A novel endovascular approach using transcalvarial emissary vein access for scalp and skull base AVMs: Case report

Abstract

Introduction and importance: Scalp arteriovenous malformations (SAVMs) are rare high-flow vascular lesions with complex angioarchitecture, often involving both superficial and deep components. When the malformation extends toward the skull base or includes deep venous drainage, traditional transarterial or percutaneous access may be insufficient. While direct puncture techniques have gained traction, transosseous access via emissary veins has not previously been described.

Case presentation: A 12-year-old girl presented with a pulsatile, fluctuant swelling over the left forehead and localized headache. Imaging revealed a mixed-type SAVM involving the left sphenoid ridge, frontal bone, and scalp, supplied by the ophthalmic artery and cortical branches of the middle cerebral artery, with multiple draining veins. Due to tortuous arterial feeders and the risk of non-target embolization, conventional transarterial access was deemed unsafe. A transcalvarial micropuncture technique was employed through a burr hole targeting an emissary vein, granting direct access to a deep venous pouch. Under fluoroscopic guidance, detachable coils were deployed, achieving complete angiographic obliteration. The patient remained neurologically intact, with no complications and an excellent cosmetic outcome. Follow-up imaging at 1, 3, and 6 months showed no recurrence.

Clinical discussion: This case demonstrates the feasibility of using a transosseous emissary vein approach for embolization of complex SAVMs. When conventional access is limited, this technique offers precise, direct venous access with reduced morbidity.

Conclusion: This is the first reported case of SAVM embolization using transcalvarial micropuncture via an emissary vein. The technique presents a novel, safe, and effective adjunct in managing complex scalp AVMs involving the skull base.

Keywords: Aneurysms; Endovascular; SAVM; Transcalvarial access.

Fig. 1

MRI Brain: A. Axial T1-weighted post-contrast MRI showing a vascular lesion in the left sphenoid ridge extending to the subcutaneous forehead. B. Coronal T2-weighted MRI demonstrating lesion extent. C. Coronal T2 showing superficial component. D. Sagittal T2 showing scalp and skull base extension.

Fig. 2

Diagnostic and Intraoperative Angiographic Imaging of Scalp Arteriovenous Malformation (SAVM). A. Left common carotid artery (CCA) angiographic run, lateral view, showing early arterial filling of a large venous pouch located at the left anterolateral skull base, supplied by multiple external carotid artery (ECA) branches. B. Oblique view of the same CCA run demonstrating additional arterial feeders and more extensive scalp venous drainage, with clear opacification of the scalp AVM nidus and venous pouch. C. Internal carotid artery (ICA) angiographic run showing partial contribution to the lesion from cortical branches of the middle cerebral artery (MCA); no direct arterial feeders from the ophthalmic artery are seen in this run. D. Post-embolization digital subtraction angiography (DSA) after transcalvarial micropuncture access and coil embolization, demonstrating significant reduction in flow to the venous pouch and absence of early venous filling, indicating near-complete obliteration of the arteriovenous shunting.

Fig. 3

Intraoperative Imaging: A. Digital subtraction angiography (DSA) image showing the nidus of the scalp arteriovenous malformation (SAVM) with early venous drainage following contrast injection, confirming the arteriovenous shunting. B. Lateral fluoroscopic view demonstrating transcalvarial micropuncture access into an emissary vein using a microwire and catheter system, guiding endovascular navigation toward the lesion. C. Superselective catheterization of a feeding artery supplying the SAVM nidus, with clear opacification of the vascular malformation. D. Final fluoroscopic image following embolization showing the deployed microcoils within the emissary vein and obliteration of the abnormal vascular nidus, confirming successful occlusion.

Fig. 4

Endovascular treatment outcome of scalp arteriovenous malformation (SAVM). A. Pre-embolization digital subtraction angiography (DSA) showing a high-flow scalp arteriovenous malformation (SAVM) with a compact nidus and multiple arterial feeders arising from branches of the external carotid artery. B. Post-embolization DSA demonstrating complete obliteration of the SAVM nidus with no residual arteriovenous shunting, following successful endovascular embolization via transcalvarial emissary vein access.