Winning workers' comp claims for carpal tunnel syndrome; understanding the symptoms and causes of this common malady will enable you to help claimants prevail.

Two recent developments have made it more important than ever that employees win their carpal tunnel syndrome (CTS) claims in the workers' compensation forum, rather than pinning their hopes on the federal courts or agencies.

First, Congress blocked funding for federal wage replacement benefits that might have become available under proposed ergonomic regulations. Then the U.S. Supreme Court made it tougher for CTS sufferers to win claims brought under the Americans with Disabilities Act (ADA). The justices ruled that even though an employee's condition precluded her return to work, she was not disabled under the ADA because she was still able to perform manual tasks "of central importance to most people's daily lives," such as household chores, bathing, and brushing her teeth. (1)

While these developments are setbacks, in most states a workers' compensation remedy still exists for the many thousands of workers with job-related carpal tunnel syndrome. (2)

To effectively represent a worker with CTS, you need to understand the anatomy and symptoms involved, the tools doctors use for diagnosis and treatment, and the work-related risk factors that can cause the syndrome. It's also important to be familiar with the risk factors that arise outside the workplace and to communicate effectively with the treating physician in order to deflect employer defenses.

The following steps are the keys to winning CTS claims.

Know the anatomy and symptoms

Carpal tunnel syndrome is caused by compression of the median nerve where it passes through the carpal tunnel, the narrow opening in the hand consisting of the carpal bones of the wrist on the bottom and the carpal ligament on top. The carpal tunnel is a relatively tight compartment of flexor tendons and nerves that serve to move and provide sensation in the fingers.

Repetitive hand tasks cause forceful contractions of the flexor tendons in the fingers, which increase the pressure within the carpal tunnel. Chronic pressure limits the flow of blood to the median nerve and surrounding tissue. This causes the tendons to swell, which leads to compression of the median nerve against the carpal ligament and an eventual loss of nerve function.

The most common CTS symptoms are sensory abnormalities in the hand--usually the middle finger, index finger, and thumb. These symptoms include irritation and hypersensitivity; a burning, tingling, "pins and needles" sensation; decreased sensibility; and numbness. Pain sometimes radiates to the shoulder or neck, and some patients complain of clumsiness or weakness. Discomfort may be worse at night because the wrist is often flexed while sleeping.

Frequently, relief is obtained by shaking, rubbing, or wringing the hands; flexing and extending the fingers; or holding the hand in a dependent position and immersing it in warm or cool water.

CTS affects more women than men. People of any age can develop the condition, but it is most common in those aged 40 to 60. (3)

Determine the cause

Causes can be systemic--related to some general disorder in the person's body--or "local." Some of the known systemic causes are rheumatoid arthritis; changes in female hormone levels associated with pregnancy or menopause; rheumatic inflammatory disorders, such as lupus; thyroid imbalance; dialysis; and diabetes, which affects nerve function in general but does not directly cause localized nerve compression. (4)

Since all of the above, and even the aging process itself, have been identified as possible causes, employers and insurers (and the "independent" medical examiners they hire) focus on these systemic factors to dispute work-related causation. However, workers' comp statutes typically require only that work exposure be a material factor in the onset or progression of the problem, not the sole cause of an individual's disability. (5) Therefore, the presence of systemic factors need not doom a workers' comp claim.

"Local" causes of CTS include:

* unaccustomed, aggressive, or excessive use of the hand and wrist

* exertion with flexed or hyperextended wrist

* sudden trauma to the wrist at the median nerve, known as acute carpal tunnel syndrome (While rare, this cause should not be overlooked, especially in jurisdictions where repetitive trauma claims are barred.)

* tumors and infections

* previous dislocation or fracture of the wrist, causing bones to protrude into the tunnel and stretch or press on the median nerve

* repetitive twisting hand movements over a long period of time, which often occur during use of vibrating tools or on jobs that require the hand and wrist to exert force in an awkward position. (6)

Some workers are known to be particularly at risk, including typists, video display terminal operators, writers/editors, carpenters, painters, assembly line workers, welders, musicians, meat-processing workers, and anyone whose job requires intensive use of hand and power tools. (7) The Occupational Safety and Health Administration (OSHA) has found that the epidemiological and biomechanical literature convincingly demonstrates a causal relationship between forceful and repetitive hand exertions, especially in combination with a flexed wrist, and an increased risk of CTS.

Know the tests

CTS is usually suspected when a worker complains of numbness and tingling that goes to the thumb, index, middle, and ring fingers, especially if these symptoms are accompanied by aching, throbbing, or sharp discomfort in the palm, wrist, and forearm. To confirm the diagnosis, physicians typically perform one or more of the following clinical tests:

* Phalen's wrist flexor test, in which a patient holds both wrists in a flexed position to see if numbness and tingling develop

* Tinel's median nerve percussion test, in which a physician taps the area of the wrist just over the nerve

* Semmes Weinstein sensory neuropathy test, which involves using calibrated equipment to get an objective measure of impaired tactile sensitivity. (8)

Some medical professionals believe that these tests may be unreliable unless corroborated by electromyography, considered the definitive test for the syndrome. (9) An electromyogram (EMG) measures the electric potential of each muscle, which is transmitted to an oscilloscope and displayed on a screen. Abnormal electrical readings indicate CTS.

But even this method yields a false negative rate of about 10 percent to 20 percent--some people who have symptoms of CTS nevertheless do not produce significant abnormal readings. And insurers and their medical experts are always quick to note that studies show EMGs occasionally pick up "electrical aberrations" in people with no functional or symptomatic problem. To combat this tactic, injured workers should submit evidence of clinical exams in combination with their EMG tests. (10)

X-rays are useful in ruling out other conditions, such as fracture or arthritis, that might cause the patient's symptoms, and a blood test may help to diagnose associated conditions like diabetes and thyroid disease.

Understand the treatment

If a worker's symptoms are mild and of short duration (two to three months), physicians typically opt for conservative treatment, especially if the symptoms are expected to disappear in the near future--for example, if certain strenuous, unaccustomed activities will no longer be required of the employee. Conservative treatment includes immobilization, medications, and change of job activities.

If conservative therapy fails, surgical intervention may be needed. Most physicians like to see measurable abnormalities before operating, but standard symptoms sometimes suffice. The purpose of the proposed surgery is twofold: to release external pressure on the median nerve, and to diagnose and treat the pathology responsible for the nerve compression.

The surgery is known as carpal tunnel release. The transverse ligament is divided to open up the carpal tunnel and relieve the pressure on the nerve. Recovery times vary, but six to eight weeks before return to limited duty is routine.

If CTS is present in both arms, doctors routinely wait until one wrist is healed before performing surgery on the other, so the recovering patient has the use of one good hand.

Evaluate risk factors

As noted above, common risk factors include force of hand movements, repetition, awkward postures, vibration, and contact stress. Put together a detailed job history with these factors in mind, both to prepare your client's direct testimony and to help your medical expert explain the causal nexus between the work exposure and the injury.

Force is the amount of physical effort required for a worker to accomplish a task or motion. Motions that require the application of higher force place higher mechanical loads on muscles, tendons, ligaments, and joints. These tasks cause muscles to tire more quickly, which can lead to tissue damage.

The force required to complete a movement increases when other risk factors are involved. For example, more physical effort may be needed to perform tasks when the speed or acceleration of motions increases, when vibration is present, or when the task requires awkward postures.

Force can be assessed quantitatively with strain gauges, spring scales, and electromyography. A qualitative assessment is based on direct observation of the amount of physical exertion required to complete a task. It is usually graded on a scale of low, medium, or high.

Repetition refers to the frequency with which a series of motions is repeated with little variation in movement. When motions are repeated often (every few seconds for long periods over the course of an entire work shift), fatigue and strain of the muscle tendons can occur because there may be inadequate time for them to recover. Repetition often involves use of only a few muscles, which can become extremely fatigued even though the rest of the body is unaffected. Repetitive motions occur frequently in manufacturing operations--where production and assembly have been broken down into small, sequential steps--and in many manual handling operations.

Repetition is typically assessed by direct observation or videotaping, or as a percentage of task "cycle time" (a cycle is a pattern of motions). Union safety committees can be a good source of these data.

Awkward postures are positions of the wrist that deviate significantly from the neutral position (as in a handshake). When employees are performing overhead work--for example, installing or repairing equipment above them or grasping objects from a high shelf--or when they are typing, wrists are far from the neutral position. Awkward postures are significant contributors to CTS because they increase the exertion and the muscle force required to accomplish the task and compress soft tissues such as nerves, tendons, and blood vessels.

Segmental vibration occurs when a specific part of the body comes into contact with vibrating objects. These might be power hand tools such as chain saws, electric drills, and chipping hammers, or equipment such as wood planers, punch presses, and packaging machinery.

Vibration from power tools is not easy to measure directly without the use of sophisticated equipment, but vibration frequency ratings are available from manufacturers for many recently designed hand tools.

Contact stress results from activities involving repeated or continuous contact between sensitive body tissues and a hard or sharp object. Some types of contact stress, such as using the hand as a hammer to operate a punch press, are really a combination of force and repetition.

Contact stress commonly affects the soft tissues; fingers, palms, and forearms. The worker's exposure to contact stress is usually determined qualitatively by talking with the employee and observing him or her on the job.

Analyze duration, frequency, and magnitude

Performing a job-hazard analysis includes determining the extent of the employee's exposure to the risk factors described above.

Focus on the following issues:

Duration refers to the total amount of time an employee is exposed to one or more risk factors. This has a substantial effect on the likelihood of localized tissue fatigue. In general, the longer the period of continuous work, the longer the recovery or rest time required. Breaks or short pauses in the work routine help reduce the effects of prolonged exposure, so find out whether the employee was allowed to take lunch or other breaks, and for how long.

Frequency is the number of times the exposure is repeated within a period of time (in contrast to duration, which refers to cumulative exposure). This can be determined by observing and counting--on videotape, in person, or mechanically--the number of repetitions, or the cycle time, associated with each task. The response of muscles and tendons depends on the number of times the tissue is required to work and the recovery time allowed.

The frequency of an activity can be measured at the micro level--for example, the number of grasps per minute or lifts per hour. With some tasks, such as lifting or pushing heavy packages, simply knowing that the activity occurs, for example, one day every week, is sufficient to establish a CTS hazard.

Magnitude is a measure of a risk factor's strength--for example, how much force a worker must use to carry out a task, or how far the wrist's posture must deviate from a neutral position. Magnitude can be measured either in absolute terms or relative to a worker's capabilities.

For work-related upper-extremity musculoskeletal disorders, the Rapid Upper Limb Assessment (RULA) evaluation survey tool is often used to investigate and evaluate jobs, such as assembly, production, sewing, janitorial, maintenance, meat-packing, grocery cashier, phone operator, dentist, and dental technician positions. (11)

To assess the magnitude of your client's risk factors, determine the following:

* In an eight-hour day, how many items (and of what weight) does he or she lift, twist, or otherwise move, and from what position?

* How long has the client been working in that specific position?

* When did the pain begin, and when did it become disabling?

* In what parts of the body does the client feel pain?

Consider personal factors

Some factors not related to work--age, genetic predisposition, and current medical conditions--may affect a person's susceptibility. Keep in mind the systemic causes listed above. Recreational activities such as volleyball, knitting, and gardening may involve repetitious hand movement, contact stress, or awkward positions. Weight, body mass index (a ratio of weight to height), and obesity are all potential risk factors.

Carpal tunnel size and wrist size have been associated with CTS; however, some studies have linked both small and large canal areas to the syndrome. Few studies examining CTS risk factors have been occupational epidemiological studies; most have used hospital-based populations that may differ substantially from working populations, so their validity in rebutting work-related CTS claims should be scrutinized. (12)

Employers often seize on nonwork activities as alternative explanations, and insurers' letters to medical examiners are rife with references to nonoccupational computer use, hobbies, second jobs, and household activities that might cause CTS. (13) Make the point that risk factors are rarely encountered with the same intensity or the same duration in the home as they are in the workplace. To show the difference, explore the magnitude, duration, and frequency of the client's exposure to risk factors in direct examination. Do the same with adverse medical experts on cross-examination.

Review employer records

Obtain personnel records from the employer with the client's specific job description, nurse's notes, and employment history. Ask for specific ADA-type "essential functions of the job" analysis showing exertion requirements. Get the names and addresses of other employees with the same symptoms.

Review medical records for exposure history

Review the initial medical history that the client gave to the treating physician and compare it with the statement he or she gave to the insurance carrier and other medical providers. The initial history will often lack the details necessary to let the physician render a conclusive opinion regarding the causal nexus between the work exposure and CTS.

Communicate with the treating physician

Treating physicians, by training and temperament, are usually more interested in relieving symptoms than in inquiring about causation. Since insurance medical examiners are hired to focus on causation, you must level the playing field by supplying the treating physician with all the relevant information about the client's exposure in the workplace.

Ask the doctor to prepare a comprehensive report answering the question, "Was the work exposure at least a material contributing causative factor in the onset or progression of the disease?"

Explore benefits and remedies

Several different types of benefits and remedies are available under workers' comp laws and paid by workers' comp insurers to employees with CTS, depending on their level of disability and other circumstances.

Temporary total disability (TTD) payments are available when the employee is unable to return to work and has not reached a healing plateau (maximum medical improvement) assigned by the employee's treating physician. Obtaining these payments is more difficult when the workers' comp carrier denies causation.

Temporary partial disability (TPD) is appropriate when the employee has returned to the job part-time or to a lesser-paying position while still subject to temporary restrictions on work.

Permanent partial disability (PPD) may be available based on the physician's assessment of the permanency of persisting symptoms, and whether or not the client has had surgery. After carpal tunnel surgery, many nerves do not return to normal conductivity, even in the vast majority of subjectively successful cases. Asking the treating physician to specify the client's functional limitations (such as through a functional capacities evaluation) facilitates an employer's decision or job accommodation.

Vocational rehabilitation is an option if the employee has permanent restrictions that the employer cannot accommodate. The workers' compensation insurance carrier may be responsible for the vocational expert's fees and for payments for tuition, books, meals, mileage, and TTD benefits to the injured worker during a school retraining program.

Penalties for refusal to rehire can be sought in some cases. Under some statutory schemes, the employer is required to rehire the employee where work that accommodates the employee's permanent restrictions is available. (14) Statutory penalties--for example, the payment of lost wages--may apply if the worker is not rehired.

Recovery for disfigurement is available for some clients. After surgery, there may be a discernable scar at the wrist that affects the employee's wage-earning capacity. Some state statutes allow for recovery for the disfiguring effects of the scar.

While payment is primarily designed as compensation for subtle employment discrimination in hiring, it ordinarily covers only those areas of the body that are likely to be exposed in normal employment and, therefore, may result in wage loss for the worker. (15)

Exposure to repetitive motion hazards continues to plague workers daily, resulting in thousands of CTS claims every year. Despite insurance industry efforts to characterize these claims as fraudulent, psychosomatic, or unrelated to work, effective and tenacious advocacy can ensure that employees with CTS receive the workers' compensation benefits to which they are entitled.

Notes

(1.) Toyota Motor Mfg. v. Williams, 534 U.S. 184 (2002).

(2.) Some states bar recovery for repetitive motion injuries that do not result from a single trauma.

(3.) Joseph Greenspan, Carpal Tunnel Syndrome, 84 POST GRADUATE MED. 7, 34 (1988).

(4.) Sigur Sandzen Jr., Carpal Tunnel Syndrome, 24 AM. FAM. PHYSICIAN 193 (1987).

(5.) In Wisconsin, for example, the requisite medical form (WKC-16-B) to be completed by the treating physician asks: "If the patient suffers from a condition caused by an appreciable period of workplace exposure, was that exposure either the sole cause of the condition or at least a material contributory causative factor in the condition's onset or progression?" The form is available at www.workerscompensation.com/ wisconsin/forms. See also Milwaukee Malleable & Grey Iron Works v. Indus. Comm'n, 2 N.W.2d 197 (Wis. 1942) (legitimate inference that working 16 to 17 years in a foundry that exposed employees to silica dust tended to promote silicotic condition in plaintiff).

(6.) NIOSH Fact Sheet, Carpal Tunnel Syndrome (June 1997), available at www.cdc.gov/niosh/ctsfs.html.

(7.) For an excellent summary of epidemiology studies examining carpal tunnel syndrome, see OSHA Ergonomics Program, 29 C.F.R. pt. 1910; 65 Fed. Reg. 68,461 (Nov. 11, 2000).

(8.) Greenspan, supra note 3, at 37-38.

(9.) Id.

(10.) OSHA accepts that specific symptoms determined during clinical exams, combined with objective evidence of median nerve dysfunction through electrodiagnostic tests, is definitive proof of CTS. OSHA also admits disagreement among experts on CTS diagnosis when symptoms exist where EMGs are normal. Without the aid of EMGs, a physician would make a false-positive CTS diagnosis in about 1 in 4 cases, while clinical examination is expected to miss a diagnosis (false negative) when CTS is present in about 1 in 6 cases. While this variance may not be acceptable in making treatment decisions (like surgery), OSHA feels that for epidemiological purposes, it is a satisfactory correlation. OSHA Ergonomics Program, 29 C.F.R. pt. 1910; 65 Fed. Reg. 68,404-05.

(11.) See OSHA Ergonomics Program, 29 C.F.R. pt. 1910, App. D-1; 65 Fed. Reg. 68,861.

(12.) See studies by Peter Nathan cited in 65 Fed. Reg. 68,446, 1988 Ex. 26-990; 1992 Ex. 26-989; 1994 Ex. 26-517.

(13.) One polemic often cited in adverse medical exam reports is Norton M. Hadler, Repetitive Upper Extremity Motions in the Workplace Are Not Hazardous, 22 J. HAND SURGERY 19 (1997).

(14.) See WIS. STAT. [section] 102.35(3)(2001).

(15.) See id. [section] 102.56.

Thomas M. Domer practices law in Milwaukee, Wisconsin.