Tomotaka Ohshima

Risk of Aneurysmal Rupture

OBJECTIVEThe aim of the present study was to clarify the risk of rupture in terminal-type intracranial aneurysms using computational flow simulation analysis. METHODSFirst, idealized three-dimensional aneurysmal models were built from a solid voxel on the computer. We focused on round terminal-type aneurysms with the positioning of the neck orifice set according to the following three patterns in relationship to the axis of the parent artery: the Type-A neck orifice was positioned directly in line with the flow of the parent artery; the Type-B neck orifice was shifted 1.5 mm offline toward the unilateral branch; and the Type-C neck orifice was shifted 3 mm offline. Computational flow simulations were applied with Fujitsu α-Flow software (Fujitusu, Tokyo, Japan). We analyzed flow patterns using modified patient-specific models. We also investigated actual clinical situations to evaluate the differences in neck-orifice positioning between 20 ruptured aneurysms and 26 unruptured ones using three-dimensional angiograms. RESULTSThe Type-A neck orifice showed completely symmetrical stream lines in the aneurysm, whereas the Type-C orifice showed a clear round circulation. The Type-B neck orifice, on the other hand, exhibited intra-aneurysmal flow separation. The clinical research demonstrated that Type-B aneurysms were more likely to be found in the ruptured group (P < 0.05). CONCLUSIONFlow separation, recognized as one of the causes of intimal injury, could be observed only in Type-B aneurysms, a result that corresponded well with our clinical experience. From the flow-dynamics point of view, this positioning of the neck orifice may be one of the risk factors most likely to induce the rupture of unruptured aneurysms.

A case of giant common carotid artery aneurysm associated with vascular Behçet disease : successfully treated with a covered stent

BACKGROUND A carotid artery aneurysm associated with vascular Behçet disease is extremely rare and often difficult to treat. In this article, we explore a definitive therapeutic strategy for pseudoaneurysm with vascular Behçet disease. CASE DESCRIPTION A 56-year-old man presented with swelling and a pulsatile subcutaneous mass of the left neck over a 6-month period. The diagnosis of vascular Behçet disease had already been established from the history of right subclavian artery aneurysm, oral ulcerations, and inflammatory skin lesions. Radiologic examination revealed a giant left CCA aneurysm (6.5 x 5.5 cm) with partial thrombosis. Another asymptomatic aneurysm was found in the right ICA. Because mass effects due to aneurysmal rupture and growth rapidly progressed, we decided on radical treatment. The endovascular reconstruction of the carotid artery was selected instead of direct surgery because of skin and connective tissue disorders at the regional site. A covered stent (8 x 60 mm, Passager, Boston Scientific, Fremont, CA) was placed from the CCA to the ICA, covering the whole aneurysmal portion. Postoperatively, the cervical mass remarkably reduced in size, and the patients symptoms dramatically improved. The left carotid artery was patent at 12-month follow-up. CONCLUSIONS A covered stent is very useful in repairing arteries with pseudoaneurysm, particularly in cases unsuitable for direct surgery with parent artery occlusion. The influence of the foreign body at the inflammatory lesion and long-term patency of covered stents should be discussed.

A novel pressure sensor with an optical system for coil embolization of intracranial aneurysms. Laboratory investigation.

OBJECT In endovascular coil embolization for an intracranial aneurysm, the excessive pressure created during coil insertion into an aneurysm can cause a catastrophic rupture or dislodge a microcatheter tip from the aneurysm dome, resulting in insufficient embolization. Such undue mechanical pressure can only be subjectively detected by the subtle tactile feedback the surgeon experiences. Therefore, the authors of this study developed a new sensor device to measure the coil insertion pressure via an optical system. METHODS This novel sensor system consists of a hemostatic valve connected to the proximal end of a microcatheter (Y-connector). The sensor principle is based on an optical system composed of a light-emitting diode (LED) and a line sensor. The latter measures how much the coil-delivery wire slightly bends in response to the insertion pressure by detecting the wire shadow. This information is translated into a given force level. Experimental aneurysm embolization was performed using this optical sensor. A silicone aneurysm model and an in vivo model (porcine aneurysm model) were used in this study. Several surgeons manually performed the coil insertions. The sensor continuously monitored the mechanical force during the insertions. RESULTS The sensor adequately recorded the coil insertion pressure during embolization. The presence of the sensor did not hinder the embolization procedure in any way. During embolization in the silicone aneurysm model, a sinusoid pattern of pressure occurred, reflecting actual clinical experience. Similar results were obtained in the in vivo study. CONCLUSIONS This new sensor device adequately measures coil insertion pressure. This system provides potentially safer and more reliable aneurysm embolizations.

Usefulness of three-dimensional digital subtraction angiography in endovascular treatment of a spinal dural arteriovenous fistula Report of 2 cases

The use of 3D digital subtraction (DS) angiography provides a better understanding of spinal vascular lesion architecture. The authors report on 2 cases involving a spinal dural arteriovenous fistula (DAVF) and demonstrate the usefulness of 3D DS angiography for endovascular treatment of these spinal DAVFs. In both cases, middle-aged male patients suffered from bilateral leg hypesthesia, gait disturbance, and urinary dysfunction several months before treatment. Spinal angiography revealed DAVFs that were fed by a radicular artery branching from the intercostal artery and draining veins proceeding superiorly along the perimedullary veins. Endovascular embolization was performed in both cases. Selective 3D DS angiography of the intercostal artery clearly demonstrated the tortuous course of the feeder and the relationship among the feeding artery, fistula point, and draining veins in each case. This information was very useful in selecting a working angle for manipulating the microcatheter and for glue injection. In addition, the maximum intensity projection image from rotational DS angiography data clearly showed the fistula point at the dural sleeve and feeder entering the spinal canal via the intervertebral foramen and the relationship with the bone structure. Successful obliteration of the fistulae was achieved in both cases. Selective spinal 3D DS angiography was very useful in understanding the complex spinal vascular architecture and in choosing the best working angle and therapeutic strategy for endovascular treatment of spinal DAVFs.

Evaluation of the characteristics of various types of coils for the embolization of intracranial aneurysms with an optical pressure sensor system

IntroductionIn coil embolization for an intracranial aneurysm, it is important to appropriately choose the coil most suitable for coping with various unforeseen situations. Additionally, because dense coil packing of the aneurysm sac is the most important factor to avoid a recurrence, properly selecting the coil is essential. In this article, the authors measured the coil insertion pressure of various types of coils with a newly developed sensor system, and coil characteristics were investigated.MethodsThe sensor consists of a hemostatic valve connected to the proximal end of a microcatheter. The sensor principle is based on an optical system. Using this, an experimental silicone aneurysm embolization was performed automatically at constant speed. The pattern of the insertion pressure and the maximum insertion pressure (MIP) were analyzed for the various types of coils. The sensor continuously monitored the mechanical force during the insertions.ResultsThe sensor adequately recorded the coil insertion pressure during embolization in each coil. MIP was generally ranked in order of the coil type. The soft type coils required relatively less insertion pressure than standard/helical and 3D type. As for the patterns of coil insertion pressure, each coil presented a saw-like pressure pattern, though we observed some slight differences. 3D type coils showed peak pressure at the moment of “painting”. Coil loop diameters barely affected MIP. However, as to the patterns of pressure, larger size coils more often presented the peak.ConclusionsCoil characteristics were well evaluated. The results obtained here reflected some actual clinical experience. Furthermore, collecting the in vivo study is mandatory, which may provide clinically useful data.

Selective Propofol Injection into the M1 Segment of the Middle Cerebral Artery (MCA Wada Test) Reduces Adverse Effects and Enhances the Reliability of the Wada Test for Determining Speech Dominance

OBJECT The Wada test is had been the most reliable for determining speech dominance. Drugs injected into the internal carotid artery, however, may be heterogeneously distributed as the result of asymmetry of the anterior cerebral arteries and the presence of a fetal-type posterior cerebral artery. Variations in drug distribution could occasionally alter consciousness and complicate the evaluation of the test results. We examined selective propofol injection into the M1 segment of the middle cerebral artery (MCA Wada test). METHODS For the MCA Wada test (17 patients), 7 or 8 mg of propofol was injected via a microcatheter navigated into the M1 segment, and language function was evaluated by patient performing several tasks. The conventional Wada test (internal carotid artery [ICA] Wada test) was performed in four patients (both the ICA and MCA Wada tests were performed in one patient). The efficacy and adverse effects of both procedures were evaluated; all tests were performed by well-trained interventional neuroradiologists. RESULTS Immediately after propofol injection during the MCA Wada test, patients developed transient contralateral hemiplegia and transient aphasia (in the case of injection on the dominant side). Confusion and other severe adverse effects did not occur during the MCA Wada test, but two of four patients who underwent the ICA Wada test showed altered consciousness that affected the performance of the test. CONCLUSIONS The MCA Wada test is a feasible and reliable preoperative evaluation, if performed by a trained team of interventional neuroradiologists.

A Stent-Retrieving into an Aspiration Catheter with Proximal Balloon (ASAP) Technique: A Technique of Mechanical Thrombectomy

OBJECTIVE The best technique for the first attempt at mechanical thrombectomy for acute ischemic stroke is a still matter of debate. In this study, we evaluate the efficacy of a stent-retrieving into an aspiration catheter with proximal balloon (ASAP) technique that uses a series of thrombus extraction by withdrawing the stent retriever into the aspiration catheter and continuous aspiration from the aspiration catheter at the first attempt. METHODS We performed a retrospective analysis of 42 consecutive patients with acute ischemic stroke caused by occlusions in the anterior circulation who were treated with the ASAP technique at our institution. Preoperative patient characteristic, including age, thrombus location, Alberta Stroke Program Early CT Score, National Institutions of Health Stroke Scale, and time from onset to puncture; postoperative Thrombolysis in Cerebral Infarction score; modified Rankin Scale score after 3 months; time from puncture to recanalization; the number of passes to achieve recanalization; and procedural complications, including intracranial hemorrhage, embolization to new territory, and distal embolization, were assessed. RESULTS A Thrombolysis in Cerebral Infarction score of 2B or 3 was achieved in 40/42 patients (95.2%). Average time from puncture to the final recanalization was 21.5 minutes. Recanalization was achieved in a single attempt in 31 patients (77.5%). Embolization to new territory was observed in only 2 patients (4.8%); no patient developed distal embolization or intracranial hemorrhage including asymptomatic subarachnoid hemorrhage. Thirty-two patients (76.2%) achieved modified Rankin Scale scores of 0-2 at 3 months postoperatively. CONCLUSIONS Our ASAP technique showed fast recanalization, minimal complications, and good clinical outcomes in this case series.

Successful Preoperative Endovascular Embolization of an Extreme Hypervascular Glioblastoma Mimicking an Arteriovenous Malformation

BACKGROUND Preoperative endovascular embolization as a treatment for hypervascular glioblastomas has not been established. We report the case of an extreme hypervascular glioblastoma mimicking an arteriovenous malformation that was successfully treated with preoperative embolization and subsequent removal. CASE DESCRIPTION A 66-year-old man presented with progressive right hemiparesis and sensory aphasia. Cranial computed tomography and magnetic resonance imaging revealed a left parietooccipital tumor with ring enhancement. Digital subtraction angiography revealed an extreme high-flow arteriovenous shunt. The patient underwent presurgical endovascular embolization using N-butyl cyanoacrylate in a manner similar to embolization for arteriovenous malformations. Subsequent tumor removal was achieved with minimal blood loss. CONCLUSIONS This is the first reported case of presurgical embolization of a glioblastoma with a high-flow shunt. Embolization of a malignant tumor with a high-flow shunt, in a manner similar to embolization of arteriovenous malformations, is feasible and effective.

Suitability of a 7-F ExoSeal Vascular Closure Device for Femoral Artery Punctures Made by 8-F or 9-F Introducer Sheaths

Purpose: To establish the safety and efficacy of the 7-F ExoSeal device for the closure of femoral puncture sites made by 8-F or 9-F introducer sheaths. Methods: Between January 2013 and December 2016, 332 patients (mean age 68.4±12.1 years; 195 men) underwent neurointerventional procedures via percutaneous puncture of the common femoral artery and an 8-F (n=272, 81.9%) or 9-F (n=60, 18.1%) introducer. The access sites were sealed with a 7-F ExoSeal in all cases. Procedure success and closure-related complication rates were evaluated, and risk factors for complications were analyzed by comparing patient characteristics between those who did and did not experience complications. Results: Procedure success rates were 99.3% in the 8-F group and 100% in the 9-F group. The overall complication rate was 6.3% (n=17; all in the 8-F group), of which 13 (4.8%) were minor sequelae, including access-site hematoma (n=8), oozing (n=3), pseudoaneurysm (n=1), and retroperitoneal bleeding (n=1). Among the 4 (1.5%) major complications were 3 instances of bleeding requiring a blood transfusion and 1 surgical vascular repair. No complications were observed in the 9-F group. Patients who experienced complications had significantly longer activated clotting times (262±46 vs 218±55 seconds; p<0.001) compared with patients without complications. Conclusion: A 7-F ExoSeal vascular closure device is safe and effective for the closure of femoral puncture sites made by 8-F or 9-F introducer sheaths.

Patterns of Recurrence After Resection of Malignant Gliomas With BCNU Wafer Implants: Retrospective Review in a Single Institution

BACKGROUND Bis-chloroethylnitrosourea (BCNU) wafers have been demonstrated to be effective for prolonging survival for patients with malignant glioma and have been approved worldwide. BCNU wafers are implantable and have a unique feature of delivering chemotherapeutic drug at high concentration at tumor margin over time after resection. BCNU wafers presumably, by this mechanistic rationale, have a beneficial effect on local tumor control and thus could change the pattern of recurrence, which is most frequently local. However, no studies have demonstrated such phenomenon after BCNU wafer implants. METHODS To investigate whether the surgeries with BCNU wafers alter the predominant tendency of local recurrence pattern, we retrospectively reviewed 8 malignant glioma patients treated with BCNU wafers (BCNU wafer group), together with 22 glioma patients who did not receive BCNU wafers (no-BCNU wafer group) for comparison. RESULTS Out of 6 patients in BCNU wafer group who exhibited recurrence, 1 showed local, 2 showed diffuse, and 3 showed a distant recurrence pattern, which was away from resection cavity. On the other hand, out of 18 patients in the no-BCNU wafer group who exhibited recurrence, 10 showed a local pattern, 8 showed a diffuse pattern, and no cases showed distant pattern. Distant pattern was observed significantly more frequently in the BCNU wafer group than in the no-BCNU wafer group. CONCLUSIONS These results suggest that BCNU wafers could have a beneficial effect on local tumor control and may provide BCNU wafers with a new profile that could be considered for establishing future chemotherapeutic strategy for glioma patients.