Osseous arteriovenous fistulas in the dorsum sellae, clivus, and condyle

Cone-beam CT-assisted microcatheter tip placement at the shunted pouch entry zone: A technical note for anterior condylar arteriovenous fistula

Accurate microcatheter placement for anterior condylar arteriovenous fistula (AVF) enables selective transvenous embolization (TVE) and helps to avoid hypoglossal nerve palsy. Anterior condylar AVF has a shunted pouch within the condylar vascular and osseous structures. Detailed anatomical comprehension of the shunted pouch is essential, in addition, we believe that it is important to have a strategy for where in the shunted pouch to start filling with coils. Specifically, we consider that it is important to structurally understand the more upstream location (arterial side) within the shunted pouch (called "shunted pouch entry zone"), guide the microcatheter there, and embolize from that site. Although several studies have discussed the usefulness of intraoperative cone-beam computed tomography (CBCT) for treating anterior condylar AVF, there are no studies which have mentioned the importance of microcatheter position before coil embolization in selective TVE as in this study. Intraoperative localization of the shunted pouch entry zone is often difficult. Herein, the authors report that cone-beam computed tomography (CBCT) can assist accurate microcatheter tip placement at the shunted pouch entry zone before staring embolization. This is the novel application of intraoperative CBCT to treat anterior condylar AVF successfully treated with precise and selective TVE.

Anterior cranial fossa osseous arteriovenous fistula of the crista galli with bone erosion: patient series

BACKGROUND

Although an anterior cranial fossa dural arteriovenous fistula (ACFdAVF) is thought to have a fistula on the dura near the olfactory groove, the detailed angioarchitecture remains unreported.

OBSERVATIONS

In case 1, a 65-year-old man was found to have an asymptomatic ACFAVF. His computed tomography angiography (CTA)-maximum intensity projection (MIP) showed the shunt point in the crista galli (CG), with the intradural drainer penetrating the destroyed bone of the CG. In case 2, a 78-year-old man had a past history of intracerebral hemorrhage and was found to have an ACFAVF. The rotational angiography (RA)-MIP showed the intraosseous fistula in the CG with the drainer passing through a tiny bone defect of the CG. In case 3, a 35-year-old man was investigated for epilepsy. The RA-MIP showed an osseous arteriovenous fistula (AVF) in the anterior cranial base, with the drainer penetrating the skull osteolytic site. In case 4, a 73-year-old woman was found to have an asymptomatic ACFAVF. Her RA-MIP showed the osseous AVF with the drainer penetrating the CG with bone erosion.

LESSSONS

All patients were diagnosed with anterior cranial fossa osseous AVF rather than dAVF, with bone erosion in the CG. These findings should be noted at the time of diagnosis and treatment.

Transosseous Veins of the Temporal Bone: Connection Between Middle and Posterior Cranial Fossa Venous Structures

BACKGROUND

The veins and dural venous sinuses of the skull base are important to understand in terms of imaging findings, diagnoses, and surgery. However, to date and to the best of our knowledge, the transosseous veins of the petrous part of the temporal bone have not been studied.

METHODS

Ten latex-injected adult cadaveric specimens (20 sides) were dissected to identify the intraosseous and transosseous veins. The petrous part of the temporal bone was drilled away, and the petrous part of the internal carotid artery and the veins of the middle and posterior cranial fossa adjacent to the petrous part of the temporal bone were exposed.

RESULTS

Transosseous veins traveling through the petrous part of the temporal bone were identified on all 20 sides. In general, these were most concentrated near the anterior and posterior parts of the petrous part of the temporal bone. Most traveled more or less vertically from the petrous ridge and related superior petrosal sinus internally through the petrous part of the temporal bone toward the inferior petrosal sinus or horizontally, uniting the veins of the floor of the middle cranial fossa with the veins of the posterior cranial fossa. These transosseous veins connected the veins in the middle cranial fossa with the veins of the posterior cranial fossa. Most (70%) of these transosseous veins were also found to have small connections to the internal carotid venous plexus.

CONCLUSIONS

To the best of our knowledge, previous studies have not reported on transosseous veins of the temporal bone or described their anatomy of connecting the veins of the middle and posterior cranial fossae.

Dural venous system: angiographic technique and correlation with ex vivo investigations

BACKGROUND

The dural vasculature plays a key role in several important conditions, including dural fistulas and subdural collections. While in vivo investigations of intrinsic dural arterial angioarchitecture are rare, no angiographic studies of dural venous drainage exist to our knowledge.

OBJECTIVE

To describe methods by which dural venous drainage might be visualized with current angiographic equipment and technique, and to correlate our results with existing ex vivo literature.

METHODS

Digital subtraction angiography and 3D angiography (rotational and Dyna CT) of dural neurovasculature were acquired in the context of subdural hematoma embolization and normal dura. Protocols for visualization of dural venous drainage were established, and findings correlated with ex vivo studies.

RESULTS

Meningeal arteries supply both the skull and dura. Normal dural enhancement is accentuated by the presence of hypervascular membranes. Intrinsic meningeal veins/sinuses parallel outer layer arteries with well-known tram-tracking appearance. Dura adjacent to main arterial trunks drains via skull base foramina into the pterygopalatine venous plexus, or via emissary veins into the temporalis venous plexus. Dura near the sinuses drains into venous pouches adjacent to the sinus, before emptying into the sinus proper-possibly the same pouches implicated in the angioarchitecture of dural fistulas. Finally, posterior temporoparietal convexity dura, situated in a watershed-like region between middle and posterior meningeal territories, frequently empties into diploic and emissary veins of the skull. Wide variation in balance is expected between these three routes. Drainage patterns appear to correlate with venous embryologic investigations of Padget and ex vivo studies in adults.

CONCLUSIONS

Continued attention to dural venous drainage may prove useful in the diagnosis and management of dural-based vascular diseases.

Four-dimensional digital subtraction angiography for exploration of intraosseous arteriovenous fistula in the sphenoid bone

Background

Intraosseous arteriovenous fistula (AVF) is a rare clinical entity that typically presents with symptoms from their effect on surrounding structures. Here, we report a case of intraosseous AVF in the sphenoid bone that presented with bilateral abducens palsy.

Case Description

A previously healthy man presented with tinnitus for 1 month, and initial imaging suspected dural AVF of the cavernous sinus. Four-dimensional digital subtraction angiography (4D-DSA) imaging and a three-dimensional (3D) fused image from the bilateral external carotid arteries revealed that the shunt was in a large venous pouch within the sphenoid bone that was treated through transvenous coil embolization. His symptoms improved the day after surgery.

Conclusion

This is a case presentation of intraosseous AVF in the sphenoid bone and highlights the importance of 4D-DSA and 3D fused images for planning the treatment strategy.

Angio-anatomical study of the pterygovaginal artery based on cone-beam computed tomography

PURPOSE

To investigate the anatomical characteristics and clinical implications of the pterygovaginal artery (PtVA), a recurrent branch from the distal internal maxillary artery (IMA), which courses through the pterygovaginal canal that connects the pterygopalatine fossa and nasopharynx.

METHODS

Eighty-two patients with 90 sides of cone-beam computed tomography (CBCT) reconstructed from rotational angiography of the external or common carotid artery with a field of view covering the pterygopalatine fossa were retrospectively reviewed. The origin from the IMA, branching type, distribution, and anastomoses was evaluated. The underlying lesions were 36 hypervascular lesions with possible supply from PtVA (17 cavernous sinus arteriovenous fistulas (AVFs), 6 anterior condylar AVFs, and 13 nasopharyngeal, parasellar, or paraclival tumors) and 46 other diseases.

RESULTS

PtVA was identified in 75 sides (83%). It originated from the pterygopalatine segment of the IMA in 45 sides (60%) and from the pterygoid segment in 30 sides (40%). It arose independently (77%), sharing the common trunk with the Vidian artery (15%) or with other branches. It ran posteromedially through the pterygovaginal canal to supply the mucosa over the nasopharyngeal roof, the choanae, and the pharyngeal ostium of the eustachian tube. It anastomosed with the ascending pharyngeal artery (n=37), the accessory meningeal artery (n=7), and the mandibular artery from the petrous internal carotid artery (n=2). It served as a feeder of osseous AVFs and skull base tumors.

CONCLUSION

PtVA was often identified by CBCT even in normal anatomy. Its detailed angio-anatomy could be evaluated in the presence of parasellar or paraclival hypervascular lesions.