Sphenoparietal Sinus Dural Arteriovenous Fistulas: A Series of 10 Patients

Selective Microsurgical Disconnection of Greater Sphenoid Wing Dural Arteriovenous Fistula Through the Subtemporal Approach Under Exoscope Magnification

OBJECTIVE

Sphenoid dural arteriovenous fistulas located on the greater sphenoid wing carry a notable risk of intracranial hemorrhage due to the frequent presence of cortical venous reflux. Because of the challenging embolization procedure, microsurgery remains a valuable option in these cases.

METHODS

In most cases, the fistula is located in the anterolateral endocranial surface of the middle cranial fossa just below the sphenoid ridge; however, in a small subset of cases, the fistula is positioned posteriorly and medially in the region between the foramen ovale and rotundum. The former region can be reached using various frontolateral approaches, whereas the latter region can be accessed through a subtemporal trajectory, minimizing temporal lobe retraction. The exoscope has been gaining popularity for improved magnification, visualization, and surgeon ergonomics expanding the surgeon's possible trajectory in skull base surgery.

RESULTS

We present a targeted subtemporal approach using the exoscope for selective occlusion of an unruptured greater sphenoid wing dural arteriovenous fistula. With proper brain relaxation, a small temporobasal craniotomy opens a direct corridor to the middle cranial fossa. Exoscope-assisted surgery could improve dissection of the middle cranial base and dynamic temporal lobe retraction and expand the range of anteromedial subtemporal trajectories, providing angles that may be challenging to achieve using the operative microscope, as well as improve the surgeon's ergonomic position.

CONCLUSIONS

An exoscopic-assisted subtemporal approach is a feasible, safe, and minimally invasive approach to treat unruptured greater sphenoid wing dural arteriovenous fistulas and could be considered an alternative to endovascular treatment.

Endovascular treatment for sphenoidal region dural arteriovenous fistula

Sphenoidal region dural arteriovenous fistulas (DAVFs) are rare. Endovascular treatment (EVT) is an effective treatment approach. However, understanding and performing EVT for sphenoidal region DAVFs are difficult and challenging. Therefore, we performed a review to explore this issue further. In this review, we discuss the dural feeders and venous structures of the sphenoidal region, the angioarchitecture of sphenoidal region DAVFs, the role and principle of EVT, various EVT techniques, and the prognosis and complications associated with EVT. We found that various EVT techniques, including transarterial embolization (TAE), retrograde transvenous embolization (TVE), and direct puncture EVT, can be used to treat sphenoidal region DAVFs. TAE represents the most commonly utilized approach. TVE and direct puncture EVT should be limited to highly selective cases. EVT must penetrate the fistula and very proximal venous recipient pouch with a liquid embolic agent or coil the fistula point to have a complete curative effect. Successful EVT can lead to the obliteration of sphenoidal region DAVFs and a good clinical outcome. However, these complications cannot be neglected.

Middle cranial fossa non-cavernous sinus dural arteriovenous fistulas: 20 years of experience

Non-cavernous sinus (CS) dural arteriovenous fistulas (DAVFs) involving the sphenoid bone are rare entities that are easily confused with one another due to the complex structure and high variability of the venous system around the middle cranial fossa. We present a large retrospective study on middle cranial fossa non-CS DAVFs and review the literature on DAVF treatment in this location as well as relative anatomy. 15 patients had DAVFs involving the lesser sphenoid wing and 11 patients had DAVFs involving the greater sphenoid wing. Six patients presented with intracranial hemorrhage or subarachnoid hemorrhage (23.1%, 6/26). The most common symptoms were eye symptoms (38.5%, 10/26). Nineteen patients were treated with trans-arterial embolization (TAE) using liquid embolic agents and two patients were treated with transvenous embolization (TVE) using Onyx or in combination with coils. Surgical disconnection of the drainage veins was performed in five patients, with three cases experiencing unsuccessful TAE. Anatomic cure was achieved in 92.3% of the patients (24/26). Twelve patients had DSA and clinical follow-up from 3 to 27 months. There was one recurrence (8.3%) of the fistula in the patient two months after the initial complete occlusion. The majority of patients can be cured endovascularly. Laterocavernous sinus DAVFs may not be embolized by transvenous approach via the cavernous sinus because there is often no connection between them in most patients. A small percentage of patients may require surgical ligation to be cured.

Case report: Sphenoid wing dural arteriovenous fistula draining into ophthalmic veins inducing pulsatile tinnitus as the sole symptom and its spontaneous closure

This case report discusses a unique instance of pulsatile tinnitus (PT) caused by a rare type of intracranial dural arteriovenous fistula (DAVF) located in the sphenoid wing (SW) region, with PT being the sole presenting symptom. The patient initially received multiple misdiagnoses and sought medical attention at various hospitals before being correctly diagnosed. Imaging studies revealed the DAVF's presence in the SW region, which led to the patient's referral to interventional radiology/neurology, although she chose conservative observation without surgical intervention. Remarkably, the patient's PT spontaneously ceased after 30 months without any apparent cause, and follow-up imaging confirmed the absence of DAVF-related abnormalities. The case highlights the importance of considering DAVF as a potential cause of PT, even when there are no evident abnormalities in proximity to the auditory apparatus. It also emphasizes the need for otolaryngologists to extend their examination to include regions beyond the temporal bone, such as the sphenoid bone and orbital areas, when PT is the exclusive symptom. The case underscores the significance of early detection and intervention for DAVFs, as they can lead to debilitating complications, despite the rare occurrence of spontaneous symptom resolution in this case.