Vibration: good or bad?

In 1862, Maurice Raynaud described one or more fingers becoming pale and cold, a phenomenon then known as‘dead finger'. It was an intermittent segmental whitening due to a sudden decrease in blood supply mainly in response to cooling. This phenomenon was later described in employees using hand‐held vibrating tools (Loriga, 1911), and it is now a well recognized industrial hazard known as the vibration white finger syndrome. Taylor & Pelmear (1975) published an edited version of papers submitted to the Department of Health and Social Security, and drew attention to four broad categories of industrial processes–chain sawing, hand and pedestal grinding, chipping with pneumatic tools, and copper tube swaging. In ail, eighteen populations were surveyed and 827 vibration‐exposed personnel were examined, along with 365 control subjects; 5·3%, of the vibration‐exposed subjects had white fingers. The longer the exposure to vibration the worse its effects, suggesting a cumulative effect. It was clear from the case histories that the disorder could progress to a stage of gross impairment of blood supply and death of the tissues. Although vibration was clearly the most important factor in the above study, it is of interest that 6·3% of the control population also had white fingers when exposed to cold. The factors responsible for white fingers in the population supposedly not exposed to vibration are unknown. In the exposed population the relevance of vibration was clearly shown both by its relationship to time of exposure and by the severity of the disorder when vibration exposure was continued over many years. In contrast to the vibration story, there is also a literature describing beneficial, hyperaemic effects of relatively acute exposure to local vibration. Vibro‐massage has a place in many physiotherapy departments particularly on the continent of Europe. Vibration is used in sports medicine to relax tense muscles, and its many beneficial effects are advertized for exhausted business men who may be persuaded to buy vibrating beds or chairs. While there is still no satisfactory explanation of either the beneficial or the harmful effects, this may yet come from a closer study of the acute changes due to vibration. These have been reported as relief from pain, ‘relaxation’, and increased blood flow. Wisham, Shaanan & Bierman (1956) showed that after short periods of vibration skin temperature was slightly raised in the toes of seven of twenty subjects and in the calves of twelve. The rate of tissue clearance of injected radioactive sodium by the blood stream was increased in thirteen out of fifteen subjects. Bierman (1960) and later Atha & Wheatley (1975) observed a remarkable increase in the extensibility of the spine and the lower limbs during touching of toes after whole‐body vibration, a phenomenon that might be due to relaxation of muscfe but could be an effect on tense ligaments swollen by tissue fluid. In this review the possibility is discussed that a unifying hypothesis of the mechanisms of tissue fluid dispersal can explain both the good and bad effects of vibration. Three aspects will be discussed: (a) causes of Raynaud's phenomenon; (b) local versus systemic influences; (c) the influence of cold.