Vibration-Induced Arterial Shear Stress

Abstract

The enhancement of arterial wall shear stress by mechanical vibration is examined from the viewpoint of its relationship to circulatory disorders found in those using vibrating hand tools. With the use of recent results, it is shown that certain arterial wall physiological processes are influenced by arterial wall shear and that for sufficiently large shear stresses, eg, approximately 1,000 dynes/sq cm, endothelial damage does occur. Calculations are presented that predict the influence of vibration on arterial wall shear. For typical arterial flow conditions, it is estimated that shear stresses in excess of 1,200 dynes/sq cm may be produced by a vibrating tool at 20 hertz with a half-amplitude of 2.5 cm and allowance for 50% attenuation of the vibration impulse.