Summary

Workers using vibrating portable tools and/or manual tools (non-vibrating) are at risk of developing hypothenar hammer syndrome (HHS), with potentially serious health implications including amputation of the fingers (Thompson and House, 2006; Honma et al., 2000; Kaji et al., 1993). The cubital artery in the palm of the hand is superficial and insufficiently protected by tissues such as muscles. It is particularly vulnerable to impact and vibrations, as well as repeated hand trauma when workers hit or pound on machined materials with the palm of their hand. The role of vibrations has yet to be documented, along with tools leading to development of the disease. Symptoms include episodes of white finger (Raynaud’s phenomenon), hand pain and intolerance to cold (Abudakka et al., 2006; Spencer-Green et al., 1987). Few papers address the issue of HHS in workers chronically exposed to vibrations (Marie et al. 2007).

This disease, which causes thrombosis or aneurysm of the cubital artery, is under-reported, under-diagnosed and distinct from vasospastic disorder in hand-arm vibration syndrome (Abudakka et al., 2006; Cooke, 2003; Stroud and Thompson, 1985). It is important to differentiate thrombosis of the cubital artery from vasospastic disorder because thrombosis may cause embolisms in the digital arteries, necessitating medical treatment and/or surgery. Furthermore, since digital ulcers may indicate either thrombosis or severe vasospastic disorder, it is important to differentiate between these two clinical presentations.

A previous study (Turcot et al., 2007), which reviewed 355 files of workers compensated by the Commission de la santé et de la sécurité du travail (CSST) for white finger, found 31 cases of cubital/radial thrombosis, more than reported in the literature for manual workers and workers exposed to hand-arm vibrations. The file review also identified 14 additional cases likely to be undiagnosed cases of HHS. Analysis of the compensation files and comparison with cases reported in the literature shows that miners, construction workers and mechanics are vulnerable to HHS. Overall, these 45 files suggest that this is a serious problem.

The clinical presentation of HHS is characterized by episodes of white finger, hand pain and intolerance to cold. Neurological phenomena of numbness may also be present if the vascular lesion irritates the branches of the cubital nerve. All these symptoms can also characterize vascular injury in vibration syndrome. It is important for the clinician to differentiate the two syndromes because the treatment will vary depending on the case. Therapeutic options include drug therapy, usually followed by surgery, and conservative therapy. The three options are described in this study, highlighting the lack of medical consensus on the best therapeutic approach.

Lastly, this study shows that it is difficult to isolate the role of vibrations from other HHS risk factors. Furthermore, it is important to recognize this disease because it can be entirely prevented by changing the work environment and using safe work methods (Van de Walle et al., 1998). Better management of symptomatic workers can also prevent the symptoms from worsening and improve the administration of treatment.

From this perspective, this study compiles findings, makes intervention recommendations for better prevention of the disease, and identifies workplace prevention solutions and avenues for future research.

Note: The full-length version of this study will be available on the website of the Institut national de santé publique du Québec.