We investigated the impact of the COVID‒19 pandemic on the transport of thrombectomy cases transported to our facility in Tokyo. The patients’ demographics, the transport time and distance, the ratio of transportation from another secondary healthcare area, and clinical outcomes were compared between before and after the declaration of Japan’s state of COVID‒19 emergency (the pandemic era was defined as the post‒declaration era). We examined the cases of 123 patients (pre‒pandemic era, n=91; pandemic era, n=32). In the pre‒pandemic and pandemic eras, the median time from the patients’ ambulance calls to departure were 25 min and 26.5 min (p=0.43), the median times from departure to our facility (door) were 11 min and 12 min (p=0.20) the median transport distances were 3.1 km and 3.6 km (p=0.38), the ratios of transportation from another area were 8.8% and 28.1% (p=0.01), and the median modified Rankin Scale values at 90 days were 3:3 (p=0.36), respectively. Although the number of patients transported to our facility from another area increased in the pandemic era, the increase did not lead to a delay in transport time or to any deterioration in patient outcomes; we attribute this to the densely located primary stroke centers and the acute stroke transport system in Tokyo.

  We report the case of a patient with a cavernous sinus (CS) dural arteriovenous fistula (dAVF) with ocular symptoms who was treated with transvenous embolization (TVE) via the facial vein (FV) connecting to the anterior jugular vein (AJV). A 76‒year‒old Japanese woman was referred to our hospital for a detailed investigation and treatment of left exophthalmos, eye pain, and diplopia. Magnetic resonance and digital subtraction angiography showed that the shunt point was the left CS, and the main venous drainage route was retrograde from the left cavernous sinus to the left superior orbital vein (SOV) due to an obstruction of the antegrade drainage route. The first TVE session resulted in no embolization of the fistula due to poor accessibility into the left CS, and postoperative computed tomography angiography (CTA) disclosed a drainage route into the left FV connecting to the left AJV and jugular venous arch. The patient underwent a second session of TVE with left AJV puncture using echo through the left AJV, FV, and SOV, and obliteration was achieved. Considerable variation exists in the anatomy of the faciocervical veins in patients with a CS dAVF. A meticulous preoperative evaluation of the venous drainage route using CTA is indispensable to achieving successful treatment outcomes in patients with a CS dAVF.

  We report the case of a 76‒year‒old Japanese male with a history of hypertension, diabetes, cerebral infarction, and iliac artery stenosis on dual antiplatelet therapy who presented with dementia, gait disturbance, and urinary incontinence that had progressed for approx. 10 years. Magnetic resonance imaging of the head showed an enlargement of the lateral ventricles, asymptomatic cerebral hemorrhage, and microhemorrhage in the putamen. We performed a ventriculoperitoneal shunt for possible idiopathic normal‒pressure hydrocephalus. However, on postoperative day 10, the patient developed consciousness disorder and left hemiplegia after an unwitnessed fall he experienced 4 days after the change of the shunt valve’s pressure to low pressure. Computed tomography showed a right putamen hemorrhage. This case demonstrates that (i) overdrainage after a shunt can also induce cerebral hemorrhage, and (ii) it is necessary to consider appropriate cerebrospinal fluid management and reduce antithrombotic drugs in such cases.

  Revascularization of the posterior circulatory system is relatively rare, and that using the extracranial vertebral artery as a recipient is extremely rare. We performed an occipital artery (OA)‒V3 bypass on a patient with symptomatic intracranial vascular stenosis before cervical posterior fusion, and the patient showed no new neurological abnormalities during the peri‒operative period. The patient was a Japanese male in his 30s, and he had experienced weakness in his right lower limb while walking for ～1 year. He visited a local physician after his symptoms had worsened for the prior month, and the physician noted a cervical spine injury and referred him to our hospital. We observed mild paralysis of the right lower limb and extremity tendon hyper‒reflexia. Cervical spine MRI showed intramedullary hyperintensity from the cranio‒cervical spine transition to C2 on T2‒weighted images. Cervical spine CT showed os odontoideum, atlanto occipital dislocation (AOD), and atlantoaxial dislocation (AAD). Posterior cervical spine fusion (CO‒C2 fixation) was deemed necessary due to the patient’s progressive myelopathy. However, head MRA revealed stenosis of the vertebrobasilar artery; in addition, head MRI T2‒weighted images revealed old infarctions in the bilateral cerebellar hemisphere, left pons, and left thalamus. Head and neck CT showed bilateral vertebral arteries, but the left vertebral artery was occluded at the C2 level. Angiography showed that the left deep carotid artery had developed compensatorily and was anastomosed with the left vertebral artery at the C2 level. When posterior cervical spine fusion is performed, the collateral circulation to the left vertebral artery running through the muscular layer may become blocked, resulting in peri‒operative cerebral ischemia. We therefore performed the OA‒V3 bypass first, and the posterior cervical fusion was performed at a later date. The patient was discharged from the hospital with no peri‒operative neurological dropout findings.

  It is well known that internal carotid artery aneurysm, dissection, and internal carotid‒cavernous sinus fistula (CCF) occur secondary to cerebrovascular injury due to severe head trauma. The effectiveness of endovascular treatment for these is high and reliable treatment is possible, so early diagnosis is important. We report a case of spontaneous cure of traumatic CCF in which priority was given to the treatment of trunk trauma, and in which recognizing the presence of traumatic subarachnoid hemorrhage resulted in a delayed diagnosis and severe sequelae. Our patient was a 17‒year‒old male with multiple trauma caused by a traffic accident. Although traumatic subarachnoid hemorrhage and pneumocephalus were found in the skull base on head computed tomography (CT), diagnosis and treatment were prioritized to first address intraperitoneal hemorrhage and hemorrhagic shock due to splenic injury. Cerebral infarction was observed on head CT on Day 3. From the beginning, a large amount of epistaxis, skull base fracture, and traumatic internal carotid artery injury were symptomatically suggested, but the patient’s condition could not be fully understood due to severe disturbance of consciousness without eye symptoms. On Day 5, when CT angiography was performed, CCF and internal carotid artery dissection were confirmed. Extensive cerebral infarction had already appeared, and conservative treatment was selected based on the patient’s condition. Spontaneous cure of CCF was confirmed by follow‒up CT, but the patient was transferred to the hospital 60 days after admission due a residual modified Rankin Scale score of 5 and severe dysfunction. For severe head trauma, it is important to consider the possibility of cerebral vascular injury and to diagnose it early using techniques such as angiography if symptoms or imaging findings suggesting it are observed.

  We report a rare case of catheter‒related thrombosis after a peritoneovenous shunt and embolic stroke of undetermined source (ESUS) with a patent foramen ovale (PFO). A Japanese male in his 70s received a peritoneovenous shunt for intractable ascites due to alcoholic cirrhosis. Since disseminated intravascular coagulation (DIC) often occurs as a postoperative complication, he was treated with a synthetic serine protease inhibitor intra‒ and postoperatively and was discharged from the hospital. On postoperative day 20, he suddenly suffered from left paralysis. He was diagnosed with a right middle cerebral artery cerebral embolism and splenic infarction with hyperthermia and high D‒dimer, but conservative treatment was selected because of his poor general condition. The diagnosis of the stroke type was ESUS. Transthoracic echocardiography confirmed the PFO, but transesophageal echocardiography could not be performed. There was a high possibility of catheter‒related thrombosis as the source of the embolism. We could not identify the causative organism, but the infection resolved after 4 weeks of vancomycin treatment. The diagnosis of paradoxical embolism was not made, as the venous thrombus at the tip of the catheter could not be demonstrated. We hypothesized that the patient originally had a PFO that changed to a high‒risk PFO after peritoneovenous shunting, and that he developed a cerebral infarction due to catheter‒related thrombosis.

  We report a case of cervical spondylotic myelopathy being triggered by heat stroke. An 83‒year old man presented with transient acute onset of bilateral lower limb weakness after working in a hot environment. Because brain MRI showed no ischemic lesion, he was diagnosed as heat stroke and treated with intravenous fluids. However, ataxic gait continued. Serial brain MRI showed no lesion and cervical MRI showed cord compression due to hypertrophy of the yellow ligament at the C3/4 level. Hence, we diagnosed cervical spondylotic myelopathy. He underwent posterior decompression and his gait disturbance improved. In this case, heat stroke might be the trigger for cervical spondylotic myelopathy.

  A point contrast effect on contrast‒enhanced computed tomography (CT) called a spot sign may be seen in an acute intracerebral hemorrhage. We report a case in which the spot sign caused by a putaminal hemorrhage was captured by angiography as a pseudoaneurysm of the lateral lenticulostriate artery. The spot sign is often recognized as extravascular leakage from a hemorrhagic vessel, but it can also indicate various other vascular abnormalities. As the accuracy of CT scans has improved in recent years, angiography is often not performed prior to surgical treatment. However, it is important to note that some spot signs, which may indicate extravascular leakage from the responsible vessel for cerebral hemorrhage, may be clearly observed as an aneurysm upon angiography, as in the present case.

  We describe a case in which a cardiogenic thrombus at the cervical internal carotid artery migrated to the middle cerebral artery. The patient was a 69‒year‒old female who had mild neurological symptoms. At her first visit, magnetic resonance diffusion‒weighted imaging indicated no acute ischemic lesion. Magnetic resonance angiography revealed occlusion of the right internal carotid artery and a patent middle cerebral artery supplied via the posterior communicating artery. The next day, the patient exhibited left hemiparesis and occlusion of both the internal carotid artery and middle cerebral artery. A mechanical thrombectomy was performed. Complete recanalization was achieved, and the patient’s neurological deficits were resolved. The mechanical thrombectomy was effective for this emergency state of thrombus migration from the cervical internal carotid artery to the terminus of the internal carotid artery. The present case demonstrates that it is possible for a thrombus of the cervical internal carotid artery to migrate to a distal intracranial artery and result in severe symptoms. In the event of such an emergency, a system for rapid treatment by mechanical thrombectomy is needed.

  A 10％‒20％ loss of cerebrospinal fluid (CSF) due to leakage complicates some cases of chronic subdural hematoma (CSDH). It is difficult to determine the diagnosis when a CSF leak is present, and as a result a deterioration of the disease state occurs. We treated a patient with bilateral CSDH and a CSF leak in whom an imminent state was avoided by the urgent application of an epidural blood patch method. Opposite intracranial pressure is a concern in such cases, but there is no established method for addressing this. The decision whether to perform trepanation or an epidural blood patch method must be considered, but both of these treatments can worsen the patient’s condition. In the present case, we found it useful to measure the intracranial pressure to help select the treatment strategy. Through our experience, we have developed a treatment algorithm for patients with CSF leak and chronic subdural hematoma.

  We report a patient in whom trapping under a craniotomy was performed to treat a subarachnoid hemorrhage related to the rupture of a dissecting aneurysm of the left vertebral artery originating directly from the aorta. Previous studies indicated the association of an anomalous origin of the vertebral artery with dissecting lesions in the presence of changes in hemodynamics or excessive wall shear stress. When a diagnosis of dissection of the left vertebral artery is being considered, the presence of an anomalous origin or a morphological abnormality of the vertebral artery, including the left vertebral artery originating from the aorta, must be considered. When craniotomy is selected, trapping may be appropriate, as routinely conducted. However, when diagnostic catheterization is performed before a craniotomy or endovascular surgery, unexpected aortic arch anomalies may be detected during the procedure.

  We report a case of sudden bilateral sensorineural hearing loss caused by atherosclerotic occlusion of bilateral vertebral arteries which improved after angioplasty.

  Case Presentation: A 59‒year‒old Japanese male who presented with sudden bilateral sensorineural hearing loss and vertigo was admitted. Magnetic resonance imaging demonstrated acute cerebral infarction in the right cerebellar hemisphere and left posterior lobe. Computed tomography angiography revealed occlusion of the bilateral vertebral arteries and the blood flow of the basilar artery and posterior cerebral artery via the posterior communicating artery. Despite medical treatment, the neurological symptoms worsened; urgent angioplasty was thus performed and led to recanalization of the left vertebral artery. The patient’s neurological symptoms gradually recovered.

  Conclusion: Because the internal auditory artery is the terminal artery of the anterior inferior cerebellar artery, sudden bilateral sensorineural hearing loss may be a precursor to bilateral vertebral artery occlusion. Early imaging and rapid endovascular treatment are needed even in the absence of other neurological symptoms.

  The patient was a 66‒year‒old Japanese man who had received a ventriculoperitoneal shunt 20 years ago. He was brought to our department due to a convulsion. Hydrocephalus and a central nervous system (CNS) infection were suspected, and he was treated with shunt pressure adjustment and antibiotics. Magnetic resonance imaging on the 25th and the 33rd hospital days showed circumferential enhancement surrounding the ventricles, and on the 35th hospital day we observed that the shunt valve did not refill. We attempted to control the infection while managing the patient’s hydrocephalus by performing external lumbar cerebrospinal fluid (CSF) drainage, but the CSF cell count remained elevated. We thus removed the shunt on the 49th hospital day. Since the ventricular catheter could not be removed by simple traction, we used a flexible neuroendoscope to observe the catheter and identified adhesions accompanied by granulation and neovascularization along the entire length of the catheter. We were able to remove the catheter by dissection and hemostasis by using a monopolar probe endoscope, without complications. The use of a flexible neuroendoscope may be a useful option for the safe removal of a blocked shunt, as new vessels may be involved in the occlusion of the ventricular catheter in patients with long‒standing postoperative shunt malfunction and a concurrent CNS infection.

  Most cases of von Willebrand disease are mild, but this condition occasionally presents with severe intracranial hemorrhage. Although Japanese guidelines were published in 2021, it is expected that some cases will be difficult. We report the case of an 82‒year‒old woman with von Willebrand disease who developed an acute subdural hematoma with impaired consciousness. Due to the appearance of anisocoria, we performed craniotomy without waiting for Factor VIII to arrive. Fortunately, intraoperative hemostasis was uneventful, and the removal of the hematoma improved the patient’s consciousness disorder. However, a computed tomography scan taken the day after surgery showed an increase in the size of the hematoma. As a result of continued antihypertensive management and under‒monitored administration, the hematoma did not increase thereafter. The perioperative risk in von Willebrand disease is not low, and it is essential for surgeons to be familiar with the appropriate response in the event of bleeding.