Next-Generation Exoscopic Surgery Featuring a Head-Mounted 3-Dimensional Display for Carotid Endarterectomy: 2-Dimensional Operative Video

Recent advancements in medical equipment have led to the use of exoscopes in neurosurgery, thereby replacing conventional operating microscopes.1,2 These devices enable surgeons to work comfortably, even in situations requiring a tilted visual axis, and their effectiveness in carotid endarterectomy (CEA) for carotid artery stenosis has been reported.3,4 However, the placement of 3-dimensional (3D) monitoring devices is challenging.3,4 To address this issue, we present a case in which CEA was performed using ORBEYE with a 3D head-mounted display. This device allows continuous 3D observation of the surgical field on the preocular screen. Case: A 79-year-old man who had undergone chemoradiotherapy for left maxillary cancer 5 years earlier was referred to our department to undergo treatment for left internal carotid artery stenosis. Computed tomography angiography revealed severe left internal carotid artery stenosis with hypoechoic vulnerable plaques on carotid ultrasound. Carotid artery stenting was considered to be a better option than CEA. However, CEA yields better outcomes, especially in patients with vulnerable soft plaques.5 Left CEA was performed using ORBEYE with a 3D head-mounted display (HOGY Medical Co., Ltd.). The procedure was successfully performed under the observation of the head-mounted display, from skin incision to closure. Postoperatively, the patient had no neurological deficits but experienced transient hoarseness. Using an exoscope under the guidance of a head-mounted display represents a next-generation surgical technique that overcomes the limitations of traditional exoscopic surgery. The patient consented to the procedure, and the participants and any identifiable individuals consented to publication of his/her image. Our institutional review board approved this publication (#B230184).

Multiple Synchronous Spinal Dural Arteriovenous Fistulas: A Systematic Literature Review

BACKGROUND AND OBJECTIVES

Spinal dural arteriovenous fistulas (SDAVFs) lead to progressive neurological decline with symptoms such as paraparesis, bowel and bladder dysfunction, and sensory disturbances because of impaired spinal cord venous drainage. This study aimed to systematically review the literature on multiple synchronous SDAVFs and present 2 cases from our institution.

METHODS

A comprehensive search was performed to identify all published cases of multiple synchronous SDAVFs. Overall, 23 patients with multiple synchronous SDAVFs were identified, including 21 from 19 articles and 2 from this study. The clinical presentation, lesion location, radiographic features, surgical treatment, and outcomes were analyzed in each patient.

RESULTS

All patients in this study were male, and the duration from symptom onset to diagnosis in many of these patients was longer than that previously reported. Previous studies suggested that multiple SDAVFs typically occurred within 3 or fewer vertebral levels. However, >50% of the examined patients had remote lesions separated by more than 3 vertebral levels. Patients with remote lesions had a significantly worse outcome (1/7 vs 8/11, 95% CI 0.001-0.998; P = .049).

CONCLUSION

Accurately locating fistulas before spinal angiography is critical for managing multiple remote SDAVFs. Considering the possibility of multiple remote SDAVFs, careful interpretation of imaging findings is essential for an accurate diagnosis and appropriate treatment planning.

Successful shrinkage of a recurrent partially thrombosed symptomatic large basilar tip aneurysm using a Target 3D Coil

Background

Standalone coil embolization is often less effective for partially thrombosed intracerebral aneurysms (PTIA) because of the risk of frequent recurrence if the coil migrates into the thrombus. This report describes a case of PTIA at the basilar tip in which simple coil embolization using a Target 3D Coil resulted in sustained remission without recurrence during long-term follow-up.

Case Description

The patient was a 63-year-old male who presented with right oculomotor nerve palsy after having undergone direct surgery for a basilar artery aneurysm 15 years earlier. Recurrence with partial thrombosis of the basilar artery aneurysm was diagnosed. Target 3D Coil embolization with frame construction in the aneurysmal sac was performed, resulting in the complete disappearance of the aneurysm and improvement of the oculomotor nerve palsy. Magnetic resonance imaging at five years postoperatively confirmed that the thrombus had completely disappeared, and there was no recurrence of the aneurysm. The closed loops in the Target 3D Coil may have contributed to the cohesive mass of coils remaining in the sac of the PTIA, potentially leading to healing.

Conclusion

The characteristics of the Target 3D Coil may have prevented migration of the coil into the thrombus, potentially contributing to the successful resolution of the aneurysm.

A vertebrobasilar junction aneurysm successfully treated with a combination of surgical clipping and flow diverter placement based on the results of computational fluid dynamics analysis: illustrative case

BACKGROUND

The treatment of vertebrobasilar junction (VBJ) aneurysms is challenging. Although flow diverters (FDs) are a possible treatment option, geometrical conditions hinder intervention. VBJ aneurysms possess dual inflow vessels from the bilateral vertebral arteries (VAs), one of which is ideally occluded prior to FD treatment. However, it remains unclear which VA should be occluded.

OBSERVATIONS

A 75-year-old male with a growing VBJ complex aneurysm exhibiting invagination toward the brainstem and causing perifocal edema required intervention. Preoperative computational fluid dynamics (CFD) analysis demonstrated that left VA occlusion would result in more stagnant flow and less impingement of flow than right VA occlusion. According to the simulated strategy, surgical clipping of the left VA just proximal to the aneurysm was performed, followed by FD placement from the basilar artery trunk to the right VA. The patient demonstrated tolerance of the VA occlusion, and follow-up computed tomography angiography at 18 months after FD treatment confirmed the disappearance of the aneurysm.

LESSONS

Preoperative flow dynamics simulations using CFD analysis can reveal an optimal treatment strategy involving a hybrid surgery that combines FD placement and direct surgical occlusion for a VBJ complex aneurysm.

Prevalence and Severity of Positional Posterior Plagiocephaly and Positional Posterior Brachycephaly in Children and Adolescents in Japan

This study aimed to assess the prevalence, severity, and natural history of positional posterior plagiocephaly (PPP) and positional posterior brachycephaly in Japan. We conducted a cross-sectional study of pediatric patients, ranging from 0 to 15 years old, evaluated for head trauma with negative computed tomography (CT) findings. The cranial vault asymmetry index (CVAI) was calculated using CT images at the superior orbital rim. Asymmetry according to CVAI values was subcategorized as follows: mild (3.5%-7%), moderate (7%-12%), and severe (>12%). The results were analyzed according to different age groups: group 1, 2-23 months (54 patients); group 2, 2-6 years (123 patients); and group 3, 7-15 years (123 patients). Overall, 300 patients were included (109 [36.3%] girls and 191 [63.7%] boys). The overall prevalence of PPP in the 300 patients was 46.7% (140 patients). PPP prevalence decreased consistently with age group: group 1, 57.4%; group 2, 47.2%; and group 3, 41.5%. Severe asymmetry was seen in all age groups. The overall mean cephalic index (CI) was 85.2. Cephalic index scores decreased consistently with age: group 1, 87.4; group 2, 85.1; and group 3, 84.3. The prevalence of PPP in Japan was higher than that reported in other countries. Although there was an overall decrease in the prevalence and severity of PPP with increasing patient age, PPP does not necessarily resolve spontaneously in all children. Furthermore, severe asymmetry was seen across all age groups.

Stereotactic radiotherapy of radiation-induced meningioma previously irradiated retrobulbar for Graves' ophthalmopathy: A case report

A 69-year-old woman was diagnosed with an asymptomatic intracranial tumor nine years ago and has been followed with annual MR imaging studies. Two years ago, the tumor had grown in size, requiring treatment. She experienced ophthalmopathy due to hyperthyroidism 27 years ago and was treated with 20 Gy in 10 fractions using parallel opposed beams to her bilateral posterior eyeballs, supplemented with steroid pulse therapy. The tumor originated in the medial aspect of the right sphenoid border and compressed the temporal lobe, while bone infiltration was observed, partially extending to the soft tissue outside the maxillary sinus. The tumor was removed by craniotomy. The pathological diagnosis was atypical meningioma (WHO grade II). Four months postsurgery, the resection cavity's tumor exhibited growth inclination, necessitating Gamma Knife radiosurgery. Radiation planning was executed at a marginal tumor dose of 30 Gy in 5 fractions. Since the optic nerve had been previously exposed to radiation, a plan was devised to minimize radiation exposure. The dose on the optic nerve was limited to 6.9 Gy in 5 fractions. She did not experience any visual or visual field disruptions postradiation. This is a case of radiation-induced meningioma resulting from radiation therapy for Graves' ophthalmopathy and is the first reported case of a grade II meningioma. The patient's condition calls for adjuvant radiation therapy following surgical removal. Accordingly, a radiation treatment plan that safeguards the optic nerve, which was previously exposed to radiation, was deemed indispensable.

Steerable microcatheter for distal access of a giant cavernous carotid artery aneurysm during treatment with Pipeline Embolization Device: A case report and review of the literature

Background

In the treatment of giant cerebral aneurysms with flow-diverting stents, access to the distal parent artery is critical but occasionally challenging. This article provides our experience with a novel steerable microcatheter in such a situation, as well as a review of the literature.

Case Description

A 73-year-old woman presented with right ptosis and external ophthalmoplegia. Magnetic resonance angiography revealed a giant right cavernous internal carotid artery aneurysm. Endovascular treatment was planned with flow diversion, but distal access was not possible using the standard technique. A 2.4-Fr steerable microcatheter, Leonis Mova Selective, was implemented, and by bending the catheter tip toward the distal parent artery, a guidewire could be guided distally. After the catheter exchange, two flow-diverting stents were deployed successfully.

Conclusion

Steerable microcatheters may provide an option in treatment with flow-diverting stents for giant cerebral aneurysms where access to the distal parent artery is compromised.

Rupture Risk Factors and Strategies for Unruptured Distal Anterior Cerebral Artery Aneurysms

BACKGROUND

Distal anterior cerebral artery (dACA) aneurysms are rare. Ruptured dACA aneurysms typically present with subarachnoid hemorrhage in conjunction with intracerebral hematoma and cause neurological deterioration. This study aimed to determine their risk of rupture and examine associated factors.

METHODS

We retrospectively analyzed patients with dACA aneurysms to compare patient and aneurysm characteristics between ruptured and unruptured aneurysms. Clinical outcome was used the modified Rankin scale. Univariate analyses were performed to identify rupture risk factors.

RESULTS

One hundred three patients with dACA aneurysms were examined (51 ruptured and 52 unruptured). The median aspect ratio of ruptured and unruptured aneurysms was 1.69 and 1.22, respectively (P < 0.01). The median maximum diameter of ruptured and unruptured aneurysms was 5.2 and 3.1 mm, respectively (P < 0.01). The median size ratio of ruptured and unruptured aneurysms was 3.32 and 2.17, respectively (P < 0.01). Maximum diameter was <5 mm in 45.2% of ruptured dACA aneurysms. dACA aneurysm, showing size ratio >2.4 and aspect ratio >1.4, had ruptured in 71.4% and 78.6%, respectively. We suggested that these are the threshold of size ratio and aspect ratio for rupture of dACA aneurysms. A total percentatge of 78.1% of aneurysms with aspect ratio >1.4 and size ratio >2.4 had ruptured.

CONCLUSIONS

Distal anterior cerebral artery (dACA) aneurysms may rupture, even when small. We found a significant difference between ruptured and unruptured aneurysms with respect to maximum diameter, aspect ratio, and size ratio. Treatment for small aneurysms should be considered based on size ratio and aspect ratio, not just size.

Subclassification of Koos grade 4 vestibular schwannoma: insights into tumor morphology for predicting postoperative facial nerve function

OBJECTIVE

Koos grade 4 vestibular schwannoma (KG4VS) is a large tumor that causes brainstem displacement and is generally considered a candidate for surgery. Few studies have examined the relationship between morphological differences in KG4VS other than tumor size and postoperative facial nerve function. The authors have developed a landmark-based subclassification of KG4VS that provides insights into the morphology of this tumor and can predict the risk of facial nerve injury during microsurgery. The aims of this study were to morphologically verify the validity of this subclassification and to clarify the relationship of the position of the center of the vestibular schwannoma within the cerebellopontine angle (CPA) cistern on preoperative MR images to postoperative facial nerve function in patients who underwent microsurgical resection of a vestibular schwannoma.

METHODS

In this paper, the authors classified KG4VSs into two subtypes according to the position of the center of the KG4VS within the CPA cistern relative to the perpendicular bisector of the porus acusticus internus, which was the landmark for the subclassification. KG4VSs with ventral centers to the landmark were classified as type 4V, and those with dorsal centers as type 4D. The clinical impact of this subclassification on short- and long-term postoperative facial nerve function was analyzed.

RESULTS

In this study, the authors retrospectively reviewed patients with vestibular schwannoma who were treated surgically via a retrosigmoid approach between January 2010 and March 2020. Of the 107 patients with KG4VS who met the inclusion criteria, 45 (42.1%) were classified as having type 4V (KG4VSs with centers ventral to the perpendicular bisector of the porous acusticus internus) and 62 (57.9%) as having type 4D (those with centers dorsal to the perpendicular bisector). Ventral extension to the perpendicular bisector of the porus acusticus internus was significantly greater in the type 4V group than in the type 4D group (p < 0.001), although there was no significant difference in the maximal ventrodorsal diameter. The rate of preservation of favorable facial nerve function (House-Brackmann grades I and II) was significantly lower in the type 4V group than in the type 4D group in terms of both short-term (46.7% vs 85.5%, p < 0.001) and long-term (82.9% vs 96.7%, p = 0.001) outcomes. Type 4V had a significantly negative impact on short-term (OR 7.67, 95% CI 2.90-20.3; p < 0.001) and long-term (OR 6.05, 95% CI 1.04-35.0; p = 0.045) facial nerve function after surgery when age, tumor size, and presence of a fundal fluid cap were taken into account.

CONCLUSIONS

The authors have delineated two different morphological subtypes of KG4VS. This subclassification could predict short- and long-term facial nerve function after microsurgical resection of KG4VS via the retrosigmoid approach. The risk of postoperative facial palsy when attempting total resection is greater for type 4V than for type 4D. This classification into types 4V and 4D could help to predict the risk of facial nerve injury and generate more individualized surgical strategies for KG4VSs with better facial nerve outcomes.

Delayed facial palsy after resection of vestibular schwannoma: does it influence long-term facial nerve functional outcomes?

OBJECTIVE

Delayed facial palsy (DFP) is a common and unique complication after resection of vestibular schwannoma (VS). Few studies have focused on the clinical question of whether patients with DFP can be expected to have the same long-term prognosis in terms of facial nerve function as those without DFP based on their facial nerve function immediately postoperatively. This study aimed to clarify the clinical impact of DFP on the long-term functional status of the facial nerve after VS resection.

METHODS

The authors retrospectively reviewed patients with sporadic VS who were treated surgically via a retrosigmoid approach between January 2002 and March 2020. DFP was defined as de novo deterioration of facial nerve function by a House-Brackmann (HB) grade ≥ I more than 72 hours postoperatively. The incidence of DFP after VS resection and its impact on long-term facial nerve function were analyzed.

RESULTS

DFP developed in 38 (14.3%) of 266 patients who met the inclusion criteria. The median latency until DFP onset postoperatively was 8.5 days. When facial nerve function was normal immediately postoperatively, the rate of preservation of favorable facial nerve function (HB grade I or II) at 24 months postoperatively was 100% for all patients regardless of whether they developed DFP. In contrast, when facial nerve dysfunction was present immediately postoperatively, the rate of preservation of favorable facial nerve function at 24 months postoperatively was significantly lower in patients with DFP than in those without DFP (77.8% vs 100% in patients with HB grade II immediately postoperatively, p = 0.001; 50.0% vs 90.3% in those with HB grade III immediately postoperatively, p = 0.042). DFP development had a significantly negative impact on the long-term functional status of the facial nerve postoperatively when age, tumor size, and HB grade immediately postoperatively were taken into account (OR 0.04, 95% CI 0.01-0.20; p < 0.001).

CONCLUSIONS

DFP can be a minor complication when normal facial nerve function is observed immediately after surgery. However, when facial nerve dysfunction is present immediately after surgery, even if mild, the long-term prognosis for facial nerve function is significantly worse in patients with DFP than in those without DFP.

Late intrathecal retraction of a lumboperitoneal shunt

Background

Lumboperitoneal (LP) shunt placement is a good option for treating elderly patients with communicating normal pressure hydrocephalus (NPH) who are also on antiplatelet therapy following endovascular treatment of unruptured bilateral internal carotid artery aneurysms. Here, in an 80-year-old male with an LP shunt, the catheter was "pinched" between adjacent spinous processes, resulting in laceration of the catheter and intrathecal catheter migration.

Case Description

An 80-year-old male was treated with a LP shunt for NPH 1 year after undergoing endovascular treatment of unruptured bilateral internal carotid artery aneurysms. The lumbar catheter was placed at the L2-3 level. Six months later, when he clinically deteriorated, the follow-up computed tomography showed recurrent ventricular enlargement. Further, studies additionally confirmed intrathecal migration of the lumbar catheter, warranting secondary ventriculoperitoneal shunt placement.

Conclusion

Patients with LP shunts may develop lumbar catheter lacerations secondary to a "pinching" effect from adjacent spinous processes, resulting in intrathecal catheter migration.

Introducing next-generation transcranial surgery with the head-mounted 3D View Vision display in extracorporeal microsurgery: illustrative cases

BACKGROUND

Exoscopy in neurosurgery offers various advantages, including increased freedom of the viewing axis while the surgeon maintains a comfortable upright position. However, the optimal monitor positioning to avoid interference with surgical manipulation remains unresolved. Herein, the authors describe two cases in which a three-dimensional head-mounted display (3D-HMD) was introduced into a transcranial neurosurgical procedure using an exoscope.

OBSERVATIONS

Case 1 was a 50-year-old man who presented with recurrent epistaxis and was diagnosed with an olfactory neuroblastoma that extended from the nasal cavity to the anterior cranial base and infiltrated the right anterior cranial fossa. Case 2 was a 65-year-old man who presented with epistaxis and was diagnosed with a left-sided olfactory neuroblastoma. In both cases, en bloc tumor resection was successfully performed via a simultaneous exoscopic transcranial approach using a 3D-HMD and an endoscopic endonasal approach, eliminating the need to watch a large monitor beside the patient.

LESSONS

This is the first report of using a 3D-HMD in transcranial surgery. The 3D-HMD effectively addressed issues with the field of vision and concentration while preserving the effectiveness of traditional microscopic and exoscopic procedures when observed on a 3D monitor. Combining the 3D-HMD with an exoscope holds the potential to become a next-generation surgical approach.

Pediatric intraparenchymal meningioma in the basal ganglia treated with gross total resection: a case report and review of the literature

INTRODUCTION

Intraparenchymal meningiomas in the basal ganglia are extremely rare, and to the best of our knowledge, only three case reports have been published to date. Owing to concerns regarding major vessels, gross total resection (GTR) is difficult to achieve; therefore, subtotal resection and radiation therapy are often chosen as treatment options. We present a pediatric case with an intraparenchymal meningioma in the left basal ganglia that was successfully treated with GTR. We also reviewed the relevant literature to discuss the pathogenesis, radiological findings, and treatment methods of this rare disease.

CASE REPORT

A 4-year-old girl presented with progressive right facial paralysis, aphasia, and right incomplete hemiplegia. Imaging revealed a mass lesion in the left basal ganglia and unilateral obstructive hydrocephalus. Neuroendoscopic septostomy, tumor biopsy, and cerebrospinal fluid reservoir placement were performed, and the initial pathological diagnosis was suspected glioma. Thus, craniotomy was performed to remove the tumor, which was white, elastic, and well-defined. Intraoperative rapid pathology revealed a meningioma. Postoperatively, the patient experienced transient worsening of the right incomplete hemiplegia, which subsequently improved. The final pathological diagnosis was a fibrous meningioma.

CONCLUSION

Surgery for intraparenchymal meningiomas in the basal ganglia is challenging owing to the proximity of major blood vessels; however, GTR may be preferable to subtotal resection, considering the possibility of recurrence. Even in cases of intraparenchymal tumors, it is important to consider meningioma as a differential diagnosis and to carefully plan the appropriate treatment.

An aggressive dural arteriovenous fistula manifested by unilateral subcortical calcification and cerebral edema: A case report

Unilateral subcortical calcifications are unique radiographic findings indicating specific focal pathologies. When the lesion is accompanied by edema, cerebral neoplasm usually leads to a differential diagnosis. This report presents a case of unilateral subcortical calcification and edema that resulted in cerebral hemorrhage and a subsequent diagnosis of an aggressive dural arteriovenous fistula. A man in his 60s presented with left hemianopsia and a progressive headache for over 6 months. Initial computed tomography revealed unilateral subcortical calcification and cerebral edema in the right occipital lobe, raising the suspicion of oligodendroglioma. However, 10 days later, a cerebral hemorrhage occurred in the lesion. Magnetic resonance imaging revealed flow void clusters and dilatation of the bilateral external carotid arteries and cortical veins, indicating a dural arteriovenous fistula. Cerebral angiography confirmed the presence of a parasagittal dural arteriovenous fistula (Borden type III). The patient was successfully treated with trans-arterial embolization using Onyx. Thus, calcifications with edema are more commonly associated with cerebral neoplasms; however, in this case, they indicated the presence of a dural arteriovenous fistula with severe corticovenous reflux. The presented case highlights the importance of recognizing these imaging features in dural arteriovenous fistulas and raises awareness of the potential danger of early hemorrhage after diagnosis. Therefore, timely evaluation of cranial vessels is essential in cases of unilateral subcortical calcification and edema to facilitate the early detection and management of aggressive dural arteriovenous fistulas.

Effects of carotid revascularization on cognitive function and brain functional connectivity in carotid stenosis patients with cognitive impairment: a pilot study

OBJECTIVE

Carotid stenosis can lead to both cognitive impairment (CI) and ischemic stroke. Although carotid revascularization surgery, which includes carotid endarterectomy (CEA) and carotid artery stenting (CAS), can prevent future strokes, its effect on cognitive function is controversial. In this study, the authors examined resting-state functional connectivity (FC) in carotid stenosis patients with CI undergoing revascularization surgery, with a particular focus on the default mode network (DMN).

METHODS

Twenty-seven patients with carotid stenosis who were scheduled to undergo CEA or CAS between April 2016 and December 2020 were prospectively enrolled. A cognitive assessment, including the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB), and Japanese version of the Montreal Cognitive Assessment (MoCA), as well as resting-state functional MRI, was performed 1 week preoperatively and 3 months postoperatively. For FC analysis, a seed was placed in the region associated with the DMN. The patients were divided into two groups according to the preoperative MoCA score: a normal cognition (NC) group (MoCA score ≥ 26) and a CI group (MoCA score < 26). The difference in cognitive function and FC between the NC and CI groups was investigated first, and then the change in cognitive function and FC after carotid revascularization was investigated in the CI group.

RESULTS

There were 11 and 16 patients in the NC and CI groups, respectively. The FC of the medial prefrontal cortex with the precuneus and that of the left lateral parietal cortex (LLP) with the right cerebellum were significantly lower in the CI group than in the NC group. In the CI group, significant improvements were found in MMSE (25.3 vs 26.8, p = 0.02), FAB (14.4 vs 15.6, p = 0.01), and MoCA scores (20.1 vs 23.9, p = 0.0001) after revascularization surgery. Significantly increased FC of the LLP with the right intracalcarine cortex, right lingual gyrus, and precuneus was observed after carotid revascularization. In addition, there was a significant positive correlation between the increased FC of the LLP with the precuneus and improvement in the MoCA score after carotid revascularization.

CONCLUSIONS

These findings suggest that carotid revascularization, including CEA and CAS, might improve cognitive function based on brain FC in the DMN in carotid stenosis patients with CI.

Combined transarterial and transvenous embolization of anterior cranial fossa dural arteriovenous fistula

Background

Excessive glue injection into the drainage vein in patients with dural arteriovenous fistula (dAVF) can result in venous obstruction. We performed transarterial embolization (TAE) combined with transvenous embolization (TVE) with coils to prevent the glue from migrating into the normal cortical veins.

Case Description

A 57-year-old man was pointed out to have a Borden Type III anterior cranial fossa dAVF during a check-up for putaminal hemorrhage. Because a left frontal normal cortical vein drained into the pathological drainage vein, excessive glue injection into the drainage vein may have caused venous obstruction. We performed TVE with coils at the foot of the draining vein to prevent excessive migration of glue into the drainer, followed by TAE with glue. With this technique, complete obliteration of the shunt without venous ischemia was obtained.

Conclusion

The combined treatment of TAE and TVE is effective in preventing venous ischemia caused by unintended migration of glue cast into the drainage vein.

2-Hydroxyglutarate magnetic resonance spectroscopy in adult brainstem glioma

OBJECTIVE

Adult brainstem gliomas (BSGs) are rare tumors of the CNS that are poorly understood. Upregulation of the oncometabolite 2-hydroxyglutarate (2HG) in the tumor indicates the mutation of isocitrate dehydrogenase (IDH), which can be detected by magnetic resonance spectroscopy (MRS). Although histological examination is required for the definitive diagnosis of BSG, 2HG-optimized MRS (2HG-MRS) may be useful, considering the difficult nature of brainstem lesion biopsy. The aim of this study was to evaluate the utility of 2HG-MRS for diagnosing IDH-mutant adult BSG.

METHODS

Patients with a radiographically confirmed brainstem tumor underwent 3T MRS. A single voxel was set in the lesion with reference to the T2 or fluid-attenuated inversion recovery image and analyzed according to the 2HG-tailored MRS protocol (point-resolved spectroscopic sequence; echo time 35 msec). All patients underwent intraoperative navigation-guided or CT-guided stereotactic biopsy for histopathological diagnosis. The status of IDH and H3K27M mutations was confirmed by immunohistochemistry and direct DNA sequencing. In addition, the authors examined the relationship between patients' 2HG concentrations and survival time.

RESULTS

Ten patients (7 men, 3 women; median age 33.5 years) underwent 2HG-MRS and biopsy. Four patients had an H3K27M mutation and 4 had an IDH1 mutation (1 R132H canonical IDH mutation, 2 R132S and 1 R132G noncanonical IDH mutations). Two had neither H3K27M nor IDH mutations. The H3K27M and IDH mutations were mutually exclusive. Most tumors were located in the pons. There was no significant radiological difference between mutant H3K27M and IDH on a conventional MRI sequence. A 2HG concentration ≥ 1.8 mM on MRS demonstrated 100% (95% CI 28%-100%) sensitivity and 100% (95% CI 42%-100%) specificity for IDH-mutant BSG (p = 0.0048). The median overall survival was 10 months in IDH-wild-type BSG patients (n = 6) and could not be estimated in IDH-mutant BSG patients (n = 4) due to the small number of deaths (p = 0.008).

CONCLUSIONS

2HG-MRS demonstrated high sensitivity and specificity for the prediction of IDH-mutant BSG. In addition, 2HG-MRS may be useful for predicting the prognosis of adult BSG patients.

Machine Learning to Predict Three Types of Outcomes After Traumatic Brain Injury Using Data at Admission: A Multi-Center Study for Development and Validation

The difficulty of accurately identifying patients who would benefit from promising treatments makes it challenging to prove the efficacy of novel treatments for traumatic brain injury (TBI). Although machine learning is being increasingly applied to this task, existing binary outcome prediction models are insufficient for the effective stratification of TBI patients. The aim of this study was to develop an accurate 3-class outcome prediction model to enable appropriate patient stratification. To this end, retrospective balanced data of 1200 blunt TBI patients admitted to six Japanese hospitals from January 2018 onwards (200 consecutive cases at each institution) were used for model training and validation. We incorporated 21 predictors obtained in the emergency department, including age, sex, six clinical findings, four laboratory parameters, eight computed tomography findings, and an emergency craniotomy. We developed two machine learning models (XGBoost and dense neural network) and logistic regression models to predict 3-class outcomes based on the Glasgow Outcome Scale-Extended (GOSE) at discharge. The prediction models were developed using a training dataset with n = 1000, and their prediction performances were evaluated over two validation rounds on a validation dataset (n = 80) and a test dataset (n = 120) using the bootstrap method. Of the 1200 patients in aggregate, the median patient age was 71 years, 199 (16.7%) exhibited severe TBI, and emergency craniotomy was performed on 104 patients (8.7%). The median length of stay was 13.0 days. The 3-class outcomes were good recovery/moderate disability for 709 patients (59.1%), severe disability/vegetative state in 416 patients (34.7%), and death in 75 patients (6.2%). XGBoost model performed well with 69.5% sensitivity, 82.5% accuracy, and an area under the receiver operating characteristic curve of 0.901 in the final validation. In terms of the receiver operating characteristic curve analysis, the XGBoost outperformed the neural network-based and logistic regression models slightly. In particular, XGBoost outperformed the logistic regression model significantly in predicting severe disability/vegetative state. Although each model predicted favorable outcomes accurately, they tended to miss the mortality prediction. The proposed machine learning model was demonstrated to be capable of accurate prediction of in-hospital outcomes following TBI, even with the three GOSE-based categories. As a result, it is expected to be more impactful in the development of appropriate patient stratification methods in future TBI studies than conventional binary prognostic models. Further, outcomes were predicted based on only clinical data obtained from the emergency department. However, developing a robust model with consistent performance in diverse scenarios remains challenging, and further efforts are needed to improve generalization performance.

Multidrug chemotherapy, whole-brain radiation and cytarabine therapy for primary central nervous system lymphoma in elderly patients with dose modification based on geriatric assessment: study protocol for a phase II, multicentre, non-randomised study

INTRODUCTION

Multidrug chemoimmunotherapy with rituximab, high-dose methotrexate, procarbazine and vincristine (R-MPV) is a standard therapy for younger patients with primary central nervous system lymphoma (PCNSL); however, prospective data regarding its use in elderly patients are lacking. This multi-institutional, non-randomised, phase II trial will assess the efficacy and safety of R-MPV and high-dose cytarabine (HD-AraC) for geriatric patients with newly diagnosed PCNSL.

METHODS AND ANALYSIS

Forty-five elderly patients will be included. If R-MPV does not achieve complete response, the patients will undergo reduced-dose, whole-brain radiotherapy comprising 23.4 Gy/13 fractions, followed by local boost radiotherapy comprising 21.6 Gy/12 fractions. After achieving complete response using R-MPV with or without radiotherapy, the patients will undergo two courses of HD-AraC. All patients will undergo baseline geriatric 8 (G8) assessment before HD-AraC and after three, five and seven R-MPV courses. Patients with screening scores of ≥14 points that decrease to <14 points during subsequent treatment, or those with screening scores <14 points that decrease from the baseline during subsequent treatment are considered unfit for R-MPV/HD-AraC. The primary endpoint is overall survival, and the secondary endpoints are progression-free survival, treatment failure-free survival and frequency of adverse events. The results will guide a later phase III trial and provide information about the utility of a geriatric assessment for defining chemotherapy ineligibility.

ETHICS AND DISSEMINATION

This study complies with the latest Declaration of Helsinki. Written informed consent will be obtained. All participants can quit the study without penalty or impact on treatment. The protocol for the study, statistical analysis plan and informed consent form have been approved by the Certified Review Board at Hiroshima University (CRB6180006) (approval number: CRB2018-0011). The study is ongoing within nine tertiary and two secondary hospitals in Japan. The findings of this trial will be disseminated through national and international presentations and peer-reviewed publications.

TRIAL REGISTRATION

jRCTs061180093.

Endovascular Treatment of Borden Type III Transverse-sigmoid Sinus Dural Arteriovenous Fistulas: a Single-center 12-year Experience

PURPOSE

The objective of this study was to evaluate our 12-year experience in treating Borden type III transverse-sigmoid sinus (TSS) dural arteriovenous fistulas (DAVFs) and discuss the technical aspects of ipsilateral and contralateral transvenous embolization (TVE) approaches.

METHODS

We retrospectively reviewed charts of consecutive patients with TSS DAVF treated with multimodal treatment between April 2008 and March 2020. The baseline patient characteristics, imaging data, details of procedure, data sets of sinus pressure monitoring, and clinical results were systematically collected.

RESULTS

Of 44 patients with TSS DAVF who were treated during study periods, 23 patients of Borden type III were extracted. Among the 23 patients, 18 with transfemoral TVE were included for analysis. TVE was performed using an ipsilateral approach in 8 patients and a contralateral approach in 10. Pressure monitoring data revealed that initial mean sinus pressure (43.5 mmHg vs. 29.5 mmHg; P = 0.033), maximum sinus pressure during the procedure (69.0 mmHg vs. 40.5 mmHg; P = 0.011), and sinus pressure gradient (22.5 mmHg vs. 5.5 mmHg; P = 0.021) were significantly higher in the ipsilateral approach group. The complete obliteration rate by primary embolization was 94% in our cohort with the recurrence rate of 5.6% with a median follow-up period of 57 months.

CONCLUSION

Our study showed the durability of TVE for patients with Borden type III TSS DAVF. TVE performed via the contralateral approach might prevent a potentially dangerous increase in intraprocedural sinus pressure and cortical venous reflux.

Endovascular Treatment of Tandem Atherosclerotic Cervical Internal Carotid Artery Occlusion in the Setting of Acute Ischemic Stroke

BACKGROUND

Among tandem occlusions, atherosclerotic cervical internal carotid artery occlusion (ACICAO) can be technically challenging and associated with its unique complications. We evaluated our experience with endovascular treatment (EVT) of ACICAO in the setting of acute ischemic stroke.

METHODS

In total, 154 consecutive patients who underwent EVT for acute anterior circulation stroke at our institute were retrospectively reviewed. Patients with tandem ACICAO were analyzed in this study. Procedures, recanalization rates, complications, and prognoses were evaluated.

RESULTS

Ten patients (6%) of all 154 patients had ACICAO. In nine (90%) of the 10 patients, cervical lesions were successfully crossed and intervened upon. Four patients underwent stenting and five underwent angioplasty alone, followed by intracranial procedure. Eight patients (80%) achieved successful recanalization following mechanical thrombectomy for intracranial occlusion. However, one patient had massive subarachnoid hemorrhage during the procedure and another patient developed massive intracranial hemorrhage after EVT, both after stenting. Four of the five patients who initially underwent angioplasty alone subsequently underwent staged endarterectomy or stenting for residual stenosis on or after the next day. The single patient in whom the cervical lesion could not be crossed and another with reocclusion after EVT underwent a rescue bypass procedure due to persistent ischemic symptoms. After 90 days, four patients (40%) were functionally independent (modified Rankin scale score 0-2).

CONCLUSIONS

Our experience suggests that EVT for ACICAO is technically feasible; however, it involves the potential risk of several significant complications. To avoid serious hemorrhagic complications, cervical lesions may be better treated with angioplasty alone first.

Intrasellar Chordoma Mimicking Pituitary Macroadenoma with Hyperprolactinemia and Hypopituitarism: Clinical Images with a Surgical Video

A purely intrasellar chordoma is rare among skull base chordomas and is recognized as originating from ectopic embryological notochord located in the sella turcica. In view of its rarity and nonspecific symptoms, clinicians may misdiagnose intrasellar chordoma as pituitary adenoma based on preoperative radiographic images. In this report, we present an intrasellar chordoma that clinically mimicked pituitary macroadenoma with hyperprolactinemia and hypopituitarism and was successfully resected by endoscopic endonasal transsphenoidal surgery. This case demonstrated radiographic features that chordoma should be suspected in sellar lesions. The enlarged sellar with thinned remodeled bone without clival destruction was firstly reminiscent of pituitary adenoma, whereas the very high signal on T2-weighted images and heterogeneous enhancement characteristically suggested chordoma. This rare diagnosis must be considered in the preoperative evaluation of sellar lesions because it can affect how the neurosurgeon prepares for surgery and the surgical goals.

Mechanical thrombectomy for acute paradoxical cerebral embolism due to pulmonary arteriovenous malformation: A case report and review of literature

Background

We report a case of acute occlusion of the middle cerebral artery (MCA) due to pulmonary arteriovenous malformation (PAVM), for which mechanical thrombectomy was performed and a good outcome was achieved.

Case Description

A 59-year-old woman presented with severe right hemiplegia and dysarthria, and a National Institutes of Health Stroke Scale (NIHSS) score of 10. Magnetic resonance imaging (MRI) diffusion-weighted imaging revealed high-signal areas in the left lenticular nucleus to the corona radiata, and right temporal lobe. Magnetic resonance angiography revealed the left MCA occlusion. Chest plain computed tomography (CT) revealed PAVM in the lower lobe of the left lung. Transvenous thrombolytic therapy was started 2 h after onset, and mechanical cerebral thrombectomy was performed with an aspiration catheter and stent retriever. A red thrombus was retrieved in one pass and complete recanalization was achieved. After treatment, her symptoms improved markedly, but a symptomatic intracerebral hematoma was observed in the contralateral right temporal lobe. The patient underwent embolization for PAVM on day 24 and was transferred for rehabilitation (NIHSS score = 2).

Conclusion

Although rare, PAVM is a treatable cause of stroke in relatively young adults; thus, it is important to keep in mind the possibility of its presence.

PulseRider "jack-up" technique for wide-necked basilar tip aneurysms that incorporate parent arteries: A technical note

Background

Treatment of intracranial wide-necked bifurcation aneurysms remains challenging. We report a novel PulseRider "jack-up" technique for the treatment of wide-necked basilar tip aneurysms.

Case Description

We performed coil embolization in three patients with an unruptured wide-necked basilar tip aneurysm. Aneurysm neck diameters ranged between 7.6 and 11 mm and dome-to-neck ratios ranged from 1.0 to 1.15. All three aneurysms were very shallow with aspect ratios of 0.51-0.69 and incorporated both posterior cerebral arteries into the aneurysm wall. Because each was difficult to embolize using the standard PulseRider procedure, the PulseRider was deployed more proximally than usual and a coil frame constructed above it. Then, the coil was pushed or "jacked up" into the aneurysm with the PulseRider. Adequate embolization was achieved in all three patients.

Conclusion

Coil embolization using the PulseRider jack-up technique is effective for treatment of wide-necked basilar tip aneurysms that incorporate parent arteries.

MPC-16 CHARACTERISTICS AND PROGNOSTIC FACTORS OF H3K27M-MUTANT DIFFUSE MIDLINE GLIOMA

H3 K27M-mutant diffuse midline gliomas (DMG) is a still challenging disease with no effective medical therapies. We analyzed the characteristics and prognostic factors of 64 patients with midline gliomas including 18 patients with H3 K27M-mutant DMG treated in Kobe University Hospital from 2006 to 2021. The median age at diagnosis in midline gliomas was 50.1 years (range: 14-82 y). All tumors were located in thalamus n=25, corpus callosum n=8, brainstem n=8, spinal cord n=6, cerebellum n=15, and pineal region n=2. Isocitrate dehydrogenase 1 (IDH1) and H3 K27 mutation was recognized in 6 and 18 patients, respectively, which was mutually exclusive. In all midline gliomas, the identification of an H3 K27M mutation was significantly a poor prognosis factor (median 19.8 months vs 27.9 months, p=0.042). Compared to midline gliomas without histone H3 and IDH1 mutations (IDH1/H3 wild type), however, H3 K27M-mutant DMG had no worse overall survival (median 19.8 months vs 15.9 months, p=0.51). H3 K27M-mutant DMG is considered as a distinct WHO Grade 4 regardless of histological features, but the biological properties of H3 K27M mutation is not yet defined in IDH1 wild-type midline gliomas.

Ror1 is expressed inducibly by Notch and hypoxia signaling and regulates stem cell-like property of glioblastoma cells

Ror1 plays a crucial role in cancer progression by regulating cell proliferation and migration. Ror1 is expressed abundantly in various types of cancer cells and cancer stem-like cells. However, the molecular mechanisms regulating expression of Ror1 in these cells remain largely unknown. Ror1 and its putative ligand Wnt5a are expressed highly in malignant gliomas, especially in glioblastomas, and the extents of Ror1 expression are correlated positively with poorer prognosis in patients with gliomas. We show that Ror1 expression can be upregulated in glioblastoma cells under spheroid culture, but not adherent culture conditions. Notch and hypoxia signaling pathways have been shown to be activated in spheroid-forming glioblastoma stem-like cells (GSCs), and Ror1 expression in glioblastoma cells is indeed suppressed by inhibiting either Notch or hypoxia signaling. Meanwhile, either forced expression of the Notch intracellular domain (NICD) in or hypoxic culture of glioblastoma cells result in enhanced expression of Ror1 in the cells. Consistently, we show that both NICD and hypoxia-inducible factor 1 alpha bind to upstream regions within the Ror1 gene more efficiently in GSCs under spheroid culture conditions. Furthermore, we provide evidence indicating that binding of Wnt5a to Ror1, upregulated by Notch and hypoxia signaling pathways in GSCs, might promote their spheroid-forming ability. Collectively, these findings indicate for the first time that Notch and hypoxia signaling pathways can elicit a Wnt5a-Ror1 axis through transcriptional activation of Ror1 in glioblastoma cells, thereby promoting their stem cell-like property.

RBIO-07. HIGHER CSF IL-10 CORRELATE WITH BRAIN ATROPHY AFTER WHOLE BRAIN RADIATION THERAPY IN PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA

Whole brain radiation therapy (WBRT) to primary central nervous system lymphoma (PCNSL) correlate with brain atrophy and leukoencephalopathy on serial computed tomography or MRI scans, negatively impacting cognitive function and quality of life. We retrospectively evaluated 53 patients with histologically proven PCNSL who underwent cerebrospinal fluid (CSF) examination including β2-MG, sIL2R, CXCL13, and IL-10 preoperatively. All patients were newly diagnosed and followed up every 3 months from the day they were discharged from the hospital. Follow up period is at least 1 year from last day of chemotherapy. Clinical data included patient demographics, radiological and characteristics; whole brain volume (mm2) calculated from BainLabTM automatically, Global Cortical Atrophy (GCA) for global brain atrophy, Medial Temporal Atrophy (MTA) for temporal atrophy, and Fazekas scale for white matter lesions. The unpaired t test and multivariable liner regression were used to examine the clinical, CSF and radiological characteristics of patients. The mean age at symptom onset was 65.2 years (47-85 years). Thirty three of 53 (62%) patients underwent WBRT with chemotherapy (WBRT group). In all patients, multivariable analysis revealed WBRT correlate with brain volume reduction (p=0.0005) and progression of temporal lobe atrophy (p=0.0056). In addition, Age correlated with increasing white matter lesions at 1 year after chemotherapy (p=0.0422). In WBRT group, multivariable analysis indicated that high CSF IL-10 level accelerated brain volume reduction (p=0.0122) and temporal lobe atrophy (p=0.0343) at 6 months after chemotherapy. However, there were no significant factor for influencing brain atrophy at 1 year. Higher IL-10 ( &gt; 100mg/ml) level demonstrated higher brain atrophy rate (p=0.0366) and severe temporal atrophy at 1 year (p=0.0214). In elderly patients with high preoperative CSF IL-10 levels, cerebral atrophy and toxic leukoencephalopathy may progress in short period of time after WBRT. We should consider treatment strategy that avoid WBRT, such as R-MPV chemotherapy, for PCNSL patients.

TMIC-20. SERINE AND ONE-CARBON METABOLISM ADAPTING GLIOMA CELLS TO LOW GLUTAMINE MICROENVIRONMENT

Cancer cells optimize nutrient utilization to supply energetic and biosynthetic pathways. This metabolic process also includes redox maintenance and epigenetic regulation through nucleic acid and protein methylation, which enhance tumorigenicity and clinical resistance. However, less is known about how cancer cells exhibit metabolic flexibility to sustain cell growth and survival from low nutrient microenvironment. Here, we find that serine and glycine levels were higher in low-nutrient regions of tumors in glioblastoma multiforme (GBM) patients than they were in other regions. Metabolic and functional studies in malignant glioma cells demonstrated that serine availability and one-carbon metabolism support glioma cell survival following glutamine deprivation. Serine synthesis was mediated through autophagy rather than glycolysis. Gene expression analysis identified upregulation of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) to regulate one-carbon metabolism in malignant glioma cells and GBM patient-derived sphere cells. In clinical samples, MTHFD2 expression was highest in the nutrient-poor areas around “pseudopalisading necrosis.” Genetic and pharmacological suppression of MTHFD2 caused tumor cell death and growth inhibition of glioma cells upon glutamine deprivation as well as autophagy inhibition did. These results may have important implications for serine-dependent one-carbon metabolism for glioma cells to survive glutamine starvation and suggest a new therapeutic strategy for patients with malignant glioma.

BIOM-40. COMPARATIVE STUDY OF INFLAMMATORY MARKERS IN THE CEREBROSPINAL FLUID OF PATIENTS WITH GLIOMA AND CENTRAL NERVOUS SYSTEM MALIGNANT LYMPHOMA

INTRODUCTION

Cytokines in the cerebrospinal fluid (CSF) are useful as markers for primary central nervous system malignant lymphoma (PCBSL). However, there are few reports of CSF markers in glioma. We analyzed and examined glioma and PCNSL CSF inflammation-related mediators.

MATERIALS AND METHODS

The patients with glioma and PCNSL who were operated on at Kobe University between 2006 and 2017 and whose histology was diagnosed, and whose CSF was stored at -80 °C before treatment. Using Bio-Plex Pro Human Inflammation Assays (Bio-Rad Laboratories, Inc.), 37 types of inflammation-related molecules such as TNF superfamilies, interferonss, and Interleukines were measured and compared with glioma and PCNSL.

RESULTS

The subjects were 53 glioma patients and 24 PCNSL patients. There were 22 types of significant differences between glioma and PCNSL, 18 with high PCNSL and 4 with high glioma. In addition to IL-10, which has been reported so far, the significant higher concentrations in PCNSL was found in Osteopontin, TNFSF8, TNFSF12, TNFSF13, TNFSF13B, TNFSF14, sTNF-R1, sTNF-R2, IL-6Ra, IL-8, IL-12(p40), IL-20, IL-27, sCD163, MMP2, MMP3, CHI3L1. On the other hand, IL-2, Il-12(p70), IL-22, and MMP-1 levels were significant higher in CSF in glioma. Although CD163 is an important molecule as a marker for M2 macrophages, immunostaining of tissues showed no significant difference in infiltration between Glioblastoma and PCNSL. This suggests that M2 macrophages infiltrating PCNSL and Glioblastoma have different activation states.

CONCLUSION

PCNSL had higher levels of inflammatory mediators such as TNF-related molecules. PCNSL was significantly higher in sCD163 than in glioblastoma, suggesting different activation of intratumoral M2 macrophages.

Randomized phase III study of high-dose methotrexate and whole-brain radiotherapy with/without temozolomide for newly diagnosed primary CNS lymphoma: JCOG1114C

BACKGROUND

The goal was to determine whether the addition of temozolomide (TMZ) to the standard treatment of high-dose methotrexate (HD-MTX) and whole-brain radiotherapy (WBRT) for primary central nervous system lymphoma (PCNSL) improves survival.

METHODS

An open-label, randomized, phase III trial was conducted in Japan, enrolling immunocompetent patients aged 20-70 years with histologically confirmed, newly diagnosed PCNSL. After administration of HD-MTX, patients were randomly assigned to receive WBRT (30 Gy) ± 10 Gy boost (arm A) or WBRT ± boost with concomitant and maintenance TMZ for two years (arm B). The primary endpoint was overall survival (OS).

RESULTS

Between September 29, 2014 and October 15, 2018, 134 patients were enrolled, of whom 122 were randomly assigned and analyzed. At the planned interim analysis, two-year OS was 86.8% (95% confidence interval [CI]: 72.5-94.0%) in arm A and 71.4% (56.0-82.2%) in arm B. The hazard ratio was 2.18 (95% CI: 0.95 to 4.98), with the predicted probability of showing the superiority of arm B at the final analysis estimated to be 1.3%. The study was terminated early due to futility. O 6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status was measured in 115 tumors, and it was neither prognostic nor predictive of TMZ response.

CONCLUSIONS

This study failed to demonstrate the benefit of concomitant and maintenance TMZ in newly diagnosed PCNSL.

Ruptured Distal Middle Cerebral Artery Aneurysms-Characteristics and Strategy

BACKGROUND

Distal middle cerebral artery (dMCA) aneurysms are very rare. Most ruptured dMCA aneurysms lead to subarachnoid hemorrhage (SAH) coexisting with intracerebral hematoma (ICH), resulting in a deteriorating state. The risk factors of rupture of dMCA aneurysms remain unknown. To elucidate the risk of rupture, we studied differences between 4 ruptured and eleven unruptured dMCA aneurysms.

METHODS

We retrospectively analyzed patients diagnosed with a dMCA aneurysm according to the maximum size of the aneurysm, aspect ratio, and aneurysm size to vessel size (size ratio).

RESULTS

Four patients presented with SAH coexisting with ICH, resulting in a midline shift, caused by rupture of the dMCA aneurysm. The median aspect ratio of ruptured and unruptured dMCA aneurysms was 2.38 and 1.65, respectively, with no significant difference. The median maximum diameter of ruptured and unruptured dMCA aneurysms was 2.98 and 3.78 mm, respectively, with nonsignificant difference. The median size ratio of ruptured and unruptured dMCA aneurysms was 3.13 and 1.84, respectively, being significant difference (P < 0.02). The outcomes of 4 patients having ruptured dMCA aneurysm were as follows: one patient died due to the initial attack, and the others were severely disabled due to cerebral infarction caused by vasospasm.

CONCLUSIONS

Distal MCA aneurysms, even if they are small, may be likely to rupture leading to SAH complicated by ICH and result in a poor neurological state and unfavorable outcomes. We recommend aggressive treatment for dMCA aneurysms considering morphological factors such as the size ratio even if they are small and unruptured.

Spinal cord infarction after coil embolization of a basilar tip aneurysm: A case report and literature review

Background:

Spinal cord infarction is a rare but serious complication of neurointervention that has been rarely documented. An association between spinal cord infarction and the placement of large bore catheters in the vertebral artery (VA) has been mentioned, but the precise etiology remains unclear.

Case Description:

A 72-year-old female presented with the right hemiparesis and left thermal hypoalgesia directly after endovascular coil embolization for an unruptured basilar tip aneurysm. Magnetic resonance imaging demonstrated right-sided upper cervical (C2-3) spinal cord infarction. Conventional bilateral vertebral angiograms revealed no opacification of the anterior spinal arteries. Cone-beam computed tomography showed a watershed area of radiculomedullary arteries that was correlated with the extent of the ischemic lesion. Thus, the spinal cord ischemia may have had multifactorial causes combined with reduced perfusion pressure to the spinal cord, which was caused by the placement of the guiding catheter in the VA and intensive hypotension during general anesthesia.

Conclusion:

Spinal cord infarction should be recognized as a serious complication of endovascular treatment involving posterior circulation.

Presence of a fundal fluid cap on preoperative magnetic resonance imaging may predict long-term facial nerve function after resection of vestibular schwannoma via the retrosigmoid approach

OBJECTIVE

Preservation of neurological function is a priority when performing a resection of a vestibular schwannoma (VS). Few studies have examined the radiographic value of a fundal fluid cap—i.e., cerebrospinal fluid in the lateral end of a VS within the internal auditory canal—for prediction of postoperative neurological function. The aim of this study was to clarify whether the presence of a fundal fluid cap on preoperative magnetic resonance images has a clinical impact on facial nerve function after resection of VSs.

METHODS

The presence of a fundal fluid cap and its prognostic impact on long-term postoperative facial nerve function were analyzed.

RESULTS

A fundal fluid cap was present in 102 of 143 patients who underwent resection of sporadic VSs via the retrosigmoid approach. Facial nerve function was acceptable (House-Brackmann grade I–II) immediately after surgery in 82 (80.4%) patients with a fundal fluid cap and in 26 (63.4%) of those without this sign. The preservation rate of facial nerve function increased in a time-dependent manner after surgery in patients with a fundal fluid cap but plateaued by 3 months postoperatively in those without a fundal fluid cap; the difference was statistically significant at 12 months (96.1% vs 82.9%, p = 0.013) and 24 months (97.1% vs 82.9%, p = 0.006) after surgery. The presence of a fundal fluid cap had a significantly positive effect on long-term facial nerve function at 24 months after surgery when tumor size and intraoperative neuromonitoring response were taken into account (OR 5.55, 95% CI 1.12–27.5, p = 0.034).

CONCLUSIONS

Neuromonitoring-guided microsurgery for total resection of VSs is more likely to be successful in terms of preservation of facial nerve function if a fundal fluid cap is present. This preoperative radiographic sign could be helpful when counseling patients and deciding the treatment strategy.

Absence of the Anterior Communicating Artery on Selective MRA is Associated with New Ischemic Lesions on MRI after Carotid Revascularization

BACKGROUND AND PURPOSE

ICA-selective MRA using a pencil beam presaturation pulse can accurately visualize anterior communicating artery flow. We evaluated the impact of anterior communicating artery flow on the perioperative hemodynamic status and new ischemic lesions after carotid revascularization.

MATERIALS AND METHODS

Eighty-three patients with carotid artery stenosis were included. We assessed anterior communicating artery flow using ICA-selective MRA. The preoperative hemodynamic status was measured using SPECT. We also measured the change in regional cerebral oxygen saturation after temporary ICA occlusion. New ischemic lesions were evaluated by DWI on the day after treatment.

RESULTS

Anterior communicating artery flow was detected in 61 patients, but it was not detected in 22 patients. Preoperative cerebrovascular reactivity was significantly higher in patients with (versus without) anterior communicating artery flow with a mean peak systolic velocity of ≥200 cm/s (39.6% [SD, 23.8%] versus 25.2% [SD, 16.4%]; P = .030). The decrease in mean regional cerebral oxygen saturation was significantly greater in patients without (versus with) anterior communicating artery flow (8.5% [SD, 5.6%] versus 3.7% [SD, 3.8%]; P = .002). New ischemic lesions after the procedure were observed in 23 patients. The multivariate logistic regression analysis revealed that anterior communicating artery flow (OR, 0.07; 95% CI, 0.012-0.45; P = .005) was associated with new ischemic lesions.

CONCLUSIONS

The absence of anterior communicating artery flow influenced the perioperative hemodynamic status in patients with carotid stenosis and was associated with an increased incidence of new ischemic lesions after carotid revascularization.

The impact of hormonal dynamics and serum sodium fluctuations on symptomatic vasospasm after subarachnoid hemorrhage

BACKGROUND

Symptomatic vasospasm (SVS) is a major cause of morbidity and mortality in aneurysmal subarachnoid hemorrhage (SAH), and serum sodium frequently decreases before SVS. Serum sodium changes might be regulated by sodium metabolism-related hormones. This multi-institutional prospective cohort study therefore investigated the measurement of sodium metabolism-related hormones to elucidate the pathophysiology of serum sodium changes in SAH.

METHODS

SAH patients were treated with clipping or coiling from September 2017 to August 2020 at five hospitals. The laboratory data of 133 SAH patients were collected over 14 days and correlations between changes in serum sodium, sodium metabolism-related hormones (plasma adrenocorticotropic hormone (ACTH), serum cortisol, plasma arginine vasopressin (AVP)), and SVS were determined. Serum sodium concentrations were measured every day and serum sodium levels >135 mEq/L were maintained until day 14.

RESULTS

Of the 133 patients, 18 developed SVS within 14 days of subarachnoid hemorrhage onset (SVS group) and 115 did not suffer from SVS (non-SVS group). Circulating AVP, ACTH, and cortisol concentrations were significantly higher on day 1 in the SVS group compared with the non-SVS group. Fluctuations in serum sodium in the SVS group were significantly higher than those in the non-SVS group. There were antiparallel fluctuations in serum sodium and potassium from days 2 to 14.

CONCLUSIONS

Elevated levels of ACTH/cortisol and AVP on day 1 may be predictive markers for the occurrence of SVS. Multiple logistic regression analysis showed that serum sodium fluctuations were associated with SVS occurrence. Serum sodium fluctuations were associated with stress-related hormonal dynamics. (249 words).

Long-term recurrence after surgery for schwannoma of the cauda equina

Background:

Cauda equina tumors are rare primary spinal tumors. Histologically, the most common tumor arising from the cauda equina is a schwannoma. However, little is known about the long-term postoperative outcomes of cauda equina schwannoma. Here, we reviewed the median-to-long-term postoperative outcomes of eight of our own patients with schwannomas of the cauda equina.

Methods:

Between 2007 and 2020, we, retrospectively, reviewed eight patients with cauda equina schwannomas (CESs) undergoing nine operations at our institution. There were five males and three females averaging 56.5 years of age who were followed for over 40 postoperative months. The study included assessment of the following variables: the modified McCormick scale, tumor size, location, extent of resection, treatment of the tumor involving nerve roots, and postoperative observational follow-up.

Results:

Gross-total resection was achieved in all eight patients; none received adjuvant therapy. The involved nerve roots were completely sacrificed in seven patients and partially resected in one. During a median follow-up of 108 months, only one patient sustained a tumor recurrence 164 months following the index surgery.

Conclusion:

CESs may recur more than 10 years after the original surgery. Radical resection of the tumor, including complete removal of the involved nerve root during the index surgery, and long-term postoperative follow-up is, therefore, essential.

Symptomatic Intracranial Artery Stenosis Due to an Unknown Embolus Following Cardiac Surgery: A Case Report

Intracranial artery occlusion due to a foreign body is a complication associated with cardiac surgery that is treated by various techniques. However, little is known about appropriate strategies for symptomatic intracranial artery stenosis due to an unknown embolic source. We reported a case of middle cerebral artery (MCA) stenosis after mitral valve repair (MVR) for infective endocarditis (IE). An 80-year-old man presented with right hemiplegia. MR angiography findings were normal, and diffusion-weighted imaging revealed subtle ischemic change in the left MCA territory. The patient was diagnosed with cardioembolic stroke owing to IE and performed MVR. Four days later, he suddenly presented with consciousness disorder and left hemiplegia. Computed tomography (CT) confirmed a very low-density area within the right MCA. MR angiography revealed right MCA stenosis, which corresponded to the low-density area on CT images. Diffusion-weighted imaging revealed new ischemic change in the right MCA territory. Angiography confirmed an irregular stenosis at the right M2 with antegrade blood flow, and the hemiplegia resolved during angiography. Conservative therapy was performed; however, the resting 123 I-IMP-single photon emission CT revealed moderate perfusion defect in the right MCA territory, and transient left hemiplegia appeared every few days. Therefore, 19 days after the initial transient ischemic attack, the patient was performed superficial temporal artery–MCA anastomosis, and the patient responded with a good clinical course without recurrence of the ischemic symptoms. This strategy may be a safe and effective treatment for symptomatic intracranial artery stenosis due to an unknown embolic source.

Acute Occlusion of the Ventriculoperitoneal Shunt Due to Factor XIII Deficiency-related Postoperative Hemorrhage: A Case Report

Coagulation factor XIII (F13) deficiency has been known to be a rare disease with estimated one per two million and one of the possible reasons of postoperative hemorrhage; however, it still remains unpenetrated to physicians. We report a case of acute ventriculoperitoneal (VP) shunt dysfunction due to delayed intraventricular hemorrhage, which could be because of F13 deficiency. The patient was a 48-year-old man with a history of post-meningitis hydrocephalus followed by VP shunt placement. He was found unconscious and transferred to our hospital. A brain CT scan demonstrated shunt malfunction, and he underwent emergency shunt revision. The postoperative course was uneventful except for unexpected neck bruises and continuous minor bleeding from the surgical wound. Three days after surgery, he suddenly became comatose and a CT scan revealed the recurrence of hydrocephalus with newly identified small volume of intraventricular hemorrhage. Emergency shunt revision was performed again. The shunt valve was filled with a hematoma and bloody cerebrospinal fluid was drained from the ventricle. Postoperative blood sample examination demonstrated no abnormal findings but a decreased level of F13 activity, which was thought to be a possible cause of postoperative hemorrhage and the shunt valve hematoma. F13 deficiency causes delayed intracranial hemorrhage 24–48 h after neurological surgery. It can only be diagnosed by checking F13 activity with suspicion. If diagnosed accurately beforehand, unexpected postoperative bleeding can be preventable with proper treatment, such as F13 concentrate and cryoprecipitate. The actual number of the patient with F13 deficiency may be more than estimated ever.

CBMS-5 One-carbon metabolism protect glioma cells under glutamine starvation through upregulation of MTHFD2

Cancer cells optimize nutrient utilization to supply energetic and biosynthetic pathways. However, less is known about how cancer cells exhibit metabolic flexibility to sustain cell growth and survival from nutrient starvation. Here, we find that serine and glycine levels were higher in low-nutrient regions of tumors in glioblastoma multiforme (GBM) patients than they were in other regions. Metabolic and functional studies demonstrated that serine availability and one-carbon metabolism support glioma cell survival following glutamine deprivation. Serine synthesis was mediated through autophagy rather than glycolysis. Gene expression analysis identified upregulation of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) to regulate one-carbon metabolism. In clinical samples, MTHFD2 expression was highest in the nutrient-poor areas around pseudopalisading necrosis. Genetic suppression of MTHFD2 and autophagy inhibition caused tumor cell death and growth inhibition of glioma cells upon glutamine deprivation. These results suggest new therapeutic targets for glioma cells adapting to a low-nutrient microenvironment.

NI-7 Diffusion-weighted imaging for monitoring acute response and recurrence after photodynamic therapy in malignant gliomas

Background

Photodynamic therapy (PDT) subsequent to surgical tumor removal is a novel light-activated localized treatment for malignant glioma. Although PDT provides effective local control, even PDT cannot completely suppress local recurrence of malignant glioma. We previously reported that the acute response of malignant glioma to PDT could be detected as linear hyperintense signals on diffusion-weighted imaging (DWI) and a decline in apparent diffusion coefficient (ADC) values that were asymptomatic and transient. However, their long-term clinical significance has not yet been examined. This study aimed to clarify the link between the hyperintense signal on DWI as an acute response and recurrence after PDT in malignant glioma.

Methods

Thirty consecutive patients (16 men, 14 women; median age 60.5 years) underwent PDT for malignant glioma at our institution between 2017 and 2020. We analyzed signal changes on DWI after PDT and the link between these findings and the recurrence pattern.

Results

In all patients, linear hyperintense signals of 5–7 mm on DWI were detected at the surface of the resected cavity from day 1 after PDT. These changes matched the PDT-irradiated area and disappeared in about 30 days without any neurological deterioration. Of the 30 patients, 19 (63%) exhibited recurrence: local recurrence in 10 (33%), distant recurrence in 1 (3%), and dissemination in 8 (27%). All local recurrences arose from areas that did not show a hyperintense signal on DWI obtained on day 1 after PDT. Patients with distant recurrence or dissemination tended to have uninterrupted hyperintense signal on DWI obtained on day 1 after PDT.

Conclusion

The local recurrence in malignant glioma after PDT occurred in the areas without hyperintense signal on DWI as the acute response to PDT. This characteristic finding could aid in the monitoring of not only PDT-irradiated area but also local recurrence site after PDT.

Contribution of Endoplasmic Reticulum Stress to the Clinical Instability of Carotid Plaques in Human Carotid Stenosis

Endoplasmic reticulum (ER) stress is an important process during the progression of atherosclerosis. The aim of this study was to elucidate the association of ER stress and clinical instability of carotid plaque. One hundred ninety-three patients with carotid stenosis undergoing carotid endarterectomies (CEAs) were enrolled. We classified the patients into 3 groups: the asymptomatic, symptomatic, and cTIA (crescendo transient ischemic attack)/SIE (stroke in evolution) groups. Immunohistological staining was performed to assess ER stress and apoptosis. The correlation between ER stress marker expression and clinical instability was analyzed by Tukey-Kramer test and ordinal logistic regression. From the 193 CEAs, 24 asymptomatic plaques and 24 symptomatic plaques were randomly selected, and all 7 plaques in the cTIA/SIE group were selected. Glycophorin A staining demonstrated significant correlation between intraplaque hemorrhage and clinical instability (odds ratio [OR], 1.27; 95%CI, 1.14-1.41). The expression of ER stress markers (glucose-regulated protein 78 [GRP78] and C/EBP homologous protein [CHOP]) exhibited a significant correlation with clinical instability (GRP78: OR, 1.25; 95%CI, 1.14-1.38, CHOP: OR, 1.39; 95%CI, 1.16-1.66). Double-label immunofluorescence demonstrated ER stress markers were detected in CD68-positive cells and smooth muscle actin (SMA)-positive cells. The coexpression of the ER stress markers exhibited a significant correlation with clinical instability (CD68/GRP78: OR, 1.13; 95%CI, 1.05-1.20, CD68/CHOP: OR, 1.092; 95%CI, 1.04-1.14, SMA/CHOP: OR, 1.082; 95%CI, 1.04-1.13). However, the colocalization of CHOP and cleaved caspase-3 (apoptosis marker) did not correlate with clinical instability. These findings indicated that the ER stress pathway may be a potential therapeutic target in the prevention of stroke.

TAMI-20. GLIOMA CELLS REPROGRAM SERINE-DEPENDENT ONE-CARBON METABOLISM TO SURVIVE GLUTAMINE STARVATION

Cancer cells optimize nutrient utilization to supply energetic and biosynthetic pathways. This metabolic process also includes redox maintenance and epigenetic regulation through nucleic acid and protein methylation, which enhance tumorigenicity and clinical resistance. However, less is known about how cancer cells exhibit metabolic flexibility to sustain cell growth and survival from nutrient starvation. Here, we find that serine and glycine levels were higher in low-nutrient regions of tumors in glioblastoma multiforme (GBM) patients than they were in other regions. Metabolic and functional studies in GBM cells demonstrated that serine availability and one-carbon metabolism support glioma cell survival following glutamine deprivation. Serine synthesis was mediated through autophagy rather than glycolysis. Gene expression analysis identified upregulation of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) to regulate one-carbon metabolism in GBM patient-derived sphere cells as well as in GBM cells. In clinical samples, MTHFD2 expression was highest in the nutrient-poor areas around “pseudopalisading necrosis.” Genetic suppression of MTHFD2 and autophagy inhibition caused tumor cell death and growth inhibition of glioma cells upon glutamine deprivation. These results may have important implications for serine-dependent one-carbon metabolism for glioma cells to survive glutamine starvation and suggest a new therapeutic strategy for patients with malignant glioma.

NIMG-15. 2-HYDROXYGLUTARATE MAGNETIC RESONANCE SPECTROSCOPY IN ADULT BRAINSTEM GLIOMA PATIENTS

OBJECTIVE

The onco-metabolite, 2-Hydroxyglutarate (2HG), is non-invasive biomarker for detecting isocitrate dehydrogenase (IDH) mutant glioma by MR-Spectroscopy. Especially 2HG-MRS may be useful in patients with brainstem lesions, where surgical biopsy presents high risk of neurological injury. Here, we examined the utility of 2HG-MRS for diagnosis of IDH mutant adult brainstem glioma.

METHODS

We conducted 3 tesla -MRS (3T-MRS) in 8 radiographically identified brainstem tumor (7 male and 1 female, median age 39). Single-voxel was localized from the T2-FLAIR using a 2HG-tailored MRS protocol (Philips, Achieva, PRESS, TE 35 ms). All patients underwent tumor biopsy using an intraoperative navigation system (Brain LABTM) or stereotactic biopsy system (Komai’s CT-stereotactic frame) before initial treatment. IDH and H3K27M status were diagnosed by IHC and DNA sequence.

RESULTS

3 cases were H3K27M and 4 cases were IDH mutant (R132H 1 case, R132S 2 cases, and R132G 1 case). 1 case were neither H3K27M nor IDH mutant. H3-K27 and IDH1 mutations were mutually exclusive. All tumor located at pons. There were no significant radiological difference between H3K27M and IDH mutant in conventional MRI sequence. Pearson's chi-square test demonstrated that 2HG concentrations &gt;1.5 mM were 100% sensitive and 75% specific for IDH mutant glioma (p = 0.0285). The median overall survival survival were 127 month in IDH mutant glioma (n=4) and 22.5 months in IDH wild-type glioma (n=4), respectively.

CONCLUSIONS

2HG in adult brainstem glioma was detected by conventional 3T-MRS successfully. A noninvasive 2HG-MRS may be useful diagnostic modality for evaluating molecular status and prognosis in brainstem glioma noninvasively.

Hyperintense signal on diffusion-weighted imaging for monitoring the acute response and local recurrence after photodynamic therapy in malignant gliomas

PURPOSE

Photodynamic therapy (PDT) subsequent to surgical tumor removal is a novel localized treatment for malignant glioma that provides effective local control. The acute response of malignant glioma to PDT can be detected as linear transient hyperintense signal on diffusion-weighted imaging (DWI) and a decline in apparent diffusion coefficient values without symptoms. However, their long-term clinical significance has not yet been examined. The aim of this study was to clarify the link between hyperintense signal on DWI as an acute response and recurrence after PDT in malignant glioma.

METHODS

Thirty patients (16 men; median age, 60.5 years) underwent PDT for malignant glioma at our institution between 2017 and 2020. We analyzed the signal changes on DWI after PDT and the relationship between these findings and the recurrence pattern.

RESULTS

All patients showed linear hyperintense signal on DWI at the surface of the resected cavity from day 1 after PDT. These changes disappeared in about 30 days without any neurological deterioration. During a mean post-PDT follow-up of 14.3 months, 19 patients (63%) exhibited recurrence: 10 local, 1 distant, and 8 disseminated. All of the local recurrences arose from areas that did not show hyperintense signal on DWI obtained on day 1 after PDT.

CONCLUSIONS

The local recurrence in malignant glioma after PDT occurs in an area without hyperintense signal on DWI as an acute response to PDT. This characteristic finding could aid in the monitoring of local recurrence after PDT.

Bone-destructive osseous arteriovenous fistula at the jugular bulb mimicking a glomus jugular tumor

BACKGROUND

Some reports have described intraosseous arteriovenous fistulas showing osteolytic changes, but an osseous arteriovenous fistula (AVF) at the jugular bulb showing extensive bone destruction is a very rare disease.

CASE DESCRIPTION

A 60-year-old man presented with pulsatile tinnitus and right facial nerve palsy. Radiological imaging showed a large homogenously enhanced osteolytic lesion at the right jugular foramen. A cerebral angiogram showed a high-flow vascular lesion of the jugular bulb associated with retrograde sinus reflux, resulting in venous congestion of the deep venous system. These findings led us to misdiagnose this lesion as a glomus jugular tumor. However, combined arterial and venous angiography after transarterial embolization revealed the precise angioarchitecture, and we finally diagnosed this lesion as a high-flow osseous AVF at the jugular bulb. We performed transvenous embolization using a triple catheter technique. The lesion was successfully obliterated, and the 6-months angiogram showed no recurrence.

CONCLUSION

A rare case of high flow osseous AVF at the jugular bulb associated with osteolytic changes in the surrounding bony structure is reported. Although many hypervascular lesions at the jugular bulb are glomus tumors, bone destructive osseous AVF at the jugular bulb should be considered.

A Case of Intracranial Vertebral Artery Dissection Undetected by CT, MRI, and MRA at the Onset of Headache That Caused Subarachnoid Hemorrhage Seven Days Later

Objective

We report a patient with normal imaging findings at the onset of preceding headache who developed subarachnoid hemorrhage (SAH) due to intracranial vertebral artery dissection 7 days later.

Case Presentation

A 51-year-old woman with a history of chronic headache visited our emergency outpatient department with a complaint of mild to moderate right nuchal pain. CT, MRA, and MRI (diffusion-weighted image, T2-weighted image, FLAIR, MR cisternography, and basi-parallel anatomical scanning) were normal. Seven days later, she was admitted to our hospital with sudden disturbance of consciousness. CT revealed SAH and CTA demonstrated dilatation of the right vertebral artery (VA). The dilated lesion with an intimal flap on the right VA proximal to the posterior inferior cerebellar artery was confirmed on DSA. The dilated lesion and the proximal VA were occluded endovascularly using coils. The condition of the patient improved gradually, and she was transferred to the rehabilitation hospital on day 45 with a modified Rankin Scale score of 2.

Conclusion

The clinical course of the presented case, although rare, should be kept in mind in daily clinical practice.

Non-Sinus-Type Laterocavernous Sinus Dural Arteriovenous Fistula Treated by Transarterial Venous Coil Embolization: A Case Report

Objective

Laterocavernous sinus dural arteriovenous fistulas (DAVFs) are rare and not always accessible transvenously due to their angioarchitecture. We report a case of non-sinus-type laterocavernous sinus DAVF treated by endovascular transarterial venous coil embolization.

Case Presentation

A 78-year-old woman was admitted to our hospital with loss of consciousness, right hemiparesis, and motor aphasia. CT demonstrated intracerebral hematoma in the left frontal lobe and subarachnoid hemorrhage. On CTA and MRA, a DAVF was found in the left laterocavernous sinus region associated with the accessory meningeal artery (AMA) and draining directly into the superficial middle cerebral vein. The diagnosis was confirmed by DSA, which revealed a DAVF fed by the large and straight AMA and the internal carotid artery's meningohypophyseal trunk. Endovascular transarterial venous coil embolization was performed through the AMA. A microcatheter was advanced beyond the shunt point into the origin of the draining vein, and coils were placed in the venous and arterial sides of the fistula. The fistula was completely occluded, and 15-month follow-up angiography demonstrated stable obliteration of the fistula.

Conclusion

Transarterial venous coil embolization may be a treatment option for non-sinus-type laterocavernous sinus DAVF with a large fistula size and a large and straight feeding artery.