Regenerative medicine using stem cells for cerebral infarction is a promising therapy, and various clinical trials are being conducted worldwide. In the development of cell therapy products for cerebral infarction, a translational study from preclinical to early clinical stages, including first-in-human trials, is also important. The results of a large number of basic studies must be translated into clinical studies, a very important stage commonly referred to as the “valley of death,” to determine whether they can be applied clinically. Basic studies are needed to prove the efficacy of cell therapy in terms of neuroprotection, cell differentiation, and angiogenesis, according to the pathological condition of cerebral infarction, as well as to conduct non-clinical safety studies in accordance with Good Laboratory Practice to determine the formulation specifications. In the treatment of cerebral infarction, there are various treatment concepts, depending on the targeted stage, such as those expected to improve blood flow or have neuroprotective effects while ischemia-induced brain damage is incomplete, and those expected to restore brain function after completion of brain damage. Currently, the development of treatment products for cerebral infarction is mainly based on somatic stem cells; however, optimal cell source, route of administration, timing of administration, frequency of administration, and number of cells for cell therapy products in clinical trials vary. Therefore, this paper outlines translational studies in stroke regenerative medicine.

Less-invasive clipping techniques for middle cerebral artery (MCA) aneurysms are required during the era of endovascular treatment. The sphenoid-ridge keyhole approach is an option. For cosmetic reasons, a skin incision is made within the temporal hair (sideburn skin incision), and the temporal muscle dissected without cutting the muscle belly to expose the skull. Visually identifying the location of a sphenoid ridge over the skull is difficult. Based on anatomical studies, the sphenoid depression is located anterior to the bony prominence caused by the sphenosquamous suture (SSS), and we recommend palpation to locate this bony depression. Using this technique, pinpoint sphenoid ridge keyhole craniotomy can be performed. After opening the dura mater, the operative field includes the centrally located Sylvian fissure. We treated 34 cases of unruptured MCA aneurysms using this technique and accomplished neck clipping in all cases, with a mean postoperative hospital stay of 3 ds. The mean maximum craniotomy diameter was 29 mm. None of the patients showed a decreased neurological status, including cognitive function. The mental state (depression scores) significantly improved 3 months following the operation. In conclusion, sphenoid ridge keyhole clipping focused on the sphenoid depression is considered an effective and less invasive surgical approach in the era of endovascular treatments.

Objectives: Some patients report conductive hearing impairment during administration of clazosentan sodium. This study aimed to investigate the frequency of patients with fluid correction in their mastoid air cells.

Methods: We selected 25 consecutive patients with subarachnoid hemorrhage who were treated with clazosentan from January 2017 to January 2023. Fluid correction in their mastoid air cells was confirmed using computed tomography or magnetic resonance imaging.

Results: Fluid correction was observed in 19 of 25 cases. Two cases complained of conductive hearing loss. Each of these patients recovered their conductive hearing to within the normal range after clazosentan was discontinued.

Conclusion: Conductive hearing loss is a significant complication that physicians should be aware of, although this knowledge was not necessary to guide additional treatment.

The patient was a 69-year-old female. She was admitted to the hospital due to disturbed consciousness. Computed tomography (CT) revealed a Fisher group 3 subarachnoid hemorrhage (SAH). A fusiform aneurysm was found in the anterior temporal artery (ATA) . We performed trapping and resection of the aneurysm on the same day. Fusiform aneurysms occur mainly in the vertebrobasilar artery, and the most common cause is cerebral artery dissection. Fusiform aneurysms in ATA are rare. To date, there have been no reports of ruling out the possibility of cerebral artery dissection and diagnosis of an atherosclerotic fusiform aneurysm by histopathology.

Vascular Ehlers–Danlos syndrome (EDS) is the most serious disease type that results from a type III collagen (COL3A1) gene mutation and causes an aneurysm, arterial dissection, gastrointestinal perforation, and uterine rupture. Here, we describe the case of a 24-year-old man with a family history of Ehlers–Danlos syndrome. Genetic testing revealed a COL3A1 mutation, confirming the diagnosis of vascular Ehlers–Danlos syndrome. Brain magnetic resonance angiography performed during screening revealed a 9-mm left fusiform middle cerebral aneurysm. Cerebral aneurysm clipping was performed via left frontotemporal craniotomy. No intraoperative complications occurred and cerebral aneurysm clipping was performed according to the standard protocol. All treatment options should be analyzed in patients with EDS. Craniotomy for fusiform middle cerebral aneurysms is possible and should be performed when deemed optimal.

A 52-year-old woman fell off her bike and sustained a head injury. In the emergency department, the patient was conscious but confused. Computed tomography (CT) revealed a subarachnoid hemorrhage (SAH) predominantly in the right Sylvian fissure. Fractures of the left temporal, clavicular, shoulder, and rib bones were also observed. Both CT angiography (CTA) and digital subtraction angiography (DSA) performed upon admission failed to identify the aneurysm. CTA performed 8 days later also failed to reveal the aneurysm. DSA performed 17 days after onset revealed a distal middle cerebral artery (d-MCA) aneurysm. Because of the traumatic event and the angiographically occult nature of the aneurysm up to 17 days after onset, it was difficult to determine whether it was a true aneurysm or a pseudoaneurysm. The patient underwent trapping and excision of the aneurysm, whereupon the pathological diagnosis was true aneurysm. The postoperative course was uneventful, and the patient was discharged 42 days after onset with no neurological deficits. Distinguishing between an aneurysmal SAH (a-SAH) and traumatic SAH (t-SAH) is difficult. In this study, we focused on identifying clinical differences between a-SAH and t-SAH and a surgical strategy for ruptured d-MCA aneurysms.

We report a case of low-flow bypass and endovascular coiling for ruptured middle portion posterior communicating artery (PCoA) aneurysm with an ipsilateral internal carotid artery occlusion. A male in his 70s, who presented with headache was referred to our hospital. Brain computed tomography (CT) and CT angiography showed subarachnoid hemorrhage and a cerebral aneurysm in the middle portion of the PCoA, along with an ipsilateral internal carotid artery occlusion. First, we performed a right superficial temporal artery–middle cerebral artery bypass to minimize the risk of perioperative cerebral ischemia and symptomatic vasospasm; subsequently, coil embolization through the posterior circulation was performed. The patient showed a successful recovery at the 3-month follow-up and showed no recurrence 4 years after the treatment. Coil embolization for the middle portion in a PCoA aneurysm has a risk of parent artery occlusion and can result in an incomplete occlusion owing to the small diameter of the PCoA. However, the combination of bypass surgery with coil embolization can be an effective treatment option. This approach reduces the likelihood of perioperative ischemic stroke, symptomatic vasospasm, and recurrence, particularly when the pathogenesis of the aneurysm is hemodynamic stress caused by an occluded artery.

We present a case of pharyngo-occipital artery (POA) originating from the stenosis of the internal carotid artery. The frequency of POA originating from the internal carotid artery is very rare. The patient was a 75-year-old male who was brought to our hospital due to sudden anarthria and drooping of the mouth corner. Cerebral infarction in the subcortical region of the right parietal lobe and stenosis of the right internal carotid artery greater than 70%, according to NASCET, were identified through brain magnetic resonance imaging (MRI) and computed tomography angiography (CTA). Because the MRI plaque imaging and ultrasound examination revealed a lesion with circumferential calcification and vulnerable plaque, we decided to perform a carotid endarterectomy (CEA). However, since POA was detected in the preoperative digital subtraction angiography (DSA) evaluation, we believed that we needed to devise a new technique. Due to concerns about regurgitation bleeding during surgery, we devised a method to block the branch vessels and improved the surgical steps. Here, we report a case in which CEA was safely performed without any intraoperative issues.

Bow hunter’s stroke is a rare disease with no established treatment. In this case report, we describe a case of Bow hunter’s stroke that was treated by embolization of the vertebral artery.

The patient was a 71-year-old male with repeated cerebral infarctions in the vertebrobasilar artery reflux area in half a year. Right vertebral angiography showed stenosis at the C5/6 level, dissecting aneurysm at the C6/7 level, and occlusion at the C7 level during right rotation of the head. The right vertebral artery was on the non-dominant side. Although no thrombus formation was observed in the right vertebral artery, we diagnosed this case as a Bow hunter’s stroke caused by an embolism. Since the patient had a recurrent cerebral infarction after medical treatment, further therapeutic intervention was necessary. We performed coil embolization of the right vertebral artery, including the dissecting aneurysm. No recurrence of cerebral infarction was noted within 2 years. Embolization of the vertebral artery may be an option for the treatment of Bow hunter’s stroke caused by an embolic mechanism, under limited conditions, such as the location of the lesion being on the non-dominant side.

When treating brain arteriovenous malformations (AVM), it is crucial to carefully consider treatment strategies, including preoperative embolization and surgical approaches, based on the nidus, feeder, and drainer locations. The treatment of AVM near the lateral ventricle poses the risk of visual field defects and language dysfunction. Among the 41 patients with AVM treated at our hospital between January 2010 and September 2022, three presented with lesions near the lateral ventricles. We compiled imaging findings, treatment strategies, and functional prognoses, focusing primarily on visual field defects. All patients experienced bleeding, but the symptoms were limited to headaches and vomiting, with no neurological deficits. Preoperative embolization using Onyx was performed in all patients. Case 1: A lesion was identified in the lateral aspect of the left ventricular trigone. The main feeder entering the base of the nidus was embolized for use as the deepest reference point during surgery. The nidus was removed using ViewSite through a high parietal approach. Although right homonymous hemianopsia was noted postoperatively, considerable improvement was observed after two weeks. Case 2: The lesion was located in the left ventricular trigone. Following embolization, it was removed using ViewSite through an occipital transcortical approach. Postoperative homonymous hemianopsia occurred but generally improved over six months. Case 3: The lesion was in the left medial temporal lobe. After embolization, the mass was removed via a subtemporal approach. Cerebral infarction occurred in the lateral part of the thalamus, resulting in right homonymous hemianopia, kanji agraphia, and sensory impairment. Careful consideration is required to avoid visual field defects when treating AVMs near the lateral ventricle. The use of ViewSites holds promise for reducing the risk of visual radiation.

We present two cases of vertebral artery aneurysm, and investigate usability, including tips and pitfalls, of the jailing technique for catheter insertion via the contralateral vertebral artery. This technique is especially useful when direct caudal insertion of the jailed catheter is preferential. Additional devices may be needed to cross the vertebra-basilar junction. For stable and safe embolization, coaxial usage of a distal access catheter is highly recommended.