Hypothenar hammer syndrome: a discrete syndrome to be distinguished from hand-arm vibration syndrome.
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BACKGROUND: Hypothenar hammer syndrome (HHS) is a cause of vascular insufficiency to the hand and may be manifest as Raynaud's phenomenon. The cause is trauma to the vulnerable portion of the ulnar artery as it passes over the hamate bone, which may result in thrombosis, irregularity or aneurysm formation. AIM: This review was undertaken in order to clarify the features of HHS that may differentiate it from hand-arm vibration syndrome. METHODS: A tiered review of world literature was undertaken using Medline and EMBase as the primary search engines. Fifty-two relevant articles were critically reviewed. CONCLUSION: Colour and temperature changes occur more diffusely in HHS than in classical Raynaud's phenomenon and the absence of the triphasic colour change may alert clinicians to the diagnosis, which may be confirmed by Allen's test. Doppler or arteriographic studies are required for confirmation. It is important to recognize the possibility of HHS in the occupational setting as a potentially curable cause of Raynaud's phenomenon, distinct from hand-arm vibration syndrome. The possibility exists of HHS occurring as a result of repeated hypothenar trauma from vibrating tools, in which case the nature and magnitude of the individual episode of trauma may be more important than the weighted acceleration level of vibration exposure. (+info)
A critique of a UK standardized test of finger rewarming after cold provocation in the diagnosis and staging of hand-arm vibration syndrome.
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BACKGROUND: Accurate diagnosis and staging of hand-arm vibration syndrome (HAVS) is important in health surveillance of vibration-exposed workers and the substantial number of related medico-legal cases. The measurement of the rewarming rate of fingers after cold provocation to the hands (CPT) has been suggested as a useful test in diagnosing HAVS. AIM: To investigate the diagnostic value of a standardized version of the CPT test using a 15 degrees C cold challenge for 5 min applied in the recent compensation assessment of UK miners. METHODS: Analysis of a subset of UK miners assessed at our unit, together with data from a small repeatability study of the standardized CPT in normal subjects. RESULTS: Rewarming time in the CPT was significantly lower in those subjects classified as vascular Stockholm stage 0 compared with Stockholm stages 1-3 combined, but did not discriminate between the stages of abnormality. Using the suggested cut-off in the CPT test, the sensitivity and specificity were calculated as 43 and 78%, respectively. Receiver operator characteristic analysis suggested that the rewarming time of highest accuracy gave a sensitivity of 66% and specificity of 59%. In 10 miners who reported unilateral hand blanching, there was no significant difference in CPT measurements between blanching and non-blanching hands. Repeat CPT measurements in normal subjects suggested mean differences of 52 and 107 s for each hand, and the Bland-Altman coefficient of repeatability was approximately 600 s for all fingers. CONCLUSION: Single application of this standardized CPT test may have limited value in diagnosing the vascular component of HAVS in an individual. (+info)
Thoracic outlet syndrome--aspects of diagnosis in the differential diagnosis of hand-arm vibration syndrome.
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BACKGROUND: Thoracic outlet syndrome (TOS) is a cause of vascular and neurological compromise to the arm and hand, and may manifest as Raynaud's phenomenon. It may be under-diagnosed. AIM: This review was undertaken in order to clarify the diagnostic and investigative features of TOS that may differentiate it from hand-arm vibration syndrome. METHODS: A tiered review of the world literature was undertaken using Medline and Embase as the primary search engines. CONCLUSION: Thoracic outlet syndrome most commonly presents with neurological symptoms in the arm. Vascular symptoms, including Raynaud's phenomenon, may occur in approximately 10% of cases. Careful clinical assessment by history and examination may reveal the elements of forearm and upper arm symptoms with postural exacerbation, which distinguish this condition from hand-arm vibration syndrome. The usefulness of investigation is unclear, but Doppler and neuroelectric studies may be valuable. Magnetic resonance imaging scan is the investigation of choice. (+info)
Median nerve trauma in a rat model of work-related musculoskeletal disorder.
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Anatomical and physiological changes were evaluated in the median nerves of rats trained to perform repetitive reaching. Motor degradation was evident after 4 weeks. ED1-immunoreactive macrophages were seen in the transcarpal region of the median nerve of both forelimbs by 5-6 weeks. Fibrosis, characterized by increased immunoexpression of collagen type I by 8 weeks and connective tissue growth factor by 12 weeks, was evident. The conduction velocity (NCV) within the carpal tunnel showed a modest but significant decline after 9-12 weeks. The lowest NCV values were found in animals that refused to participate in the task for the full time available. Thus, both anatomical and physiological signs of progressive tissue damage were present in this model. These results, together with other recent findings indicate that work-related carpal tunnel syndrome develops through mechanisms that include injury, inflammation, fibrosis and subsequent nerve compression. (+info)
Prognosis of shoulder tendonitis in repetitive work: a follow up study in a cohort of Danish industrial and service workers.
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BACKGROUND: The physical and psychosocial work environment is expected to modify recovery from shoulder disorders, but knowledge is limited. METHODS: In a follow up study of musculoskeletal disorders in industrial and service workers, 113 employees were identified with a history of shoulder pain combined with clinical signs of shoulder tendonitis. The workers had yearly re-examinations up to three times. Quantitative estimates of duration, repetitiveness, and forcefulness of current tasks were obtained from video recordings. Perception of job demands, decision latitude, and social support was recorded by a job content questionnaire. Recovery of shoulder tendonitis was analysed by Kaplan-Meier survival technique and by logistic regression on exposure variables and individual characteristics in models, allowing for time varying exposures. RESULTS: Some 50% of workers recovered within 10 months (95% CI 6 to 14 months). Higher age was strongly related to slow recovery, while physical job exposures were not. Perception of demands, control, and social support at the time when the shoulder disorder was diagnosed, were associated with delayed recovery, but these psychosocial factors did not predict slow recovery in incident cases identified during follow up. CONCLUSION: The median duration of shoulder tendonitis in a cross sectional sample of industrial and service workers was in the order of 10 months. This estimate is most likely biased towards too high a value. Recovery was strongly reduced in higher age. Physical workplace exposures and perceived psychosocial job characteristics during the period preceding diagnosis seem not to be important prognostic factors. (+info)
Seasonal variation in neck and shoulder symptoms.
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The objective of the investigation was to study the course of neck and shoulder symptoms and the predictors for these symptoms among women in light sedentary work. Postal surveys were conducted among 351 tellers (age 20-50 years) of a bank company in September, December, March, and May. The response rates were 74-90%. The outcome was the frequency of the symptoms during the previous three months. In the analysis, univariate explorations and random-effects logistic binomial regression for distinguishable responses were used. A change in the frequency of neck and shoulder symptoms was seen in 40.5% of the subjects during the follow-up period from autumn to spring. The frequency of the symptoms decreased from autumn and winter towards spring. The stability of the frequency of the symptoms was positively associated with age. Seasonal variation in symptoms should be considered when preventive programs against neck and shoulder disorders are planned and evaluated. (+info)
Electromyographic signs of shoulder muscle fatigue in repetitive arm work paced by the Methods-Time Measurement system.
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Surface electromyographic (EMG) recordings from the lateral and cervical portions of the descending trapezius muscle and from the infraspinatus muscle were assessed for six female subjects performing a standardized repetitive work simulation task for 1 h. The work pace was determined according to the Methods-Time Measurement system to 2466 cycles.h-1. The variation in load levels were high and indicated dynamic muscle activity. A decrease in the EMG mean power frequency and an increase in the root-mean-square amplitudes, both indicating muscle fatigue, developed in all muscles of most of the subjects. EMG signs of fatigue, analyzed separately for each 5-min period, showed variable fatigue patterns both between muscles and between subjects. It is therefore suggested that dynamic work movements do not protect the muscles of the shoulder and neck from fatiguing processes in highly repetitive work with short cycle times. (+info)
Repetitive strain disorder: towards diagnostic criteria.
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Thirteen women (mean age 48.2 years; range 25-60 years) all of whom had developed musculoskeletal symptoms during employment in an industrial job with repetitive tasks were referred by their trade unions for adjudication on the cause of symptoms. One had rheumatoid arthritis. A study of the other 12 women provided an opportunity to document the natural history of repetitive strain disorder. Early symptoms of weakness were diffuse but were always relieved by rest. Several months later localisation of symptoms at a tendon, nerve, or enthesis could be predicted from the analysis of the action required in the particular repetitive task. Six of the 12 women required an operation several years later, thus providing histological confirmation of the presence of a lesion. Early loss of grip strength measured by a sphygmomanometer cuff compared with an unaffected control subject and improved by rest may be the most valuable sign in excluding compensation neurosis. The estimated prevalence of repetitive strain disorder defined by these strict criteria was at least 2% in conveyor belt workers. (+info)