Vibration-induced White Finger Research Articles

Vibration syndrome in industry: dermatological viewpoint.

Long-term use of hand-held vibratory tools has been implicated in the development of a clinical condition known under several names including occupational Raynaud's phenomenon, vibration-induced white finger (VWF) disease, and "dead" or "wax" finger. The syndrome is characterized in its early stages by tingling, numbness, or blanching of the finger tips provoked usually by exposure to cold temperatures; later these symptoms may extend to the base of all of the digits on both hands. As vibration exposure continues, the attacks become more frequent and cause manual impairment and social disability. This complex of VWF and associated arterial and related complications is now termed vibration syndrome (VS). Although epidemiologic studies indicate that large percentages of the population of workers at greatest risk are affected, the acceptance of VS as an industrial disease is only recent. This paper reviews some of the salient features of VS from the point of view of the dermatologist, since he may be the first health professional to see patients with this syndrome. Terminology, risk factors, preventative measures, therapy, and occupational guidelines are discussed.

Exploratory electromyography in the study of vibration-induced white finger in rock drillers : D. S. Chatterjee, D. D. Barwick and A. Petrie 1982 British Journal of Industrial Medicine39, 89–97. (9 pages, 9 tables, 27 references)

Exploratory electromyography in the study of vibration-induced white finger in rock drillers : D. S. Chatterjee, D. D. Barwick and A. Petrie 1982 British Journal of Industrial Medicine39, 89–97. (9 pages, 9 tables, 27 references)

Preliminary evaluation of dose-effect relationships for vibration induced white finger in Japan.

Habitual use of many vibrating tools has been found to be connected with the appearance of various disorders affecting the blood vessels, nerves, bones, joints, muscles or connective tissues of the hand and forearm. The vibration exposures required to cause these diseases are not known exactly, either with respect to vibration intensity and the vibration frequency spectrum, or with respect to daily exposure time and total exposure period. The purpose of this study is to investigate available data on the physical conditions in Japan that have caused vibration induced white finger (VWF) and attempt to establish approximate relationships between vibration conditions and prevalence of VWF. The vibration conditions were evaluated using the method of vibration assessment recommended by the International Standardized Organization, which uses the weighted vibration level of the frequency weighted, dominant, single axis component of vibration directed into the hand. A clear correlation between level, prevalence of VWF and exposure period can be found. The results also suggest the relationship between the weighted levels and latent intervals. These dose-effect relationships enable the prediction of the average latent interval for a population group and the range of progression of the disorders--all from a measurement of the vibration entering the hands. In Japanese cases, 4, 8, and 15% of VWF prevalence correspond with 10, 20, and 40% of VWF prevalence in the Draft International Standard ISO/DIS 5349 (1982) within the weighted vibration level range of 2 to 50m X s-2.

Effect of the air hammer on the hands of stonecutters. The limestone quarries of Bedford, Indiana, revisited.

In the limestone quarries of Indiana, USA, pneumatic percussive hammers replaced the mallet and hammer around 1900. By 1917 the air hammer was being used exclusively for periods of eight to ten hours a shift. In 1918 Alice Hamilton investigated an unusual "disease" in these stonecutters of Bedford, Indiana, who complained of "attacks of numbness and blanching of the fingers coming on suddenly under the influence of cold and then disappearing." The prevalence of vibration induced white finger (VWF) found in this population of 38 stonecutters was 89%, with decreased light touch, pain, and temperature appreciation in advanced cases. In 1978 a VWF research team revisited these limestone quarries. During the 60 year interval the stonecutting industry had contracted from 4000 workers in 40 quarries in 1918 to 3-400 in 10 quarries in 1978, with only 50 employees remaining in the Bedford area. In a population of 30 stonecutters the prevalence of VWF in 1978 was 80%, with similar sensory loss in light touch, pain, and temperature appreciation. Between 1918 and 1978 no change had taken place in the design of the air hammers used for stonecutting. Vibration levels of 4859 metres/s2 on the chisel, and 2010 metres/s2 on the barrel were measured over a frequency range 6.3 to 1000 Hz. The fundamental frequency was 75 Hz. These measured vibration levels are outside the ISO/DIS/5349 (1979) recommended limits for human exposure to vibration transmitted to the hand. The VWF data presented in this paper, and those originally reported by Hamilton in 1918, call for an immediate redesign of stonecutting pneumatic hammers in order to remove one cause of Raynaud's phenomenon of occupational origin.

High impulse acceleration levels in hand-held vibratory tools. An additional factor in the hazards associated with the hand-arm vibration syndrome.

The measurement of the root-mean-square (rms) acceleration of vibration does does not take into consideration the short high peak values of the vibratory signal, which may be a hazard contributing to the development of vibration-induced disease. A method for evaluating the impulse character of vibratory signals is given, and impulsiveness is defined as the difference between the peak and rms signals. Measurements were taken during pedestal grinding, during chain sawing with three different generations of saws, and during chiseling with a pneumatic hammer. The measurements comprised (i) analyses done according to the International Organization for Standardization (ISO) draft, (ii) an evaluation of impulsiveness, and (iii) an analysis of the short-time history transient. The risk of vibration-induced white fingers was estimated by the ISO method, and the results were compared with those observed. It was found that the analysis of impulsiveness provided additional data and partly explained the observed symptoms of vibration-induced white fingers. The parameters for the impulsiveness of the vibration signal agreed with the short-time history analysis.

Blood pressure, flow, and peripheral resistance of digital arteries in vibration syndrome.

The peripheral circulation was studied in 19 lumberjacks and in 12 control subjects. Twelve of the lumberjacks were free from vascular symptoms and seven had vibration induced white finger (VWF). Using the strain-gauge plethysmographic technique, the digital circulation was examined at rest, during cooling of the upper body, and during heating of the upper body. At rest and during vasodilatation no significant differences were found between the lumberjacks and the controls. During reflexive vasoconstriction, digital blood flow in the upper body was more reduced in lumberjacks with VWF than in control subjects. Furthermore, digital blood pressure of the lumberjacks with VWF fell more than in the control group. The peripheral resistance also increased more, but this difference was not statistically significant. There was no evidence that the exaggerated vasoconstriction of VWF resulted from a narrowing of the lumen of arterioles due to hypertrophy of the vessel wall. The present findings suggest that VWF is produced by the highly sensitive responsiveness of the affected vessel to normal vasoconstrictor stimuli.

Vibration syndrome and vibration in pedestal grinding.

At one Finnish foundry all the workers had typical symptoms of vibration induced white finger (VWF) after they began using a new type of pedestal grinding machine. The objectives of this study were to establish the severity of the symptoms and the difference in vibration exposure between the new and the old machines. Vibration detection thresholds and grip forces were measured, as well as the vibration in the casting and in the wrist simultaneously. The mean latency for VWF among the grinders was 10.3 months after the change of pedestal grinding machines. All the grinders had numbness in their hands. The vibration detection threshold was significantly higher for the grinders than for their referents. At the same circle speed, the new wheels caused vibration levels up to 12 dB more than the old wheels. The circle speed had a slight influence on the vibration. The vibration levels of light (0.5 kg) casting were up to 25 dB higher than the heavy (5 kg) casting. The use of a pneumatic pressing device decreased the vibration levels in the wrist by 5-10 dB. The increase in vibration, which occurred when the new wheels were taken into use, was too small to explain such a dramatic outbreak of VWF. This led to the conclusion that some other feature such as the impulse character of the vibration also contributed to the effects of vibration.

Platelet function and clotting parameters of vibration-exposed foundry workers.

Platelet aggregation and blood clotting parameters were studied in 22 workers (84 %) using pneumatic riveting and grinding hand tools and in 20 workers (90 %) not exposed to vibration but comparable with respect to age, anthropometric data, smoking and drinking habits, and atherogenic risk factors. The weighted acceleration levels of the vibrating tools are reported. According to Taylor's grading system for vibration-induced white fingers, 15 exposed workers (57 %) were in stage OT, 9 (34 %) in stage 0N, and 1 (4 %) in stage 1. Between the reference and the vibration-exposed groups no differences in the platelet aggregation indices both "in vitro" (adenosine-diphosphate, epinephrine, threshold adenosine-diphosphate concentration) and "in vivo" (platelet factor four, beta-thromboglobulin) were found. In addition the clotting parameters (prothrombin index, activated partial thromboplastin time, fibrinogen, antithrombin III) and the immunoglobulins G, A, and M were normal in the two groups. The measurement of skin temperature of the third right finger before and after the cold provocation test showed that the vibration exposed workers experienced a stronger vasoconstriction of the digital vessels than the referents. It is concluded that, in the early stages of vasospastic disorders, segmental vibration can induce peripheral vascular hyperreactivity without changes in the platelet function and clotting parameters.

Factors modifying the local arterial hyperresponsiveness of vibration-induced white finger.

The extent and duration of the vibration-induced hyperresponsiveness of arterial smooth muscle to noradrenaline increased as the period of vibratory stimulation became longer. Division of a fixed stimulation time into a few shorter units interposed by intermissions decreased the extent and duration of the hyperresponsiveness. The shorter the length of each unit, the less the hyperresponsiveness. Verapamil effectively suppressed the appearance of the hyperresponsiveness, whereas pretreatment with phentolamine only partially inhibited its appearance. Administration of vitamin E was effective in suppressing the vibration-induced rise of responsiveness to noradrenaline in plasma.

Clonidine in the treatment of vibration-induced white fingers.

The effect of clonidine, a centrally acting drug diminishing the sympathetic activity of peripheral nerves, was examined in a double-blind study of 60 forest workers with vibration-induced white fingers. Clonidine was administered in daily doses of 0.450 mg or 0.100 mg during 30 d. The results were evaluated from a self-administered questionnaire. No significant differences were discerned between the active and placebo groups in respect to either recovery time after an attack or frequency of attacks. Neither did the subjective evaluation of the overall effectiveness of the drug show any differences between the groups. In two subjects clonidine provoked Raynaud's phenomenon, which subsided after the cessation of treatment. The recording of finger pulse plethysmography for two subjects treated with 0.450 mg of clonidine daily revealed comparatively well preserved vascular reflexes, whereas sympathetic mass reflexes such as galvanic skin response were almost absent.

Cold response of digital arteries in chain saw operators

ABSTRACT In a study of vibration-induced white finger (VWF) 39 chain saw operators, being representative of 365 lumberjacks according to a completed questionnaire, underwent clinical investigation. In a medical interview 13 of the 39 had VWF and 26 were without finger symptoms. In the subjects with VWF both hands were equally affected, the third and fourth finger most frequently; the thumbs were always normal. A cold provocation test, measuring the finger systolic blood pressure with a cuff technique during combined body cooling and finger cooling to 30, 15, and 6°C, was applied to the 39 chain saw operators and to 20 age-matched outdoor workers who had not used vibrating hand tools. The finger most often showing Raynaud's phenomenon was cold provoked, and a non-affected finger was used as a reference. The systolic pressure gradient measured at 30°C from the upper arm to the cooled finger was increased in the chain sawyers most severely affected by VWF compared with the control group and with the chain sawyers without VWF (p <0·02). Raynaud's phenomenon was verified by digital arterial closure (zero pressure in the finger) at 15 or 6°C in 12 of 13 chain sawyers having anamnestic and clinical evidence of VWF. Chain sawyers without VWF had an increased digital arterial response to cold at 15 and 6°C compared with the control group (p <0·05) and had a decreased cold response compared with chain sawyers with VWF (p <0·05). In chain sawyers without VWF 13 subjects with an exposure period of 10-23 years had an increased cold response at 6°C compared with 13 subjects with an exposure period of one to three years (p <0·05). Only one of 38 chain saws did not exceed the exposure limit proposed by the International Standardisation Organisation. The results of the present study indicate that vibrations induce hyperresponsiveness to cold in the exposed arteries, even in chain sawyers without finger symptoms. The exposure to vibration therefore should be reduced to eliminate this damage. The presented cold provocation test may be used to diagnose Raynaud's phenomenon and to disclose an abnormal digital arterial cold response before subjective symptoms have appeared.

Exploratory electromyography in the study of vibration-induced white finger in rock drillers.

Electrophysiological observations made in the hands of a group of 16 rock-drillers were compared with 15 controls. Motor and sensory conduction velocities in the median and ulnar nerves together with the latency, duration, and amplitude of the evoked action potentials were measured. The differences between the groups were statistically significant mainly in latency, duration, and amplitude, especially of the sensory action potentials. Measurement of the conduction velocities, in general, proved to be less sensitive, and the only significant change observed was in the sensory conduction velocity in the median nerve when the first digit in the right hand was stimulated. The most interesting result was evidence of an increased prevalence of possible carpal tunnel syndrome in the exposed (44% compared with 7% in the control group). A similar set of data, but exclusively sensory and not standardised for age and sex, was obtained from 25 university students for comparison with the assigned groups. The results showed that apart from sensory duration the control group had values that were closest to the students while the vibration group had values furthest away.

Hand-arm vibration in the aetiology of hearing loss in lumberjacks.

A longitudinal study of hearing loss was conducted among a group of lumberjacks in the years 1972 and 1974--8. The number of subjects increased from 72 in 1972 to 203 in 1978. They were classified according to (1) a history of vibration-induced white finger (VWF), (2) age, (3) duration of exposure, an (4) duration of ear muff usage. The hearing level at 4000 Hz was used to indicate the noise-induced permanent threshold shift (NIPTS). The lumberjacks were exposed, at their present pace of work, to noise, Leq values 96-103 dB(A), and to the vibration of a chain saw (linear acceleration 30-70 ms-2). The chain saws of the early 1960s were more hazardous, with the average noise level of 111 dB(A) and a variation acceleration of 60-180 ms-2. When classified on the basis of age, the lumberjacks with VWF had about a 10 dB greater NIPTS than subjects without VWF. NIPTS increased with the duration of exposure to chain saw noise, but with equal noise exposure the NIPTS was about 10 dB greater in lumberjacks with VWF than without VWF. With the same duration of ear protection the lumberjacks with VWF consistently had about a 10 dB greater NIPTS than those without VWF. The differences in NIPTS were statistically significant. The possible reason for more advanced NIPTS in subjects with VWF is that vibration might operate in both of these disorders through a common mechanism--that is, producing a vasoconstriction in both cochlear and digital blood vessels as a result of sympathetic nervous system activity.

Prevalance of vibration-induced white finger in fluorspar mines in Weardale : D. S. Chatterjee, A. Petrie and W. Taylor 1978 British Journal of Industrial Medicine 35, 208–218. (11 pages, 6 figures, 7 tables, 14 references)

Prevalance of vibration-induced white finger in fluorspar mines in Weardale : D. S. Chatterjee, A. Petrie and W. Taylor 1978 British Journal of Industrial Medicine 35, 208–218. (11 pages, 6 figures, 7 tables, 14 references)

Hand grip forces during chain saw operation and vibration white finger in lumberjacks.

The hand grip forces at the front and rear handles of a chain saw were measured during work, in 89 professional lumberjacks. The symptoms caused by vibration to the upper limbs were compared with the hand grip force (HGF) during work. To allow better comparison between subjects we used the ratio of hand grip force (HGF) to the maximal voluntary compression force (MVC), HGF/MVC expressed as a percentage. The mean HGF during sawing varied from 5 to 12 N in all subjects. The variation in HGF was greater at the front handle than at the rear handle, during sawing. The lumberjacks who had vibration-induced white fingers (VWF), had a higher HGF/MVC in both hands than the lumberjacks without VWF. Those lumberjacks affected by VWF used over 12% of their MVC at work. Subjects without HGF/MVC ratio. The lumberjacks with and without numbness in their hands had equal HGF/MVC ratios.

A decrease in the prevalence and severity of vibration-induced white fingers among lumberjacks in Finland.

One hundred and eighty-seven lumberjacks in eastern Finland and 582 lumberjacks (in two groups of 501 and 81) in different parts of Finland were studied. In the first part of the study with 187 lumberjacks the prevalence of vibration-induced white fingers (VWF) was decreased from 40% in 1972 to 25% in 1975. Retrospectively, the attacks of VWF became more common after 1965, the number of attacks being highest in 1970-1972. The severity of VWF among men who still had attacks was reduced in 1975 in comparison to 1972. The latent period of VWF was about 5,500 chain saw operating hours, which corresponds to five years of operating time, both in 1972 and in 1975. In the second part of the study 40% of 501 lumberjacks had had symptoms indicating VWF during the last two years. The severity of VWF was reduced in half of the subjects with VWF, but the reduction was not as marked as in the first part of the study. Numbness of hands and arms was present in more than half of the subjects in both phases of the study. No evident relief of this symptom had occurred during the follow-up period. The most probable reason for the decrease in the prevalence of VWF appeared to be the vibration damping of chain saws introduced in 1969. In part two of the study 81 lumberjacks had used only antivibration saws. The prevalence of VWF among them was 16% after an exposure time which equaled the mean latent period of VWF.

Prevalence of vibration-induced white finger in fluorspar mines in Weardale.

A combined epidemiological and clinical study of vibration-induced white finger (VWF) was carried out involving 115 men in four fluorspar mines. The overall prevalence of VWF was found to be 50% among 42 vibration-exposed subjects, while that of constitutional white finger (CWF) was 5-6% in all men studied. The VWF latent interval was 1-19 years with a mean of 5-6 years. An association was observed between the exposure time and VWF stages which included 18 men in Stage 0, three in the intermediate Stage of 0T/0N, five in Stage 2 and 16 in Stage 3; no men were seen at Stage 1. Among those with VWF in Stage 3, the index, middle and ring fingers were affected in both hands and the little fingers and thumbs were last to be involved. Clinically, on general examination, apart from vibration-induced white finger, the men in the 'vibration' group were not as healthy as those in the 'control' group. The circumference of the index fingers was not significantly different for the different groups. Neurological tests showed that the ridge test and, to a lesser extent, the two-point discrimination and the light touch tests, could be regarded as useful for the diagnosis of VWF.

Measurement of the energy dissipated in the hand and arm whilst using vibratory tools

Acceleration levels during hand-held grinding have been measured. By controlling the input to a vibration shaker the same acceleration levels were introduced into a specially designed handle gripped by a human hand. From measurements of force, acceleration and phase the power dissipated in the hand was calculated in third-octave bands. Approximate agreement was achieved with power dissipation estimates obtained from the acceleration alone by assuming the hand-arm system to be a linear, single degree of freedom system. The power dissipated is proposed as an important parameter affecting vibration-induced white finger.

Vibration-induced white fingers and manipulative dexterity: P. A. Banister and F. V. Smith 1972 British Journal of Industrial Medicine29, 264–267 (4 pages, 3 tables, 12 references)

Vibration-induced white fingers and manipulative dexterity: P. A. Banister and F. V. Smith 1972 British Journal of Industrial Medicine29, 264–267 (4 pages, 3 tables, 12 references)

Occupational aspects of Raynaud's disease: a critical historical survey.

The literature is reviewed beginning with the first descriptions of occupational Raynaud's disease in the second decade of this century. At the beginning of the fourth decade, the importance of vibration in the ætiology of the disease started to gain acceptance, and this idea solidified during this decade and the next to the extent that the disease is now called “vibration disease”, or “vibration-induced white fingers”, instead of “Raynaud's disease”. The writer maintains that vibration was accepted erroneously as an ætiological factor, and that the perpetuation of this error has confounded investigations into the ætiology of the disease ever since. In the appendix, it is pointed out that certain occupational manifestations of Raynaud's disease have been recently described as a new disease named “occupational acro-osteolysis” and spurious ætiological factors have been postulated for it.