Pre-Emptive Brachial Plexus Block as an Access-Facilitating Technique for Transradial Neuroendovascular Procedures in Patients with a Small Radial Artery.

Objective: The transradial approach (TRA) for neurointerventional procedures is often limited by small radial artery (RA) diameter and vasospasm, especially when large-bore devices are required. Case Presentation: We report the case of a woman in her 50s with a small RA (1.8 mm) who required stent-assisted coiling for an unruptured internal carotid artery aneurysm. To address the high sheath-to-artery diameter ratio (1.38) and the risk of spasm, an ultrasound-guided brachial plexus block (BPB) was performed before the procedure. After the block, the RA diameter increased to 2.3 mm, lowering the ratio to 1.08. This allowed smooth insertion of a 6-Fr sheath and successful complete aneurysm occlusion without access-site complications or systemic hemodynamic instability, which can sometimes occur with intra-arterial vasodilators. Conclusion: Although the existing literature often excludes patients with an RA caliber of less than 2.0 mm, these findings suggest that ultrasound-guided BPB may be a practical, safe, and effective technique for expanding the feasibility of TRA in patients with challenging vascular anatomy.