Digital & Ulnar Artery Aneurysm and Hypothenar Hammer Syndrome

The combination of a manual worker with cold, painful ulnar-side digits - the ring and little fingers - the thumb spared, and a tender, likely pulsatile lump in the hypothenar palm is the classic picture of hypothenar hammer syndrome with an ulnar artery aneurysm. The mechanism is repetitive blunt trauma to the palm, using the hypothenar eminence as a hammer or from vibrating tools, which damages the superficial ulnar artery where it crosses the hook of hamate in Guyon's canal, producing an aneurysm and/or thrombosis that embolises distally to the ulnar digits. I would examine the hand, perform an Allen test to assess the radial and ulnar contributions and the competence of the palmar arch, and look for splinter haemorrhages and ulceration. I would image with duplex and CT, MR or catheter angiography, which typically shows the ulnar artery aneurysm or occlusion with a corkscrew deformity, distal embolic occlusions, and the completeness of the palmar arch and digital filling, and I would exclude mimics such as Buerger's disease and a proximal embolic source. Management begins with removing the cause - stopping the repetitive palmar trauma and vibration, smoking cessation, warmth, treating vasospasm, and antiplatelet or anticoagulation, with thrombolysis for acute embolic ischaemia. For a symptomatic aneurysm I would resect the diseased segment to remove the embolic source, then decide on reconstruction based on perfusion: if the palmar arch is complete and the hand is well perfused, simple ligation is safe; if collateral flow is inadequate, I would reconstruct with a reversed vein interposition graft. Endovascular coil embolisation is an option in selected cases, but only after confirming adequate collateral circulation through the palmar arch.