Introduction and purpose Access to the intracranial pathology through tortuous vasculature has often been the limiting factor in treating certain patients. To address this issue, the 6 French Neuron (0.053 inches) delivery catheter (Penumbra Inc, Alameda, California, USA) was developed to provide greater proximal guide support and enable distal microcatheterization of the intracranial vasculature. A few articles have described the technique but guide positions in these publications were below the level of the dura. The purpose of this paper is to describe our experience with very distal placement of the guide catheter within the intracranial and extracranial vasculature enabling treatment of various neurovascular pathologies.

Materials and methods In 12 patients, attempts were made to initially treat the neurovascular pathology with a standard guide catheter and microcatheter but they were unsuccessful either due to tortuous supra-aortic, cervical, extracranial or intracranial vasculature. The 6 F Neuron delivery catheter was substituted through a 6 F sheath for greater distal purchase and support.

Results The 6 F Neuron guide catheter was delivered in very distal vascular locations providing excellent support for advancement of the microcatheter and treatment of the lesion. The guide catheter was positioned in the following locations for treatment: origin of ophthalmic artery, M1 segment, M2 segment, A1 segment, P1 segment, basilar artery, origin of the anterior inferior cerebellar artery, distal internal maxillary artery, distal occipital artery, distal superficial temporal artery, cavernous sinus and distal superficial temporal vein. Three patients were treated for carotid cavernous fistula, three patients for arteriovenous malformations, three patients for dural arteriovenous fistulas, two patients for intracranial aneurysms and one patient for vasospasm following subarachnoid hemorrhage. There was no evidence of vasospasm or complications related to the distal position of the guide catheter.

Conclusion Utilization of the guide catheter in extremely distal positions is safe and effective, allowing for treatment of traditionally inaccessible lesions. The guide catheter allows for more distal placement and greater proximal support to access neurovascular lesions in the setting of tortuous cervical and/or intracranial vasculature.