Exposure
Prevalence (%)
Additional information
References
Vibration
Pneumatic drillers, knives, hammers, rock breakers, grinders, chippers
30.2–45
Commonly used in quarries, by stone cutters
Halving the years of exposure allows a doubling of the energy equivalent vibration
Vibration exposure level correlates with severity of vasospastic disease
Symptoms of vasospasm and abnormalities after cold provocation persist despite removal of exposure
Higher frequency of vasospasm among current smokers
Surgical instruments (a type of vibration exposure)
Reported in five patients using pneumatically powered surgical instruments to harvest bone for bone banks
[78]
Developed after 7–32 months of use
3.70
Study of orthopedists
[11]
Dental instruments
4.8–6.1
Studies of dental technicians and dentists
Chain saw operators
5–53
Extensive data in lumberjacks
Risk increases with higher vibration magnitudes and exposure durations
Risk substantially higher in smokers than nonsmokers
Road drilling/breaking
24 % with blanching
Risk of blanching rose with lifetime hours used and dose of vibrating tools
[81]
Chiseling
[28]
Impact wrench use
5.5–26.3
Risk increased exponentially after 12 years of use in one study
Riveting machines/hammers
25.30
340 riveters in aircraft industry studied; 86 with Raynaud’s
[84]
Among the subgroup exposed for >10 years, 50 % had Raynaud’s even though mean daily exposure was ~1 minute/day
Pounding and lasting machines
[28]
Brush saws
Japanese longitudinal study from 1961–1980
[85]
12 % prevalence in cohort starting in 1961–1962; 0 % in cohort beginning in 1969–1970
Prevalence increases with exposure time
Often used during warmer season for grass trimming and limbing; may account for lower prevalence rate than reported with chain saws
Sewing machines
4.30
Grinding or polishing machines
3.7–23
Lower body weight was a risk factor in a study of Swedish aircraft employees
Single axle tractors
10
If used 8 h/day in full load, high risk of white finger after only 3–4 years
[88]
Car mechanics
15
Increased to 25 % after 20 years
[89]
High pressure hose use
[90]
Mechanical percussion and palmar trauma
Carpenters
[68]
Masons
[68]
Metal workers
[68]
Factory workers
[68]
Typists
[28]
Pianists
[28]
Recreational exposure through martial arts or other sports
[68]
Cold
Meat cutters and wrappers
9 % of women/2 % of men
Risk higher if >5 years of working in poultry slaughterhouse, <4 rest breaks, taking breaks in nonheated room, exertion of the hand or arm, and performing continual repetition of the same series of operations
[91]
Fishing company employees
Risk of Raynaud’s was higher in workers exposed to alternating heat and cold compared to workers with long term cold exposure
[92]
Acute thermal injury such as frostbite
In a study of 1,095 reindeer herders, frostbite was more common in patients with vibration-induced vasospasm (27 %) than in patients without vasospasm (5 %)
[93]
Electric shock injury
[94]
Prevalence and Risk Factors
The reported prevalence of Raynaud’s phenomenon of traumatic and occupational origin varies significantly across geographic region of study, in part due to differing climate and occupational exposures. Most prevalence estimates in the literature focus on a particular profession (see Table 9.1 for details) rather than a large regional or national workforce. In addition, many estimates in the literature predate the use of antivibration devices on tools and are now outdated.
Roquelaure and colleagues performed a cross-sectional study in the Loire Valley area of West-Central France between 2002 and 2005 [5]. In this area, an occupational physician examines all French workers annually. The study population consisted of 2,161 men and 1,549 women, and 31 men (1.4 %) and 56 women (3.6 %) were diagnosed with Raynaud’s phenomenon. Risk factors for the development of Raynaud’s phenomenon included female gender, older age, lower body mass index, exposure to a cold environment or object for >4 h/day, and performance of highly repetitive tasks. High psychological demands at work and low support from supervisors were also noted to be risk factors in women.
In Great Britain, investigators mailed a questionnaire to a random sample of 22,194 working age adults to ascertain the prevalence of Raynaud’s phenomenon [6]. Responses were obtained from 6,913 men and 5,994 women; 14.2 % endorsed a history of finger blanching, 11.8 % noted blanching was cold induced, and 4.6 % noted there was clear border of demarcation between pallor and normal color in their finger. Smoking was a risk factor for Raynaud’s phenomenon in men. It was estimated that approximately one-third of Raynaud’s phenomenon cases among men in Britain were attributable to hand vibration exposure. The authors estimated that, at the time this study was conducted, 222,000 men nationally had extensive blanching (affecting 8+ digits or 15+ phalanges) attributable to hand transmitted vibration.
In a Japanese population, Harada and colleagues studied 1,875 men and 1,998 women to determine the local prevalence of Raynaud’s phenomenon [7]. A physician interviewed all individuals, and it was estimated that 3.3 % of males and 2.5 % of females had Raynaud’s phenomenon. For men, the prevalence rate of Raynaud’s phenomenon was seven times higher in manual laborers than in desk workers; Raynaud’s phenomenon cases were attributed to vibration exposure in 49 % of male cases, to trauma in 15 %, and to collagen vascular disease in 3 %. In comparison, only 4 %, 6 %, and 4 % of female cases were attributed to vibration, trauma and collagen vascular disease, respectively. Interestingly, the prevalence rate of Raynaud’s phenomenon increased with age among men and decreased with age among women (Fig. 9.1).
Fig. 9.1
Prevalence rate of Raynaud’s phenomenon divided into three parts according to presumed causes (upper: vibration syndrome; middle: trauma to the fingers; and lower: other causes). Reprinted with permissions from SAGE Publications
In one US investigation, authors examined the incidence and natural history of Raynaud’s phenomenon in the community-based Framingham cohort study [8]. Approximately 11 % of women and 7.8 % of men had baseline prevalent Raynaud’s phenomenon; over the study follow-up period, incident Raynaud’s phenomenon developed in 2.2 % of women and 1.5 % of men. Subjects were followed for an average of 7.1 years. Raynaud’s phenomenon symptoms persisted over the study period in ~36 % of men and women, and remitted in the remainder. Among men, 11.3 % of those without Raynaud’s phenomenon had a history of occupational vibratory tool use compared to 22.2 % of men with incident Raynaud’s and 27.8 % of men with persistent Raynaud’s.
Lastly, one study examined the geographic variation in Raynaud’s phenomenon prevalence across five regions, one in South Carolina, USA and four in France [9]. Climate was clearly a major driver of the development of Raynaud’s phenomenon, and the majority of Raynaud’s cases had lived their entire lives in a cold climate. Patients with Raynaud’s in warmer climates had previously lived in colder climates. In the multivariable model, the relative odds of Raynaud’s phenomenon was 1.93 (95 % CI 1.07, 3.49) times higher in individuals using vibrating tools than in those who do not use such tools. Older age, lower BMI, frequent outings lasting more than 1 day in duration, cardiovascular disease and a family history of Raynaud’s were also predictors for the development of Raynaud’s.
Features Unique to Vibration Exposure
The United States National Institute of Occupational Safety and Health has estimated that approximately two million workers in the USA and UK have clinically significant hand-arm vibration [3]. The cumulative vibration dose, which is a function of vibration magnitude/acceleration and exposure duration, is strongly predictive of the development and the severity of traumatic vasospastic disease [3, 10–15]. In one study, the prevalence of vasospastic disease was 0–4.8 % among workers exposed to hand-transmitted vibration levels of 1.1–2.5 m/s2 and reached 9.6 % among workers exposed to levels of 2.7–5.1 m/s2 [11]. The prevalence of vasospastic disease at these lower vibration doses may not differ significantly from the expected prevalence of Raynaud’s phenomenon in the general population, although the safe vibration threshold may vary by ethnicity or geography [16]. In another survey, full time pneumatic grinders working in a shipyard had a significantly higher prevalence of vibration induced vasospastic disease compared to workers with part time vibration exposure (71 % vs. 33 %) [12]. Lastly, a third longitudinal study examined changes in the prevalence of vibration induced vasospastic disease among professional forestry workers in Finland from 1972 to 1990 [13]. Over this follow-up time, the weighted vibration acceleration of chain saws decreased significantly from ~14 to 2 m/s2 [13]. The prevalence of vasospastic disease correspondingly decreased from 40 to 5 % [13]. In addition to vibration magnitude, exposure duration is a significant risk factor for the development of vasospastic disease. In a study of 447 Japanese chain saw operators, the prevalence of vasospastic disease increased with exposure duration: 2.5 % with ≤14 years of use, 5 % with 15–19 years of use, 11.7 % with 20–24 years of use, 13.1 % with 25–29 years of use, and 20.9 % with ≥30 years of use [17].
As detailed above, smoking, a family history of Raynaud’s phenomenon, prior arm injury, and exposure to a cold climate are also risk factors for developing vibration induced vasospastic disease [18]. Smokers have more advanced vasospastic disease based on symptoms and increased vasoreactivity on cold provocation testing [19, 20]. Concomitant cold and vibration exposure significantly increases the risk of Raynaud’s phenomenon. In a study of 134,757 Swedish male construction workers, the relative odds of developing white fingers was 1.7 times higher in vibration exposed workers in a colder climate than exposed workers in a warmer climate [21]. Similarly, a Chinese study detected a higher prevalence of vibration induced vasospastic disease in riveters, chippers and grinders from cooler regions (19.2–19.4 %) compared to those from warmer regions (7.3–9.1 %) [22].
Clinical Characteristics
Pallor and numbness characterize vasospastic episodes of a traumatic origin, and it is reported that cyanosis and pain are less common [23]. These episodes are often asymmetric with the hand that has been traumatized being more severely affected [1, 24]. In one study, it was noted that men with vibration induced Raynaud’s phenomenon had fewer involved fingers but more frequent attacks than men with primary Raynaud’s disease [7]. Most cases of digital trauma-induced Raynaud’s phenomenon are localized to the traumatized digit or just a few fingers [7, 25, 26]. However, it has been reported that the contralateral hand may be more frequently or severely affected than the exposed hand [27]. The feet are generally spared [28].
Vasospastic attacks can be precipitated by ongoing use of vibratory tools or cold exposure. Symptoms may persist years after removal from the exposure, however [29]. In a longitudinal study of 204 symptomatic, former users of pneumatic tools, skin temperature recovery after cold challenge remained impaired for years after eliminating the exposure [29]. Interestingly in one study, lumberjacks with Raynaud’s phenomenon had vasospastic episodes triggered by chain-saw noise alone [30].
Medium sized arterial thrombosis and digital necrosis can develop in severe cases [25, 31]. While palmar trauma is a major cause of hypothenar hammer syndrome (see details below), vibration has also been reported to cause hypothenar hammer syndrome in a subset of patients [32, 33].
Patients with vibration exposure may also have hearing loss, digital polyneuropathy, and carpal tunnel syndrome [34–36]. Vibrotactile senses are often impaired resulting in impaired grip force with a tendency to drop items, numbness, and difficulty with finger dexterity including tasks such as buttoning and pouring from a jug [37, 38].
Diagnostic Approach
Correctly diagnosing Raynaud’s phenomenon of traumatic or occupational origin is critical as this often affects workman’s compensation claims. Subjective history alone is often unreliable. In one study of 36 workers with a history of occupational hand-arm vibration exposure and a diagnosis of Raynaud’s phenomenon, only 57 % of individuals were able to demonstrate photographic evidence consistent with Raynaud’s phenomenon [39]. In another study, 83.5 % of compensation claimants reported Raynaud’s symptoms, but only 46.8 % had evidence of vasospasm after provocative testing using a severe cooling protocol [40]. Elms and colleagues have suggested a highly sensitive 6-item screening questionnaire to assess for hand arm vibration syndrome (Table 9.2) [41], and severity of disease is staged according to the Stockholm Workshop scale [42]. Nailfold capillary abnormalities may be present in patients with vibration induced vasospastic disease. In one small study, ten patients with vibration induced vasospastic disease were compared to ten age matched controls [43]. Seventy percent of patients had capillary dropout, and 30 % had tortuous, elongated capillary loops; these abnormalities were not present in the controls [43]. In another investigation, lumberjacks with Raynaud’s phenomenon were compared to a control population and similarly demonstrated a reduction in the number of nailfold capillaries [44].
Sensorineural questions |
Do you suffer from numbness in response to the cold? |
Do you suffer from tingling in response to the cold? |
Do you suffer from tingling (for longer than 20 min) after using vibratory tools? |
Do you suffer from numbness (for longer than 20 min) after using vibratory tools? |
Vascular questions |
Have you ever suffered with your fingers going white on exposure to cold? |
Do you suffer from numbness during attack of whiteness? |
Tools to improve accuracy in diagnosis, such as infrared thermometry or assessment of finger systolic blood pressure after cold challenge, are an active area of research in the occupational health literature. Studies have demonstrated that patients with vibration induced Raynaud’s have an altered digital cutaneous temperature [45], a long rewarming time after cold water immersion [45, 46], and abnormal finger systolic blood pressure measurements [47–49]. Further validation studies are needed to determine whether these tools are sensitive and specific for the diagnosis of trauma induced vasospastic disease. If traumatic vasospastic disease is suspected, referral to an occupational health specialist is recommended.
Pathophysiology and Pathology
The exact mechanism causing abnormal vascular reactivity following vibration or traumatic injury is not fully defined. Vibration may result in direct vascular damage and neural dysfunction, both of which may contribute to vasospasm and Raynaud’s phenomenon [50]. Dysautonomia due to sympathetic hyperactivity or parasympathetic depression may result in vasoconstriction [50–54]. Data also support the presence of peripheral neural dysfunction that may result in peripheral vasoconstriction, increased vibration and thermal perception thresholds, and slowed digital sensory and motor nerve conduction velocities [50]. In one study, 21 patients with vibration white finger and 17 controls underwent cold water immersion of their right hand for 10 min, and power spectral analysis of heart rate variability was performed to assess autonomic nervous function [34]. The patients with vibration white finger had evidence of increased sympathetic activity with cold water immersion, and they had significantly lower cutaneous temperature after 5 min of cold water immersion and in the recovery period [34]. Vascular manifestations may reflect a combination of microangiopathy, vasospasm and arterial thrombosis [55]. Vascular biomarker studies suggest that there is endothelial damage and dysfunction, impairment in smooth muscle responses to nitric oxide, and an increase in adhesion molecules that may contribute to microvascular damage in patients with vibration-induced Raynaud’s [50, 56, 57]. Additional data about the pathophysiology of cutaneous vasospastic diseases are covered in Chap. 11.
Pathologic abnormalities have been detected in blood vessels, surrounding nerves and connective tissue in patients with vibration induced vasospastic disease [58]. Hypertrophy of muscle cells of arteries and medial thickening, periarterial fibrosis, a marked loss of peripheral nerve fibers, severe loss of myelin sheath, regenerated smaller axons without myelin, and collagen deposition in perivascular and perineural lesions with destruction of elastic fibers have been observed [58].
Treatment and Prevention
Affected patients need to change their occupational exposure to minimize recurrent attacks, and if this is not feasible, modifications in the work routine may be required to reduce vibration exposure time and cold work environments [59]. In addition, patients should be advised to grip their tools lightly to reduce vibration transmission [59]. Smoking cessation is also critical. In a cross-sectional study of former users of pneumatic tools, smokers had more severe vasospasm, as assessed by cold challenge plethysmography, than nonsmokers [60]. Subjects who quit smoking had comparable test results with those of nonsmokers, with physiologic benefits persisting 1 year after smoking cessation [60]. Standard vasodilator therapy including calcium channel blockers may also be beneficial [59, 61].
Anti-vibration devices on tools have increased the latent interval between vibration exposure and the development of Raynaud’s syndrome, and there has been significant progress in the modification and design of new tools in high risk groups [3]. Device modifications include using isolation and damping techniques to reduce vibration transmission, properly servicing and maintaining older tools, and ensuring hand tools are ergonomically designed to minimize strain on the user [59, 62]. The use of vibration proof tools has dramatically reduced the risk of vibration induced Raynaud’s phenomenon [63]. Patients at risk should wear gloves to maintain warmth and attenuate vibration exposure [59]. In developed countries, regulations to minimize exposure and to monitor individuals at risk with robust occupational health care systems have also led to significant decreases in the prevalence of hand-arm vibration syndrome [3, 64]. Workers paid by the hour may be incentivized to have greater exposure and therefore risk of complications [3, 62], and job rotation or adequate rest periods between use are encouraged [59, 65].
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