Hypothenar hammer syndrome: Proposed etiology

Purpose: Finger ischemia caused by embolic occlusion of digital arteries or iginating from the palmer ulnar artery in a person repetitively striking ob jects with the heel of the hand has been termed hypothenar hammer syndrome (HHS). Previous reports have attributed the arterial pathology to traumatic injury to normal vessels. A large experience leads us to hypothesize that HHS results from trauma to intrinsically abnormal arteries. Methods: We reviewed the arteriolgraphy, histology, and clinical outcome of all patients treated for HHS in a university clinical research center stud y of hand ischemia, which prospectively enrolled more than 1300 subjects fr om 1971 to 1998. Results: Twenty-one men had HHS. All had occupational (mechanic, carpenter, etc) or avocational (woodworker) exposure to repetitive palmar trauma. All patients underwent upper-extremity and hand arteriography, unilateral in e ight patients (38%) and bilateral in 13 patients (62%). By means of arterio gram, multiple digital artery occlusions were shown in the symptomatic hand , with either segmental ulnar artery occlusion in the palm or characteristi c "corkscrew" elongation, with alternating stenoses and ectasia, Similar ch anges in the contralateral asymptomatic (and less traumatized) hand were sh own by means of 12 of 13 bilateral arteriograms (92%). Twenty-one operation s, consisting of segmental ulnar artery excision In the palm and vein graft ing, were performed on 19 patients. Histology was compatible with fibromusc ular dysplasia with superimposed trauma. Patency of arterial repairs at 2 y ears was 84%. One patient (5%) required amputative debridement of necrotic finger tips, No other tissue loss occurred. There have been no recurrences of ischemia in patients with patent bypass grafts. Conclusion: To our knowledge, this is the largest reported group of HHS pat ients, The characteristic angiographic appearance, histologic findings, and striking incidence of bilateral abnormalities in patients with unilateral symptoms lead us to conclude that HHS occurs when persons with preexisting palmar ulnar artery fibrodysplasia experience repetitive palmar trauma. Thi s revised theory for the etiology of HHS explains why HHS does not develop in most patients with repetitive palmar trauma.