This study included 42 patients with moyamoya disease hospitalized at our institution between August 1995 and September 2012. We retrospectively examined their medical records for the disease course, patients' baseline characteristics, and outcomes of the surgical intervention.
Twenty-five patients were female (59.5%) and 17 were male (40.5%). Their age at the time of diagnosis ranged from 1 to 70 years (mean age, 37 years). Fourteen (33.3%) patients showed hemorrhage, 11 (26.2%) patients experienced transient ischemic attack, 6 (14.3%) patients showed cerebral infarction, 2 (4.8%) patients showed epilepsy, and 3 (7.1%) patients experienced headache at the time of diagnosis. In the case of 4 patients, the disease was incidentally detected, and in the case of 2 patients, the cause was unknown. Thirteen (76.5%) patients with ischemic symptoms, 2 patients (14.3%) with hemorrhage, 2 patients (100%) with epilepsy, and 2 patients who were asymptomatic underwent surgical intervention. In 3 of 18 (16.7%) patients who underwent surgical intervention and in 8 of 24 (33.3%) patients who did not undergo surgical intervention, the outcome was poor (modified Rankin Scale [mRS] score, 5 or 6). According to the classification of the patients by the disease onset, 4 of 17 (23.5%) patients with ischemic onset and 7 of 14 (50%) patients with hemorrhagic onset showed poor outcomes (mRS 5 or 6). Patients with hemorrhagic onset showed poorer outcomes than did those with ischemic onset, and the poorer outcomes were the consequence of bleeding. A method for the prevention of bleeding in patients with moyamoya disease needs to be established.

View full abstract

The authors experienced a curious phenomenon in an adult moyamoya patient. Mouth opening caused reversible occlusion of the donor superficial temporal artery (STA), and the patient exhibited transient cerebral ischemic symptoms. The aim of this study was to assess the incidence of such occlusion and the mechanisms behind this phenomenon.
Twelve adult moyamoya patients (15 affected sides) who underwent STA-middle cerebral artery anastomosis were included in the “direct group”. Ten patients with 15 affected sides who underwent indirect bypass surgery with STA as the donor vessel, were included in the “indirect group”. Ultrasound examination was performed postoperatively to determine whether mouth opening affects blood flow of the donor STA and leads to any ischemic symptoms. When changes in the blood flow of the donor STA were recognized, computed tomography angiography (CTA) or digital subtraction angiography (DSA) was performed under both mouth opening and closing conditions.
Under wide mouth opening condition, steno-occlusion of the donor STA occurred in 5 out of 15 sides (33.3%) in the direct group. On one side (6.7%), complete occlusion induced ischemic symptoms. In the indirect group, 1 out of 15 sides (6.7%) showed stenosis without any symptoms. Steno-occlusion occurred by at least two mechanisms; either the stretched temporalis muscle pushed the donor STA against the edge of the bone window, or the redundant donor STA kinked when the muscle was stretched.
Ischemic symptoms seem to occur rarely even with temporary occlusion of the donor STA. However, to avoid the “big bite ischemic phenomenon”, we recommend securing a sufficient distance between the donor STA and the edge of the bone window, and avoiding a redundant course of the donor STA within the muscle layer.

View full abstract

In our institution, 346 operations on 175 moyamoya disease patients aged less than 16 years, and 188 operations on 121 moyamoya disease patients aged 16 years and over have been performed between March 1, 2001 and December 31, 2013. Direct anastomosis was used in 173 operations in the former group and 122 operations in the latter. Five procedures, all in the former group, which had a recipient artery of diameter 0.3 mm or less, were performed with direct anastomosis. Under such conditions, direct anastomosis is possible, and we discuss its strategy here.
Fishmouth opening of a fine recipient should be performed by a single incision technique and should be as small as possible.
The tip of the microneedle should be moved to the inner surface of the arterial wall at the time when the surface of the brain is situated at the highest level, and it should pass the arterial wall when the surface of the brain moves downward. Finally, definite fixation and fine movement of a microneedle is mandatory for its passing of a recipient's arterial wall.

View full abstract

Cavernous carotid aneurysm (CCA) often causes cranial nerve symptoms via its mass effect. Because performing direct surgery is difficult anatomically, internal carotid artery (ICA) occlusion (i.e., parent artery occlusion [PAO]) is performed as an effective treatment for symptom improvement. However, bypass surgery is sometimes necessary depending on the results of the examination for cerebral blood-flow reserve.
PAO with or without bypass surgery is associated with a risk of ischemic complications during the perioperative period and during the long-term postoperative period. The indications for endosaccular coil embolization (ESC), which permits ICA patency with a relatively lower risk, have expanded with its approved use for intracranial stenting. However, because the mass effect of the aneurysm remains, the level of improvement of symptoms with the use of ESC is uncertain compared with that with the use of PAO.
In 10 CCA cases, we performed PAO with high-flow bypass in 2 cases, PAO with low-flow bypass in 2, ESC without stenting in 3, and ESC with stenting in 3. With PAO, the neurological symptoms improved, but ischemic complications occurred in a case for which PAO was performed with high-flow bypass. With ESC, although no ischemic complications occurred, the neurological symptoms did not improve in 2 cases.
Currently, the PAO-based procedure is the first choice for symptomatic CCAs. However, according to therapeutic purposes, ESC, which is less invasive and carries a lower risk of complications, could be applied. Furthermore, it seemed to be a potentially useful treatment for preventing the progression of asymptomatic cases.

View full abstract

Aneurysms arising from the intracavernous carotid artery account for 3-5% of all intracranial aneurysms. Bilateral intracavernous carotid artery aneurysms are rare, and there are few reported cases that have been treated surgically. Here, we present the case of a 65-year-old woman with bilateral giant and large aneurysms, who was successfully treated with surgery for bilateral aneurysms. The patient presented with progressive left oculomotor and abducens nerve palsies, and magnetic resonance imaging (MRI) showed bilateral intracavernous mass lesions. Cerebral angiography revealed left giant and right large aneurysms at the intracavernous carotid artery. As a treatment for the symptomatic left aneurysm, balloon test occlusion (BTO) of the left internal carotid artery (ICA) was performed using ¹⁵O gas positron emission tomography (PET). The PET study during the BTO showed slightly decreased cerebral blood flow (CBF) in the left hemisphere, without any neurological symptoms. Therefore, left ICA proximal ligation with low-flow bypass was performed. Just after the treatment, thrombosis of the aneurysm began, and the left cranial nerve palsies gradually improved. Three months after the surgery for the left aneurysm, the right aneurysm was treated by using endovascular coil embolization with a stent assist. The postoperative course was uneventful, and the PET study performed 6 months after surgery showed normal CBF, even in the left hemisphere. Bilateral intracavernous carotid artery aneurysms are rare, and surgical treatment is controversial because there is no strict indication for the treatment. However, surgical treatment for patients with progressive symptoms should be considered carefully.

View full abstract

The authors present an analysis of their experience in treating vertebral artery (VA) dissecting aneurysms (DAs) and proposed a surgical management strategy retrospectively. Between 2008 and 2013, 32 patients with VA-DAs, 20 of whom presented with subarachnoid hemorrhage (SAH), and 12 without SAH, were treated with a direct microsurgical intervention at their institution. The treatment strategy applied to the posterior inferior cerebellar artery (PICA) proximal segment of the dissected site involved proximal occlusion (PO) of the parent artery. Treatment of PICA-involved DA included proximal occlusion with or without trapping, followed by occipital artery (OA)-PICA bypass, and PICA distal-type proximal occlusion just distal to the VA-PICA origin or trapping. The direct VADA treatment was completed within 12 h after the patient was diagnosed with SAH. The OA-PICA anastomosis was performed in 4 patients, and all recipients obtained good flow. In 31 of the patients, angiography revealed complete occlusion of the DA segment. Postoperative modified Rankin Scales measures were 0 in all unruptured cases, 0-2 in 11 cases, and 3-6 in 9 ruptured cases. Treatment-related complications were re-rupture of DAs in 1 case, lateral medullary infarction in 6, lower cranial nerve palsy in 6, and massive cerebellar infarction in 1. Parent artery occlusion of the long segment led to medullary infarction, and trapping procedure of distal VA produced lower cranial nerve injury. Each complication was associated with unfavorable outcomes after treatment. It was superior in preserving perforating arteries of the VA, led to safe revascularization, and prevented the re-rupture of DAs in the direct microsurgery, as compared to internal coil occlusion.

View full abstract

Endovascular coil embolization of large and giant aneurysms is technically difficult for anatomical reasons, particularly when the neck is wide. The Enterprise and Neuroform stents are specially designed to treat wide-necked aneurysms.
We retrospectively analyzed 38 patients (41 treatments) with large (maximum diameter ≥ 10 mm) aneurysms treated with endovascular coil embolization, and divided them into two groups: patients treated after (27 patients, 29 treatments) and before (11 patients, 12 treatments) the intracranial stents were approved in Japan. In the 29 treatments after the stent approval, 9 aneurysms were treated with the balloon-assisted technique; 3, with the double catheter technique; and 14, with the stentassisted technique. Immediate radiological outcomes showed complete occlusion (CO) in 27.6% of the aneurysms, neck remnant (NR) in 27.6%, and body filling (BF) in 44.8%. Early radiological follow-up (3-12 months) showed CO in 54.5% of the aneurysms, and late follow-up (>12 months) showed CO in 75.0%. Twelve of 14 aneurysms (85.7%) treated with the stent-assisted technique showed no change or improved radiological findings in the follow-up studies. In the group of patients treated before the stent approval, immediate radiological outcomes showed CO in 25.0% of the aneurysms, NR in 33.3%, and BF in 41.7%. The radiological follow-up showed no CO' NRs were seen in approximately 40%.
In summary, adjunct techniques, especially stent-assisted techniques, are frequently used to treat large aneurysms. Although the immediate radiological outcome was not satisfactory, follow-up studies showed favorable radiological results in many cases, especially those in which the stent was used in the treatment. The overall radiological outcomes of the patients treated after the approval of the stent were obviously better than those of patients treated before the stents were approved.

View full abstract

Endovascular treatment is an emerging alternative for acute ischemic stroke. Recently, various endovascular approaches are being applied by using various devices. The aim of this study was to analyze technical and clinical results of patients with acute ischemic stroke treated for large intracranial vessel occlusion with endovascular procedure. The efficacy of mechanical thrombectomy using Merci Retriever and Penumbra System is evaluated.
Methods: We reviewed the clinical records of 55 consecutive patients who underwent endovascular treatment for acute ischemic stroke between October 2005 and September 2013. Mean patient age was 67 years (range 19-86); 75% were men. Median National Institutes of Health Stroke Scale at presentation was 20 (range 7-40). The occluded vessels were the internal carotid artery (ICA) in 21, middle cerebral artery (MCA) in 14, basilar artery in 17, and vertebral artery in 1 patient. Main endovascular procedure had shifted from intra-arterial thrombolysis and percutaneous transluminal angioplasty to mechanical thrombectomy since October 2010. Successful recanalization was defined as thrombolysis in cerebral infarction (TICI) grades 2b to 3. Good clinical outcome was defined as modified Rankin Scale (mRS) score of 0-2.
Results: Of the 55 patients, successful recanalization was achieved in 44% (24) of patients, and good clinical outcome at 3 months in 27% (15) patients. Procedure-related complication occurred in 9% (5/55) of patients. Subarachnoid hemorrhage due to vessel injury and symptomatic intracranial hemorrhage occurred in 7% (4/55) of patients each. One patient required surgery due to puncture site pseudo-aneurysm formation. Mortality was 15% (8/55) at 3 months. The introduction of mechanical thrombectomy was found to significantly reduce the procedure time. However, it was not significantly associated with successful recanalization and good clinical outcome. In the group of patients with ICA and proximal MCA occlusion, mechanical thrombectomy showed a tendency of good clinical outcome. Conclusion: Introduction of mechancical thrombectomy tends toward a favorable outcome among the patients with ICA and proximal MCA occlusion.

View full abstract

Nicardipine, a calcium channel blocker, is a peripheral vasodilator agent. It may play a potential role in preventing cerebral vasospasm after subarachnoid hemorrhage (SAH). We evaluated the effect of nicardipine in preventing cerebral vasospasm following SAH in 256 patients treated with surgical clipping between 2006 and 2014. The patients were classified into two groups: Group A (controls, 191 patients) and Group B (nicardipine, mean dose: 0.58 μg/body weight/min: γ, 1.98 mg/h; 65 patients who received their respective treatments from postoperative day 1 to 14). The incidence of symptomatic vasospasm and new cerebral infarction due to vasospasm as observed on magnetic resonance imaging (MRI) and the need for interventional neuroendovascular therapy were significantly lower in the nicardipine-treated group than the control group. The incidences of symptomatic vasospasm cases were 21.5% (Group A) and 3.1% (Group B), the incidences of new cerebral infarction due to vasospasm were 19.4% (Group A) and 4.6% (Group B), and the incidences of the need for interventional neuroendovascular therapy were 12% (Group A) and 1.5% (Group B). Our results suggest that continuous intravenous infusion of low dose nicardipine, in combination with fasudil hydrochloride, prevents cerebral vasospasm after SAH.

View full abstract

Noninvasive monitoring of regional cerebral oxygen saturation (rSO₂) has been introduced in settings for estimation of cerebral perfusion and cerebral blood flow. We predicted the risk of cerebral hyperperfusion syndrome following carotid endarterectomy (CEA) by rSO₂ monitoring using INVOS^TM. A 77-year-old woman with asymptomatic right internal carotid artery (ICA) stenosis was admitted to our hospital and underwent CEA with INVOS monitoring. INVOS value was 70 in the right ICA and 66 in the left ICA before ICA clamping, and 59 and 79, respectively, after ICA clamping. Immediately after declamping, INVOS value was 82 in the right and 71 in the left ICA. As increase in the INVOS value of the right ICA suggested cerebral hyperperfusion, blood pressure was controlled strictly under anesthesia with propofol. Mean flow velocity ratio in the middle cerebral artery (MFV ratio) on the day after the operation was 1.81, and SPECT showed cerebral hyperperfusion in the ipsilateral cerebral hemisphere. Continuous monitoring of rSO₂ using INVOS enabled estimation of the risk of cerebral hyperperfusion syndrome. MFV ratio decreased to 1.35 five days after surgery, and the patient awakened from anesthesia. This patient was able to avoid the risk of cerebral hyperperfusion syndrome. In conclusion, INVOS was useful for monitoring hyperperfusion syndrome following CEA.

View full abstract

Basilar artery trunk aneurysms (BATAs) are rare, and among the treatments for all aneurysms, the surgical treatment of BATAs is the most difficult. Endovascular treatment (EVT) of BATAs is comparatively easy; however, EVT of large, wide-necked BATAs remains challenging. Here, we describe a multiple microcatheter technique for detachable coil treatment combined with the use of a stent in 2 patients with large (>20 mm), wide-necked BATAs. 【Case 1】 A 30-year-old man presented with difficulty in swallowing. Angiography showed a large, wide-necked basilar trunk aneurysm. Three microcatheters were positioned in different parts of the sac through each side of the vertebral artery, and a stent was positioned across the aneurysm neck. The aneurysm was occluded with coils placed via the 3 microcatheters. 【Case 2】 A 63-year-old man presented with sudden-onset severe headache and consciousness disturbance. Computed tomography (CT) revealed subarachnoid hemorrhage, and angiography showed a large aneurysm in the lower basilar artery fenestration. One microcatheter each was positioned in the upper and lower part of the aneurysm, and a stent was deployed in the left limb, where a larger part of the aneurysm neck was thought to be present. The aneurysm was then embolized with coils. For the treatment of large, wide-necked aneurysms, stent-assisted coil embolization is useful to avoid coil herniation. However, because the mobility of the microcatheter is often restricted, deviated or unbalanced coiling occurs. Because BATAs can be accessed from both the sides of the vertebral artery, multiple microcatheters can be used to pack the aneurysms uniformly and tightly.

View full abstract