Lumboperitoneal Shunt Surgery under Spinal Anesthesia on Idiopathic Normal Pressure Hydrocephalus Patients.

Since the publication of guidelines for managing idiopathic normal pressure hydrocephalus (iNPH) in 2004, an increasing number of patients with iNPH have been undergoing shunt surgery in Japan. However, shunt surgeries for iNPH can be challenging because the procedures are performed on elderly patients. General anesthesia-related risks, such as postoperative pneumonia or delirium, are higher in the elderly. To decrease these risks, we applied spinal anesthesia on a lumboperitoneal shunt (LPS). Herein, we analyzed our methods focusing on the postoperative outcomes. We retrospectively analyzed 79 patients who underwent LPS at our institution with more than one year of follow-up. The patients were divided into two groups based on the anesthetic approach, that is, 1) general anesthesia and 2) spinal anesthesia, and were examined in terms of postoperative complications, delirium, and postoperative hospital stay. In the general anesthesia group, two patients had respiratory complications after the surgery. The postoperative delirium score using the intensive care delirium screening checklist (ICDSC) was 0 (2) (median [interquartile range]), and the length of postoperative hospital stay was 11 (4) days. In the spinal anesthesia group, no patients had respiratory complications. The postoperative mean ICDSC was 0 (1), and the length of postoperative hospital stay was 10 (3) days. Although there was no significant difference regarding postoperative delirium existed, LPS under spinal anesthesia decreased respiratory complications and significantly shortened the postoperative hospital stay. LPS under spinal anesthesia could be an alternative to general anesthesia in elderly patients with iNPH and possibly lessen the general anesthesia-related risks.

Comparison of creatinine-based equations for estimating renal function for digoxin dose adjustment in patients with atrial fibrillation and heart failure.

The aim of this study was to determine an appropriate equation for estimating renal function to dose regulate the serum digoxin trough concentration to a target of <0.9 ng/ml in patients with atrial fibrillation (AF) and heart failure (HF). All patients received 0.125 mg oral digoxin daily. The estimated glomerular filtration rate by the Modification of Diet in Renal Disease (eGFRMDRD ) equation deindexed based on body surface area had the highest correlation with digoxin trough concentrations (r = -0.450) compared to the Cockcroft-Gault equation (r = -0.415) or deindexed eGFR based on the Chronic Kidney Disease Epidemiology Collaboration (eGFRCKD-EPI ) equation (r = -0.416). The median digoxin trough concentrations were 0.60, 0.77, 0.97 and 1.30 ng/ml in patients with a deindexed eGFRMDRD ≥ 60, 45-59, 30-44 and < 30 ml/min, respectively. The deindexed eGFRMDRD is an appropriate equation for digoxin dose adjustment in patients with AF and HF.

Control of Diabetes Mellitus and Long-Term Prognosis in Stroke Patients: The Shiga Stroke and Heart Attack Registry.

BACKGROUND: The relationship between diabetes control status and long-term prognosis after stroke incidence remains unclear. This study aimed to investigate the effect of diabetes status at admission on long-term survival in patients with first-ever stroke. METHODS: A retrospective cohort study was conducted based on the Shiga Stroke and Heart Attack Registry in Japan. Patients were classified according to their diabetes status and glycated hemoglobin (HbA1c) value at hospital admission into the following: (1) free of diabetes (no history of diabetes and HbA1c <6.5%); (2) good control (history of diabetes and HbA1c <7%; free of history and 6.5% ≤HbA1c <7%); and (3) poor control (with or without a history of diabetes and HbA1c ≥7%). Multivariable Cox regression models were used to evaluate the association between diabetes status and long-term survival from stroke onset. Additionally, we also evaluated the association between diabetes status and conditional survival, beginning 29 days after stroke onset. RESULTS: A total of 6,331 first-ever stroke patients were eligible for this study. Among study patients, the mean (±SD) age was 72.85 ± 13.19 years, and the mean (±SD) follow-up year was 2.76 ± 1.66 years; additionally, 42.09% of patients were women. Among patients with all strokes, considering the free-of-diabetes group as the reference group, the adjusted hazard ratio (95% confidence interval) for mortality was 1.26 (1.10, 1.44) in the good control group and 1.22 (1.05, 1.41) in the poor control group. Among patients with ischemic stroke, the adjusted hazard ratio was 1.24 (1.06, 1.46) in good control group and 1.27 (1.08, 1.50) in poor control group. After excluding patients who died within 28 days, the adjusted hazard ratio for conditional mortality in the poor control group was 1.31 (1.12, 1.54) among all stroke patients and 1.29 (1.08, 1.54) among ischemic stroke patients. No significant associations were observed between diabetic status and long-term mortality in intracerebral hemorrhage patients. CONCLUSIONS: The findings suggest that first-ever stroke patients with diabetes exhibited a higher risk of all-cause mortality than those without diabetes, particularly in the overall stroke and ischemic stroke populations. Additionally, in stroke populations after 28 days of onset, high risk of long-term mortality was stated in stroke patients with poor HbA1c control.

Indication for a skull base approach in microvascular decompression for hemifacial spasm.

BACKGROUND: A thorough observation of the root exit zone (REZ) and secure transposition of the offending arteries is crucial for a successful microvascular decompression (MVD) for hemifacial spasm (HFS). Decompression procedures are not always feasible in a narrow operative field through a retrosigmoid approach. In such instances, extending the craniectomy laterally is useful in accomplishing the procedure safely. This study aims to introduce the benefits of a skull base approach in MVD for HFS. METHODS: The skull base approach was performed in twenty-eight patients among 335 consecutive MVDs for HFS. The site of the neurovascular compression (NVC), the size of the flocculus, and the location of the sigmoid sinus are measured factors in the imaging studies. The indication for a skull base approach is evaluated and verified retrospectively in comparison with the conventional retrosigmoid approach. Operative outcomes and long-term results were analyzed retrospectively. RESULTS: The extended retrosigmoid approach was used for 27 patients and the retrolabyrinthine presigmoid approach was used in one patient. The measurement value including the site of NVC, the size of the flocculus, and the location of the sigmoid sinus represents well the indication of the skull base approach, which is significantly different from the conventional retrosigmoid approach. The skull base approach is useful for patients with medially located NVC, a large flocculus, or repeat MVD cases. The long-term result demonstrated favorable outcomes in patients with the skull base approach applied. CONCLUSIONS: Preoperative evaluation for lateral expansion of the craniectomy contributes to a safe and secure MVD.

Effect of high-dose delivery on the attachment of meningiomas in Gamma Knife surgery: a retrospective study.

BACKGROUND: Meningiomas have vascular supply from the tumor attachment on the dura mater. Gamma Knife radiosurgery (GKS) is known to have a vascular obliterating effect. This study aims to determine the benefits of high-dose irradiation to the tumor attachment compared to conventional dose planning in the long-term control of tumor growth with GKS. METHODS: Two different dose plannings were retrospectively compared in 75 patients with meningioma treated with GKS as a primary treatment. Forty-three patients were irradiated over 20 Gy to the tumor attachment. The remaining 32 patients were treated with conventional-dose planning. Tumor growth control, reduction of enhancement on the gadolinium-enhanced magnetic resonance imaging (MRI), and neurological status were retrospectively assessed. RESULTS: The maximum dose on the tumor attachment was significantly higher in the high-dose group (23 Gy) than in the conventional group (16 Gy). The tumor margin was irradiated with the median of the 50% isodose line in both groups. The prescription doses resulted in 14 Gy and 12 Gy, respectively. The tumor control rate achieved 91% in both groups during the median follow-up period of 54 months. A decrease of enhancement on follow-up MRI was noted in one patient in each group. Kaplan-Meier analysis revealed no statistical difference in the progression-free survival between the two groups. The number of patients with improved neurological status showed no statistical difference. CONCLUSIONS: No obvious benefit of high-dose irradiation to the tumor attachment and margin was found in tumor control and neurological status in the long term.

Seasonal Variation in Incidence of Stroke in a General Population of 1.4 Million Japanese: The Shiga Stroke Registry.

INTRODUCTION: The purpose of this study was to investigate seasonal variation in stroke incidence using data from a large-scale stroke registry of general population in current Japan. METHODS: Shiga Stroke Registry (SSR) is an ongoing population-based registry of stroke that occurred in the Shiga Prefecture in central Honshu, Japan. A total 6,688 cases of first-ever stroke, with onset dates ranging from 1 January 2011 to 31 December in 2013 were included in this study. Incidence rates of first-ever stroke in each season were estimated using the person-year approach and adjusted for age and sex using the Poisson regression models. RESULTS: From 2011 to 2013, we identified a total of 6,688 stroke cases (3,570 men, 3,118 women), of which 4,480 cases had ischemic stroke (2,518 men, 1,962 women), 1,588 had intracerebral hemorrhage (857 men, 731 women) and 563 had subarachnoid hemorrhage (166 men, 397 women). Age- and sex-adjusted incidence rates of total stroke were 151 (95% confidence interval [CI] 144-160, p = <0.001 vs. summer) in spring, 130 (95% CI 122-137) in summer, 141 (95% CI 133-149, p = 0.020 vs. summer) in autumn and 170 (95% CI 161-179, p = <0.001 vs. summer) in winter. Seasonal variation was more pronounced in intracerebral hemorrhage than in ischemic stroke. CONCLUSION: In the present large-scale stroke registry of general population, incidence rates of stroke were highest in winter and lowest in summer in current Japan.

Bridge technique for hemifacial spasm with vertebral artery involvement.

BACKGROUND: To assess efficacy and safety of a newly developed decompression technique in microvascular decompression for hemifacial spasm (HFS) with vertebral artery (VA) involvement. METHODS: A rigid Teflon (Bard® PTFE Felt Pledget, USA) with the ends placed between the lower pons and the flocculus creates a free space over the root exit zone (REZ) of the facial nerve (bridge technique). The bridge technique and the conventional sling technique for VA-related neurovascular compression were compared retrospectively in 60 patients. Elapsed time for decompression, number of Teflon pieces used during the procedure, and incidences of intraoperative manipulation to the lower cranial nerves were investigated. Postoperative outcomes and complications were retrospectively compared in both techniques. RESULTS: The time from recognition of the REZ to completion of the decompression maneuvers was significantly shorter, and fewer Teflon pieces were required in the bridge technique than in the sling technique. Lower cranial nerve manipulations were performed less in the bridge technique. Although statistical analyses revealed no significant differences in surgical outcomes except spasm-free at postoperative 1 month, the bridge technique is confirmed to provide spasm-free outcomes in the long-term without notable complications. CONCLUSIONS: The bridge technique is a safe and effective decompression method for VA-involved HFS.

Redo surgery for trigeminal neuralgia: reasons for re-exploration and long-term outcomes.

BACKGROUND: To investigate the causes of failure and recurrence after microvascular decompression (MVD) for trigeminal neuralgia (TGN) and to analyze the results of redo surgery. METHODS: Sixty-three cases of redo surgery were retrospectively reviewed. Reasons for re-exploration were categorized into 4 groups based on the operative findings. Patient characteristics, outcomes of re-exploration, and operative complications were analyzed by Kaplan-Meier and logistic regression analyses. RESULTS: Reasons for redo surgery were divided into arterial compression in 13 patients (21%), venous compression in 11 patients (17%), prosthesis-related in 25 patients (40%), and adhesion or negative exploration in 14 patients (22%). Immediate pain relief was obtained in 59 patients (94%) postoperatively with newly developed facial numbness in 17 patients (27%). Of these, 48 patients (76%) maintained pain-free 1 year postoperatively. Overall recurrence was noted in 17 patients (27%) during the median 49-month follow-up period. Most recurrences occurred within 1 year after redo surgery, but the prosthesis-related patients showed a continuous recurrence up to 4 years. Patients having vascular compression showed significantly better pain control than those without vascular contact in Kaplan-Meier analyses (p = 0.0421). No prognostic factor for pain-free 1 year after redo surgery was found. CONCLUSIONS: Redo surgery is effective for patients with remaining vascular compression rather than those without vascular contact. Teflon contact onto the nerve root should be avoided because it is a potential risk for recurrence and causes poor prognosis after redo surgery.

Association of self-measured home, ambulatory, and strictly measured office blood pressure and their variability with intracranial arterial stenosis.

OBJECTIVE: Hypertension and intracranial artery stenosis (ICAS) are closely related; however, few studies have compared the strength of the relationship between strictly measured office and out-of-office blood pressure (BP) measurements. The relationship of day-by-day or short-term variability in BP to asymptomatic ICAS also remains unclear. METHODS: In apparently healthy 677 men (mean age, 70 years) from a population-based cohort, we examined the association of strictly measured office BP and 7-day home BP with ICAS on magnetic resonance angiography. We conducted 24-h ambulatory BP monitoring in 468 of the men. Variability indices included day-by-day, daytime, and night-time variability, nocturnal decline, and morning pressor surge. Any ICAS was defined as either mild (1-49%) or severe (≥50%) stenosis. RESULTS: We observed mild and severe ICAS in 153 (22.6%) and 36 (5.3%) participants, respectively. In multivariable-adjusted Poisson regression with robust error variance, higher SBP in office, home, or ambulatory BP monitoring was associated with the presence of any or severe ICAS. The associations with ICAS were comparable between office, home, and ambulatory SBP (all heterogeneity P values >0.1). Independent of mean SBP, greater nocturnal decline or morning pressor surge, but not day-by-day, daytime, or night-time variability, in SBP was associated with higher burden of any or severe ICAS. CONCLUSION: The magnitude of association of strictly measured office BP for asymptomatic ICAS was comparable with that of BP measured at home or in ambulatory BP monitoring. Circadian BP variation based on ambulatory BP monitoring was positively associated with asymptomatic ICAS burden.

Double collagen matrix grafting for dural closure in microvascular decompression: an alternative use of autologous fascial grafting.

BACKGROUND: Watertight dural closure is a crucial step in preventing postoperative cerebrospinal fluid (CSF) leak and subsequent infection in posterior fossa surgery. The aim of this study is to assess an alternative use of collagen matrix double grafting in microvascular decompression (MVD). METHODS: Dural closure using double collagen matrix grafts was retrospectively compared with autologous fascial grafting in 120 patients who underwent MVD. Double collagen matrix grafting technique, a combination use of inlay and onlay grafting (DuraGen®, Integra Lifesciences, Plainsboro, NJ, USA, $700-800 for an MVD craniotomy size), was applied in 60 patients (the collagen matrix group). In the remaining 60 patients, an autologous fascial graft was sutured in a watertight fashion to the dural defect (the fascia group). Postoperative wound complications, such as CSF leak and infection, were retrospectively compared between the two groups. RESULTS: CSF leaks were observed in 3 patients (5.0%) in the fascia group and in 2 patients (3.3%) in the collagen matrix group. All cases of CSF leakage presented with pseudomeningoceles except one patient who developed an incisional CSF leak. A repair surgery for CSF leak was required in this one patient in the fascia group. Subcutaneous abscesses were noted in 2 patients (3.3%) in the fascia group. There was no patient who developed a subcutaneous abscess in the collagen matrix group. One patient in each group developed aseptic meningitis. Statistical analyses revealed that the collagen matrix group showed non-inferior outcomes to the fascia group in CSF leaks and infectious complications. CONCLUSIONS: Double grafting technique with a combination of inlay and onlay collagen sheets is a safe and secure alternative for watertight dural closure despite a cost limitation.

Location of the abducens nerve stretched by a tortuous vertebrobasilar artery in trigeminal neuralgia.

BACKGROUND: Trigeminal neuralgia (TGN) caused by the vertebrobasilar artery (VBA) is uncommon. The abducens nerve root is frequently dislocated by a tortuous VBA near the trigeminal nerve root. This unusual location of the root is not well known. This study aimed to investigate the location of the stretched abducens nerve root. METHODS: The objective is 26 patients with VBA-related TGN who underwent microvascular decompression (MVD). We retrospectively investigated the course of the abducens nerve root with magnetic resonance imaging (MRI) with three-dimensional (3D) imaging and surgical findings. The displacement of the abducens nerve root on the affected side was compared to the contralateral side. RESULTS: The abducens nerve root was distorted by a tortuous VBA (46.2%) or the anterior inferior cerebellar artery (53.8%). The average length of the cisternal segment was stretched to 23.4 mm versus 12.4 mm on the contralateral side. The peak point of the elevated abducens nerve root was mostly located rostro-medial (65.4%) or caudo-medial (34.6%) to the neurovascular compression site of the trigeminal nerve with a mean distance of 9.1 mm. Contact with the trigeminal nerve root was observed in 7 patients (26.9%). Three-dimensional imaging was consistent with the surgical findings and useful in predicting the location of the abducens nerve root. No abducens nerve palsy was noted in our series. CONCLUSIONS: The abducens nerve root is located near the trigeminal nerve root in VBA-related TGN. Preoperative understanding of the unusual course of the abducens nerve root contributes to avoiding accidental nerve injury during MVD.

Microvascular decompression for trigeminal neuralgia attributable to the vertebrobasilar artery: decompression technique and significance of separation from the nerve root.

BACKGROUND: Separation of the vertebrobasilar artery (VBA) from the trigeminal nerve root in microvascular decompression (MVD) is technically challenging. This study aimed to review the clinical features of VBA involvement in trigeminal neuralgia and evaluate surgical decompression techniques in the long term. METHODS: We retrospectively reviewed the surgical outcomes of 26 patients (4.4%) with VBA involvement in 585 consecutive MVDs for TGN using a Teflon roll for repositioning the VBA. The final operative status of the nerve decompression was categorized into two groups: the separation group and the contact group. Separation of the VBA from the nerve root was completed in 13 patients in the separation group, and slight vascular contact remained in the remaining 13 patients of the contact group. The clinical features of VBA-related TGN were investigated and the operative results were analyzed. RESULTS: Multiple arteries are involved in neurovascular compression (NVC) in most cases. The anterior inferior cerebellar artery was the most common concomitant artery (69%). The site of the NVC varies from the root entry zone to the distal portion of the root. All patients were pain-free immediately after surgery and maintained medication-free status during the follow-up period, except for one patient (3.8%) who had recurrent facial pain 8 years after surgery. Postoperative facial numbness was observed in six patients (23%). Of these, one patient showed improvement within 3 months and the other five patients had persistent facial numbness (19.2%). Other neurological deficits include one dry eye, one diplopia due to trochlear nerve palsy, two decreased hearing (< 50 db), two facial weaknesses, and two cerebellar ataxia. Although most of them were transient, one dry eye, two hearing impairments, and one cerebellar ataxia became persistent deficits. Statistical analyses revealed no difference in surgical efficacy or complications in the long term between the two groups. CONCLUSIONS: Slightly remaining vascular contact does not affect pain relief in the long term. Our study indicated that once the tense trigeminal nerve is loosened, further attempts to mobilize the VBA are not necessary.

Petrosal Vein Involvement in Neurovascular Conflict in Trigeminal Neuralgia: Surgical Technique and Clinical Outcomes.

BACKGROUND: Contact of the main stem of the petrosal vein (PV) to the nerve root is a rare cause of trigeminal neuralgia (TGN). The implication of the PV in relation with neurovascular contact (NVC) is not fully understood. OBJECTIVE: To assess the operative procedures in microvascular decompression (MVD) in patients with PV involvement in the long-term. METHODS: We retrospectively reviewed 34 cases (7.0%) in 485 consecutive MVDs for TGN, whose PV main stem had contact with the trigeminal nerve root (PV-NVC). PV-NVCs were divided into 2 groups: concomitant arterial contact or no concomitant arterial contact. Surgical techniques, outcomes, complications, and recurrence were assessed. RESULTS: The anatomical relationship of the PV with the trigeminal nerve root was consistent with preoperative 3-dimensional imaging in all patients. Pain relief was obtained in most patients immediately after surgery (97.1%) by separating the PV from the nerve root. Postoperative facial numbness was noted in 9 patients (26.5%). Symptomatic venous infarctions occurred in 2 patients (5.9%). Recurrence of facial pain occurred in 3 patients (8.8%) with a median 48 mo follow-up period. Re-exploration surgery revealed adhesion being the cause of recurrence. The statistical analyses showed no difference in the surgical outcomes of the 2 groups. CONCLUSION: Separating the PV from the nerve root contributes to pain relief in patients with PV conflict regardless of concomitant arteries. Preserving venous flow is crucial to avoid postoperative venous insufficiency.

A convexity meningioma presenting with an acute subdural hematoma.

BACKGROUND: Meningiomas presenting with acute subdural hematomas are extremely rare. To the best of our knowledge, only 45 cases have been reported to date. We report on a case of a meningioma mimicking an acute subdural hematoma as well as a thorough literature review. CASE DESCRIPTION: A 67-year-old man with no history of trauma was referred to our hospital with sudden onset of decreased level of consciousness and left hemiplegia. Computed tomography revealed an acute convexity subdural hematoma. Emergency surgery to remove the hematoma was performed. The hematoma was found to exist in the extra-axial space and the attached dura mater and pia mater remained intact. Pathological examination revealed a transitional meningioma, the World Health Organization Grade 1. Detailed medical history taken postoperatively revealed that a convexity meningioma had been diagnosed incidentally at another facility 1 year earlier. CONCLUSION: Acute subdural hematomas due to meningiomas are rare, and establishing the cause is challenging. Prompt and precise diagnosis of such entities may afford patients a better prognosis.

Long-Term Survival after Stroke in 1.4 Million Japanese Population: Shiga Stroke and Heart Attack Registry.

BACKGROUND AND PURPOSE: Although numerous measures for stroke exist, stroke remains one of the leading causes of death in Japan. In this study, we aimed to determine the long-term survival rate after first-ever stroke using data from a large-scale population-based stroke registry study in Japan. METHODS: Part of the Shiga Stroke and Heart Attack Registry, the Shiga Stroke Registry is an ongoing population-based registry study of stroke, which covers approximately 1.4 million residents of Shiga Prefecture in Japan. A total 1,880 patients with non-fatal first-ever stroke (among 29-day survivors after stroke onset) registered in 2011 were followed up until December 2016. Five-year cumulative survival rates were estimated using the Kaplan-Meier method, according to subtype of the index stroke. Cox proportional hazards models were used to assess predictors of subsequent all-cause death. RESULTS: During an average 4.3-year follow-up period, 677 patients died. The 5-year cumulative survival rate after non-fatal first-ever stroke was 65.9%. Heterogeneity was present in 5-year cumulative survival according to stroke subtype: lacunar infarction, 75.1%; large-artery infarction, 61.5%; cardioembolic infarction, 44.9%; intracerebral hemorrhage, 69.1%; and subarachnoid hemorrhage, 77.9%. Age, male sex, Japan Coma Scale score on admission, and modified Rankin Scale score before stroke onset were associated with increased mortality during the chronic phase of ischemic and hemorrhagic stroke. CONCLUSIONS: In this study conducted in a real-world setting of Japan, the 5-year survival rate after non-fatal first-ever stroke remained low, particularly among patients with cardioembolic infarction and large-artery infarction in the present population-based stroke registry.

CT Angiography of Agenesis of the Left Internal Carotid Artery.

Online supplemental material is available for this article.

Two-Year Recurrence After First-Ever Stroke in a General Population of 1.4 Million Japanese Patients　- The Shiga Stroke and Heart Attack Registry Study.

BACKGROUND: Despite many effective strategies for the prevention of recurrent stroke, individuals who survive an initial stroke have been shown to be at high risk of recurrent stroke. The aim of this study was to investigate the current status of stroke recurrence after first-ever stroke using a population-based stroke registry in Japan.Methods and Results:As part of the Shiga Stroke and Heart Attack Registry, the Shiga Stroke Registry is an ongoing population-based stroke registry study that covers approximately 1.4 million residents of Shiga Prefecture, Japan. A total of 1,883 first-ever stroke survivors at 28 days was registered in 2011 and followed-up until the end of 2013. Recurrence was defined as any type of stroke after 28 days from the onset of an index event. Two-year cumulative recurrence rates were estimated using cumulative incidence function methods. Over a mean 2.1-year follow-up period, 120 patients experienced recurrent stroke and 389 patients died without recurrence. The 2-year cumulative recurrence rate was higher in patients with index ischemic stroke (6.8%) than in those with index hemorrhagic stroke (3.8%). CONCLUSIONS: Two-year cumulative recurrence rate after first-ever stroke remained high, particularly among patients with ischemic stroke, in the present population-based registry study in a real-world setting in Japan. Further intensive secondary prevention strategies are required for these high-risk individuals.

Preoperative Evaluation of the Effects of Sigmoid Sinus Ligation with both Endovascular and Open-Field Occlusion Tests before Removal of Petroclival Tumors.

Background Surgery for petroclival tumors is very challenging for neurosurgeons because the position of the tumor in relation to the brainstem, cranial nerves, and posterior fossa vessels greatly restricts the surgical field. Some papers have described using sigmoid sinus ligation to open the surgical field; however, pre- and intraoperative evaluations of the safety of ligation have been limited, despite the risk of complications from venous insufficiency. Here, we describe our method of preoperatively evaluating the potential safety of a retrolabyrinthine transsigmoid approach with nondominant ipsilateral sigmoid sinus ligation (RLTSwSSL). Methods A retrospective review was conducted on petroclival tumors treated over a 5-year period with RLTSwSSL after evaluation with both an endovascular balloon occlusion test (BOT) and an open-field sinus clipping occlusion test (COT). Changes in pressure of < 10 mm Hg and the absence of neurodegeneration during the tests indicated that it would be safe to proceed with permanent ligation. Results Four patients with large petroclival tumors underwent surgery via RLTSwSSL after detailed preoperative evaluations with both BOT and COT. All patients had uneventful courses of recovery without developing any complications derived from venous insufficiency. Conclusion In our case series, we have described a protocol for using both BOT and COT to evaluate the likely outcomes after sigmoid sinus ligation and thereby to improve safety. Further studies are needed to establish definite criteria for both occlusion tests that will ensure good outcomes.

Intracranial Artery Stenosis and Its Association With Conventional Risk Factors in a General Population of Japanese Men.

Background and Purpose- Few community-based studies have reported the prevalence of intracranial artery stenosis (ICAS) assessed with magnetic resonance angiography. The aim was to determine the prevalence of ICAS using magnetic resonance angiography in a general population of Japanese men and to investigate the associations between ICAS and conventional cardiovascular risk factors. Methods- The Shiga Epidemiological Study of Subclinical Atherosclerosis randomly recruited and examined participants from Kusatsu City, Shiga, Japan, in 2006 to 2008 (baseline); 740 men returned for follow-up and underwent 1.5 T brain magnetic resonance angiography in 2012 to 2015. Participants were categorized as having no-ICAS, mild-ICAS (1 to <50%), or severe-ICAS (≥50%) in any of the arteries examined. After excluding the men with a history of stroke, 709 men were analyzed using multivariable logistic regression to assess independent associations of conventional cardiovascular risk factors with reference to the no-ICAS group. Results- The participants' mean age was 68.0 years. The age-standardized prevalences of mild and severe-ICAS were 20.7% and 4.5%, respectively (with the population of the 2010 Japanese vital statistics as the reference). Age, hypertension, diabetes mellitus, and dyslipidemia were associated with a higher prevalence of severe-ICAS after simultaneous adjustment for conventional cardiovascular risk factors. Conclusions- In a community-based sample of Japanese men, ICAS was estimated to be present in 25.2%, and related to metabolic risk factors, in addition to hypertension and age. These results support the importance of comprehensive management of conventional cardiovascular risk factors for stroke prevention.