We have developed a new superficial temporal artery (STA)-superior cerebellar artery (SCA) bypass procedure via the trans-sylvian approach that can provide wider surgical space than that in routine STA-SCA bypass via the subtemporal approach, which could be associated with technical difficulties when performing deep and narrow microvascular anastomoses. Our method utilizes the combined pterional/anterior temporal approach and tentorial edge resection. Anastomosis is performed at the anterior pontomesencephalic segment of the SCA just lateral to the oculomotor nerve. We report and illustrate two cases that we encountered in our preliminary clinical experience in order to demonstrate the development and techniques of the procedure.

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We investigated the sensitivity and safety of postoperative neuroimaging in finding a 10-0 suture needle lost in the cranium during brain bypass surgery. A custom-made brainskull phantom with a 10-0 suture needle was used in this study.
The needle was barely detectable on digital X-ray photograph of the skull. Using computed tomography (CT), the intracranial location of the needle could be approximately determined; however, the location of the needle could not be precisely determined with either two-dimensional (2D) or 3D reconstruction imaging. Magnetic resonance imaging (MRI) depicted the needle as a metal artifact, and the intracranial location of the needle was more easily detected using MRI than by using CT. Diffusion weighted image (DWI) and T2^*WI were found to be more sensitive for detecting needles compared to T1WI and T2WI. In the gantry of the MRI scanner, although a needle hung by a thread held by the titanium forceps was pulled into the magnetic field, it could be retained with minimal resistance. The heat given off by the needle because of the magnetic field did not melt a chocolate tip beneath the needle.
The results of this study suggested that postoperative MRI is safe and can be used to find a lost needle in the cranium.

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A 43-year-old man presented with cerebral proliferative angiopathy (CPA) that manifested as convulsions and transient ischemic attacks (TIA). Single-photon emission computed tomography imaging demonstrated decreased perfusion around the nidus; therefore, indirect revascularization was performed. Cerebral angiography, performed 3 years after the surgery, demonstrated no neovascularization, although the patient did not develop convulsions or TIA after anticonvulsant treatment. Indirect revascularization may not be effective to sufficiently improve cerebral blood flow, and hence, direct revascularization may be a better treatment option for middle-aged individuals with CPA.

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Endovascular treatment has been established as first line therapy for the treatment of cerebral aneurysm in the United States and Europe, and currently, cases of cerebral aneurysm are more commonly treated by neurosurgeons rather than radiologists. Considering the current practices in the treatment of cerebral aneurysm, it is important for a neurosurgeon to master the techniques of both, neuroendovascular surgery and direct surgery; such surgeons are called “Hybrid Neurosurgeons”. However, it is a matter of concern whether a single surgeon can master both these techniques. We report the role of a Hybrid Neurosurgeon and the key factors crucial for their training.

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The procedural time to recanalization is becoming a determining factor in managing acute main-trunk artery occlusion (MAO). Here we report our experience with 27 patients treated with endovascular techniques for MAO without the availability of full-time endovascular specialists.
Between July 2012 and March 2014, we targeted 27 patients with acute MAO who received endovascular treatment. Of them, three were transferred to treatment support institutions for treatment (Drip, Ship), while for the remaining 24 patients, an endovascular specialist was called in from an outside medical facility (Drip, Call, and Retrieve).
The three patients treated by the Drip, Ship paradigm included two men and one woman with a mean age of 77 (range, 64-85) years. The cerebral infarction was caused by cardiogenic embolism in two patients and by arteriosclerotic embolism in one patient. The mean time interval from the magnetic resonance imaging at our institution to arrival at a treatment support institution was 184 (range, 153-244) minutes, and the mean interval from onset to recanalization was 434 (range, 395-455) minutes.
The 24 patients treated with the Drip, Call, and Retrieve paradigm included 11 men and 13 women with a mean age of 77 (range, 62-89) years. Fourteen were administered tissue plasminogen activator, and 21 had arterial fibrillation. The median National Institute of Health Stroke Scale was 15, and the median Alberta Stroke Program Early Computed Tomography Score on diffusion-weighted imaging was 8. Occlusion was observed in 5, 13, 5, and 1 case occurring at the internal carotid artery, middle cerebral artery (M1), M2, and proximal basilar artery. The mean door to puncture time was 117 (range, 39-345) minutes, while the mean time interval from onset to recanalization was 319 (range, 175-555) minutes. A Thrombolysis in Cerebral Infarction (TICI) score ≥2a was achieved in 21 cases (87.5%), while a TICI ≥2b was achieved in 15 (62.5%). The modified Rankin scores at 3 months after treatment were 0-2 in five cases.
The Drip, Call, and Retrieve protocol does not require patient transport and is an effective form of medical collaboration that can achieve earlier treatment initiation and serve as an effective educational system for endovascular specialists.

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Background: The incidence of atherosclerotic carotid artery stenosis is increasing in Japan. Here we report on the effectiveness of the balloon distal protection carotid artery stenting (CAS) method using an autologous aspirated blood transfusion from the carotid artery during treatment.
Method: Between November 2007 and July 2014, 218 patients (233 lesions) diagnosed with carotid artery stenosis were treated with CAS in our institute. We divided these patients into four groups stratified by protection device and intervention date. The four groups were defined as: ANGIOGUARD (AG) (intervention from Nov 2007 to May 2010), Filter Wire (FW) (June 2010 to Nov 2011), PercuSurge GuardWire (PS) (Dec 2011 to Sept 2012), and self-transfused blood combined with PS (SB) (Oct 2012 to July 2014). We reviewed the diffusion-weighted imaging (DWI) positivity rate and ipsilateral ischemic events for a period of 30 days post-intervention.
Results: Transient ischemic attack occurred in four patients, but there were no long-term sequelae in patients treated with the AG and the DWI positivity rate was 64.0%. Two cases of retinal ischemia and one of a minor completed stroke were recorded for those treated with the FW, and the DWI positivity rate was 20.4%. Retinal ischemia occurred in one patient treated with the PS and the DWI positivity rate was 47.8%. In those patients treated with autologous blood transfusion and SB, there were no observed ischemic complications and the DWI positivity rate was 17.8%.
Conclusion: The combined method of autologous blood transfusion and the PS balloon protection device is more effective and safer than CAS combined with other protection methods.

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Subarachnoid hemorrhage (SAH) occurs when a pre-existing aneurysm ruptures. Dissecting aneurysms may cause both SAH and pseudoaneurysm formation. We reviewed the records of 11 patients with pseudoaneurysms treated at our institute during the last 5 years. Six of the 11 patients had pseudoaneurysms at the anterior wall of the internal carotid (IC) artery, so-called blister-like aneurysms, while the other five patients had pseudoaneurysms at the posterior communicating artery or anterior cerebral artery. Here, we report five non-IC pseudoaneurysms in detail and compare their characteristics with those of IC pseudoaneurysms.

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Object: Here, we evaluated the role of various methods of intraoperative monitoring in cerebrovascular surgery.
Materials and Methods: A total of 263 patients underwent cerebrovascular surgery using intraoperative monitoring after the introduction of a 16-channel Neuromaster. There were 229 cerebral aneurysm (85 ruptured, 144 unruptured), five arteriovenous malformation (AVM), 19 bypass, seven carotid endarterectomy (CEA), and three cavernous angiomas cases. Motor-evoked potential (MEP), somatosensory-evoked potential (SEP), and visual-evoked potential (VEP) were selected considering the pathogenesis types and sites. MEP contained transcranial and direct cortical stimulation and SEP, median nerve (upper extremity) and posterior tibial nerve (lower extremity) stimulation. Bilateral regional saturation of oxygen (rSO₂) using near-infrared spectroscopy (NIRS) was also monitored in patients who underwent CEA.
Results: Intraoperative monitoring was successfully performed in all 263 cases. MEP could not be recorded and an upper-extremity SEP was performed in three cases because of preexisting hemiparesis. In 15 cases, MEP disappeared after temporary occlusion of the parent artery or aneurysmal clipping but reappeared after release of the temporary occlusion or re-clipping; one patient whose MEP amplitude recovered to 50% of the control developed transient hemiparesis (4/5). Another two patients, in whom the MEP disappeared until the end of surgery, developed permanent hemiparesis (4/5). In a patient with a posterior cerebral artery (PCA) aneurysm, VEP was transiently decreased after temporary PCA occlusion. In a patient with the premotor AVM, the MEP was transiently decreased after the precentral artery was temporarily occluded. In a patient with an occipital cavernous angioma, the VEP transiently decreased after dissection around the posterior horn and the patient was discharged from the hospital without any visual field disturbances. Three patients with CEA in whom the transcranial MEP and upper extremity SEP decreased, recovered after insertion of the internal shunt.
Conclusions: In cerebrovascular surgery, various methods of monitoring enable us to detect intraoperative ischemia and feedback to the operative maneuvers.

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We reviewed 2 cases of unclippable unruptured cerebral aneurysms treated using a wrap and clip method and report the findings and techniques used. A 55-year-old woman with a middle cerebral artery fusiform aneurysm underwent a wrap and clip procedure. The aneurysm was covered with two pieces of Gore-Tex sling and clipped using the Weck clip, and several Weck clips were then added to pack the space between the aneurysm and the surrounding Gore-Tex sling. A 39-year-old man developed a pseudoaneurysm at the A2 segment of the anterior cerebral artery. A Gore-Tex sling was applied to the entire parent artery and to the pseudoaneurysm circumferentially and was clipped with the proximal portion of the aneurysm. Then the Gore-Tex sling and a residual portion of the aneurysm was clipped with another clip in tandem to prevent the clip from slipping out of the sling. The wrap and clip technique resulted in a favorable outcome in both cases, without any observed aneurysm growth or rupture for 61 and 2 months after the procedure, respectively. We believe the wrap and clip method confers protection from aneurysm growth or rupture in cases of unclippable unruptured cerebral aneurysms.

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Here we report two cases of a delayed mass after gamma knife surgery (GKS) for a cerebral arteriovenous malformation (AVM). Case 1 involved a 71-year-old man who had been treated with GKS for a ruptured AVM at 63 years of age. Computed tomography showed a cystic formation 2 years after the GKS. Magnetic resonance imaging 68 months later revealed a round mass in the irradiated area. The mass gradually increased in size and was resected 8 years after the GKS. Histological examination identified an expanding hematoma. Case 2 involved a 12-year-old girl who had been treated with GKS for a ruptured left occipital AVM diagnosed as Osler-Weber-Rendou disease at 5 years of age in another hospital. She presented with high fever, nausea, and general fatigue caused by an abscess in the left frontal lobe and a round mass with edema in the left occipital lobe. With conservative treatment, the frontal abscess disappeared and the occipital mass gradually reduced 3 months later. She was discharged without neurological deficits after 72 days. Our results show that serial long-term follow up is necessary, even if angiographic obliteration has been achieved after GKS for AVM.

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Here, we report a case of a proximal anterior cerebral artery (A1 segment) aneurysm requiring neck clipping for recurrence following stent-assisted coil embolization. A 63-year-old woman with an unruptured A1 aneurysm presented with progressive aneurysm growth over 6 months. The aneurysm was treated with stent-assisted coil embolization. Cerebral angiography performed 3 months after embolization showed in-stent stenosis (ISS) and aneurysmal recurrence. Cerebral angiography at 6 months after embolization revealed ISS resolution as well as aneurysmal regrowth. A successful neck clipping was performed without any complications. To our knowledge, this is the first known report of neck clipping after stent-assisted coil embolization. We propose that neck clipping for recurrence should be performed more than 6 months after stent-assisted coil embolization.

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