Clipping of cerebral aneurysms is an important skill in neurosurgery. However, as the number of clipping procedures is decreasing, young neurosurgeons have insufficient experience with cerebral aneurysms. Therefore, a training model for clipping is needed. Here, we present a training model for cerebral aneurysm clipping. The concepts underlying the model were 1: creating a cerebral aneurysm clipping training model for beginners, 2: three-dimensional (3D) manipulation in a deep operating field using an operating microscope, 3: 3D data simulation of the anatomical relationship between the aneurysm and surrounding tissue. Skull, brain, arteries, and veins were produced using a 3D printer based on DICOM data. Skull, brain, and vessels were made of polyvinyl alcohol (PVA). The characteristic softness of the brain and vessels was reproduced. Thus far, six training courses have been conducted, and the trainees were overall satisfied with the training, according to a survey. This model is useful for training young neurosurgeons in cerebral aneurysm surgery.

Objective: We evaluated the efficacy of intraoperative motor evoked potential monitoring (MEP) and a novel laser light imaging system to simultaneously visualize visual light and near-infrared fluorescence for indocyanine green angiography (dual-image VA [DIVA]) in aneurysm surgery.

Materials and Methods: Four hundred and five patients who underwent aneurysm surgery were intraoperatively monitored with a direct transcortical electrical stimulation MEP (DCS -MEP), and 104 patients were monitored with a transcranial electrical stimulation MEP (TES-MEP). The TES-MEP threshold was measured before temporary interruption of the cerebral artery or aneurysm clipping as the threshold can fluctuate throughout surgery. Recently, we also performed a number of surgeries using a newly developed laser light in conjunction with the DIVA system.

Results: In 4 cases, the DCS-MEP and TES-MEP signals disappeared during surgery and did not recover. As a result, these patients developed permanent hemiparesis. Two cases developed transient postoperative hemiparesis even though the DCS-MEP and TES-MEP did not change. The MEP monitoring could not detect intraoperative ischemia except for in the pyramidal tract. The laser light, in conjunction with the DIVA system, clearly showed the blood flow in the perforating arteries with the cranial structures in the background.

Conclusions: MEP monitoring is essential in aneurysm surgery, but it cannot predict ischemia apart from that in the pyramidal tract. The laser light, in conjunction with the DIVA system, was useful in avoiding ischemic complications.

Background and Objective: Preoperative imaging of the structures adjacent to intracranial aneurysms is vital for safe and effective surgery. Although computed tomography angiography (CTA) can be used to evaluate arterial, venous, and bony structures, it is unable to depict the surface of the brain parenchyma. This has precluded practical simulation of operative findings. Contrast-enhanced magnetic resonance imaging (MRI) visualizes both the venous structures and brain surface. There-fore, MRI may be able to contribute to optimal preoperative simulation imaging. In this article, we evaluated the validity of contrast-enhanced MRI in the preoperative assessment of unruptured intracranial aneurysm clipping.

Methods: For 2 cases with unruptured intracranial aneurysms, contrast-enhanced MRI was obtained, and virtual endoscopic processing was performed. We compared this imaging with the intraoperative findings, focusing on the relationships between the aneurysm, venous structures, and brain parenchyma.

Results: Virtual endoscopic imaging with contrast-enhanced MRI helped in the visualization of a deep vein crossing the arterial structures and brain parenchyma overlying the aneurysm. Moreover, virtual endoscopic imaging provided a practical 3D-like simulation of the surgical approach.

Conclusion: Virtual endoscopic processing of contrast-enhanced MRI was effective in predicting the intraoperative findings of unruptured intracranial aneurysm clipping.

Venous infarction and/or brain edema resulting from venous injury can be serious complications of clipping surgery. The central venous system has many variations and collaterals compared to the arterial system. Therefore, it can be challenging to estimate venous congestion when venous injury happens. Venous reconstruction should be performed based on the preoperative and intraoperative angiograms. Here, we present our methods for venous reconstruction.

Background: With aging of the Japanese population, there is an increasing number of senile patients with subarachnoid hemorrhage (SAH) undergoing direct surgery. However, the long-term prognosis remains to be elucidated. This study aimed to clarify treatment outcome and long-term prognosis of direct aneurysm surgery in SAH patients aged 80 and over.

Methods: Medical charts of 34 consecutive patients with SAH over 80 years old, who underwent direct aneurysm surgery between February 2010 and August 2017, were retrospectively reviewed. The patients were classified into a good outcome group (mRS [modified Rankin Scale]: 0-3) and a poor outcome group (mRS: 4-6), and the characteristics, perioperative data, and long-term prognosis of each patient were analyzed.

Results: Twelve patients (36%) had good outcome and 22 patients (64%) had poor outcome at discharge. Factors associated with good outcome included good activities of daily living (ADL) (mRS: 0-3) before the hemorrhagic event, short hospital stays, early walking exercise (within 14 days), and no postoperative symptomatic cerebral infarctions. There was no significant difference in the surgical time between the two groups. Patients with good outcome at discharge were associated with a significantly better long-term survival rate compared to those of the poor outcome group.

Conclusions: Even in SAH patients older than 80 years, good outcome can be expected if they had good ADL before the event and if they do not present postoperative cerebral infarctions. Independent walking at discharge can be considered a good indicator of good prognosis in the long long-term.

Endoscopic hematoma evacuation is a key minimally invasive procedure learned by young neurosurgeons. It can help them to improve their surgical technique and understand the differences between techniques, including microscopic surgery. The surgical indication for endoscopic hematoma evacuation should be performed in compliance with the guidelines for stroke management.

The hematoma clots can be removed using a rigid endoscope and a suction tube in a transparent sheath. The surgical procedure is performed in four steps. First, the position of the burr hole should be determined. Second, a transparent sheath should be inserted into the hematoma cavity. This has to be done very carefully because a wrong trajectory may cause severe morbidity. The sheath tip should be guided to the boundary between the brain parenchyma and the hematoma. Third, hematoma aspiration should commence under an endoscopic view. Finally, a suction tube should be used as a probe adapted to the monopolar coagulator system for hemostasis. Continuous irrigation using artificial cerebrospinal fluid can also be useful for confirming the bleeding point.

Endoscopic hematoma evacuation may be advantageous than microscopic surgery for cerebellar hemorrhage and intraventricular hematoma (IVH). In patients with IVH, the hematoma can be removed from the bilateral lateral ventricle and third ventricle via a one-side anterior puncture. In patients with spontaneous cerebellar hemorrhage, it is possible to remove an intraparenchymal hematoma and a hematoma in the fourth ventricle through a single burr hole. Furthermore, the operation time and the hematoma removal ratio are significantly improved.

Sensory disturbances are common in the area innervated by the great auricular nerve (GAN) after carotid endarterectomy (CEA). However, we do not know if protecting the GAN against drying and heat injury intraoperatively improves sensory outcomes. We attempted to protect the GAN from heat damage using a polyurethane dressing film moistened with saline. The sensory outcomes of the GAN after CEA were analyzed in ten patients who received the film [film (＋) group], and ten patients who did not receive the film [film (−) group] at 1, 3, 6, and 12 months postoperatively. At 1 month, 7 and 9 cases exhibited symptoms in the film (＋) and film (−) groups, respectively. At 3 months, 6 and 9 cases exhibited symptoms in the film (＋) and film (−) groups, respectively. At 6 months, 4 and 7 cases exhibited symptoms in the film (＋) and film (−) groups, respectively. Finally, at 12 months there was one case in the film (−) group that continued to exhibit symptoms. The polyurethane film appeared to decreased the duration of postoperative sensory deficits; however, there were no significant between-group differences for the incidence rate or sensory outcomes. Although one patient in the film (−) group continued to exhibit a sensory disturbance after 12 months, it did not interfere with the patient’s daily activities. These findings suggest that use of protective film during CEA exerts a protective effect on the GAN and may hasten recovery of postoperative sensory deficits.

Objective: The American Heart Association/American Stroke Association guidelines recommend that patients should receive mechanical thrombectomy if the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is ≧6. However, its benefits are uncertain if the ASPECTS is ＜6. This study aimed to identify the outcomes of mechanical thrombectomy in patients with ASPECTS ＜6.

Methods: Thirty-nine patients with acute ischemic stroke with diffusion weighted imaging (DWI)-ASPECTS ≦5, with internal carotid artery or middle cerebral artery segment 1 (M1) occlusion were treated with mechanical thrombectomy between May 2014 and April 2018. We retrospectively compared patients with a good outcome [modified Rankin Scale (mRS): 0-2] and those with a poor outcome (mRS 3-6) at 3 months.

Results: The good-outcome group comprised 16 patients (41%) and the poor outcome group comprised 23 patients (59%) at 3 months. There were no significant differences in the baseline characteristics [age, sex, occluded artery, National Institutes of Health Stroke Scale score and DWI-ASPECTS] between the two groups. The onset to recanalization time was shorter in the good-outcome group (192 versus 210 minutes, p=0.0083). The mean DWI-ASPECTS of the good-outcome group did not change between arrival and post thrombectomy (5 versus 4, p=0.24), but the mean DWI-ASPECTS of the poor-outcome group worsened (5 versus 2, p=0.0014) between hospitalization and after thrombectomy.

Conclusions: The outcome of mechanical thrombectomy could be good even in patients with low DWI-ASPECTS and a magnetic resonance angiography-DWI mismatch.

Background and Purpose: Endoscopic evacuations of intracerebral hematomas (ICHs) and intraventricular hematomas (IVHs) have become increasingly popular in recent years. However, evacuation of hematomas can occasionally be insufficient. The purpose of this study was to identify the factors making evacuation difficult.

Methods: Between 2010 and 2017, endoscopic evacuations of a total of 55 ICHs and IVHs were performed in 53 patients. Insufficient hematoma evacuation was defined as follows: an ICH evacuation rate of less than 50% and a Graeb score (GS) decreasing rate of less than 50%. Clinical variables were analyzed.

Results: The average evacuation rate was 71.6% for ICHs, and the GS decreasing rate was 60.4% for IVHs. Insufficient evacuations tended to be more for IVHs than for ICHs, but without a statistically significant difference (28.9% vs 5.0%, p = 0.127). There were no significant differences in factors, such as age, sex, Glasgow Coma Scale (GCS) score, GS, time to surgery, or modified Rankin scale (mRS) score, between them. Administration of antithrombotic drugs (ADs) was significantly higher in patients with insufficient evacuation of an IVH, and they showed an unfavorable prognosis on a univariate analysis (p = 0.008 and 0.040 respectively). There was a history of AD administration or thrombocytopenic disease (TD) in 72% of patients with insufficient evacuation and 5.0% of patients with non-insufficient evacuation (p = 0.001). Hematoma evacuation was difficult in 11 of 13 patients because of hardness, and ADs were used in 5 of those 11 patients. Hematoma evacuation was difficult in 11 of 42 patients in the first 2 days (26.2%) and 2 of 8 patients (25%) from 3 to 5 days. Five of 11 patients used ADs, and 1 of 11 had a TD within 2 days while there was no AD or TD between 3 and 5 days. There was no case of insufficient evacuation after 6 days.

Conclusions: Hematoma evacuation is difficult in patients with AD or TD, particularly within 5 days from onset. It is recommended that endoscopic evacuation be performed 6 days from onset, if surgery can be postponed.

The treatment of intracranial fusiform vertebral artery aneurysms (FVAAs) with preservation of the parent artery is challenging. We evaluate the feasibility, safety, and efficacy of stent-assisted coil embolization of FVAAs with a reconstructive technique. Between November 2010 and June 2017, a total of 30 FVAA patients were treated with stent-assisted coil embolization with a reconstructive technique. Clinical presentation included subarachnoid hemorrhage (SAH) in 9 patients (30.0%), mass effect in 2 patients (6.7%), headache in 17 patients (56.6%), and no symptoms in 2 patients (6.7%). The appearance of contralateral VA was as follows: normal in 13 patients (43.3%), hypoplasty in 8 patients (26.7%), aplasty in 3 patients (10.0%), posterior inferior cerebellar artery-end in 2 patients (6.7%), dissection in 3 patients (10.0%), and post-parent artery occlusion state in 1 patient (3.3%). A total of 5 procedure-related complications (16.6%) were experienced. Three procedure-related symptomatic ischemic strokes (10.0%), including two cerebellar infarctions and one medullary infarction, occurred. One patient (3.3%) presented with an asymptomatic stent occlusion, confirmed by digital subtraction angiography (DSA) on post-procedure day 7. We observed intra-operative SAH due to bleeding from FVAA in one SAH patient (3.3%). She died due to SAH-induced complications at two months post-procedure. There were no patients with delayed complications and aneurysmal rupture during the followup period (median, 32.5 months; range, 2-93 months). Overall, the morbidity and mortality rates at 6 months post-procedure was 6.7% (2/30) and 3.3% (1/30), respectively. Of the 30 patients, post-procedure DSA revealed complete occlusion in 8 patients (26.7%), near-complete occlusion in 9 patients (30.0%), and incomplete occlusion in 13 patients (43.3%). DSA was available in 12 patients at a median of 10 months (range, 1-16 months) whose post-procedure DSA findings were near-complete or incomplete occlusion. The findings revealed complete occlusion in 7 patients (53.8%), near-complete occlusion in 2 patients (15.4%), incomplete occlusion in 3 patients (23.1%), and asymptomatic stent occlusion in 1 patient (7.7%). DSA of two patients with incomplete occlusion showed major recanalization and required retreatment. In conclusion, stent-assisted coil embolization of FVAAs with a reconstructive technique is feasible, safe, and effective with good short- to mid-term angiographic and clinical outcomes for patients without sufficient collateral circulation.

We report a case of arteriovenous malformation (AVM) with symptomatic venous outflow impairment, which improved following percutaneous transluminal angioplasty (PTA). A 48-year-old woman, diagnosed with Spetzler-Martin Grade 4 AVM, was admitted to our hospital for an epileptic seizure. Magnetic resonance imaging (MRI) demonstrated AVM in the left frontal lobe with edema. The edema was not observed earlier. Angiography revealed severe stenosis of the superior sagittal sinus (SSS), which is the main drainage route of AVM. Comparison with angiography that was performed one month prior to admission revealed that the SSS stenosis had progressed. We performed PTA to decrease the risk of hemorrhage and improve the symptoms. After PTA, patient’s aphasia, paresthesia, and headache improved within a day. These observations suggest that for AVM with symptomatic venous outflow impairment, especially in inoperable or difficult cases, PTA is a valid approach.