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.
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.
A case of persistent primitive hypoglossal artery (PPHA) associated with arteriovenous malformation (AVM) is reported. A 46-year-old male suddenly developed severe headache followed by transient unconsciousness and was admitted to our hospital 2 hours later. A computed tomographic scan showed subarachnoid hemorrhage. Angiograms revealed an AVM in the left cerebellar hemisphere and an ipsilateral PPHA. The AVM was completely removed and he was discharged 1 month after surgery without neurological deficit. Only three cases of PPHA associated with intracranial AVM have been reported in the literature. One patient died of rebleeding from the AVM before surgery, and another was conservatively treated because the AVM was too large for resection. The remaining one was surgically treated only by ligation of the feeding arteries. Ours is the first case treated by total removal of the AVM. Since these four cases, including ours, account for 3.0% of 134 cases of PPHA reported, PPHA associated with AVM is considered rare.
A 61-year-old woman was admitted for head injury after a traffic accident. Two months later, she developed abducens nerve palsy, chemosis, and pulsatile tinnitus. Right internal carotid angiography demonstrated a high flow direct carotid-cavernous fistula (CCF) at the C 5 portion with reflux into the superficial and deep sylvian veins, superior ophthalmic vein, superior petrosal sinus, and inferior petrosal sinus. Intravascular ultrasonography (IVUS) revealed a large fistula at the C 5 portion of the internal carotid artery (ICA). Coil embolization via transarterial and transvenous approaches under IVUS monitoring was performed. During the procedure, IVUS accurately detected protrusion of a coil into the parent ICA, and the parent artery could be preserved. IVUS monitoring is useful for embolization of direct CCF with coils.
We report a rare case of a ruptured internal carotid-posterior communicating artery (IC-PC) aneurysm forming kissing aneurysms with an unruptured C2 aneurysm. A 60-year-old woman was transferred to our hospital due to subarachnoid hemorrhage (Hunt & Kosnik Grade I, WFNS Grade I).At the time of admission, she had a mild headache for ten days and no neurological abnormality.Three-dimensional computed tomographic angiography (3D-CTA) revealed a right IC-PC and C2 aneurysm, which were observed to be in contact with each other. After the right internal carotid artery was exposed in the neck, right frontotemporal craniotomy was performed to obliterate the aneurysms on the day after admission. Intraoperative findings demonstrated a ruptured right IC-PC aneurysm adhered to an unruptured C2 aneurysm. Neck clipping was performed with meticulous dissection, especially between both aneurysmal domes. She was discharged without any neurological deficits 2 weeks postoperatively and has since resumed her previous work. Due to the difficulty in dissecting fibrous adherence, the operation for kissing aneurysms has been recognized as challenging. We emphasize that sufficient preoperative discussion, careful intraoperative observation, and meticulous dissection with temporary occlusion of the parent artery are necessary to have good outcomes.
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