Successful Coil Embolisation With Isolation Technique of Ulnar Artery Aneurysm in Hypothenar Hammer Syndrome: A Case Report.

Introduction: Hypothenar hammer syndrome is a rare vascular condition characterised by ulnar artery damage, which can manifest as thrombosis or aneurysm formation. While surgical treatment has been the mainstay of therapy, endovascular treatment may offer a minimally invasive alternative. Reports of successful coil embolisation of ulnar artery aneurysms in hypothenar hammer syndrome are extremely limited in the literature. Report: A woman in her sixties with a history of smoking and atrial fibrillation on anticoagulants presented with a one month history of a painful pulsatile mass in her dominant right hypothenar eminence. Imaging revealed a 15 mm ulnar artery aneurysm with corkscrew deformity characteristic of hypothenar hammer syndrome. Digital subtraction angiography demonstrated adequate collateral circulation through palmar arches during selective compression tests. Endovascular coil embolisation using isolation technique was performed via the ipsilateral brachial artery access under axillary nerve block. A triple coaxial system was used to deploy detachable coils for aneurysm isolation. The procedure achieved complete aneurysm occlusion while maintaining adequate blood flow to all digits through collateral circulation from the radial artery via the palmar arch. Three month follow up contrast enhanced magnetic resonance imaging demonstrated complete resolution of the ulnar artery aneurysm with no evidence of ischaemic complications. Discussion: Pre-procedural confirmation of adequate collateral circulation is essential for endovascular treatment, which can provide effective minimally invasive treatment for ulnar artery aneurysm in hypothenar hammer syndrome without leaving a palmar surgical scar. While the initial results are promising, careful patient selection and longer follow up are needed to establish the durability of this treatment approach.