Watch Out for Multiple MSDs

Understanding the full range of work-related musculoskeletal disorders will help you prevent them.

• By Birnie Campeau
• Apr 01, 2006

MUSCULOSKELETAL disorders (MSDs) are conditions that involve the nerves, tendons, muscles, and supporting structures of the body. Besides the intense physical pain and suffering associated with many MSDs, these types of injuries often cause lengthy absences from work, which can be economically troubling for both the employer and employee affected.

Inferior workstation setup, poor postural habits, and a lack of proper equipment and training are common factors that can lead to MSDs. Fortunately, ergonomic solutions, especially those implemented proactively, can significantly reduce the incidences of MSDs in any workplace.

According to NIOSH, a substantial body of credible epidemiologic research provides strong evidence of an association between MSDs and certain work-related physical factors, particularly when there are high levels of exposure. And, because these high-risk work activities are often an unavoidable part of an employee's responsibilities, it is the employer's duty to provide equipment and education to maximize their safety and comfort.

This article is designed to provide the reader with an overview of some of the most common work-related MSDs and offer a few simple solutions for prevention. However, alone, these solutions are not enough. To effectively identify and eliminate all potential hazards, incorporate the right equipment to aid in prevention, and develop a comprehensive worker protection program, you should consult an experienced safety supplier.

Carpal Tunnel Syndrome
Carpal tunnel syndrome, a common and well-known MSD, is a good example of just how widespread and significant these types of disorders can be. The Bureau of Labor Statistics reported a total of 26,794 carpal tunnel syndrome cases involving days away from work in 2001. With an average of 25 workdays missed in these cases, the severity of the disorder is obvious.

Enclosed by bones and ligaments, the carpal tunnel is a constricted passageway located on the palm side of one's wrist. This tunnel shelters a main nerve to the hand and nine tendons that bend the fingers. Excessive pressure placed on the nerve from overuse creates the numbness, pain, and hand weakness associated with carpal tunnel syndrome. According to research conducted by NIOSH, job tasks involving highly repetitive manual acts--as well as those involving wrist bending, other stressful wrist postures, or vibrating tools--are linked to carpal tunnel syndrome and related problems. There is extremely strong evidence of a positive association between exposure to a combination of risk factors (e.g., force and repetition, force and posture) and carpal tunnel syndrome. Epidemiologic surveillance data, both nationally and internationally, has consistently indicated the highest rates of this disorder occur in occupations with high work demands for intensive manual exertion. These types of occupations include meatpackers, poultry processors, and automobile assembly workers.

Wrist supports that are available from most safety distributors can be tremendously useful in reducing the amount of strain on the wrist. These supports operate similarly to external ligaments, enabling total finger movement while helping to keep the wrist in a neutral position and limit the flexion (downward movement) and extension of the wrist. To help ease the harmful vibration from power tools, vibration-reducing gloves are offered. These usually feature pads that cover the palm, web, and thumb to absorb impact.

Neck MSDs and Work-Relatedness
One example of a neck MSD often associated with workplace factors is neck sprain, also known as neck strain. Work-related neck sprain usually occurs from excessive stretching or tearing of the soft tissue (muscles, ligaments, joints) of the neck. Neck sprain often causes pain, spasms, and stiffness of the neck. Other less common symptoms of neck sprain include sore throat, fatigue, and headache.

Neck MSDs often plague individuals who spend the majority of their day sitting at a desk using a computer. Likewise, workers who must regularly lift heavy objects are also widely affected. Inadequate posture and poor body mechanics are two of the most predominant causes of back and neck pain and injury on the job. Based on NIOSH's review of epidemiological research, there is evidence linking forceful exertion and the occurrence of neck MSDs. Most of the epidemiologic studies reviewed by NIOSH defined "forceful work" for the neck/shoulder as work activities that involve forceful arm or hand movements that generate loads to the neck/shoulder area. NIOSH also found strong evidence that working groups with high levels of static contraction, prolonged static loads, or extreme working postures involving the neck/shoulder muscles are at increased risk for neck/shoulder MSDs.

Employees who consistently sit at a desk for long periods of time should be taught proper positioning techniques for eliminating unnecessary stress on their arms, shoulders, and neck. A range of safety products can help them create and maintain this ergonomically correct positioning. Those who must frequently lift heavy loads should be reminded that common sense and supporting studies show it is safest to lift by using the body's strongest muscles, the legs. It is also essential to avoid any twisting of the body. For that reason, scores of products, including a broad assortment of belt supports, are offered to help employees stay centered to lift loads correctly.

Shoulder MSDs and Work-Relatedness
The shoulder joint has the widest range of motion of any joint in the body. It is due in part to its vast mobility that the shoulder holds such a great risk for injury and problems. Many of these injuries are associated with the rotator cuff, the collective name for the four muscles and their tendons that surround the shoulder joint. The rotator cuff is susceptible to many problems that can cause weakness, tenderness, and pain. Shoulder bursitis and rotator cuff tendonitis, common shoulder MSDs, are both characterized by inflammation of the rotator cuff tendons and the bursa that surrounds these tendons.

According to NIOSH, there is evidence for a relationship between repeated or sustained shoulder postures with greater than 60 degrees of flexion or abduction and shoulder MSDs. The evidence for specific shoulder postures is strongest where there is combined exposure to several physical factors. An example of this is holding a tool while working overhead. Because this type of work is performed in a wide range of industries, many individuals are vulnerable to developing work-related shoulder conditions.

When possible, safety-conscious employers should make an effort to limit the length of time an employee must remain in positions that involve extreme outward rotation of the shoulder or placing the hands above the shoulders. Keep in mind that some dangers may not be easily recognized. For example, on a shop floor, lifting items overhead to place them on a shelf is often a common task. This can easily lead to excessive strain and, ultimately, a shoulder MSD. However, this can be quickly remedied. An experienced safety supplier can come up with a simple solution, such as a stepladder. Other simple, but nonetheless extremely valuable, safety accessories can also greatly reduce hazards.

Elbow MSDs (Epicondylitis) and Work-Relatedness
The term Repetitive Strain Injury is an umbrella term used to depict a number of individual musculoskeletal conditions, including epicondylitis, which is commonly referred to as tennis elbow. This is a well-defined condition affecting the elbow. It is characterized by pain at the epicondyle, the bony parts on the inside and outside of the elbow joint. For those suffering from epicondylitis, the pain becomes more intense when their wrist is bent.

Twisting or extension of the arm during work activities may strain these muscles and irritate their attachment at the elbow. Per NIOSH, there is strong evidence for a relationship between exposures to a combination of risk factors (e.g., force and repetition, force and posture) and epicondylitis. Epicondylitis is often seen in plasterers, mechanics, painters, meatpackers, construction workers, and many other work groups. When it comes to preventing epicondylitis, personal protection equipment such as elbow supports becomes essential. Elbow supports facilitate the redirection of strain and vibration, keeping it away from the elbow. In simple terms, the supports work to trick the body into believing the forearm muscle that attaches to the tendon at the elbow really attaches below the elbow. This effectively transfers the stress from the elbow to the belly of the muscle.

Hand/Wrist Tendonitis and Work-Relatedness
Tendonitis is characterized by inflammation or irritation of a tendon. Tendons are bundles or bands of thick, fibrous cord that attaches muscle to bone. Tendons function as the power source for generating a muscle contraction to move a bone. Tendonitis can affect any extremity, but in the workplace it is most commonly found in the wrist and fingers. For those affected with hand/wrist tendonitis, movement in these areas is often painful and difficult.

Occupational risk factors include repetitive tension and motion, bending, and vibration. Based on research by NIOSH, there is strong evidence that job tasks that require a combination of risk factors (e.g., highly repetitious, forceful hand/wrist exertions) increase risk for hand/wrist tendonitis. Further studies show a high risk for workers in the manufacturing industry, meat sector, and many other occupations that involved forced, repetitive movements.

Ergonomically friendly work practices and equipment reduce repetitive movements and awkward and/or static postures. As is the case with every MSD prevention plan, the safety program to reduce tendonitis should incorporate proper training and education. Training programs should be mandatory for individuals at all levels. This ensures that standards are consistent and understood company-wide.

Low-Back MSDs and Work-Relatedness
Low back disorders include spinal disc problems such as hernias and spondylolisthesis, muscle and soft tissue injuries, and many others. Most low-back MSDs are a result of some sort of back strain, which can be brought on by lifting, twisting, bending, awkward movements, stretching, and stationary postures. Back pain can be extremely painful and render patients completely immobile. Depending on the severity, immobility can last for either short or extended periods of time.

In its recent review of low-back musculoskeletal disorders and work-relatedness, NIOSH considered five physical workplace factors: 1) heavy physical work, 2) lifting and forceful movements, 3) bending and twisting (awkward postures), 4) whole-body vibration (WBV), and 5) static work postures. The review provided evidence for a positive relationship between back disorder and heavy physical work, although risk estimates were more moderate than for lifting/forceful movements, awkward postures, and WBV. This was perhaps due to subjective and imprecise characterization of exposures.

Strategies for prevention of low-back MSDs include an integrated approach of both workplace-based and health care-based interventions. It is important to remember that training alone is unlikely to be effective if the ergonomic factors in the work remain inadequate. Basic training should teach employees how to spot potential risks and appropriate protocol for reporting report them. Employees should act as added support for uncovering safety problems.

The Safest Approach
A complete facility analysis is the perfect way to launch a comprehensive MSD protective program. The audit works best when a trained, third-party professional is invited to walk through the entire plant and observe practices in every area.

Professional safety consultants, including dedicated safety distributors, can provide an objective assessment of your safety needs and make the timely development of a working plan a priority. Using an integrated team approach--that is, by working in partnership with safety, purchasing, and other management, as well as with plant employees--a safety consultant will develop a plan tailored to your needs that is based on experience with numerous other companies.

They will be able to anticipate the challenges and offer proven solutions to overcoming obstacles and will be involved in planning, measuring, and reviewing performance. In addition to consulting, many safety specialists offer convenient full-service safety programs, including necessary on-site training. In addition, the safety distributor carries multiple lines of protective equipment, allowing both safety and purchasing directors to weigh the myriad options and develop the best value protection for the facility's employees. A good place to start a safety audit is a thorough examination of the plant's injury rate. By working together to analyze these records, plant safety professionals and auditors can develop objectives for the rest of the survey.

This article appeared in the April 2006 issue of Occupational Health & Safety.

This article originally appeared in the April 2006 issue of Occupational Health & Safety.