Exertional Vertebrobasilar Insufficiency 6 Years after Vertebral Artery Dissection Treated with Occipital Artery-posterior Inferior Cerebellar Artery Anastomosis.

Exertional vertebrobasilar insufficiency (VBI) secondary to the non-atherosclerotic cause is uncommon. We herein report the case of a patient who developed exertional VBI long after extracranial right vertebral artery (VA) dissection. At the time of dissection, the right VA was completely occluded near its origin, but the distal flow was compensated by the collateral flow from the right deep cervical artery (DCA). After conservative management, the patient was discharged without neurologic deficit. Six years later, he developed recurrent VBI in association with the exertion of his right shoulder. A vascular evaluation revealed that the right proximal VA was still occluded, and there was no evidence of right subclavian artery lesions. The intracranial right VA flow was markedly reduced during the period, while branches of the right DCA were given off to the muscles of the right shoulder and neck. Then, occipital artery (OA)-posterior inferior cerebellar artery (PICA) anastomosis was performed. Intraoperative indocyanine green videoangiography (ICG) confirmed that the flow of the right PICA was predominantly supplied from the compensatory flow from the contralateral VA, and the antegrade flow in the right VA was clearly delayed in comparison to that of the left VA while there were prominent branches providing the blood flow to the medulla oblongata. After the anastomosis, these medullary branches provided the blood flow to the medulla oblongata more quickly and extensively than before. Postoperatively, VBI no longer occurred even after exertion. Surgical revascularization can be a viable option in the treatment of refractory VBI of the non-atherosclerotic cause.

A Comprehensive Analysis of Dural Arteriovenous Fistula Involving the Superior Sagittal Sinus: A Systematic Review.

Objective: To evaluate published papers concerning dural arteriovenous fistula involving the superior sagittal sinus (SSS dAVF) treated with endovascular intervention. Methods: A literature review was performed to identify studies reporting the clinical characteristics, vascular anatomy, endovascular techniques, embolic materials, angiographical result, and outcomes of SSS dAVF. Results: The analysis consisted of 40 case reports or series, comprising a total of 51 cases of SSS dAVF treated with endovascular intervention. Clinical symptoms included hemorrhage (29.4%), infarction (17.6%), and seizure (7.8%). The arterial supply included the middle meningeal artery (MMA) (100%), superficial temporal artery (STA) (62.7%), and occipital artery (OA) (49.0%). Bilateral MMAs supplied in 78.4% of the cases. A pial arterial supply was observed in 21.6% of the cases. Stenosis or occlusion of the sinus was seen in 37.3% of the cases. The distribution of the Borden classification was as follows: I (7.8%), II (37.3%), and III (54.9%). The endovascular techniques were transvenous embolization (TVE) alone (11.8%), transarterial embolization (TAE) alone (74.5%), and a combination thereof (13.7%). The types of embolic materials for TAE were a coil (25.5%), n-butyl-2-cyanoacrylate (NBCA) (33.3%), and Onyx (45.1%). The arterial pedicles for TAE included MMA (86.3%), STA (17.6%), and OA (9.8%). Direct surgical exposure for the alternative endovascular access was performed to the SSS (5.9%), MMA (3.9%), STA (5.9%), and OA (3.9%). Sinus angioplasty with or without stenting was done in 9.8% of the cases. Balloon-assisted Onyx TAE was done with proximal flow control (7.8%), collateral devascularization (5.9%), and sinus protection (3.9%). Complete occlusion was achieved in 86.3% of the cases while the number of endovascular sessions varied among patients: single (74.5%), double (15.7%), and triple (9.8%). The rate of a postoperative modified Rankin Scale (mRS) score of 0-2 was 89.3%, with morbidity and mortality rates of 7.8% and 3.9%, respectively. Two patients died, possibly due to postoperative acute SSS occlusion. Conclusion: The current systematic review disclosed several specific results, namely, the angioarchitectures of the SSS dAVF, the relationship between classification and hemorrhagic presentation, the diversity of treatment techniques, the association between the complete occlusion rate and the SSS condition, and the difficulty of achieving curable occlusion in a single session. These findings underscore the need for the development of endovascular techniques and devices to treat this challenging lesion. Improvements in adjunctive endovascular procedures, such as balloon-assisted techniques for Onyx TAE, may help support to the safe and effective obliteration of SSS dAVF.

Balloon-assisted Onyx Embolization in the Management of Complicated Dural Arterioevenous Fistula.

Objective: Dural arteriovenous fistula (dAVF) is an abnormal vascular communication between the meningeal artery and vein at the dura mater, with frequent recruitment of collateral arterial pedicles. In recent years, Onyx embolization has become the mainstay intervention for dAVF at various locations, although an unfavorable vascular anatomy often limits effective obliteration of the lesion. Balloon assistance may facilitate curable occlusion of the abnormal shunt with Onyx while preserving the patency of the affected sinus, even in complicated dAVFs. Methods: We retrospectively reviewed the clinical and angiographic findings of patients with dAVF treated endovascularly in our institution between September 2018 and August 2019. Based on the detailed analysis of individual angioarchitecture, we defined complicated dAVF as lesions for which a complete cure is considered difficult to achieve with simple transarterial Onyx embolization alone, primarily due to a high flow and/or diffuse shunt with or without drainage to the functioning but compromised sinus. We evaluated the preoperative symptoms, anatomical classification, endovascular procedure, radiologic results, and clinical outcomes of these patients. Results: Five patients met our criteria, all of whom were treated with balloon-assisted Onyx embolization (two superior sagittal sinus dAVF, two transverse-sigmoid sinus dAVF, and one torcular dAVF). In four cases, Onyx was injected from a tiny branch of the middle meningeal artery under balloon occlusion of the collateral arteries or balloon devascularization of the competitive inflow. In three cases, balloon sinus protection was performed to prevent the inadvertent occlusion of the vital venous outflow with Onyx. In one case, for the complementary occlusion of the remnant shunt through the previously coiled but recanalized occipital artery, Onyx was injected from the wire lumen of a dual-lumen balloon catheter to avoid undesirable reflux. The angiographic results were an anatomical cure in four cases and near-complete occlusion in one case. No procedural complications were observed in any cases. The clinical outcome was a complete cure in four cases and improvement in one case. Conclusion: Our cases suggest that balloon devascularization can improve the unfavorable flow environment and simplify the vascular anatomy. Balloon sinus protection can support not only securing the patency of the normal venous outflow but also encourage aggressive intervention. Onyx injection via a dual-lumen balloon catheter can augment the controllability of embolization while preventing reflux. Each of these techniques can facilitate safe and effective Onyx embolization in the treatment of complicated dAVFs, and their combination may further expand the therapeutic horizon.

Mechanical thrombectomy utilising a collateral pathway in a patient with dysgenesis of the internal carotid artery.

We describe a case of acute middle cerebral artery occlusion in a patient with ipsilateral internal carotid artery dysgenesis successfully treated with mechanical thrombectomy utilising a collateral pathway. During the procedure, a triaxial system using a balloon guiding catheter, flexible large lumen aspiration catheter and stent retriever was advanced from the left vertebral artery to the occluded left middle cerebral artery through the left posterior communicating artery. Because proximal aspiration from the balloon guiding catheter alone might have insufficient suction force due to the retrograde blood flow from large vascular communications (e.g. vertebral artery union), the tip of the flexible large lumen aspiration catheter was set at the proximal left middle cerebral artery, and distal aspiration was added during stent retrieval. A thrombolysis in cerebral infarction 2b result was achieved after the first pass. In this case, identification of carotid canal hypoplasia on computed tomography allowed for an immediate attempt of this alternative approach, avoiding a delay in the time to reperfusion.

Aquaporin Positron Emission Tomography Differentiates Between Grade III and IV Human Astrocytoma.

BACKGROUND: Aquaporin (AQP) water channels play a significant role in mesenchymal microvascular proliferation and infiltrative growth. AQPs are highly expressed in malignant astrocytomas, and a positive correlation is observed between their expression levels and histological tumor grade. OBJECTIVE: To examine the utility of aquaporin positron emission tomography (PET) for differentiating between astrocytoma grade III and grade IV using the AQP radioligand [11C]TGN-020. METHODS: Fifteen astrocytoma patients, grade III (n = 7) and grade IV (n = 8), and 10 healthy volunteers underwent [11C]TGN-020 aquaporin PET imaging. Surgical tissues of astrocytoma patients were examined for histopathological grading using the WHO classification standard and expression of AQP1 and AQP4 immunohistochemically. RESULTS: Mean standardized uptake values of astrocytoma grade III and IV (0.51 ± 0.11 vs 1.50 ± 0.44, respectively) were higher than normal white matter (0.17 ± 0.02, P < .001) for both tumor grades. Importantly, mean standardized uptake values of astrocytoma grade IV were significantly higher than grade III (P < .01). CONCLUSION: Our study demonstrated that [11C]TGN-020 aquaporin PET imaging differentiated between astrocytoma grades III and IV. We suggest its clinical application as a noninvasive diagnostic tool would lead to advancements in the management of these malignant brain tumors.

Evidence for cerebellar motor functional reorganization in brain tumor patients: An fMRI study.

Functional reorganization of the motor system following brain damage has been studied extensively in stroke patients, in which not only the cerebrum but also the cerebellum (Cbll) undergoes substantial reorganization. However, the role of Cbll in motor functional reorganization in brain tumor patients remains poorly investigated. Because brain damages in brain tumor patients occur much more slowly than in stroke patients, the neural mechanisms for motor functional reorganization might differ between these two disease conditions. This functional magnetic resonance imaging (fMRI) study investigated whether Cbll constitutes the neural substrates for motor functional reorganization in eighteen supratentorial brain tumor patients who exhibited no clinical signs of paresis. The patients and normal volunteers underwent a unilateral hand movement task. In the patients, the locus of primary sensory motor (SM1) activation during contralesional hand movement was significantly displaced by the tumor, suggesting functional compromise and/or reorganization in the central sulcus region. In addition, their contralesional Cbll activation during contralesional hand movement was substantially increased as compared to normal controls. The finding represents the first conclusive evidence that Cbll is involved in the motor-related functional reorganization in patients with brain tumor.

The Posterior Limb of the Internal Capsule as the Subcortical Transitional Zone of the Anterior and Posterior Circulations: Insights from Human 7T MRI.

BACKGROUND: In patients with cerebral infarction, identifying the distribution of infarction and the relevant artery is essential for ascertaining the underlying vascular pathophysiological mechanisms and preventing subsequent stroke. However, visualization of the basal perforating arteries (BPAs) has had limited success, and simultaneous viewing of background anatomical structures has only rarely been attempted in living human brains. Our study aimed at identifying the BPAs with 7T MRI and evaluating their distribution in the subcortical structures, thereby showing the clinical significance of the technique. METHODS: Twenty healthy subjects and 1 patient with cerebral infarction involving the posterior limb of the internal capsule (ICpost) and thalamus underwent 3-dimensional fast spoiled gradient-echo sequence as time-of-flight magnetic resonance angiography (MRA) at 7T with a submillimeter resolution. The MRA was modified to detect inflow signals from BPAs, while preserving the background anatomical signals. BPA stems and branches in the subcortical structures and their origins were identified on images, using partial maximum intensity projection in 3 dimensions. RESULTS: A branch of the left posterior cerebral artery (PCA) in the patient ran through both the infarcted thalamus and ICpost and was clearly the relevant artery. In 40 intact hemispheres in healthy subjects, 571 stems and 1,421 branches of BPAs were detected in the subcortical structures. No significant differences in the numbers of stems and branches were observed between the intact hemispheres. The numbers deviated even less across subjects. The distribution analysis showed that the subcortical structures of the telencephalon, such as the caudate nucleus, anterior limb of the internal capsule, and lenticular nucleus, were predominantly supplied by BPAs from the anterior circulation. In contrast, the thalamus, belonging to the diencephalon, was mostly fed by BPAs from the posterior circulation. However, compared with other subcortical structures, the ICpost, which marks the anatomical boundary between the telencephalon and the diencephalon, was supplied by BPAs with significantly more diverse origins. These BPAs originated from the internal carotid artery (23.1%), middle cerebral artery (38.5%), PCA (17.3%), and the posterior communicating artery (21.1%). CONCLUSIONS: The modified MRI method allowed the detection of the relevant BPA within the infarcted area in the stroke survivor as well as the BPAs in the subcortical structures of living human brains. Based on in vivo BPA distribution analyses, the ICpost is the transitional zone of the anterior and posterior cerebral circulations.

Expansion of sensorimotor cortical activation for unilateral hand motion during contralateral hand deafferentation.

Acute deprivation of unilateral sensory input rapidly enhances contralateral hand motor function, but the underlying mechanisms remain poorly understood. We herein used functional MRI to evaluate, in 14 healthy individuals, motor cortical activation for right finger motion before, during, and after sensory deprivation of left forearm induced by reversible, noninvasive ischemic nerve block (INB). Before INB, the motor task activated the left primary sensorimotor cortex (SM1) as expected. During INB, the volume of the left SM1 activation significantly increased, and, after INB, it returned to the pre-INB, baseline level. The effectiveness of the INB of the left forearm was ensured by confirming disappearance of the activation in right primary sensory cortex that is normally caused by tactile stimulation of the left index finger. These findings demonstrate that acute deafferentation of unilateral forearm causes rapid and reversible changes in the neural substrates for contralateral finger motion, mediated possibly by attenuation of transcallosal interhemispheric inhibition.

Efficacy and safety of postoperative early mobilization for chronic subdural hematoma in elderly patients.

BACKGROUND: The incidences of chronic subdural hematoma (CSDH) will probably increase with the aging of the population; thus, postoperative care of elderly CSDH patients may play a more important role in surgical management. The aim of this study was to evaluate the efficacy of and adverse effects after postoperative early mobilization (EM) for elderly CSDH patients. METHODS: This is a single-institution historical control study. One hundred eighty-two patients with CSDH aged 65 years and older underwent one burr-hole surgery between 2001 and 2008. This institution has prospectively conducted an EM protocol after surgery since 2005. The emphasis of the EM was helping patients not only to an upright position but also to walk beginning the day of operation. The incidences of postoperative complications and recurrence of CSDH were compared between the EM group (n = 91; 76.5 +/- 6.5 years old) and a delayed mobilization (DM) group (n = 91; 77.9 +/- 7.5 years old). RESULTS: Postoperative complications, such as pneumonia and urinary tract infection, was observed in 24 (26.4%) in the DM group and 11 (12.1%) in the EM group (p < 0.05). The rate of recurrence did not differ between the two groups (6.6% and 8.8%, respectively; p = 0.58). CONCLUSIONS: The results suggest that EM after one burr-hole surgery prevents postoperative complications without increasing the risk of recurrence in CSDH patients > or =65 years of age.

Low birth weight as a risk factor for seizure following acute subdural hematoma.

PURPOSE: The purpose of this study is to determine the factors associated with posttraumatic seizure in patients under 2 years old with acute subdural hematoma (ASDH). METHODS: Twenty-one patients under 2 years old (15 males and six females) with ASDH, who were admitted to our hospital between January 2002 and September 2008, were studied retrospectively. Clinical findings including birth weight and gestational age were defined. A head computed tomography scan was conducted at admission. Outcome at time of discharge was assessed using the score. RESULTS: Seizures occurred in eight patients (38%). Recurrent seizures occurred in three of eight patients (38%). In patients with seizures, birth weight, gestational age, and birth weight ratio were significantly lower than for those without seizure (p < 0.05). CONCLUSIONS: Special attention should be paid to infants with ASDH who have a history of low birth weight, low gestational age, and low birth weight ratio because risk for posttraumatic seizure is considered higher in these infants than in other infants.