Yutaka Mitsuhashi

Direct surgery for spinal arteriovenous fistulas of the filum terminale with intraoperative image guidance.

Study Design. A technical case report of direct surgery for spinal arteriovenous fistulas of the filum terminale. Objective. We present 2 cases of spinal arteriovenous fistulas of the filum terminale directly fed by the anterior spinal artery that were successfully obliterated with intraoperative image guidance such as digital subtraction angiography, intra-arterial dye injection technique, or indocyanine green video angiography. Summary of Background Data. The goal of direct surgery for spinal arteriovenous fistulas is the complete obliteration of shunt vessels while preserving the normal circulation of spinal cord. Safe isolation of feeding arteries, nidus, and draining veins needs to be obtained first. Vascular flow or anatomical orientation of shunt vessels also needs to be ensured with intraoperative image guidance. Methods. Two cases are presented. The first patient (case 1) had the lesion with a nidus formation at the L2 spinal level supplied directly by the anterior spinal artery via left L1 segmental artery. The second patient (case 2) had a lesion at the L4–L5 spinal level also supplied directly by the anterior spinal artery via the left T11 intercostal artery. Standard exposure of the lesion followed intraoperative image guidance to achieve the appropriate vascular flow or anatomical orientation of the shunt vessels. Results. Complete obliteration of shunt vessels was successfully achieved without any complications in both cases. Conclusion. Although intraoperative image guidance is certainly not a prerequisite, the concept of safe and minimally invasive surgery makes it indispensable. It can facilitate identification of crucial or important landmarks where anatomic structures may be distorted.

Dural Venous System in the Cavernous Sinus: A Literature Review and Embryological, Functional, and Endovascular Clinical Considerations

The cavernous sinus (CS) is one of the cranial dural venous sinuses. It differs from other dural sinuses due to its many afferent and efferent venous connections with adjacent structures. It is important to know well about its complex venous anatomy to conduct safe and effective endovascular interventions for the CS. Thus, we reviewed previous literatures concerning the morphological and functional venous anatomy and the embryology of the CS. The CS is a complex of venous channels from embryologically different origins. These venous channels have more or less retained their distinct original roles of venous drainage, even after alterations through the embryological developmental process, and can be categorized into three longitudinal venous axes based on their topological and functional features. Venous channels medial to the internal carotid artery “medial venous axis” carry venous drainage from the skull base, chondrocranium and the hypophysis, with no direct participation in cerebral drainage. Venous channels lateral to the cranial nerves “lateral venous axis” are exclusively for cerebral venous drainage. Venous channels between the internal carotid artery and cranial nerves “intermediate venous axis” contribute to all the venous drainage from adjacent structures, directly from the orbit and membranous skull, indirectly through medial and lateral venous axes from the chondrocranium, the hypophysis, and the brain. This concept of longitudinal venous axes in the CS may be useful during endovascular interventions for the CS considering our better understandings of its functions in venous drainage.

Post-embolisation susceptibility changes in giant meningiomas: multiparametric histogram analysis using non-contrast-enhanced susceptibility-weighted PRESTO, diffusion-weighted and perfusion-weighted imaging

PurposeTo investigate imaging characteristics of post-embolised meningioma and to determine if SW imaging can delineate tumour ischaemia.Materials and methodsSixteen patients were studied before and after preoperative embolisation therapy (8 histopathologically determined with ischaemia, 8 with non-ischaemia). In each patient, a slice-wise ROI for the entire tumour was established, and histogram variables (mean, SD, minimum, maximum, histogram width, mode, and peak height) of SW, ADC, CBV, CBF, MTT, and TTP maps were compared between ischaemic and non-ischaemic groups. Changes in SW histogram were correlated with histopathological characteristics.ResultsSignal intensity on the SW map tended to decrease in the ischaemic group and partially increased in the non-ischaemic group. A similar trend was observed on the ADC map. The PW histogram showed an MTT increase in ischaemic group; however, CBV did not show significant changes between ischaemic and non-ischaemic groups. Microhaemorrhage was slightly correlated with Δpeak height in the SW histogram.ConclusionPost-embolisation changes of intrinsic T2*-weighted MR contrasts on SW map are most likely associated with alterations in deoxyhaemoglobin levels and arterial blood flow.Key Points•Endovascular embolisation is now accepted as an adjuvant therapy for intracranial meningioma.•Magnetic resonance imaging is used to assess the effects of embolisation.•Unenhanced susceptibility-weighted MRI can delineate ischaemic and non-ischaemic areas.•Signal changes at SW imaging are associated with diffusion and perfusion abnormalities.•Three-dimensional high-resolution SW imaging offers a new imaging biomarker in assessing ischaemia.

Anomalous Origin of the Anterior Choroidal Artery

We describe a very rare case of anomalous origin of the anterior choroidal artery. In our case the anterior choroidal artery arises from the internal carotid artery proximal to the posterior communicating artery.

An innovative technique for detecting the caudal end of occluded inferior petrosal sinus in cavernous arteriovenous fistula using intravascular ultrasonography—technical note

IntroductionAlthough cavernous sinus (CS) dural arteriovenous fistulas (d-AVFs) are usually treated with transvenous embolization (TVE) via the inferior petrosal sinus (IPS), IPSs are sometimes thrombosed and angiographically invisible. In such cases, the first obstacle to TVE is detecting the entry to the IPS. We report a new technique for TVE via IPS using intravascular ultrasonography (IVUS).MethodsThree consecutive cases of CS d-AVF with ipsilateral or bilateral IPS occlusion were involved in this study. On TVE, the orifice of the IPS was investigated with IVUS placed in the jugular vein or jugular bulb.ResultsThis technique has been successfully adapted in all three cases. In two of these cases, IPS was well visualized with the help of IVUS, and TVE was successfully performed.ConclusionTo our knowledge, this is the first report to mention the usefulness of IVUS for detecting angiographically occult IPS.

The Usefulness of Subcutaneous Infiltration of Epinephrine-Containing Lidocaine for Curative Transarterial Embolization of Dural Arteriovenous Fistula: A Technical Note

Recently, transarterial embolization (TAE) with liquid embolic materials has been recognized as one of the curative therapeutic options for non-sinus type dural arteriovenous fistula (d-AVF). To prevent glue fragmentation and incomplete obliteration, flow reduction of transosseous high-flow feeders is one of the key points of this therapy. However, flow reduction of transosseous feeders is sometimes difficult with previously reported techniques such as particle embolization, manual compression, or proximal balloon occlusion. This report introduces a new technique to reduce the flow of transosseous feeders using epinephrine-containing lidocaine, and describes a case of intracranial d-AVF successfully treated with this technique. The usefulness and efficacy of the technique are discussed.