Effects on Spinal Health, and the Predisposition to Spinal Injury of the Lumbar Spine

Over the years, it has been documented that load carriers are often faced with the challenge of low back pain and repetitive sprain/strain. Noticeable among this class of people are the numerous FedEx and UPS truck drivers who on a daily basis lift thousands of pounds at ground, waist and shoulder levels, often becoming susceptible to injuries on the job (www. comp. state. nc. us/ncic/pages/court/915185. htm). Unnoticed however, are the hundreds of thousands of letter carriers around the country who walk their beat daily with a loaded sack of mail weighing heavily on a single shoulder of their body.

The purpose of this study is to determine if US mail/letter carriers, who carry conventional, single pouch/unilateral carrying strap mail bags, are more susceptible to sprain/strain injuries than those who distribute mail by alternative means (i. e. mail carts, etc…). Data will be collected via the US Postal Service with regards to number of injuries reported annually and identification of their method of mail distribution. Studies have shown how children suffer from repetitive back pain and injury from carrying weighted backpacks and the effects on cervical and shoulder upright, static and dynamic posture (Wilson, Grimmer & Dansie; 2001).

Similarly, there is information gathered on women who carry children using kangaroo carrying pouches and the postural effects that this may have on posture and peak forces throughout the lumbo-sacral spine (Pirie & Herman; 1995). Results of this research, could be pertinent in not only a universal procedural change by the US Postal Service, but also help save the US Government large quantities of money over the course of a year. Worker’s Comp claims, rehabilitation services and subsequent paid time off, are the catalysts which drive the spending of billions of dollars annually.

Research Question What are the effects of excessive loading of the spine on an individual’s health and posture during static and dynamic mobility activities (i. e. standing/walking with a weighted bag)? Is there a higher incidence of sprain/strain injuries amongst mail/letter carriers who carry a conventional, single pouch, unilateral carrying strap mail bag comparing to those who use alternative methods for mail delivery (i. e. mail pull cart). Introduction – Relevance and Significance

To date there has been relatively little definitive research examining occupational injuries, low back pain and repetitive sprain/strain among letter load carriers. Occupational injuries in service industries such as the Postal service sector are of great concern in today’s society, due to the vast amount of resources and expenses that are linked to management and prevention. In 2004 there were over 350,000 compensable injuries and illnesses reported to the Workplace Safety and Insurance Board (WSIB) accounting for approximately $4.

05 billion dollars of benefit costs to this organization, of which %2. 81 billion was paid directly to the workers receiving benefits (WSIB, 2004a&b). Globally it has been estimated that occupational injuries cost the economy $1. 25 trillion dollars annually and that there are approximately 270 million reported work accidents (ILO, 2003), many of which involve the back or shoulder. Indeed, Borenstein et al. , (1995) stated that back pain was the second most common human affliction next to the common cold.

The annual prevalences of low back pain (LBP) have been reported to be as high as 55% (Anderson, 1999; Leboeuf-Yde et al. , 1996; Picavet, 1999). Furthermore, LBP has been termed a lifelong chronic condition due to recurrence rates as high as 70% (Strong et al. , 1995), and this problem is magnified with the current aging of the workforce. Furthermore, the World Health Organization in 23003 to declare LBP as severe public health issue resulting from its status as the leading cause of chronic health problems and long term disability (Ehrlich et al. , 2003).

Another important fact when dealing with this issue is the source of LBP, of which 37% cases have been attributed to an individual’s occupation (Punnet et. al. , 2005). While back-related injuries have garnered much attention from researchers there are also other body locations that have high incidence and prevalence of occupational injury. One such area is the upper extremity where a point prevalence range of 1. 6%-53% and 12-month prevalence range of 2. 6-41% were reported in a 2006 systematic review on incidence and prevalence of upper extremity disorders by Huisstede et al.

(2006). Of the upper extremities, the shoulders significantly contributes to occupational injury rates, as is seen in statistics, where injuries to the upper extremity accounts for 29. 3% of reports, with the shoulder attributing 6. 0% of all injuries on its own (fourth most frequently reported injury location)(WSIB, 2004). A key component of understanding and studying occupational injury is to gain knowledge of those factors that place workers at an increased probability of developing chronic conditions or experiencing an acute injury on the job site.

Therefore, in order to develop appropriate strategies to manage these risks, researchers need to take a holistic approach to studying occupational injuries. In order to accomplish this goal an important issue of this thesis is the measurement of risk and the differences in information that can be obtained with various research techniques which is specially important to consider given the fact that relatively little work has been done with the postal service industry.

In 1995, Gabe noted that an entire industry has been spawned in the last half century based on societal need to understand and assess risks in order to make informed decisions concerning health risks. Gabe also discussed the assessment of risks by scientific researchers, such as engineers and physical and life scientists, who employ quantitative methodologies that allow for comparisons between risk outcomes and considerations of the costs and benefits of choices.

Somewhat complementary to this approach has been the development of risk perception research by psychologists who use quantitative approaches to risk research. Finally, the most recent development in risk research has come from the social scientists, who have identified the need to understand risk at a micro level, dealing with the individual perceptions and beliefs, and at a macro level concerning more public issues of health-related risks.

Qualitative methodologists have been adapted by researchers employing sociological approaches due to the complex phenomena examined, the ability to tap into experience and interpretation and when unknown categories of risks are a possibility (Sofaer, 1999). A beneficial attribute of qualitative methodology is the open-ended questioning approach, which avoids the potential for research bias introduced with pre-set and close-ended questions typically used in quantitative strategies.

This is an important issue during the initial phases of risk evaluation. While the more customary quantitative approach remains a critical component of understanding risk in any area, the addition of a qualitative approach to understanding risk at a more individual level also has its merits. For instance, the issue of risk experts and expert sources of knowledge is one area in which this more sociological approach could be beneficial when attempting to better understand that face workers, especially when dealing with relatively unstated population.

Gabe (1995) noted that experts and workers use different assessment criteria when evaluating workplace risk, which is the case of the workers, not only incorporates cause, but also experience (Williams & Popay, 1994). Given the differences in research approaches that can be available during the early stages of risk research, the use of a qualitative methodology when evaluating worker risk perceptions could prove beneficial to further understanding of occupational injuries.

In fact, multi-method research is becoming increasingly common owing to its ability to enhance confidence in research findings (Dixon-Woods et al. , 2004). Furthermore, Bryman (2001) states the rationale for using multi-method research lies in the inherent ability to counteract the short-comings of single research designs. One discipline born out of the need to reduce the potential risk of occupational injury is ergonomics. Before describing the role ergonomics play in the control and reduction of occupational injuries, it is important to define the discipline.

The International Ergonomics Association (IEA) Council officially defined the discipline of ergonomics in 2000 as “the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance. ” From this definition, it is important then for ergonomics experts to be well-versed in not only risk factors associated with occupational injuries, but also in methods and sources of information that can be used to design optimal intervention strategies.

An ergonomic study by De Looze et al. (2001) proposed six key factors to consider when designing successful projects including 1) direct participation of workers` and support of management, 2) a stepwise approach, 3) analysis focusing on more than just musculoskeletal load, 4) the establishment of a responsible group, 5) evaluation of effects and side effects, and 6) a positive cost-benefit ration, all of which were later confirms by Kronigsveld et al. (2005). These principles espoused by De Looze et al. and Kroninsveld et al. coincide with the increasing practice of participatory ergonomics.

Unanimous support for participatory ergonomics has not yet occurred, however many key principles off this approach are shared by a majority of members in this discipline and are presented in ergonomics practice literature by Cole et al. , (2005), De Looze et al. (2001), Kroningsveld et al. , (2005), and Haines et al. , (2002). The elements required fro a successful interventions are organizational involvement, including the workers, a broad focus examining more than just musculoskeletal load, close monitoring of risk factors for developing work-related injuries, careful attention to research methodology, and availability of information.

Of these elements, two are of critical importance at the beginning stages of developing a participatory program, in the views of this researcher: 1) the need to understand risk factors related to occupational injury in the population to be studied, and 2) the involvement and support of all levels of an organization. As was stated, one of the key ingredients and precursors to successful ergonomic practice is the ability to identify the inherent risk factors related to work. Unfortunately, there have been relatively few studies examining the occupational risks in the Postal service industry as a whole.

The few epidemiological studies that have been reported focusing on this sector suggest injuries or pain reported in the upper extremity, back, and shoulder, are of key concern. Therefore, it is important to research the potential risk factors for development of occupational injuries specific to these regions of the body in order to provide a basis as to what predictors may be present within this population and the classification and presentation of relevant risk factors for developing low back and shoulder pain.

This framework, the International Classification of Functioning, Disability and Health (ICF), was developed for the purpose of providing “a unified and standard language and framework for the description of health and health-related states” by incorporating physical, physiological, psychological, environmental, and personal aspects of health (Word Health Organization, 2001). As a quick overview, the ICF describes health status in the context of three components of functioning are body functions and structures, activity, and participation.

Influencing the components of functioning are contextual factors that can either positive or negatively affect an individual’s ability. These contextual factors are classified as either environmental or personal. Environmental factors include the individuals physical (e. g. job work size, workplace size, sector), and social (e. g. work relationships) surroundings, while personal factors are comprised of social (e. g. family support), psychological (e. g. depression), and demographic (e. g. age) features that are descriptors of the individuals themselves.

Of the ICF categories, risk factors classified as contextual factors which reflect the environment and the person, were the most abundant in the scientific literature. Environmental factors most frequently reflected the work environment and varied across in terms of the specificity of each risk factor. A few examples of common risk factors that can be related to the development of low back and shoulder pain in FSW, from very specific to general, included peak shear force, usual hand force, cumulative lumbar compression loads, trunk velocity and flexion (Jansen at al. , 2004), static loading or standing, (Buckle, 1997), higher physical work demands (Ostergen et al. , 2005), repetitive work (LeClerc et al. , 2004), work pace (Crook et al. , 2002), and low job control (Crook et al. , 2002).

These risk factors associated with the functioning, activity and participation levels of the ICF were less frequently reported in the predictive risk factors research. Factors of particular interest for the food services working population are previous injuries including those not specific to the back or shoulder (Crook et al.

, 2002; Kerr et al. , 2001; Lee et al. , 2000; Truchon and Fillion, 2000), co- morbidities (Buckle, 1997; Crook et al. , 2002), reported pain (Crook et al. , 2002; Ostergen et al. , 2005), and level of functioning or disability (Schultz et al. , 2004; Truchon and Fillion, 2000; van Tulder et al. , 2002). When beginning research and investigations into occupational injuries in relatively understudied working populations a good understanding of the specific occupational context for the risk factors reported above can be beneficial for developing research plan.

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