Association between Carotid Bifurcation Angle and Vulnerable Plaque Volume Using Black Blood Magnetic Resonance Imaging.

The morphology of the internal carotid artery (ICA) bifurcation is increasingly being recognized as the cause of atherosclerosis and vulnerable plaque leading to cerebral infarction. In this study, we investigated the relationship between carotid bifurcation angle and carotid plaque volume evaluated using black blood magnetic resonance imaging (BB-MRI). Among the 90 patients who underwent revascularization for atherosclerotic symptomatic carotid stenosis between April 2016 and October 2022 using BB-MRI, carotid plaque was evaluated in 57 patients. Relative overall signal intensity (roSI) was defined as the signal intensity of the plaque on T1-weighted images relative to the signal intensity of the sternocleidomastoid muscle in the same slice as the common carotid bifurcation. Regions showing roSI ≥ 1.0 were defined as plaque, and the plaque volume and relative plaque volume were measured from roSI ≥1.0 to ≥2.0 in 0.1 increments. We calculated the angles between the common carotid artery (CCA) and the ICA and between the CCA and the external carotid artery (ECA) on magnetic resonance angiography. We classified two groups according to carotid bifurcation angles based on the ICA angle: Group A = <35° and Group B = ≥35°. Compared with Group A (n = 42), Group B (n = 15) showed a greater relative plaque volume between roSI ≥ 1.3 and roSI ≥ 1.5. A significant correlation was identified between relative plaque volume with roSI ≥ 1.4 and ICA angle (p = 0.049). Vulnerable plaque was significantly more frequent in the group with an ICA angle of ≥35. Moreover, the ICA angle was significantly greater in patients with a roSI of ≥1.4.

Multifocal primary central nervous system angiosarcoma: illustrative case.

BACKGROUND: Angiosarcoma is a malignant mesenchymal tumor derived from vascular endothelial cells in which a primary intracranial origin is extremely rare. Most previous reports of primary central nervous system (CNS) angiosarcoma have been solitary cases. OBSERVATIONS: The authors report a case of primary CNS angiosarcoma that caused the development of multiple disseminated cerebral hemorrhagic lesions within a short period of time. This rapid progression of symptoms resulted in the death of the patient. During surgery, several nodules suggestive of a tumor were removed from just below the surface of the brain, mixed into the hematoma. A pathological examination revealed atypical cells mimicking blood vessels in the subarachnoid space that were positive for specific vascular endothelial markers. LESSONS: In this case, multifocal angiosarcoma occurred on the brain surface and ventricles, suggesting cerebrospinal fluid dissemination. If multiple cerebral hemorrhages are found on the brain surface, multifocal angiosarcoma should also be considered.

Surgical treatment of sural nerve entrapment aided by imaging- and electrography-based diagnosis: illustrative case.

BACKGROUND: The sural nerve (SN) is a cutaneous sensory nerve that innervates the posterolateral side of the distal third of the leg and lateral side of the foot. The SN has wide variation in its course and is fixed to the subcutaneous tissue and superficial fascia. Idiopathic spontaneous SN neuropathy is rarely surgically treated because of the difficulty in detecting SN entrapment. OBSERVATIONS: Herein, the authors present a rare case of surgically treated spontaneous SN neuropathy. A 67-year-old male patient presented with right foot pain for several years. Magnetic resonance imaging and ultrasonography showed SN entrapment slightly proximal and posterior to the lateral malleolus. A nerve conduction study showed SN disturbance. After undergoing neurolysis, the patient's foot pain was alleviated. LESSONS: Idiopathic SN neuropathy can be treated surgically when SN entrapment is detected with comprehensive evaluation methods.

History of Carotid Artery Reconstruction around the World and in Japan.

Since ancient times, physicians have been aware of correlations between the carotid artery and consciousness; however, carotid stenosis was only recently identified as the cause of atherothrombotic ischemic stroke. In 1658, Wepfer described the first suggestion of a link between symptoms of cerebral arterial insufficiency and carotid pathology. In 1951, Fisher reported details of the symptoms and pathological findings and emphasized that cervical atheromatous lesions induced cerebral infarction with various symptoms. The beginning of carotid artery surgery was ligation of the carotid artery for neck or head injury, but surgeons were aware that this operation induced cerebral symptoms due to lack of blood supply. Carotid endarterectomy (CEA) was first reported by Eastcott et al. in 1954, and in Japan, Kimoto performed a successful CEA in 1962. In 1979, percutaneous transluminal angioplasty (PTA) was performed for patients with fibromuscular dysplasia, and then, carotid artery stenting (CAS) was first performed in 1989 by Mathias. In Japan, Kuwana et al. were the first to perform carotid PTA, in 1981, whereas Yamashita et al. performed the first CAS in 1997. Yoshimura et al. proposed staged carotid stenting to prevent hyperperfusion syndrome. Some issues in carotid reconstruction are still debated today, which include conventional (standard) CEA versus the eversion technique, CEA versus CAS versus medical therapy, and medical economic problems. In the future, we must continue to develop more effective, safer, and less expensive therapeutic methods to prevent carotid stroke, carrying on the efforts of the ancient peoples who pioneered this research.

Preoperative elevated eosinophils in peripheral blood for prediction of postoperative recurrence of chronic subdural hematoma.

OBJECTIVE: Chronic subdural hematoma (CSDH) is a common neurological disease with a significant postoperative recurrence rate. There are numerous reported studies of the development of CSDH. In recent years, fibrinolysis, angiogenesis, and inflammation have all been identified as relevant factors in the development of CSDH. While several authors have reported risk factors associated with CSDH recurrence, differential blood count of leukocytes has not yet been discussed. Therefore, in this study the authors aimed to retrospectively investigate the association between differential blood leukocyte count and the rate of CSDH recurrence. METHODS: The authors retrospectively reviewed 476 patients with 529 CSDHs who underwent surgery at a single institution between January 2011 and December 2021. After exclusion of patients who had not undergone a differential blood test of leukocytes preoperatively, CSDHs in 517 cerebral hemispheres of 466 patients were included in the study. Peripheral blood eosinophil counts ≥ 100/µL were considered eosinophil rich. RESULTS: CSDHs in 494 cerebral hemispheres of 445 patients were followed up postoperatively for at least 3 months or until resolution indicated by CSDH disappearance. Postoperative recurrence of CSDH was observed in 46 cerebral hemispheres (9.3%). Among the preoperative differential blood counts of all leukocytes, eosinophils alone were significantly associated with CSDH recurrence (median [IQR] 76/µL [30-155/µL] vs 119/µL [39-217/µL]; p = 0.03). Multivariable regression analysis showed thrombocytopenia (adjusted OR [aOR] 5.23, 95% CI 1.85-14.79; p = 0.002), use of anticoagulant drugs (aOR 2.51, 95% CI 1.17-5.38; p = 0.02), hematoma volume (10 mL per increase) (aOR 1.08, 95% CI 1.00-1.16; p = 0.04), and eosinophil-rich peripheral blood (aOR 2.22, 95% CI 1.17-4.23; p = 0.02) were all independent predictors for CSDH recurrence. CONCLUSIONS: This study showed that preoperative peripheral blood eosinophil count was an independent risk factor for CSDH recurrence. Therefore, patients with CSDH who have elevated eosinophils preoperatively in peripheral blood require careful follow-up.

Clinical Presentation, Treatment, and Outcome of Nontraumatic Subarachnoid Hemorrhage in Patients with Preceding Antithrombotic Therapy.

With the aging of the population, the number of people taking antithrombotic drugs is increasing. Few reports have described the clinical presentation, treatment, and outcomes of nontraumatic subarachnoid hemorrhage (SAH) in patients with preceding antithrombotic therapy. This study included 459 patients with nontraumatic SAH who had been treated between April 2009 and May 2021. Overall, 39 of the 459 patients with aneurysmal SAH were on antithrombotic therapy before ictus (8.5%). Therefore, we classified patients into two groups: Group A (n = 39), patients with preceding antithrombotic therapy and Group B (n = 420), patients without preceding antithrombotic therapy. Hunt and Kosnik (H&K) grade on admission was significantly higher in Group A than in Group B (p = 0.02). Patients in Group A more frequently received endovascular treatment. The rate of endovascular therapy for symptomatic vasospasm after SAH was significantly lower in Group A (2.6%) than in Group B (15.5%; p = 0.03). The outcomes at 3 months after onset were significantly poorer in Group A patients than in Group B patients (p = 0.03). Patients with preceding antithrombotic drugs tended to be at greater risk of unfavorable outcomes, but this difference was not significant in the univariate analysis. In the multivariate analysis, patient age, H&K grade ≥4, and subdural hematoma remained as risk factors for poor outcomes; however, preceding use of antithrombotic drugs was not a significant risk factor.

Chronic Subdural Hematoma-Evolution of Etiology and Surgical Treatment.

In this paper, I review the historical changes in the etiological concepts and surgical treatments for chronic subdural hematoma (CSDH) across the world and in Japan. I also examine future problems associated with its surgical procedures and medical costs. CSDH was first reported by Wepfer in 1657 as "delayed apoplexy." In 1857, Virchow described the famous concept of so-called "pachymeningitis hemorrhagica interna." He considered that the etiology of CSDH involved inflammation. In 1914, Trotter described the origin of CSDH as traumatic. Currently, CSDH is considered to arise with a first leak of blood from dural border cells after mild trauma. Inflammatory cells are then drawn to the border cell layer. At this point, new membranes form from activated inflammation; then, the hematoma enlarges, promoted by angiogenic factors and new capillaries. In 1883, Hulke reported successful trepanning of a patient with CSDH. Burr holes and craniotomy for removal of the hematoma were subsequently reported, and new methods were developed over the course of several decades around the world. In Japan, after the first report by Nakada in 1938, many Japanese pioneering figures of neurological surgery have studied CSDH. After Mandai reported the middle meningeal artery embolization in 2000, this method is now considered useful as an initial or second treatment for CSDH. However, the age of patients is increasing, so more minimally invasive surgeries and useful pharmacotherapies are needed. We must also consider the costs for treating CSDH, because of the increasing numbers of surgical cases.

Intra-abdominal hemorrhage due to segmental arterial mediolysis of an ovarian artery pseudoaneurysm and concomitant aneurysmal subarachnoid hemorrhage: illustrative case.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (SAH) is one of the most severe neurosurgical diseases in which systemic management is important from the acute phase to the chronic phase. The authors reported a case of aneurysmal SAH associated with intra-abdominal hemorrhage possibly caused by segmental arterial mediolysis (SAM). OBSERVATIONS: A 60-year-old woman collapsed suddenly at home. On arrival at our hospital, she was comatose and her head computed tomography (CT) showed SAH, probably from an anterior cerebral artery aneurysm. Simultaneous body CT to screen for pneumonia associated with COVID-19 incidentally detected an intra-abdominal hematoma and the bleeding point. Emergent ventriculostomy was conducted first. Because abdominal angiography detected a ruptured pseudoaneurysm of an ovarian artery, emergency embolization was subsequently performed for hemostasis. However, she deteriorated again, and her pupils became fully dilated. The patient died on day 3 of hospitalization. LESSONS: Patients with aneurysmal SAH rarely have intra-abdominal hemorrhage in the acute stage and may have a fatal outcome. Intra-abdominal hemorrhage should be suspected in the setting of unstable vital signs, and prompt treatment is necessary.

Impact of COVID-19 on the Volume of Acute Stroke Admissions: A Nationwide Survey in Japan.

This study aimed to measure the impact of the COVID-19 pandemic on the volumes of annual stroke admissions compared with those before the pandemic in Japan. We conducted an observational, retrospective nationwide survey across 542 primary stroke centers in Japan. The annual admission volumes for acute stroke within 7 days from onset between 2019 as the pre-pandemic period and 2020 as the pandemic period were compared as a whole and separately by months during which the epidemic was serious and prefectures of high numbers of infected persons. The number of stroke patients declined from 182,660 in 2019 to 178,083 in 2020, with a reduction rate of 2.51% (95% confidence interval [CI], 2.58%-2.44%). The reduction rates were 1.92% (95% CI, 1.85%-2.00%; 127,979-125,522) for ischemic stroke, 3.88% (95% CI, 3.70%-4.07%, 41,906-40,278) for intracerebral hemorrhage, and 4.58% (95% CI, 4.23%-4.95%; 13,020-12,424) for subarachnoid hemorrhage. The admission volume declined by 5.60% (95% CI, 5.46%-5.74%) during the 7 months of 2020 when the epidemic was serious, whereas it increased in the remaining 5 months (2.01%; 95% CI, 1.91%-2.11%). The annual decline in the admission volume was predominant in the five prefectures with the largest numbers of infected people per million population (4.72%; 95% CI, 4.53%-4.92%). In conclusion, the acute stroke admission volume declined by 2.51% in 2020 relative to 2019 in Japan, especially during the months of high infection, and in highly infected prefectures. Overwhelmed healthcare systems and infection control practices may have been associated with the decline in the stroke admission volume during the COVID-19 pandemic.

An Older Thrombus Delays Reperfusion after Mechanical Thrombectomy for Ischemic Stroke.

BACKGROUND: Thrombosis is a dynamic process, and a thrombus undergoes physical and biochemical changes that may alter its response to reperfusion therapy. This study assessed whether thrombus age influenced reperfusion quality and outcomes after mechanical thrombectomy for cerebral embolism. METHODS: We retrospectively evaluated 185 stroke patients and thrombi that were collected during mechanical thrombectomy at three stroke centers. Thrombi were pathologically classified as fresh or older based on their granulocytes' nuclear morphology and organization. Thrombus components were quantified, and the extent of NETosis (the process of neutrophil extracellular trap formation) was assessed using the density of citrullinated histone H3-positive cells. Baseline patient characteristics, thrombus features, endovascular procedures, and functional outcomes were compared according to thrombus age. RESULTS: Fresh thrombi were acquired from 43 patients, and older thrombi were acquired from 142 patients. Older thrombi had a lower erythrocyte content (p < 0.001) and higher extent of NETosis (p = 0.006). Restricted mean survival time analysis revealed that older thrombi were associated with longer puncture-to-reperfusion times (difference: 15.6 minutes longer for older thrombi, p = 0.002). This association remained significant even after adjustment for erythrocyte content and the extent of NETosis (adjusted difference: 10.8 minutes, 95% confidence interval [CI]: 0.6-21.1 minutes, p = 0.039). Compared with fresh thrombi, older thrombi required more device passes before reperfusion (p < 0.001) and were associated with poorer functional outcomes (adjusted common odds ratio: 0.49; 95% CI: 0.24-0.99). CONCLUSION: An older thrombus delays reperfusion after mechanical thrombectomy for ischemic stroke. Adding therapies targeting thrombus maturation may improve the efficacy of mechanical thrombectomy.

Incidence and clinical characteristics of spinal arteriovenous shunts: hospital-based surveillance in Okayama, Japan.

OBJECTIVE: There have been no accurate surveillance data regarding the incidence rate of spinal arteriovenous shunts (SAVSs). Here, the authors investigate the epidemiology and clinical characteristics of SAVSs. METHODS: The authors conducted multicenter hospital-based surveillance as an inventory survey at 8 core hospitals in Okayama Prefecture between April 1, 2009, and March 31, 2019. Consecutive patients who lived in Okayama and were diagnosed with SAVSs on angiographic studies were enrolled. The clinical characteristics and the incidence rates of each form of SAVS and the differences between SAVSs at different spinal levels were analyzed. RESULTS: The authors identified a total of 45 patients with SAVSs, including 2 cases of spinal arteriovenous malformation, 5 cases of perimedullary arteriovenous fistula (AVF), 31 cases of spinal dural AVF (SDAVF), and 7 cases of spinal epidural AVF (SEAVF). The crude incidence rate was 0.234 per 100,000 person-years for all SAVSs including those at the craniocervical junction (CCJ) level. The incidence rate of SDAVF and SEAVF combined increased with advancing age in men only. In a comparative analysis between upper and lower spinal SDAVF/SEAVF, hemorrhage occurred in 7/14 cases (50%) at the CCJ/cervical level and in 0/24 cases (0%) at the thoracolumbar level (p = 0.0003). Venous congestion appeared in 1/14 cases (7%) at the CCJ/cervical level and in 23/24 cases (96%) at the thoracolumbar level (p < 0.0001). CONCLUSIONS: The authors reported detailed incidence rates of SAVSs in Japan. There were some differences in clinical characteristics of SAVSs in the upper spinal levels and those in the lower spinal levels.

Case Report: Bow Hunter's Syndrome Caused by Compression of Extracranially Originated Posterior Inferior Cerebellar Artery.

Bow hunter's syndrome (BHS) is most commonly caused by compression of the vertebral artery (VA). It has not been known to occur due to an extracranially originated posterior inferior cerebellar artery (PICA), the first case of which we present herein. A 71-year-old man presented with reproducible dizziness on leftward head rotation, indicative of BHS. On radiographic examination, the bilateral VAs merged into the basilar artery, and the left VA was predominant. The right PICA originated extracranially from the right VA at the atlas-axis level and ran vertically into the spinal canal. During the head rotation that induced dizziness, the right PICA was occluded, and a VA stenosis was revealed. Occlusion of the PICA was considered to be the primary cause of the dizziness. The patient underwent surgery to decompress the right PICA and VA via a posterior cervical approach. Following surgery, the patient's dizziness disappeared, and the stenotic change at the right VA and PICA improved. The PICA could be a causative artery for BHS when it originates extracranially at the atlas-axis level, and posterior decompression is an effective way to treat it.

Variations and management for patients with craniocervical junction arteriovenous fistulas: Comparison of dural, radicular, and epidural arteriovenous fistulas.

BACKGROUND: Craniocervical junction arteriovenous fistulas (CCJAVFs) are known to be rare, but variations and clinical behaviors remain controversial. METHODS: A total of 11 CCJAVF patients (M: F=9:2, age 54-77 years) were investigated. Based on the radiological and intraoperative findings, they were categorized into three types: dural AVF (DAVF), radicular AVF (RAVF), and epidural AVF (EDAVF). RESULTS: There were four symptomatic patients (subarachnoid hemorrhage in two, myelopathy in one, and tinnitus in one) and seven asymptomatic patients in whom coincidental CCJAVFs were discovered on imaging studies for other vascular diseases (arteriovenous malformation in one, intracranial DAVF in two, ruptured cerebral aneurysm in two, and carotid artery stenosis in two). Of these 11 patients, 2 (18.2%) had multiple CCJAVFs. Of 14 lesions, the diagnoses were DAVF in 5, RAVF in 3, and EDAVF in 6 (C1-C2 level ratio =5:0, 2:1, 3:3). Patients with DAVF/RAVF in four lesions with intradural venous reflux underwent surgery, although an RAVF remained in one lesion after embolization/radiation. Since all six EDAVFs, two DAVFs, and one RAVF had neither feeder aneurysms nor significant symptoms, no treatment was provided; of these nine lesions, one DAVF and one RAVF remained unchanged, whereas six EDAVFs showed spontaneous obliteration within a year. Unfortunately, however, one DAVF bled before elective surgery. CONCLUSION: CCJAVFs have many variations of shunting site, angioarchitecture, and multiplicity, and they were frequently associated with coincidental vascular lesions. For symptomatic DAVF/RAVF lesions with intradural drainage, surgery is preferred, whereas asymptomatic EDAVFs without dangerous drainage may obliterate during their natural course.

Microbleeds and clinical outcome in acute mild stroke patients treated with antiplatelet therapy: ADS post-hoc analysis.

BACKGROUND AND PURPOSE: In this post-hoc analysis using acute dual study dataset, the impacts of cerebral microbleeds (MBs) after mild stroke on clinical outcome were investigated. METHODS: The number of MBs on admission was categorized as 1) no MBs, 2) MBs 1-4, 3) MBs 5-9, and 4) MBs ≥ 10. The efficacy outcome was defined as neurological deterioration and stroke recurrence within 14 days. Safety outcomes included ICH and/or SAH as well as extracranial hemorrhages. RESULTS: Of the 1102 patients, 780 (71%) had no MBs on admission, while 230 (21%) had MBs 1-4, 48 (4%) had MBs 5-9, and 44 (4%) had MBs ≥ 10. The number of MBs was not associated with the neurological deterioration and/or stroke recurrence (p = 0.934), ICH and/or SAH (p = 0.743), and extracranial hemorrhage (p = 0.205). Favorable outcome was seem in 84% in the No MBs group, 83% in the MBs 1-4, 94% in the MBs 5-9, and 85% in the MBs ≥ 10 (p = 0.304). Combined cilostazol and aspirin therapy did not alter any rates of efficacy and safety outcomes among the no MBs, MBs 1-4, MBs 5-9, and MBs ≥ 10 groups compared to aspirin alone (all p > 0.05). By multivariate regression analysis, a history of ICH and diastolic blood pressure were the independent parameters to all of the MBs criteria (presence, MBs ≥ 5, and MBs ≥ 10). CONCLUSIONS: MBs did not alter the clinical outcome at 3 months of onset. Elevated diastolic blood pressure and a history of ICH were the essential parameters related to the MBs.

Visualisation of the non-linear correlation between age and poor outcome in patients with aneurysmal subarachnoid haemorrhage.

OBJECTIVE: To visualise the non-linear correlation between age and poor outcome at discharge in patients with aneurysmal subarachnoid haemorrhage (SAH) while adjusting for covariates, and to address the heterogeneity of this correlation depending on disease severity by a registry-based design. METHODS: We extracted data from the Japanese Stroke Databank registry for patients with SAH treated via surgical clipping or endovascular coiling within 3 days of SAH onset between 2000 and 2017. Poor outcome was defined as a modified Rankin Scale Score ≥3 at discharge. Variable importance was calculated using machine learning (random forest) model. Correlations between age and poor outcome while adjusting for covariates were determined using generalised additive models in which spline-transformed age was fit to each neurological grade of World Federation of Neurological Societies (WFNS) and treatment. RESULTS: In total, 4149 patients were included in the analysis. WFNS grade and age had the largest and second largest variable importance in predicting the outcome. The non-linear correlation between age and poor outcome was visualised after adjusting for other covariates. For grades I-III, the risk slope for unit age was relatively smaller at younger ages and larger at older ages; for grade IV, the slope was steep even in younger ages; while for grade V, it was relatively smooth, but with high risk even at younger ages. CONCLUSIONS: The clear visualisation of the non-linear correlation between age and poor outcome in this study can aid clinical decision making and help inform patients with aneurysmal SAH and their families better.

Emergent stenting after intravenous thrombolysis for isolated basilar artery dissection in a patient with acute ischemic stroke: a case report.

BACKGROUND: Isolated basilar artery dissection (IBAD) is a rare but important cause of ischemic stroke. Anti-thrombotic therapy is often used to treat IBAD-related ischemic stroke, but selected cases might need more aggressive treatment. There is no previous report of emergent stenting for IBAD-related ischemic stroke after intravenous thrombolysis. CASE PRESENTATION: A 53-year-old Japanese woman was admitted to our hospital with disturbance of consciousness, right hemiplegia, severe dysarthria, and total gaze paralysis. Brain magnetic resonance imaging revealed no ischemic lesion, but magnetic resonance angiography showed stenosis in the basilar artery. After initiation of intravenous thrombolysis, her neurological symptoms dramatically improved. Five hours later, however, her symptoms deteriorated again. Cerebral angiography showed IBAD. Emergent stenting was successfully performed. At 90 days after stroke onset, she had no significant disability, with a modified Rankin scale score of 1. CONCLUSIONS: Emergent stenting can be an effective treatment for patients with IBAD-related ischemic stroke who are resistant to IV-rtPA.

Trends in Incidence of Intracranial and Spinal Arteriovenous Shunts: Hospital-Based Surveillance in Okayama, Japan.

BACKGROUND AND PURPOSE: To date, the incidence of intracranial and spinal arteriovenous shunts has not been thoroughly investigated. We aimed to clarify recent trends in the rates of intracranial and spinal arteriovenous shunts in Japan. METHODS: We conducted multicenter hospital-based surveillance at 8 core hospitals in Okayama Prefecture between April 1, 2009 and March 31, 2019. Patients who lived in Okayama and were diagnosed with cerebral arteriovenous malformations, dural arteriovenous fistulas (DAVFs), or spinal arteriovenous shunts (SAVSs) were enrolled. The incidence and temporal trends of each disease were calculated. RESULTS: Among a total of 393 cranial and spinal arteriovenous shunts, 201 (51.1%) cases of DAVF, 155 (39.4%) cases of cerebral arteriovenous malformation, and 34 (8.7%) cases of SAVS were identified. The crude incidence rates between 2009 and 2019 were 2.040 per 100 000 person-years for all arteriovenous shunts, 0.805 for cerebral arteriovenous malformation, 1.044 for DAVF, and 0.177 for SAVS. The incidence of all types tended to increase over the decade, with a notable increase in incidence starting in 2012. Even after adjusting for population aging, the incidence of nonaggressive DAVF increased 6.0-fold while that of SAVS increased 4.4-fold from 2010 to 2018. CONCLUSIONS: In contrast to previous studies, we found that the incidence of DAVF is higher than that of cerebral arteriovenous malformation. Even after adjusting for population aging, all of the disease types tended to increase in incidence over the last decade, with an especially prominent increase in SAVSs and nonaggressive DAVFs. Various factors including population aging may affect an increase in DAVF and SAVS.

Postoperative recurrence of chronic subdural hematoma is more frequent in patients with blood type A.

OBJECTIVE: Because of an aging society, the incidence of chronic subdural hematoma (CSDH) is increasing. This lesion is treated with simple burr hole irrigation, but one of the major issues is that CSDH frequently recurs. ABO blood type may be associated with a bleeding tendency and inflammation. However, its association with the recurrence of CSDH remains unknown. Therefore, the authors of the present study aimed to retrospectively investigate the association between ABO blood type and CSDH recurrence. METHODS: The authors retrospectively analyzed symptomatic CSDHs in 425 cerebral hemispheres of 376 patients who had undergone surgical treatment with irrigation of the hematoma via burr holes at their institution from January 2011 to September 2019. Among these were 366 CSDHs in 320 patients whose ABO blood type had been determined and who were included in this study. RESULTS: In the study, 307 patients with CSDHs in 350 hemispheres were followed up postoperatively until the disappearance of the CDSH or for at least 3 months. Recurrence of CSDH was observed in 37 patients (10.6%) after surgical treatment. Blood type A was found to be significantly associated with CSDH recurrence compared to non-A blood types: 24 of 153 CDSHs (15.7%) versus 13 of 197 CDSHs (6.6%) (p = 0.008). In the multivariable regression analysis, blood type A, in addition to thrombocytopenia, was a significant independent predictor of the recurrence of CSDH. CONCLUSIONS: The study results showed that blood type A is an independent risk factor for the postoperative recurrence of CSDH and that careful follow-up in these patients may be needed.

Comparison of Single and Dual Monitoring during Carotid Endarterectomy.

We compared the rate of selective shunt and pattern of monitoring change between single and dual monitoring in patients undergoing carotid endarterectomy (CEA). A total of 121 patients underwent 128 consecutive CEA procedures. Excluding five procedures using internal shunts in a premeditated manner, we classified patients according to the monitoring: Group A (n = 72), patients with single somatosensory evoked potential (SSEP) monitoring; and Group B (n = 51), patients with dual SSEP and motor evoked potential (MEP). Among the 123 CEAs, an internal shunt was inserted in 12 procedures (9.8%) due to significant changes in monitoring (Group A 5.6%, Group B 15.7%, p = 0.07). The rate of shunt use was significantly higher in patients with the absence of contralateral proximal anterior cerebral artery (A1) on magnetic resonance angiography (MRA) than in patients with other types of MRA (p <0.001). Significant monitor changes were seen in 16 (12.5%) in both groups. In four of nine patients in Group B, SSEP and MEP changes were synchronized, and in the remaining five patients, a time lag was evident between SSEP and MEP changes. In conclusion, the rate of internal shunt use tended to be more frequent in patients with dual monitoring than in patients with single SSEP monitoring, but the difference was not significant. Contralateral A1 absence may predict the need for a shunt and care should be taken to monitor changes throughout the entire CEA procedure. Use of dual monitoring can capture ischemic changes due to the complementary relationship, and may reduce the rate of false-negative monitor changes during CEA.

Improvement of Hemifacial Spasm after Stent-assisted Coil Embolization for Ipsilateral Vertebral Artery Dissecting Aneurysm.

Microvascular decompression (MVD) is the gold standard in the treatment of hemifacial spasm (HFS), and endovascular surgery has been described as a treatment only for aneurysm-induced HFS in several previous cases. We describe symptomatic HFS caused by a normal vertebral artery (VA) trunk adjacent to the ipsilateral dissecting VA aneurysm completely cured after stent-assisted coil embolization. A 52-year-old man presented with a 2-month history of gradually worsening left HFS. Magnetic resonance imaging (MRI) and cerebral angiography revealed a dissecting VA aneurysm on the left side. Based on the findings from preoperative MRI, not the aneurysmal dome itself, but the VA trunk just distal to the aneurysmal dome was considered likely to be compressing the root exit zone (REZ) of the facial nerve. Stent-assisted coil embolization was conducted for the VA aneurysm, and the stent was deployed to cover the wide neck of the aneurysm and offending zone of the VA trunk simultaneously. HFS started to show improvement just after the procedure and complete disappearance within 1 year. HFS was completely resolved by stenting of the offending artery. Stents may show efficacy for "intra-arterial decompression" by reducing pulsatility against the REZ of the facial nerve due to the thickness and rigidity of the stent metal and delayed endothelialization.