred in 23 patients (4.2%), TVR occurred in 16 patients (2.9%), and either ISR or TVR occurred in 25 patients (4.5%). The incidence of ISR or TVR was significantly lower in the cilostazol-treated group than in the untreated group (1.4% vs 6.4%; log-rank P = .006). In a multivariate analysis, cilostazol treatment (hazard ratio [HR], 0.28; 95% confidence interval [CI], 0.08-0.95; P = .041) and stent diameter (HR, 0.73/1-mm increase; 95% CI, 0.54-0.99; P = .044) were independent factors for the occurrence of ISR or TVR. The incidence of a composite of events, including thromboembolism, hemorrhage, death, and TVR, tended to be lower in the cilostazol-treated group than in the untreated group (15.0% vs 19.9%; log-rank P = .17). Periprocedural cilostazol treatment was associated with lower rates of ISR and retreatment after CAS. A prospective randomized controlled trial is needed to clarify the effect of cilostazol on ISR after CAS.

Selective arterial embolization with n-butyl cyanoacrylate in the treatment of aneursymal bone cyst of the thoracic vertebra: a case report.

Study Design. A case report of aneurysmal bone cyst of the mobile spine. Objective. To present a pediatric case of aneurysmal bone cyst (ABC) of the mobile spine treated successfully by selective arterial embolization (SAE) with n-butyl cyanoacrylate (NBCA). Summary of Background Data. The endovascular treatment is an important treatment option for the ABC of the mobile spine. However, there are few reported case treated by SAE with NBCA. Methods. A 12-year-old healthy boy was introduced with a complaint of back pain. Computed tomography showed an osteolytic expanding mass in the pedicle, lamina, and spinous process on the level of T10. Magnetic resonance imaging revealed a multicystic mass with fluid-fluid levels that extended into the spinal canal and compressed the spinal cord from the dorsal side. Digital subtraction angiography showed an abnormal blood supply from the posterior spinal branch of the left T9 artery. An abnormal mass was diagnosed as an ABC based on these neuroradiologic examinations. Result. The patient underwent SAE with NBCA (Histoacryl, B. Braun, Melsungen, Germany) diluted with Lipiodol (Laboratorie Guerbet, France) in a rate of 1:4. Computed tomography performed 1 month after treatment revealed partial ossification of the bone cortex. MR imaging showed shrinkage of the cyst and decompression of the spinal cord. Back pain of the patient disappeared and the shrunken cyst was stable without recurrence during the 3-year follow-up period. Conclusion. SAE in a pediatric case with ABC of the mobile spine was effective in improving of clinical symptom and shrinking of the cyst.

Ruptured aneurysm of the ophthalmic artery trunk demonstrated by three-dimensional rotational angiography: case report.

OBJECTIVE AND IMPORTANCE Aneurysms arising from the ophthalmic artery are extremely rare, compared with carotid-ophthalmic aneurysms arising from the wall of the internal carotid artery. We present a very unusual type of aneurysm arising from the ophthalmic artery itself. CLINICAL PRESENTATION A 54-year-old man presented with a sudden onset of headache and was transferred to a local hospital. Computed tomography demonstrated subarachnoid hemorrhage around the left anterior clinoid process, but digital subtraction angiography failed to localize the source of the hemorrhage. The patient was referred to our hospital for further evaluation and treatment. Conventional cerebral angiography did not reveal the source of the hemorrhage, but three-dimensional rotational angiography clearly demonstrated an aneurysm arising from the ophthalmic artery trunk, apart from the internal carotid artery. INTERVENTION The patient underwent microsurgical clipping of the aneurysm via a left pterional craniotomy. The aneurysm originated from the bifurcation of the ophthalmic artery and a perforating artery to the optic nerve. The aneurysm was successfully obliterated, and the postoperative course was uneventful. CONCLUSION This report is the first to describe a case of a ruptured aneurysm arising from the ophthalmic artery trunk. We discuss the clinical significance of an aneurysm at this site, as well as the role of three-dimensional rotational angiography in determining the source of subarachnoid hemorrhage.

Recent trends in neuroendovascular therapy in Japan: analysis of a nationwide survey--Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2.

The present study retrospectively analyzed the database of the Japanese Registry of Neuroendovascular Therapy 1 and 2 (JR-NET1&2) to determine annual trends, including adverse events and clinical outcomes at 30 days after undergoing neuroendovascular therapy. JR-NET1&2 are surveys that targeted all patients in Japan who underwent neuroendovascular therapy delivered by physicians certified by the Japanese Society of Neuroendovascular Therapy (JSNET) between 2005 and 2009. Medical information about the patients was anonymized and retrospectively registered via a website. Data from 32,608 patients were analyzed. The number of treated patients constantly increased from 5,040 in 2005 to 7,406 in 2009 and the rate of octogenarians increased from 7.0% in 2005 to 10.4% in 2009. The proportion of procedures remained relatively constant, but ratios of angioplasty slightly increased from 32.8% in 2005 to 33.7% in 2009. Procedural complications were associated more frequently with acute stroke (9.6%), ruptured aneurysms (7.4%), intracranial artery disease (ICAD) (5.4%), and arteriovenous malformation (AVM, 5.2%). The number of patients requiring neuroendovascular treatment in Japan is increasing and the outcomes of such therapy are clinically acceptable. Details of each type of treatment will be investigated in sub-analyses of the database.