Theodore K. Courtney

Occupational slip, trip, and fall-related injuries can the contribution of slipperiness be isolated?

To determine if the contribution of slipperiness to occupational slip, trip and fall (STF)-related injuries could be isolated from injury surveillance systems in the USA, the UK and Sweden, six governmental systems and one industrial system were consulted. The systems varied in their capture approaches and the degree of documentation of exposure to slipping. The burden of STF-related occupational injury ranged from 20 to 40% of disabling occupational injuries in the developed countries studied. The annual direct cost of fall-related occupational injuries in the USA alone was estimated to be approximately US

Injuries at Work in the US Adult Population: Contributions to the Total Injury Burden

6 billion. Slipperiness or slipping were found to contribute to between 40 and 50% of fall-related injuries. Slipperiness was more often a factor in same level falls than in falls to lower levels. The evaluation of the burden of slipperiness was hampered by design limitations in many of the data systems utilized. The resolution of large-scale injury registries should be improved by collecting more detailed incident sequence information to better define the full scope and contribution of slipperiness to occupational STF-related injuries. Such improvements would facilitate the allocation of prevention resources towards reduction of first-event risk factors such as slipping.

The role of friction in the measurement of slipperiness, Part 2: Survey of friction measurement devices

OBJECTIVES We estimated the contribution of nonfatal work-related injuries on the injury burden among working-age adults (aged 18-64 years) in the United States. METHODS We used the 1997-1999 National Health Interview Survey (NHIS) to estimate injury rates and proportions of work-related vs non-work-related injuries. RESULTS An estimated 19.4 million medically treated injuries occurred annually to working-age adults (11.7 episodes per 100 persons; 95% confidence interval [CI]=11.3, 12.1); 29%, or 5.5 million (4.5 per 100 persons; 95% CI=4.2, 4.7), occurred at work and varied by gender, age, and race/ethnicity. Among employed persons, 38% of injuries occurred at work, and among employed men aged 55-64 years, 49% of injuries occurred at work. CONCLUSIONS Injuries at work comprise a substantial part of the injury burden, accounting for nearly half of all injuries in some age groups. The NHIS provides an important source of population-based data with which to determine the work relatedness of injuries. Study estimates of days away from work after injury were 1.8 times higher than the Bureau of Labor Statistics (BLS) workplace-based estimates and 1.4 times as high as BLS estimates for private industry. The prominence of occupational injuries among injuries to working-age adults reinforces the need to examine workplace conditions in efforts to reduce the societal impact of injuries.

Clinical management and the duration of disability for work-related low back pain

This paper seeks to address questions related to friction measurement such as how friction is related to human-centred assessment and actual slipping, and how repeatable friction measurements are. Commonly used devices for slipperiness measurement are surveyed and their characteristics compared with suggested test conditions from biomechanical observations summarized in Part 1. The issues of device validity, repeatability, reproducibility and usability are examined from the published literature. Friction assessment using the mechanical measurement devices described appears generally valid and reliable. However, the validity of most devices could be improved by bringing them within the range of human slipping conditions observed in biomechanical studies. Future studies should clearly describe the performance limitations of any device and its results and should consider whether the device conditions reflect these actual human slipping conditions. There is also a need for validation studies of more devices by walking experiments.

Physicians' Initial Management of Acute Low Back Pain Versus Evidence-Based Guidelines: Influence of Sciatica

Clinical practice guidelines recommend a conservative approach to management of acute low back pain (LBP). The present study sought to determine whether health care utilization and the physician’s initial management of work-related LBP were associated with disability duration. Clinical management information was obtained for 98 randomly selected, workers’ compensation claimants with acute, uncomplicated, disabling work-related LBP. Length of disability was based on indemnity (wage replacement) payments. Disability was significantly associated with increased utilization of specialty referrals (P = 0.013) and provider visits (P < 0.001), use of magnetic resonance imaging (P = 0.003), and use of opioids for more than 7 days (P = 0.013). Effects of early diagnostic imaging (first 30 days of care) on length of disability were observed (P = 0.001). Patients whose treatment course did not involve extended opioid use and early diagnostic testing were 3.78 times more likely (95% confidence interval, 1.6 to 8.9) to have gone off disability status by the end of the study. The nature of the association between these initial clinical management aspects and LBP disability duration merits further exploration.

Using narrative text and coded data to develop hazard scenarios for occupational injury interventions.

BACKGROUND: Little information is available on physician characteristics and patient presentations that may influence complicance with evidence-based guidelines for acute low back pain.OBJECTIVE: To assess whether physicians’ management decisions are consistent with the Agency for Health Research Quality’s guideline and whether responses varied with the presentation of sciatica or by physician characteristics.DESIGN: Cross-sectional study using a mailed survey.PARTICIPANTS: Participants were randomly selected from internal medicine, family practice, general practice, emergency medicine, and occupational medicine specialties.MEASUREMENTS: A questionnaire asked for recommendations for 2 case scenarios, representing patients without and with sciatica, respectively.RESULTS: Seven hundred and twenty surveys were completed (response rate=25%). In cases 1 (without sciatica) and 2 (with sciatica), 26.9% and 4.3% of physicians fully complied with the guideline, respectively. For each year in practice, the odds of guideline noncompliance increased 1.03 times (95% confidence interval [CI]=1.01 to 1.05) for case 1. With occupational medicine as the referent specialty, general practice had the greatest odds of noncompliance (3.60, 95% CI=1.75 to 7.40) in case 1, followed by internal medicine and emergency medicine. Results for case 2 reflected the influence of sciatica with internal medicine having substantially higher odds (vs case 1) and the greatest odds of noncompliance of any specialty (6.93, 95% CI=1.47 to 32.78), followed by family practice and emergency medicine.CONCLUSIONS: A majority of primary care physicians continue to be noncompliant with evidence-based back pain guidelines. Sciatica dramatically influenced clinical decision-making, increasing the extent of noncompliance, particularly for internal medicine and family practice. Physicians’ misunderstanding of sciatica’ natural history and belief that more intensive initial management is indicated may be factors underlying the observed influence of sciatica.

Measurement of slipperiness: fundamental concepts and definitions.

Objective: To determine whether narrative text in safety reports contains sufficient information regarding contributing factors and precipitating mechanisms to prioritize occupational back injury prevention strategies. Design, setting, subjects, and main outcome measures: Nine essential data elements were identified in narratives and coded sections of safety reports for each of 94 cases of back injuries to United States Army truck drivers reported to the United States Army Safety Center between 1987 and 1997. The essential elements of each case were used to reconstruct standardized event sequences. A taxonomy of the event sequences was then developed to identify common hazard scenarios and opportunities for primary interventions. Results: Coded data typically only identified five data elements (broad activity, task, event/exposure, nature of injury, and outcomes) while narratives provided additional elements (contributing factor, precipitating mechanism, primary source) essential for developing our taxonomy. Three hazard scenarios were associated with back injuries among Army truck drivers accounting for 83% of cases: struck by/against events during motor vehicle crashes; falls resulting from slips/trips or loss of balance; and overexertion from lifting activities. Conclusions: Coded data from safety investigations lacked sufficient information to thoroughly characterize the injury event. However, the combination of existing narrative text (similar to that collected by many injury surveillance systems) and coded data enabled us to develop a more complete taxonomy of injury event characteristics and identify common hazard scenarios. This study demonstrates that narrative text can provide the additional information on contributing factors and precipitating mechanisms needed to target prevention strategies.

Conceptual and definitional issues in occupational injury epidemiology

The main objective of this paper is to give an overview of basic concepts and definitions of terms related to the ‘measurement of slipperiness’ from the onset of a foot slide to a gradual loss of balance and a fall. Other unforeseen events prior to falls (e.g. tripping) are sparingly dealt with. The measurement of slipperiness may simply comprise an estimation of slipping hazard exposures that initiate the chain of events ultimately causing an injury. However, there is also a need to consider the human capacity to anticipate slipperiness and adapt to unsafe environments for avoiding a loss of balance and an injury. Biomechanical and human-centred measurements may be utilized for such an approach, including an evaluation of relevant safety criteria for slip/fall avoidance and procedures for validation of slip test devices. Mechanical slip testing approaches have been readily utilized to measure slipperiness in terms of friction or slip resistance but with conflicting outcomes. An improved understanding of the measurement of slipperiness paradigm seems to involve an integration of the methodologies used in several disciplines, among others, injury epidemiology, psychophysics, biomechanics, motor control, materials science and tribology.

Disabling occupational injury in the US construction industry, 1996

This paper presents several models that further define the concept of occupational injury. While traditional models have proved successful in isolating specific research questions and health phenomena, the conceptual model presented permits a broader view of all injury morbidity. This model is based on both the level and frequency of energy transfers. A process model of occupational injury is also presented to describe the basic pathophysiological relationships associated with tissue effects/damage and recovery/repair. Numerous tradeoffs exist in variable selection, and a third model explores some of these tradeoffs. Differences in terminology and fundamental principles can limit the progress of occupational injury research. Accordingly, an argument is made for consolidation and consensus of terms. Finally, considerations for research are suggested, with an emphasis on the severity of the injury, the risk ratio, and the population at risk.

Welding related occupational eye injuries: a narrative analysis

In 1996 the US construction industry comprised 5.4% of the annual US employment but accounted for 7.8% of nonfatal occupational injuries and illnesses and 9.7% of cases involving at least a day away from work. Information in the published literature on the disability arising from construction injuries is limited. The construction claims experience (n = 35,790) of a large workers’ compensation insurer with national coverage was examined. The leading types and sources of disabling occupational morbidity in 1996 in the US construction industry were identified. Disability duration was calculated from indemnity payments data using previously published methods. The average disability duration for an injured construction worker was 46 days with a median of 0 days. The most frequently occurring conditions were low back pain (14.8%), foreign body eye injuries (8.5%), and finger lacerations (4.8%). Back pain also accounted for the greatest percentage of construction claim costs (21.3%) and disability days (25.5%). However, the conditions with the longest disability durations were sudden-onset injuries, including fractures of the ankle (median = 55 days), foot (42 days), and wrist (38 days). Same-level and elevated falls were the principal exposures for fractures of the wrist and ankle, whereas elevated falls and struck by incidents accounted for the majority of foot fractures. Manual materials handling activities were most often associated with low back pain disability. The results suggest that these most disabling injuries can be addressed by increasing primary prevention resources in slips and falls and exposures related to injuries of sudden-onset as well as in reducing manual materials handling and other exposures associated with more gradual-onset injuries.