Evaluation of Work-Related Carpal Tunnel Syndrome

Objectives: Carpal tunnel syndrome (CTS) is common in the industrial setting but there are still some advocates who argue that CTS is not a work related problem. There are also controversies about the proper way to establish the diagnosis and whether screening for CTS in the industrial setting is warranted. Methods: A comprehensive literature review. Results: The literature does demonstrate that the prevalence of CTS in the industrial setting is significantly higher than in the general population. Numerous epidemiologic studies have identified independent risk factors, which include repetitiveness of work, forceful exertions, mechanical stress, posture, and vibration as well as several personal co-factors. The strength of these associations are discussed. The diagnostic criteria for establishing work-related CTS are discussed as well as the effectiveness of various screening methods that are commonly used in the workplace. The sensitivity and specificity of nerve conduction studies to establish or confirm the diagnosis of CTS is presented along with normative data for the industrial worker. Conclusions: CTS has both work-related and personal risk factors. The diagnosis is best established using a combination of history, symptom distribution and confirmation using the relative latency of median sensory testing using normative data. Screening for CTS in the industrial setting has questionable benefit.     

Association of Occupational and Non-occupational Risk Factors with the Prevalence of Work Related Carpal Tunnel Syndrome

PURPOSE: Several occupational and personal risk factors cause the development of carpal tunnel syndrome (CTS). The purpose of the study was to evaluate both non-occupational and occupational factors associated with CTS in industrial workers. METHODS: A cross sectional study was designed with 400 industrial workers (77% male, 23% female) randomly selected. Workers' upper extremities were examined and related signs and symptoms were assessed. Questionnaires about personal and occupational risk factors were completed and suspicious cases were referred for NCV (nerve conduction velocity) testing and documentation of diagnosis. RESULTS: About 395 workers from automobile industry factories in Iran were assessed by interview and electrodiagnostic studies. Among 395 workers, 47 met the definition of CTS to yield a prevalence of 11.9%. These 47 workers averaged 29.85 years of age (SD = 6.28), and the mean age of the healthy group was 27.95 (SD = 4.86). 395 workers included 91 women (23%) and 304 men (77%). Using multivariate logistic regression model the largest adjusted odds ratios of personal and occupational factors for CTS were: exertion of force over one kilogram 6.38 (1.91-2.02); bending/twisting of the hands/wrists > 30 degrees , 5.62 (0.56-55.6); history of cigarette smoking 4.68 (1.80-11.80); rapid movement of hands 4.44 (1.41-14.02); and use of vibrating tools 3.23 (1.46-7.15). CONCLUSION: Some occupational factors including force exertion, bending/twisting of the hands, rapid movement of the hands and vibration are associated with CTS.     

The Impact of Carpal Tunnel Syndrome on Work Status: Implications of Job Characteristics for Staying on the Job

This prospective study tested the contribution of occupational factors to a multifactorial predictive model of work status among patients with carpal tunnel syndrome (CTS). The study recruited a community-wide sample of patients and included cases that were non-occupational as well as occupational in etiology. At baseline and follow-up 18 months later, trained interviewers administered a structured telephone questionnaire to 102 participants, that included items on demographics, medical history, psychosocial, and occupational factors. Multivariate logistic regression analyses indicated that patients presenting with CTS were more likely to continue working if they had modifications to their jobs, worked for employers with fewer than 250 employees, and held jobs not characterized by the frequent use of force. We also found that White (non-Hispanic) patients were more likely to continue working than those from other ethnic groups. Our findings also suggest that job strain may contribute to earlier changes in work status following diagnosis. The receipt of worker compensation was not found to be a significant predictor of work status. Workplace assessment and job modification appear to be important aspects of care for the worker presenting with CTS, regardless of whether the CTS is occupationally caused or not.     

A Longitudinal Study of Industrial and Clerical Workers: Incidence of Carpal Tunnel Syndrome and Assessment of Risk Factors

This study followed workers over an extended period of time to identify factors which may influence the onset of Carpal Tunnel Syndrome (CTS). The purpose was to evaluate incidence of CTS and to create a predictive model of factors that play a role in the development of CTS. This prospective study followed 432 industrial and clerical workers over 5.4 years. Incident cases were defined as workers who had no prior history of CTS at baseline testing and were diagnosed with CTS during the follow-up period or at the follow-up screening. On the basis of logistic regression, significant predictors for CTS include baseline median-ulnar peak latency difference, a history of wrist/hand/finger tendonitis, a history of numbness, tingling, burning, and/or pain in the hand, and work above the action level of the peak force and hand activity level threshold limit value. This longitudinal study supports findings from previous cross-sectional studies identifying both work related ergonomic stressors and physical factors as independent risk factors for CTS.     

Applicability of the Brighton Collaboration Case Definition for seizure after immunization in active and passive surveillance in Canada

Background

The Canadian Adverse Event Following Immunization Surveillance System (CAEFISS) receives reports via active syndromic surveillance for selected serious AEFI from the Canadian Immunization Monitoring Program Active (IMPACT) and via targeted passive surveillance from Federal/Provincial/Territorial health jurisdictions. Post-immunization seizure is a target of active and passive surveillance. Since 2009, the revised national AEFI reporting forms enable capture of terms specific to several Brighton Collaboration Case Definitions (BCCD) including generalized seizure and fever.

Objective

To evaluate feasibility of applying the BCCD for generalized seizure to adverse event following immunization (AEFI) reports collected by IMPACT and targeted passive surveillance (non-IMPACT).

Methods

Reports to CAEFISS coded as seizure in children <2 years of age (vaccination dates 1998–2011) were reviewed retrospectively. A BCCD level (1–5 or unclassifiable) was assigned. The effects of reporting source (IMPACT versus non-IMPACT), seriousness [serious (e.g., hospitalized) versus non-serious], vaccination year (1998–2008 versus 2009–2011), and data submission method to CAEFISS (electronic versus paper) were assessed by stratified analysis.

Results

There were 459 IMPACT and 908 non-IMPACT cases analyzed, of which 99.6% and 27%, respectively, were serious reports. The revised reporting form that captured the BCCD components (2009–2011) was associated with increased proportions of IMPACT and non-IMPACT cases meeting the BCCD for generalized seizure.

Conclusions

Incorporating the BCCD components (level of consciousness, motor manifestations and fever ≥38 °C) into the national reporting form and guidelines appeared to improve the feasibility of their use in AEFI surveillance. This effect was more pronounced among active syndromic surveillance compared to targeted passive surveillance reports.     

Carpal tunnel release surgery: small-area variation and impact of ambulatory surgery in the autonomous region of Valencia,Spain

Objective

This study aimed to analyze variability in rates of carpal tunnel release surgery among the healthcare areas of the autonomous region of Valencia, and to evaluate the contribution of ambulatory surgery and referrals to private hospitals to the variability found.

Methods

We carried out a cross-sectional, population-based study, describing the rates of carpal tunnel release surgery, standardized by age and sex, among areas in the region of Valencia in 2006. The observed variation was then analyzed using small-area analysis methods. Data from hospital admissions, referrals to private hospitals, population statistics and hospital resources were used to construct standardized rates, and Spearman's correlation was used to test the association with surgical setting and hospital resources.

Results

There were 8.2 carpal tunnel release surgeries per 10,000 inhabitants in the region of Valencia in 2006. Most (88.2%) of these interventions were performed as ambulatory surgery. After we excluded areas outside the 5th-95th percentiles, variation among areas was moderate and was similar for men and women. Variation was not associated with the proportion of the distinct surgical settings (admission to a public hospital, outpatient clinic, or referral to a private hospital) used in each area, or with the availability of resources.

Conclusions

Variation in carpal tunnel release surgery among areas in the region of Valencia is moderate, but has a strong impact on the population because of the high prevalence of this disorder. This variation is not explained by the hospital resources available in each area or the surgical setting.     

Prevalence and Work-Relatedness of Self-Reported Carpal Tunnel Syndrome Among U.S. Workers: Analysis of the Occupational Health Supplement Data of 1988 National Health Interview Survey

To estimate the prevalence and work-relatedness of self-reported carpal tunnel syndrome (CTS) among U.S. workers, data from the Occupational Health Supplement of 1988 National Health Interview Survey (NHIS) were analyzed. Among 127 million “recent workers” who worked during the 12 months prior to the survey, 1.47% (95% CI: 1.30; 1.65), or 1.87 million self-reported CTS, and 0.53% (95% CI: 0.42; 0.65), or 675,000, stated that their prolonged hand discomfort was called CTS by a medical person. Occupations with the highest prevalence of self-reported CTS were mail service, health care, construction, and assembly and fabrication. Industries with the highest prevalence were food products, repair services, transportation, and construction. The risk factor most strongly associated with medically called CTS was exposure to repetitive bending/ twisting of the hands/wrists at work (OR = 5.2), followed by race (OR = 4.2; whites higher than nonwhites), gender (OR = 2.2; females higher than males), use of vibrating hand tools (OR = 1.8), and age (OR = 1.03; risk increasing per year). This result is consistent with previous reports in that repeated bending/twisting of the hands and wrists during manual work is etiologically related to occupational carpal tunnel syndrome.     

Reliability of a digital electroneurometer for the determination of motor latency of the median nerve

Measurement of distal motor latencies of the median nerve are often part of electrodiagnostic studies used to verify a diagnosis of peripheral neuropathy. Since electrodiagnostic studies are time consuming, expensive, and impractical for large-scale screening of at-risk individuals, a portable digital electroneurometer was developed for measuring motor latencies as a screening tool for early detection of nerve compression syndromes, including carpal tunnel syndrome. The purpose of this study was to determine the intertester and intratester reliability of a digital electroneurometer in subjects with (n=12) and without (n=20) clinical signs of carpal tunnel syndrome. This study addressed only the reliability and not the validity of this device. Using a repeated measures design, three evaluators performed two distal motor latency tests on the median nerve of each of the subjects. Pearson product-moment correlations for intratester reliability ranged from 0.94 to 0.99, and the intraclass correlation coefficient for intertester reliability was 0.96. Two examiners obtained statistically larger latency values on the second test, although these differences are judged to be clinically insignificant. Use of an electroneurometer may expand motor latency testing to a wider variety of settings.     

Comparison of a digital electroneurometer and standard nerve conduction studies for the measurement of median nerve sensory latency

The purpose of this study was to determine the validity of measuring median nerve distal sensory latency with a portable digital electroneurometer. The results from the digital electroneurometer were compared to standard nerve conduction studies in 51 subjects (40 asymptomatic hands and 12 hands with probable carpal tunnel syndrome). There was a high correlation (r=0.92) between the latencies obtained from the electroneurometer and the onset latencies measured by standard nerve conduction studies. The mean difference between distal sensory latencies for matched pairs of latency measurements was 0.09 (+/–0.21) ms. The use of the digital electroneurometer for obtaining distal sensory latencies proved to be objective and valid. The electroneurometer would be useful in a variety of occupational and clinical settings for screening of peripheral neuropathy where standard nerve conduction equipment may be unavailable or impractical.