Bridging veins at the craniocervical junction: from anatomy to clinical significance in dural arteriovenous shunts.

PURPOSE: Bridging veins (BVs) serve as a route of pial venous reflux, and its anatomy is essential to understand the pathophysiology of dural arteriovenous shunts (dAVSs) around the craniocervical junction (CCJ) (from the jugular foramen level to the atlantal level). However, the anatomical variations of the BVs and their proximal connections remained poorly elucidated. This study aimed to radiologically investigate the anatomy of the bridging veins around CCJ and discuss the clinical significance of these BVs in the dAVS. METHODS: We investigated normal venous anatomy of the BVs from the jugular foramen level to the atlantal level using preoperative computed tomography digital subtraction venography in patients undergoing elective neurosurgery. BVs affected by the dAVSs in the same region were also evaluated. The three types of dAVS, craniocervical junction, anterior condylar, and proximal sigmoid sinus, were investigated. RESULTS: We identified six BV groups: superolateral, anterolateral, lateral, posterior, inferolateral, and inferoposterior. The superolateral and inferolateral groups, connected with the proximal sigmoid sinus and suboccipital cavernous sinus, respectively, were the largest groups. Each group has a specific downstream venous connection. The association with dVASs was observed only in the inferolateral group, which was typically the sole venous drainage in most dAVSs at the CCJ. CONCLUSION: We reported detailed anatomy of BVs from the jugular level to the atlantal level, which enhanced our understanding of the pathophysiology of dAVSs in the corresponding region.

Exploration of postural effects on the external jugular and diploic venous system using upright computed tomography scanning.

PURPOSE: Few studies have investigated the influence of posture on the external jugular and diploic venous systems in the head and cranial region. In this study, we aimed to investigate the effects of posture on these systems using upright computed tomography (CT) scanning. METHODS: This study retrospectively analysed an upright CT dataset from a previous prospective study. In each patient, the diameters of the vessels in three external jugular tributaries and four diploic veins were measured using CT digital subtraction venography in both supine and sitting positions. RESULTS: Amongst the 20 cases in the original dataset, we eventually investigated 19 cases due to motion artifacts in 1 case. Compared with the supine position, most of the external jugular tributaries collapsed, and the average size significantly decreased in the sitting position (decreased by 22-49% on average). In contrast, most of the diploic veins, except the occipital diploic veins, tended to increase or remain unchanged (increased by 12-101% on average) in size in the sitting position compared with the supine position. However, the changes in the veins associated with this positional shift were not uniform; in approximately 5-30% of the cases, depending on each vein, an opposite trend was observed. CONCLUSION: Compared to the supine position, the contribution of external jugular tributaries to head venous drainage decreased in the sitting position, whilst most diploic veins maintained their contribution. These results could enhance our understanding of the physiology and pathophysiology of the head region in upright and sitting positions.

"Missing-piece" sign with dural arteriovenous fistula at craniocervical junction: A case report.

OBJECTIVES: Spinal dural arteriovenous fistula (sDAVF) is a rare and often underdiagnosed spinal disease. Early diagnosis is required because the deficits are reversible and delays in treatment cause permanent morbidity. Although the abnormal vascular flow void is a critical radiographic feature of sDAVF, they are not always present. A characteristic enhancement pattern of sDAVF has been recently reported as the "missing-piece" sign which can lead to the early and correct diagnosis. METHODS: We presented imaging findings, treatment decisions, and the outcome of a rare case of sDAVF, in which the "missing-piece" sign appeared atypical. RESULTS: A 60-year-old woman developed numbness and weakness in her extremities. Spinal MRI revealed longitudinal hyperintensity in the T2-weighted image, extending from the thoracic level to medulla oblongata. At first, myelopathy with inflammation or tumor was suspected because of the lack of flow voids and vascular abnormalities in CT-angiography and MR-DSA. However, we administered intravenous methylprednisolone and her symptom got worse with the appearance of the "missing-piece" sign. Then, we successfully diagnosed sDAVF by angiography. The "missing-piece" sign was considered to derive from inconsistency of the intrinsic venous system of spinal cord, with the abrupt segments without enhancement. The same etiology was considered in our case. CONCLUSIONS: Detecting the "missing-piece" sign can lead to the correct diagnosis of sDAVF, even if the sign appeared atypical.

Treatment-resistant diabetic chorea manifesting with psychiatric symptoms: a case report.

We report a case of a 69-year-old man with treatment-resistant diabetic chorea presenting psychiatric symptoms. The right chorea lasted for 3 months and was refractory to control of diabetes mellitus or administration of haloperidol and benzodiazepines. Only administration of tiapride was efficacious. Magnetic resonance spectrometry and dopamine transporter-single photon emission computed tomography suggested that sustained ischemia at the striatum may lead to impaired expression of dopamine transporters, thereby resulting in deterioration in the indirect pathway. Tiapride inhibited dopamine D2 receptors, thereby restoring the function of the indirect pathway and resulting in improvement of diabetic chorea.

Clinical Effectiveness of Mirogabalin Besylate for Trigeminal Neuropathy after Skull Base Surgery: Illustrative Cases.

BACKGROUND: Postoperative trigeminal neuropathy may be seen after surgery for middle and posterior cranial fossa lesions. Although neuropathic pain is a cause of reduced quality of life, global consensus on postoperative pain management is lacking. Mirogabalin besylate is a selective ligand for the α2δ subunit of voltage-gated calcium channels. Although mirogabalin has been used for patients with postherpetic neuralgia and painful diabetic peripheral neuropathy, few reports have assessed the effect on postsurgical neuropathy. In this report, we describe a clinical effectiveness of mirogabalin for trigeminal neuropathy after skull base surgery. CASE DESCRIPTION: Case 1: A 51-year-old female with right trigeminal schwannoma was operated on via the anterior transpetrosal approach. She had tingling and numb feelings in the right face postoperatively. Mirogabalin was orally administered after the operation. Her continuous facial numbness immediately improved. Case 2: A 55-year-old female with left middle fossa base meningioma extending into the infratemporal fossa was operated on via the infratemporal fossa approach. She had a tingling feeling in the left face postoperatively. Mirogabalin was orally administered for this symptom after the operation, which gradually improved. CONCLUSIONS: Mirogabalin may show significant pain relief for patients with trigeminal neuropathy after skull base surgery. Further studies using a larger number of patients are warranted to confirm these findings.

Case report: meningeal lymphangiogenesis around ependymoma forming along the dura matter.

Recently, there has been growing interest in the presence and function of meningeal lymphatic vessels, with no direct evidence linking these vessels to primary brain tumors. We report a unique case of recurrent ependymoma in the dura mater, showing histopathological signs of lymphatic proliferation at the tumor attachment site. The patient initially presented with a headache, and was diagnosed with ZFTA fusion-positive supratentorial ependymoma, central nervous system WHO Grade 3. Following multiple dura mater recurrences and surgery, the fifth procedure revealed numerous tumors contralateral to the original site, with genetic testing confirming ZFTA fusion positivity, indicating recurrent ependymoma. Immunohistochemical analysis showed D2-40+ lymphatic vessel proliferation around tumor attachment sites within the dura mater. Elevated expression of ZEB1, which is an epithelial-to-mesenchymal transition factor, was also observed, implicating potential involvement in the unique pathophysiology. The present case suggests a new process of metastasis through meningeal lymphatic vessels, although we were unable to visually confirm tumor cell infiltration into the lymphatic vessels. This case is the first report suggesting ependymoma metastasis through dural lymphatic vessels, underlining the need for further case accumulation and study to understand the mechanisms of this phenomenon.

Role of Endovascular Approach as Diagnostic Technique and First-Line Therapy for the Patients with Micro-Arteriovenous Malformations: A Case Report and Literature Review.

Objective: We describe a rare case report of micro-arteriovenous malformation (micro-AVM) treated by the endovascular approach in addition with literature review. Case Presentation: A 12-year-old boy presenting with a spontaneous intracerebral hematoma in the left occipital lobe underwent conventional diagnostic workups. The results of initial catheter angiography were considered to be equivocal as the AVM. Superselective angiography (SA) demonstrated a micro or small AVM (single feeder and single drainer type) with an aneurysmal dilatation. Immediate transarterial embolization (TAE) might fail to occlude the whole of nidus area completely, and subsequently, we switched to the surgical exploration of AVM lesion. Intraoperative findings demonstrated that the whole of AVM lesion had already been occluded completely, indicating the complete occlusion by TAE only. Pathological findings of the surgical specimen showed an aneurysmal dilatation was a venous aneurysm with vulnerable vascular wall structure, which was certainly the source of bleeding. Based on the above results, the retrospective revaluation of superselective angiogram permitted us to understand that the nidus of AVM was micro nidus type and TAE had resulted in the complete nidus occlusion. Conclusion: SA is the most useful diagnostic modality to clarify the angioarchitecture of micro-AVM and AVM-related aneurysms. If SA is successfully performed and relatively safe TAE is expected to be possible, the subsequent attempt to do curative embolization as a first-line treatment may be worthy of consideration. However, the surgical procedure should be fully reserved for the possible incomplete obliteration and hemorrhagic complications.

Acute Subdural Hematoma Complicating Heparin-induced Thrombocytopenia: A Case Report.

Heparin-induced thrombocytopenia (HIT) is an antibody-mediated drug reaction to heparin use that causes platelet aggregation, followed by thrombocytopenia. Despite the thrombocytopenia, the main complications of HIT are thromboembolic in nature rather than hemorrhagic, and in particular, intracranial hemorrhage is rare. Herein, we describe a case of atraumatic acute subdural hematoma secondary to HIT, which was treated by platelet transfusion and surgery. A 77-year-old woman was admitted to our hospital for the treatment of severe aortic valve stenosis. Unfractionated heparin was administered during the preoperative period and during the aortic valve replacement surgery. Three days after the cardiac surgery, the patient presented with coma consistent with an acute subdural hematoma in the posterior fossa and obstructive hydrocephalus. Laboratory examination revealed a marked decrease of the platelet count to 40000/µL, and subsequent serological assay confirmed the diagnosis of HIT. The patient was treated by transfusion of platelets and fresh frozen plasma, and surgical removal of the hematoma. We started the administration of argatroban for substitution of heparin 4 days after the craniotomy. On day 13 after the neurosurgery, the patient developed cerebral infarction due to left middle cerebral artery occlusion and persistent right hemiparesis. We presented a rare case of the patient who developed acute subdural hematoma complicating HIT. Emergency craniotomy was successfully performed after administering platelet transfusions. Our experience with the present case suggests that platelet transfusions may be effective for performing emergency surgery for intracranial hemorrhage, even in patients with HIT.

Inter-patient and Intra-tumor Heterogeneity in the Sensitivity to Tumor-targeted Immunity in Colorectal Cancer.

  Efficacy of immune checkpoint inhibitors such as PD-1 antibody for colorectal cancer remains to be proved except in microsatellite-instability-high (MSI-H) cases. While the objective response rate of MSI-H cases was 40%, that of microsatellite-stable (MSS) cases was 0%, showing that response rate to immune checkpoint inhibitors varies even among the microsatellite status. Some possible mechanisms that confer each patient variation in the response to immunotherapy should be considered. We focused on the combination of inter-patient heterogeneity and intra-tumor heterogeneity as a determining factor of immune reaction. An example of intra-tumor heterogeneity is the low expression of tumor antigen by CD271+ cells in melanoma. It is not surprising that similar mechanism exists in CRC. Other related intra-tumor heterogeneity includes EMT and autophagy, both molecular mechanisms that are thought to promote immune-evading phenotype. Besides the microsatellite status, inter-patient heterogeneity in response to tumor immunity includes hypermutator phenotype, which is driven by POLE mutation, intrinsic cytokine production, and microbiota in the gut.