A Case of Multiple Intracranial Hemorrhages due to a Ruptured Neoplastic Cerebral Aneurysm Secondary to Metastasis of Poorly Differentiated Parotid Gland Carcinoma.

Neoplastic cerebral aneurysms (NCAs) are rare. This study reported a case of an NCA secondary to a poorly differentiated carcinoma of the parotid gland. An 84-year-old Japanese woman undergoing treatment for parotid gland cancer was admitted to our hospital with headache and progressive loss of consciousness. Based on computed tomography (CT) and CT angiography (CTA), a diagnosis of subarachnoid hemorrhage due to rupture of a left posterior inferior cerebellar artery aneurysm was made, and emergency aneurysmectomy was performed. Pathological examination of the resected aneurysm showed an NCA secondary to parotid carcinoma. After the aneurysmectomy, her condition stabilized; however, 33 days later, the patient developed an intracerebral hemorrhage, and a new aneurysm was confirmed in the right middle cerebral artery. To the best of our knowledge, there have been no previous reports on cases of NCAs secondary to parotid carcinoma. The pathology and clinical course strongly suggest that NCAs derived from malignant tumors may have an aggressive course.

The Usefulness of the 3.1-mm-diameter 4K Rigid Endoscope for Intracerebral Hematoma Evacuation.

The indication for surgical intervention in spontaneous intracerebral hemorrhage remains controversial. Although many clinical trials have failed to demonstrate its efficacy over medical treatment, less invasive endoscopic treatment is expected to demonstrate its superiority. A novel endoscopic system for hematoma removal consisting of a 3.1-mm-diameter 4K high-resolution rigid endoscope was used.The system was used in eight cases of spontaneous intracerebral hemorrhage. It provided improved maneuverability of the surgical instrument while maintaining satisfactory image quality. The surgical goal was achieved in all cases without any complications, including perioperative rebleeding.Endoscopic hematoma removal using the 3.1 mm high-resolution endoscope is an alternative minimally invasive approach to spontaneous intracerebral hemorrhage with improved reliability.

A novel predictor of ischemic complications in the treatment of ruptured middle cerebral artery aneurysms: Neck-branching angle.

Objective: The risk factors of procedural cerebral ischemia (CI) in ruptured middle cerebral artery (MCA) aneurysms are unclear. This study proposed the neck-branching angle (NBA), a simple quantitative indicator of the aneurysm neck and branch vessels, and analyzed its usefulness as a predictor of procedural CI in ruptured MCA aneurysms. Methods: We retrospectively analyzed 128 patients with ruptured saccular MCA aneurysms who underwent surgical or endovascular treatment between January 2014 and June 2021. We defined the NBA as the angle formed by the MCA aneurysm neck and M2 superior or inferior branch vessel line. The superior and inferior NBA were measured on admission via three-dimensional computed tomography angiography on admission. We divided the patients into clipping (106 patients) and coiling (22 patients) groups according to the treatment. Risk factors associated with procedural CI were analyzed in each group. Results: Both groups showed that an enlarged superior NBA was a significant risk factor for procedural CI (clipping, P < 0.0005; coiling group, P = 0.007). The receiver operating characteristic curve showed the closed thresholds of the superior NBA with procedural CI in both groups (clipping group, 128.5°, sensitivity and specificity of 0.667 and 0.848, respectively; coiling group, 130.9°, sensitivity and specificity of 1 and 0.889, respectively). Conclusion: The NBA can estimate the procedural risk of ruptured MCA aneurysms. In addition, an enlarged superior NBA is a risk factor for procedural CI in both clipping and coiling techniques.

Glycolytic System in Axons Supplement Decreased ATP Levels after Axotomy of the Peripheral Nerve.

Wallerian degeneration (WD) occurs in the early stages of numerous neurologic disorders, and clarifying WD pathology is crucial for the advancement of neurologic therapies. ATP is acknowledged as one of the key pathologic substances in WD. The ATP-related pathologic pathways that regulate WD have been defined. The elevation of ATP levels in axon contributes to delay WD and protects axons. However, ATP is necessary for the active processes to proceed WD, given that WD is stringently managed by auto-destruction programs. But little is known about the bioenergetics during WD. In this study, we made sciatic nerve transection models for GO-ATeam2 knock-in rats and mice. We presented the spatiotemporal ATP distribution in the injured axons with in vivo ATP imaging systems, and investigated the metabolic source of ATP in the distal nerve stump. A gradual decrease in ATP levels was observed before the progression of WD. In addition, the glycolytic system and monocarboxylate transporters (MCTs) were activated in Schwann cells following axotomy. Interestingly, in axons, we found the activation of glycolytic system and the inactivation of the tricarboxylic acid (TCA) cycle. Glycolytic inhibitors, 2-deoxyglucose (2-DG) and MCT inhibitors, a-cyano-4-hydroxycinnamic acid (4-CIN) decreased ATP and enhanced WD progression, whereas mitochondrial pyruvate carrier (MPC) inhibitors (MSDC-0160) did not change. Finally, ethyl pyruvate (EP) increased ATP levels and delayed WD. Together, our findings suggest that glycolytic system, both in Schwann cells and axons, is the main source of maintaining ATP levels in the distal nerve stump.

Growth risk classification and typical growth speed of convexity, parasagittal, and falx meningiomas: a retrospective cohort study.

OBJECTIVE: Meningiomas are the most common primary intracranial tumors, and their clinical and biological characteristics vary by location. Convexity, parasagittal, and falx meningiomas account for approximately 50%-65% of intracranial meningiomas. Focusing only on these locations, the aim of this study was to determine the typical speed of tumor growth, to assess the growth risk, and to show the possible tumor volume that many lesions can reach after 5 years. METHODS: Patients with radiologically suspected convexity, parasagittal, or falx meningiomas at the authors' institution were studied retrospectively. The relative growth rate (RGR) and annual volume change (AVC) were calculated from MRI at more than 3-month intervals. Based on sex, age, and signal intensity on T2-weighted MRI, the cases were classified into three groups: extremely high-growth, high-growth, and low-growth groups. RESULTS: The data of 313 cases were analyzed. The median RGR and AVC for this entire cohort were 6.1% (interquartile range [IQR] 2.4%-16.0%) and 0.20 (IQR 0.04-1.18) cm3/year, respectively. There were significant differences in sex (p = 0.018) and T2-weighted MRI signal intensity (p < 0.001) for RGR, and T2-weighted MRI signal intensity (p < 0.001), tumor location (p = 0.025), and initial tumor volume (p < 0.001) for AVC. The median RGR and AVC were 17.5% (IQR 8.3%-44.1%) and 1.05 (IQR 0.18-3.53) cm3/year, 8.2% (IQR 2.9%-18.6%) and 0.33 (IQR 0.06-1.66) cm3/year, and 3.4% (IQR 1.2%-5.8%) and 0.04 (IQR 0.02-0.21) cm3/year for the extremely high-growth, high-growth, and low-growth groups, respectively, with a significant difference among the groups (p < 0.001). A 2.24-times, or 5.24 cm3, increase in tumor volume over 5 years was typical in the extremely high-growth group, whereas the low-growth group showed little change in tumor volume even over a 5-year follow-up period. CONCLUSIONS: For the first time, the typical speed of tumor growth was calculated, focusing only on patients with convexity, parasagittal, and falx meningiomas. In addition, the possible tumor volume that many lesions in these locations can reach after 5 years was shown based on objective indicators. These results may allow clinicians to easily detect lesions that require frequent follow-up or early treatment by determining whether they deviate from the typical range of the growth rate, similar to a growth chart for children.

Association of Gut Microbiome with Early Brain Injury After Subarachnoid Hemorrhage: an Experimental Study.

The occurrence of early brain injury (EBI) following subarachnoid hemorrhage (SAH) is crucial in the prognosis of SAH; however, no effective treatment for EBI has been developed. Gut microbiome (GM) composition influences the outcome of various diseases, including ischemic stroke. Here, we evaluated whether prior GM alteration could prevent EBI following SAH. We altered the GM of 7-week-old male rats by administering antibiotic-containing water for 2 weeks and performing fecal microbiome transplantation after antibiotic induction. Composition of the GM was profiled using 16S rRNA. We induced SAH by injecting blood in the subarachnoid space of control rats and rats with altered GM. We evaluated EBI indicators such as neurological score, brain water content, Evans blue extravasation, and neuronal injury. Additionally, we studied inflammatory cells using immunohistochemistry, immunocytochemistry, quantitative PCR, and flow cytometry. EBI was significantly averted by alterations in GM using antibiotics. The altered GM significantly prevented neutrophil infiltration into the brain among inflammatory cells, and this anti-inflammatory effect was observed immediately following SAH onset. The altered GM also prevented neutrophil extracellular trap formation in the brain and blood, indicating the systemic protective effect. The cause of the protective effect was attributed to a significant decrease in aged neutrophils (CXCR4high CD62Llow) by the altered GM. These protective effects against EBI disappeared when the altered GM was recolonized with normal flora. Our findings demonstrated that EBI following SAH is associated with GM, which regulated neutrophil infiltration.

Excess intracellular ATP causes neuropathic pain following spinal cord injury.

Intractable neuropathic pain following spinal cord injury (NP-SCI) reduces a patient's quality of life. Excessive release of ATP into the extracellular space evokes neuroinflammation via purinergic receptor. Neuroinflammation plays an important role in the initiation and maintenance of NP. However, little is known about whether or not extracellular ATP cause NP-SCI. We found in the present study that excess of intracellular ATP at the lesion site evokes at-level NP-SCI. No significant differences in the body weight, locomotor function, or motor behaviors were found in groups that were negative and positive for at-level allodynia. The intracellular ATP level at the lesion site was significantly higher in the allodynia-positive mice than in the allodynia-negative mice. A metabolome analysis revealed that there were no significant differences in the ATP production or degradation between allodynia-negative and allodynia-positive mice. Dorsal horn neurons in allodynia mice were found to be inactivated in the resting state, suggesting that decreased ATP consumption due to neural inactivity leads to a build-up of intracellular ATP. In contrast to the findings in the resting state, mechanical stimulation increased the neural activity of dorsal horn and extracellular ATP release at lesion site. The forced production of intracellular ATP at the lesion site in non-allodynia mice induced allodynia. The inhibition of P2X4 receptors in allodynia mice reduced allodynia. These results suggest that an excess buildup of intracellular ATP in the resting state causes at-level NP-SCI as a result of the extracellular release of ATP with mechanical stimulation.

Tentorial Dural Arteriovenous Fistula Presenting with Venous Congestive Edema of the Upper Cervical Cord.

Tentorial dural arteriovenous fistula (DAVF) is an aggressive vascular lesion causing progressive neurological deficits. Venous congestive cervical edema is a rare phenomenon caused by tentorial DAVF. Obliteration of the fistula and venous drainage should be the goal of treatment. A 62-year-old man was admitted with lower limb weakness and numbness. Magnetic resonance imaging (MRI) revealed extensive edema of the upper cervical cord with signal flow void at the anterior spinal cord. Internal carotid angiography revealed a tentorial arteriovenous shunt near the superior petrosal sinus fed mainly by the tentorial artery. The petrosal vein was dilated, with the transverse pontine vein, medial medullary vein, and anterior spinal vein as the main drainage route. This suggests that venous hypertension triggered the upper cervical cord edema. MRI with gadolinium enhancement showed that the varix was located just distal to the shunt. Microsurgical obliteration of the fistula and venous drainage were achieved via a suboccipital approach. A postoperative evaluation showed the disappearance of the cervical cord edema with improved clinical symptoms. Tentorial DAVF with spinal venous drainage presents with mild and slow progression of symptoms. Differential diagnosis and definite treatment are mandatory to avoid a delayed diagnosis and irreversible symptoms.

Dysbiosis of Gut Microbiome Is Associated With Rupture of Cerebral Aneurysms.

BACKGROUND AND PURPOSE: Environmental factors are important with respect to the rupture of cerebral aneurysms. However, the relationship between the gut microbiome, an environmental factor, and aneurysm rupture is unclear. Therefore, we compared the gut microbiome in patients with unruptured intracranial aneurysms (UIAs) and ruptured aneurysms (RAs) to identify the specific bacteria causing the rupture of cerebral aneurysms. METHODS: A multicenter, prospective case-control study was conducted over one year from 2019 to 2020. The fecal samples of patients with stable UIAs and RAs immediately after onset were collected. Their gut microbiomes were analyzed using 16S rRNA sequencing. Subsequently, a phylogenetic tree was constructed, and polymerase chain reaction was performed to identify the specific species. RESULTS: A total of 28 RAs and 33 UIAs were included in this study. There was no difference in patient characteristics between RAs and UIAs: age, sex, hypertension, dyslipidemia, diabetes status, body mass index, and smoking. No difference was observed in alpha diversity; however, beta diversity was significantly different in the unweighted UniFrac distances. At the phylum level, the relative abundance of Campylobacter in the RA group was larger than that in the UIA group. Furthermore, the gut microbiome in the RA and UIA groups exhibited significantly different taxonomies. However, Campylobacter was focused on because it is widely known as pathogenic among these bacteria. Then, a phylogenetic tree of operational taxonomic units related to Campylobacter was constructed and 4 species were identified. Polymerase chain reaction for these species identified that the abundance of the genus Campylobacter and Campylobacter ureolyticus was significantly higher in the RA group. CONCLUSIONS: The gut microbiome profile of patients with stable UIAs and RAs were significantly different. The genus Campylobacter and Campylobacter ureolyticus may be associated with the rupture of cerebral aneurysms.

An increase in the posterior subarachnoid space accelerates the timing of syrinx resolution after foramen magnum decompression of type I Chiari malformation.

Syrinx resolution has been associated with an increase in the size of the posterior subarachnoid space (pSAS) after foramen magnum decompression (FMD) for type I Chiari malformation (CM1). The present study investigated the influence of pSAS increase on syrinx resolution and symptom improvement after FMD. 32 patients with CM1 with syrinx were analyzed retrospectively. FMD was performed for the 24 patients with CM1 with syrinx. pSAS areas were measured on sagittal magnetic resonance images. Neurological symptoms were grouped into three clinical categories and scored. The rates of symptom improvement in the CM1 patients with syrinx after FMD was 19.7% ± 12.9%. The mean times to the improvement of neurological symptoms in CM1 patients with syrinx after FMD was 23.4 ± 50.2 months. There were no significant differences between the patients with and without improvement of syrinx after FMD with regard to the age, length of tonsillar herniation, BMI, and preoperative pSAS areas. The rate of increase in the pSAS areas was significantly higher in the group with syrinx improvement within 1 year (p < 0.0001). All patients with a > 50% rate of increase in the pSAS area showed syrinx improvement. Our results suggested that the increasing postoperative pSAS area accelerated the timing of syrinx resolution.

Ophthalmic Artery Flow Pattern-related Stump Pressure and Ischemic Tolerance during Balloon Test Occlusion of the Internal Carotid Artery.

Very few studies have described the blood flow pattern in the ipsilateral ophthalmic artery (OphA) during internal carotid artery (ICA) balloon test occlusion performed to estimate the risk of cerebral ischemia associated with therapeutic ICA sacrifice. This study aimed to investigate the relationship between ipsilateral OphA flow patterns just after ICA temporary occlusion and balloon test occlusion findings. We retrospectively reviewed 32 balloon test occlusion procedures performed at our institution between 2010 and 2019, and analyzed the OphA flow patterns and the conventional balloon test occlusion assessment items: neurological symptoms, stump pressure, stump-pressure ratio, collateral circulations, and venous phase delay. The flow patterns were categorized as type I (retrograde flow reaching the middle cerebral artery [MCA]), type II (retrograde flow to the ICA not reaching the MCA), or type III (no retrograde flow). Tolerance to balloon test occlusion was observed in 4/21 patients (19.0%), 4/6 patients (66.7%), and all five patients with types I, II, and III flows, respectively. The mean pressure ratios during balloon test occlusion in flow types I, II, and III were 35.6% ± 3.5%, 56.4% ± 6.5%, and 69.4% ± 7.1%, respectively (P <0.001). The mean stump pressures in flow types I, II, and III were 36.2 ± 3.6 mmHg, 46.6 ± 6.7 mmHg, and 66.6 ± 7.3 mmHg, respectively (P = 0.003). The mean venous phase delay in flow types I, II, and III were 0.99 ± 0.14 s, 0.25 ± 0.25 s, and 0.0 ± 0.28 s, respectively (P = 0.004). All the above variables showed significant flow-related differences. These results suggest that the OphA flow patterns may provide an additional diagnostic criterion for balloon test occlusion.

Transnasal flow reduction in endovascular treatment for anterior cranial fossa dural arteriovenous fistula.

Transarterial embolization (TAE) is a useful option for anterior cranial fossa-dural arteriovenous fistula (ACF-dAVF) as endovascular devices have progressed. Liquid agents are usually injected via a microcatheter positioned just proximal to the shunt pouch beyond the ophthalmic artery; however, high blood flow from the internal maxillary artery (IMA) often impedes penetration of embolic materials into the shunt pouch. Therefore, reducing blood flow from the IMA before embolization can increase the success rate. In the present case, to reduce blood flow from branches of the IMA, we inserted surgical gauze infiltrated with xylocaine and epinephrine into bilateral nasal cavities. Using this method, we achieved curative TAE with minimal damage to the nasal mucosa. Transnasal flow reduction is an easy, effective and minimally invasive method. This method should be considered in the endovascular treatment of ACF-dAVF, especially in patients with high blood flow from theIMA.

Sphenoid Ridge Keyhole Approach Using the Lone Star Retractor System in Clipping of Unruptured Middle Cerebral Artery Aneurysms: Technical Note.

BACKGROUND: We report a technique for the sphenoid ridge keyhole approach using the Lone Star (LS) retractor system as an extracranial tissue retractor in microsurgical clipping of unruptured middle cerebral artery aneurysms. METHODS: The LS retractor system is used as the extracranial tissue retractor. A skin incision (50-60 mm) without shaving is made. The temporal fascia is cut, and skin and fascia flap are reflected anteriorly. On the temporal muscle, keyhole craniotomy is registered using the navigation system such that the lateral edge of the sphenoid ridge is the center of the craniotomy. After the temporal muscle is split in the direction of the muscle fiber, keyhole craniotomy of approximately 30 mm in diameter is created. After dural incision, the Sylvian fissure is dissected by a standard microsurgical technique using brain retractors, and the target aneurysm is clipped. RESULTS: By precise registration of the sphenoid ridge keyhole craniotomy, the Sylvian fissure emerged in the center of the keyhole. Using the LS retractor system, a flat and shallow operative field was obtained. There were no complications using this method. CONCLUSIONS: We optimized the craniotomy, manipulating the target aneurysm in the center of the keyhole. It did not interfere with conventional microsurgical techniques.

Conservative and Surgical Management of Spinal Cord Cavernous Malformations.

OBJECTIVES: We present a case series of spinal cord cavernous malformations (SCCMs) to describe clinical presentation and outcomes of both surgical and conservative management. METHODS: The clinical courses of patients diagnosed with SCCMs at our institution were retrospectively reviewed. Neurologic symptoms were evaluated using the Modified McCormick Scale. RESULTS: A total of 18 patients were identified. Five patients (27.8%) presented with acute onset bleeding, 4 of whom underwent immediate surgical resection. Thirteen patients (72.2%) were initially managed conservatively. Eight patients (38.9%) developed a hemorrhage during follow-up, and 8 (38.9%) required surgical resection due to bleeding or neurological worsening. The mean (range) duration from primary symptoms to subsequent hemorrhage or deterioration of symptoms was 1.42 (range: 0.25-4.33) years. The mean duration from primary symptoms to surgery was 2.10 (range: 0.25-5.0) years. No patients experienced subsequent hemorrhage after surgical resection. Eleven patients (84.6%) in the surgery group showed improved neurological status, and 2 patients (15.4%) remained unchanged. The annualized subsequent hemorrhage risk was 3.7%. Patients in the immediate surgical group had a significantly larger lesion compared with those in the conservative group. There was significance between the worst Modified McCormick Scale grades at the time of debilitating symptoms and the length of hemorrhage, but not the size of the lesion. CONCLUSIONS: Surgery for SCCMs resulted in no recurrence of hemorrhage or exacerbation of neurological symptoms, and should be considered for patients who experienced acute onset of hemorrhage or debilitating symptoms during follow-up.

Freehand Technique of an Electromagnetic Navigation System Emitter to Avoid Interference Caused by Metal Neurosurgical Instruments.

BACKGROUND: Electromagnetic (EM) navigation has been reported to be a noninvasive and easy-to-use technique. However, the use of metal neurosurgical instruments (e.g., skin hooks, head frames, brain retractors systems) can interfere with the magnetic fields of such systems. We present the freehand technique, a new technique involving the manual manipulation of the emitter of an EM navigation system, which helps to prevent interference caused by metal instruments during surgery. METHODS: The AxiEM Electromagnetic StealthStation Navigation System (Medtronic) was used in this study. The emitter was placed in the sterilized surgical field, which allowed it to be moved freely during surgery. When navigation was necessary during the procedure, the assistant held the emitter at an appropriate angle to the sterile surgical field to avoid interference caused by the metal neurosurgical instruments. RESULTS: During surgery involving metal surgical instruments, all of the functions of the EM navigation system were available throughout the procedure. The accuracy of the navigation system was sufficient to allow craniotomy and intradural manipulation to be conducted. CONCLUSIONS: During the use of EM navigation systems, the freehand technique with the emitter can prevent interference caused by metal instruments.

A case of T2 radiculopathy after anterior C5-6 fusion.

Thoracic radiculopathy is a rare entity. Symptomatic adjacent-segment disease after anterior cervical fusion occurs commonly in the lower cervical spine segment. We describe the clinical presentation and treatment of T2 radiculopathy after C5-6 anterior fusion. A 60-year-old man presented with the right axillary pain for 3 months. He had undergone C5-6 anterior fusion for cervical spondylosis 5 years prior. Computed tomography (CT) and magnetic resonance images showed T2-3 degenerative disease. C5-6 anterior fusion exacerbated the T2-3 segment involved in the patient's scoliotic deformity. After 2 months of conservative treatment, we decompressed the T2 foramen via T2-3 hemilaminectomy and partial facet resection. After the surgery, his symptoms disappeared. T2 radiculopathy is rare but should be considered in the differential diagnosis of chest pain. Surgeons should pay attention not only to adjacent-segment disease but also to segmental degeneration at the apex of a scoliotic deformity after cervical anterior fusion.

Disproportionately Enlarged Subarachnoid Space Hydrocephalus in Idiopathic Normal-Pressure Hydrocephalus and Its Implication in Pathogenesis.

Idiopathic normal-pressure hydrocephalus (iNPH) has become socially significant in Japan. Japanese guidelines for iNPH in 2011 described the diagnostic importance of "disproportionately enlarged subarachnoid space hydrocephalus" (DESH) on magnetic resonance imaging (MRI). However, some patients with iNPH have equivocal or no features of DESH. To clarify the diversity of MRI findings in iNPH, we classified iNPH into three types based on MRI findings. Using this, we investigate predictable MRI findings for shunt effectiveness in iNPH. A total of 83 patients with suspected iNPH who were treated with shunt surgery were reviewed in this study. All patients had a positive cerebrospinal fluid (CSF) tap test. Among the 83 patients, DESH was noted in 64 %, incomplete DESH in 23 %, and no DESH in 13 % (see Fig. 3). Among the three types of incomplete DESH, incomplete DESH-v (ventricle) was 0 %, DESH-c (convexity) in 13 %, and DESH-s (Sylvian fissure) in 10 %. A high improvement rate after the shunt surgery was noted in the DESH and incomplete DESH-s groups, showing 73.5 % and 87.5 %, respectively. The non-DESH group showed a fairly large improvement of 63.6 %. A common MRI finding in DESH and incomplete DESH-s was high convexity tightness with ventriculomegaly. This combination was promising for shunt effectiveness in patients with suspected iNPH. Further study is necessary to elucidate the pathogenesis.