RESNA 28th Annual Conference - Atlanta, Georgia
Karen L. Williams, BEME, Scott Haynes, MBME
Low back pain (LBP) affects the lives of millions of working age adults and contributes to billions of dollars in medical expenses and lost productivity. A literature review revealed that there are many causes of the condition and symptoms may be present for only a number of days or last years. For many people, symptoms can be relieved by lumbar flexion or lying supine. While some are able to continue to operate productively with some pain, many people find that the demands of the workplace conflict with their need to relieve the chronic discomfort. More research should be done on the effectiveness of non-traditional work postures on productivity and pain relief.
KEYWORDS: low back pain; recumbent posture; supine
LBP is America’s most common work related disability for people under the age of 45 and its most expensive worker’s compensation claim (1). Annually, the US spends $50-$100 billion on medical bills, disability, and lost productivity at work due to the condition (2, 3). It has been estimated that 60%-80% of the population will experience LBP as some point in their lives (3, 4). As trends continue toward a more overweight, sedentary, and stressful lifestyle, the incidence of back pain is expected only to increase (3).
For many people, LBP limits their ability to find and maintain gainful employment. Unfortunately, vocation often dictates the posture that a person must assume in the workplace. While many manual labor positions may require movements such as twisting and lifting that present a large risk for re-injury, more stationary jobs such as a machine operator or computer programmer may require a person to stand or sit for extended periods of time, often aggravating their condition. The purpose of this review is to identify the major causes of LBP, how posture impacts the disorder, and to discuss how posture might be adjusted for people with LBP in order to accommodate the demands of the workplace.
The methods used to identify literature for this review included internet searches and an investigation of reference books and published journals specific to human factors and ergonomics, medicine, occupational health and safety, and assistive technology. While there are people with many different disabilities that might benefit from working in alternative postures, information gathered focused on low back pain because it is such a prevalent disability in industrialized countries.
The major types and causes of LBP were identified through a literature review. Defined as localized discomfort between the 12 th rib and the lower buttock (5, 6), LBP can inhibit normal everyday activities such as sitting, standing, walking, lifting, and sleeping (7). Pain often results when nerve roots become compressed or irritated due to over straining or pressure (2). Instances of pain can be acute (lasting less than 12 weeks) or chronic (lasting more than 12 weeks) (5). LBP can be categorized as non-mechanical, where pain is present without motion, or mechanical, where the discomfort is present only during activity (8). Mechanical LBP accounts for up to 97% of cases and is a result of overuse, trauma, or a disorder in the region (1, 5).
Acute LBP disorders most often the result of musculoligamentous injuries or muscle strains (1). Also common are herniated or ruptured discs and sciatica, caused when the disc weakens and cartilage or disc material pushes into the spinal column (1, 2, 5). The pain associated with these conditions is intensified by certain physical activities such as sitting, walking, or straining, but can be relieved by others (5).
While chronic LBP is much less common than reoccurring episodes of acute LBP (40% of patients will have a reoccurrence of acute LBP within 6 months), they account for 70-90% of back pain health care, social security, compensation, and work loss costs (1, 2, 9, 10). The most common cause of chronic LBP is the degeneration of the structures of the lumbosacral spine. This can cause osteoarthritis and eventually lead to spinal stenosis, the narrowing of the spinal canal, resulting in pain that can last months or even years. Discomfort is usually experienced while standing or walking, and is relieved by lumbar flexion (5, 8).
Common methods of LBP treatment include physical therapy, surgery, and pain management. Frequent changes in position are recommended to keep back muscles strengthened, improve circulation and disc nutrition, relieve muscle tension, and increase alertness (2, 11, 12). Spinal flexion and assuming a supine position were identified as methods of pain relief for most mechanical LBP conditions because they minimize the intradiscal pressure of the lower spine and stress on back muscles (10, 11). It may also serve as a preventative measure. Populations that habitually assume postures that flatten their lumbar spine were found to be less likely to experience disc degeneration (10). Although the onset of LBP is due to physiological reasons, the duration of disability or ability to deal with pain has been linked to non-physical influences such as depression, employment dissatisfaction, and coping strategies (4, 13).
The goal of rehabilitation professionals is to improve the quality of life a person with a disability, and return to work is a major component of this for working age adults. Duration of unemployment due to disability has a significant impact of the likelihood of a person to return to the workplace. After six months, 50% return to employment. Following one year, this rate drops to 25% and there is almost no re-entry into the workforce after 2 years of unemployment (7). Because most cases of LBP are mechanical in nature and can be relieved by lumbar flexion, providing workplace accommodations that allow a person to work in an alternative posture that supplies relief may reduce their chances of permanent unemployment. This method of relief in today’s occupational settings, however, can be difficult because of space limitations and productivity demands. As well as designing within the size constraints of the workplace, considerations should be made so that a worker may continue to function efficiently while assuming a variety of postures. Working in significantly reclined or supine positions may also prove beneficial to people with conditions other than LBP, such as fatigue, limited trunk strength, or pregnancy with mandated bed rest.
While many back injuries are the result of manual labor tasks, LBP is also common in more stationary professions such as data entry. The constrained and unhealthy postures required for many occupations can exacerbate the degenerative process associated with ageing. As the workforce matures and sedentary occupations and lifestyles become more prevalent, the need to investigate non-traditional work postures as a preventative measure or permanent accommodation may become more apparent. While there is a considerable amount of literature published regarding traditional standing and sitting postures in the workplace, very little information was found related to the ability of people to work from a supine or significantly reclined position.
Although not a means of eliminating the condition, alternative postures may help to relieve the symptoms related to LBP so that a person may obtain and maintain employment. In traditional workspaces, however, the need to lie supine in order to relieve pressure from the lower spine might impact the ability to perform required vocational tasks unless accommodations are made. More research is needed to identify the benefits of working supine as a method of LBP relief and functional disadvantages of operating from that position. In addition, currently marketed systems that allow for posture changes in the workplace should be evaluated for their ability to provide pain relief and prevention, as well as impacts on productivity.
This paper was supported by NIDRR through the Workplace Accommodations RERC, Grant # H133E020720.
Karen Williams, BEME
Center for Assistive Technology and Environmental Access
Georgia Institute of Technology
490 10 th Street, NW
Atlanta, GA 30332-0156