To evaluate the long-term outcomes of stereotactic radiosurgery (SRS) for cerebral arteriovenous malformation (AVM) in pediatric patients, we retrospectively analyzed our treatment data of 117 consecutive patients aged ≤18 years who underwent gamma knife radiosurgery (GKRS) for AVM from 1990-2013. Eighty-five patients (73%) experienced hemorrhage before GKRS. The median follow up period was 104 months (range, 14-282 months). Actuarial rates of nidus obliteration after a single session of GKRS were 61% and 82% at 3 and 5 years, respectively. Nidus volume ≤2 cm³ was significantly associated with obliteration in univariate and multivariate analyses. Only one patient died because of massive hemorrhage. Some permanent deficits were observed in eight patients (6.8%) during the follow up periods. Eloquent location was the only statistically significant predictive factor for permanent deficits. Considering the effectiveness and less invasive nature of the procedure, GKRS could be a first-line therapeutic option for AVMs in children and adolescents. Long-term follow up is recommended for possible radiation-induced delayed complications as well as nidus recurrence.

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Background: Arteriovenous malformations (AVMs) in the pediatric population exhibit clinical and pathological characteristics that are different from those in adults. Pediatric AVMs are more frequently associated with diffuse and small AVMs than adult AVMs, rendering it difficult to make a correct and prompt diagnosis in the acute phase of hemorrhage. Besides, AVMs in pediatric patients are correlated to a higher risk of recurrence. However, the optimal observation strategy for pediatric AVMs has not been well established.
Methods: A cohort of children aged 18 years or younger who had AVM and underwent treatment at our institution between 2008 and 2012 were included in the study. The characteristics investigated included initial clinical presentations, Spetzler-Martin grade, type of nidus (compact/diffuse/micro), timing of AVM detection, treatment methods, and outcome. In addition, the radiological modalities to confirm the obliteration and risks of residual or recurrence of AVMs were evaluated. To confirm the obliteration during surgery, we utilized the repetitive intraoperative indocyanine green-based videoangiography instead of intraoperative angiography.
Results: Twenty-three patients were included in this study. The initial presentation was hemorrhage in 22 patients. The numbers of cases classified as Spetzler-Martin grades I, II, III, and IV were 7, 13, 1, and 2, respectively. The type of nidus was compact in 10, micro-AVM in 7, and diffuse in 6. Among six patients whose angiography result on admission was negative, 5 had diffuse or micro-AVM. Fourteen patients had craniotomy, while 9 received stereotactic radiotherapy or gamma knife surgery. The favorable treatment outcome (modified Rankin Scale score of 0-2) was achieved in 91.3%. Except for one case of mortality immediately after surgery, no residual or recurrence was observed in the patients treated with craniotomy during the mean follow-up period of 3.7 years (0.4-10.5).
Conclusions: Pediatric AVMs should be treated with a deep understanding of their discrete characteristics. Although a high index of suspicion for AVM is essential in the treatment of cerebral hemorrhage in pediatric patients, failure of the initial angiography to reveal AVMs is not rare because nidi tend to be diffuse or small. The repetitive and aggressive search for AVMs by using angiography should be conducted after the mass effect is reduced. Our data suggest that intraoperative angiography is not mandatory to minimize the risk of residual AVM or recurrence. Indocyanine green-based videoangiography is effective especially for superficial diffuse or micro-AVMs. Considering the recurrence rate of pediatric AVMs is higher than that of adult AVMs, we advocate angiographical evaluation at 1-year follow-up after surgery, followed by magnetic resonance imaging until patients reach adulthood.

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Surgical resection of pontine cavernomas remains a particularly formidable challenge in the neurosurgical field because of their deep-seated and eloquent locations. We report and discuss our experience and surgical approaches in the treatment of pontine cavernomas via a transpetrosal approach. We investigated eight cases of pontine cavernomas who underwent resection via an anterior or combined transpetrosal approach at our hospital between 2008 and 2015. These eight patients comprised six men and two women with a mean age of 46.9 years. All cases presented with neurological deficits caused by hemorrhage before surgery. We used an anterior transpetrosal approach in six cases and a combined transpetrosal approach in two. Gross total resection of the tumor was achieved in all cases. No postoperative complications, viz., worsening of facial nerve palsy, ocular movement disorder, or hemiplegia were noted in any patient. It is possible to obtain a wide surgical corridor from the ventral and lateral side via an anterior or combined tranpetrosal approach for treatment of pontine cavernomas. A small cortical incision with multi-directional dissection is the best approach to avoid additional neurological deficits. We conclude that resection of pontine cavernomas via a transpetrosal approach might be superior to other approaches to minimize postoperative neurological deficits.

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Brainstem cavernous hemangiomas with recurrent bleeding and gradual neurological deterioration should be considered an indication for surgical treatment. However, surgery is challenging for cavernous hemangiomas located in the ventral part of the pons. In such cases, safe surgical access to the brainstem is limited and obtaining a good surgical field, regardless of the approach selected, is often difficult. We successfully treated a 73-year-old man with a history of three episodes of intracranial bleeding associated with a cavernous hemangioma located in the ventral pons. The hemangioma was removed via the supratrigeminal zone of the brainstem using an anterior transpetrosal approach. We conclude that the anterior transpetrosal approach is particularly useful for accessing lesions located in the upper ventral pons via the supratrigeminal zone because it provides a wide and shallow surgical field above the trigeminal nerve without requiring retraction of the cerebellum.

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We present our three-dimensional digital subtraction angiography (3DDSA)-magnetic resonance imaging (MRI) fusion method and an assessment of its usefulness in the preoperative simulation of craniotomy. In three patients (2 with arteriovenous malformation [AVM] and 1 with distal middle cerebral artery aneurysm), 3DDSA-MRI fusion was performed for preoperative simulation. In the AVM cases, fusion imaging visualized lesion localization and the positional relationship between the lesion and the eloquent area. In the aneurysm case, fusion imaging contributed to the target bypass and selection of the approach route to the aneurysm.

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Purpose: The treatment outcomes of subarachnoid hemorrhage in patients aged >80 years are considered poor. We analyzed the clinical results of endovascular coil embolization for ruptured cerebral aneurysm in patients over 80 years old.
Materials and Methods: Between 2000 and 2015, 43 patients over 80 years old were treated with coil embolization as the first choice for ruptured aneurysm. All the patients were women and the ages ranged from 80 to 91 (average 84 years). The aneurysms involved the internal carotid artery in 28 patients, the anterior communicating artery in 5, the middle cerebral artery in 2, and the vertebrobasilar artery in 8 (including one vertebral artery dissection). The Hunt and Kosnik grade on admission was 1 in 6 patients, 2 in 6 patients, 3 in 12 patients, 4 in 13 patients, and 5 in 6 patients. We assessed angiographic results, complications, and the association between perioperative conditions and outcome at discharge.
Results: Embolization results immediately after treatment showed complete occlusion in 17 patients (40%), dome filling in 10 (23%), neck remnant in 15 (35%), and parent artery occlusion in 1 patient. Fourteen patients (33%) had emergency ventricular drainage for acute hydrocephalus. Procedure-related complications occurred in 4 patients (9%), with a negative impact on the outcome. Eleven patients underwent shunt surgery in the chronic stage. There was no case with rebleeding during the follow-up period. The modified Rankin Scale score at discharge was 0-2 in 11 patients (26%), 3 in 2 (5%), 4-5 in 24 (56%), and 6 in 6 (14%). Patients with mild or moderate disability on admission had relatively good outcomes. Patients with a poor score on admission had very poor outcomes, primarily because of brain damage or poor general condition. However, some patients with mild or moderate disability showed functional decline during hospitalization because of disuse syndrome and dementia.
Conclusion: The outcomes of coil embolization for patients over 80 years old with ruptured cerebral aneurysms are poor. However, this minimally invasive treatment option may be useful to enable early rehabilitation.

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When treating an unruptured large aneurysm (AN) that is not suitable for simple clipping, proximal occlusion of the parent artery with revascularization is common practice. However, a thrombus might develop in the blind alley after occlusion of the parent artery due to stagnation of blood flow, and ischemia involving perforators can develop despite antithrombotic therapy. Therefore, we tried to create flow outlets at the blind alley in two cases. The first case was a 68-year-old-man with a regrowing basilar artery-superior cerebellar artery aneurysm (BA-SCA AN) after coil embolization. Superficial temporary artery (STA)-SCA bypass, STA-posterior cerebral artery (PCA) bypass, and proximal occlusion (PO) of the BA were performed. The BA and associated perforators were not visualized with intraoperative indocyanine green angiography. We then performed transposition of the SCA into the blind alley as a flow outlet for stagnant blood. During occlusion of the BA and perforating arteries, motor evoked potentials (MEPs) transiently disappeared, but recovered to 70% of preocclusion levels after removal of temporary clips. Thrombosis of the BA was prevented, but ischemic complications subsequently developed in perforators. The second case was a 72-year-old man with a fusiform AN of the middle cerebral artery (MCA). After STA-M2 bypass, STA-anterior temporal artery (ATA) bypass from the AN, and PO of the MCA were performed. Perforators arising from the distal AN were thought to be at risk of ischemia based on intraoperative MEPs; therefore, the proximal ATA was not occluded to preserve a flow outlet from the AN. Delicate pressure balance resulted in indolent thrombosis of the AN without causing ischemic complications. The AN was not apparent two weeks later, and has still not recurred after 33 months of follow-up. Creation of a flow outlet in a deep and narrow space is difficult. Moreover, delayed postoperative ischemia involving perforators is not always predictable. Even with use of intraoperative monitoring, careful planning is required.

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Transfemoral stenting of stenosis at the common carotid artery (CCA) is a relatively uncommon procedure compared with that for a stenotic lesion of the cervical internal carotid artery (ICA). It may be technically difficult to advance and stabilize the guiding catheter during the procedure. It is particularly difficult in the left common carotid artery (LCCA) because of its anatomical features. However, the degree of difficulty differs depending on the distance from the orifice to the stenotic lesion and the angle of the LCCA and aortic arch. Here, we report guiding catheter techniques for revascularization of LCCA stenosis.
We choose an appropriate method based on the degree of difficulty. When there is enough distance between the LCCA orifice and the stenotic lesion, and the LCCA does not branch at an acute angle, advancement of the guiding catheter may be possible using a routine method. However, if the LCCA branches at an acute angle, it might be necessary to pass through the lesion using a guidewire or an inner catheter before advancing the guiding catheter. First, a guiding catheter is placed at the LCCA orifice using a triple coaxial system, and a 300-cm GuardWire (Medtronic, Minneapolis, MN, USA) is placed at the ICA. Once the 4-Fr inner catheter is removed under distal balloon protection, a 0.035-inch guidewire is inserted into the external carotid artery and the guiding catheter can be easily and safely placed at the optimal position. When the stenotic lesion is at the LCCA orifice, a pull-through technique is performed using a 300-cm 0.014-inch guidewire between the superficial temporal artery and femoral artery. A 0.035-inch-compatible, balloon-expandable stent system is also introduced over the 0.014-inch guidewire, with a GuardWire placed at the ICA.
Several endovascular techniques have been described for revascularization to treat LCCA stenosis. In general, a more invasive method is required for complete protection and stabilization of the guiding catheter. Selection of an appropriate method to treat LCCA stenosis based on the degree of difficulty is mandatory to ensure feasibility and safety.

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We report three cases that involved the use of the Wingspan stent (WS) system for the treatment of intracranial atherosclerotic disease and review the literature. The first patient was an 80-year-old man who presented with recurrence of a transient ischemic attack and medically refractory restenosis of the left petrous internal carotid artery (ICA). He underwent percutaneous transluminal angioplasty (PTA) and stenting using the WS. There have been no ischemic events and no restenosis after treatment. The second patient was a 73-year-old man who presented with minor stroke due to chronic total occlusion of the left ICA. He underwent PTA and stenting using the WS for dissection of the left ICA. There have been no ischemic events and no restenosis after treatment. The third patient was a 65-year-old woman who presented with minor stroke due to stenosis of the right middle cerebral artery (MCA). She underwent PTA and stenting using the WS for dissection of the right MCA. There have been no ischemic events and no restenosis after treatment. The WS system was useful for the treatment of medically refractory restenosis and dissection of intracranial arteries after PTA.
The 1-year risk of recurrence of ischemic stroke in the treatment of symptomatic intracranial arterial stenosis (ICAS) with the WS system was lower than that in the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial. However, the Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis (SAMMPRIS) trial demonstrated that aggressive medical treatment was superior to stenting with the WS system in preventing recurrent ischemic stroke. Further evaluation of clinical outcome is required to confirm the safety and efficacy of the WS system for symptomatic ICAS.

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The development and subsequent rupture of an aneurysm due to infundibular dilatation (ID) has rarely been documented. An 84-year-old woman was admitted to our hospital with a massive headache since the previous night. Computed tomography showed a diffuse subarachnoid hemorrhage and magnetic resonance angiography (MRA) demonstrated a right internal carotid-posterior communicating artery (IC-PC) aneurysm (AN), which protruded inward. In addition, an ID was noted at the junction of the right IC-PC junction. Neck clipping of the right IC-PC AN was performed the same day. Unexpectedly, the AN bulged outward from the internal carotid (IC); the AN was clipped, and we carefully explored the inside of the IC. The bulging portion was identified, and appeared to be the infundibulum.
Immediate postoperative computed tomography angiography confirmed the remaining AN inside the IC-PC. Neck clipping was performed to remove the residual lesion. The patient was discharged with no neurological deficit.
We analyzed follow-up MRAs. She was diagnosed as having a right IC-PC AN protruding in the lateral-inferior direction at the first examination, and has been followed up every 6 months or yearly. Almost 3 years later, we have confirmed de novo AN formation at the IC-PC junction, and the AN has been growing gradually.
ID has been defined as a triangular, conical, or rounded dilatation, and it is primarily located in the IC-PC. It is unclear whether this dilatation may be a preaneurysmal condition. Cases of progression to a saccular AN with the risk of rupture of a previously demonstrated ID have rarely been reported. We have conducted follow-up MRA for 5 years in our patient, and have only observed a de novo AN developing from ID of the right IC-PC junction. This case is another example indicating that ID may be a precursor to ANs.

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We report a case of cerebral infarction associated with adult moyamoya disease in a patient using oral conjugated estrogen (Premarin^®). A 44-year-old woman with adult moyamoya disease presented with a right-sided cerebral infarction. She had been administered oral conjugated estrogen for ovarian insufficiency. Direct revascularization could not be achieved owing to thrombosis of anastomosis sites. After surgery, we examined the cause of thrombosis of the anastomosis sites and discontinued use of oral conjugated estrogen, which was substituted with Kampo medicine (Chinese herbal medicine) for ovarian insufficiency. An anastomosis site was recanalized 3 months after surgery. We conclude that use of conjugated estrogens increases the risk of stroke and propose that oral conjugated estrogens should be used with caution in the perioperative period, especially in stroke patients.

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