Carpal tunnel syndrome: a challenge for rehabilitation.

The present article is an exploration of the impact of the increasing number of workers with carpal tunnel syndrome on the field of rehabilitation. The causes, incidence, and intervention strategies are summarized. Implications for the field of vocational rehabilitation are posited.

Carpal Tunnel Syndrome (CTS) has been known for sometime, but with changing technology CTS will play a significantly greater role in the general rehabilitation counselor's caseload than in the past. Carpal Tunnel Syndrome is one specific type of injury included in a broader category known as "motion injuries." Motion injuries, also termed, "cumulative trauma disorders" may comprise 50% of workmen's compensation cases in the year 2000 (Mallory and Bradford, 1989). CTS also has been classified as a compression or entrapment neuropathy (Goodgold, 1981). The present article contains a discussion of what constitutes CTS, the prevalence of the syndrome, current diagnostic and intervention methods, and the implications these factors have for rehabilitation counseling professionals.

What is CTS?

Green (1988) and Goodgold (1981) state that Carpal Tunnel Syndrome (CTS) is the most common form of compression neuropathy. A compression neuropathy is a condition involving pressure usually affecting a superficial nerve in and around bony prominences (Berkow, 1987). CTS has been classified as an "entrapment neuropathy" (Stearin, 1988). Stearin defines an entrapment neuropathy as "... A region of traumatic neuritis in which the nerve is maintained in an irritated state by external pressure created from a nearby anatomical configuration...." (p. 948). Schenectady (1989) describes CTS as an "... An increase in the volume of the contents of the carpal canal or decrease in the space of the canal" (p. 226). Schenectady explains that the carpal canal is a conduit-like space on the palm side of the wrist. The median nerve along with nine flexor tendons pass through this canal. Rapid and traumatic flexing and extension of the wrist (example, hammering), a strong gripping action (example, stapling gun), or a vibrating force (example, pneumatic hammer) may cause enlargement of the flexor tendons and, indirectly, chronic irritation of the median nerve. Pregnancy also has been shown to result in and/or exacerbate CTS (Berkeley, 1982). Although CTS has received considerable attention recently, it was first described in medical literature by Sir James Paget in 1863 (Green, 1988). Modus coined the term for CTS in 1938 and Wright and Wilkes described the first recorded surgical treatment for CTS in 1947 (Green, 1988). Thus, prior work has resulted in the identification of a variety of symptoms associated with CTS which includes weakness and/or clumsiness of the hand, faulty sensation in the area innervated by the median nerve, and aggravation of symptoms with increased use of the hand, especially grasping. Manifestations of CTS are varied, but usually include pain, numbness and weakness of the hand. If left untreated, CTS can result in partial or complete disability of the hand (Center for Disease Control [CDC], 1989).

Prevalence of CTS

Schenck (1989) estimates that 26,000 CTS operations are performed each year. The popular press, i.e., newspapers and magazines, has given considerable attention to the impact of CTS on certain segments of the work force. One such article indicates reports of CTS related injuries have risen from 20,000 in 1983 to almost 74,000 in 1987 (Business Week, January 1989). This same source estimates that rapid motion injuries will comprise 50% of workers' compensation claims by the year 2000. Carpal Tunnel Syndrome seems to be common to many occupations including butchers, garment workers, grocery checkers, electronic assembly workers, typists, computer terminal operators, musicians, carpenters and packers. One case of a surgeon with CTS has been reported (Belsole & Greeley, 1988). A survey of one county in California in 1987 found that 7,214 cases were treated in that year (Center for Disease Control [CDC], 1989). Margolis and Kraus (1987) found 62.5% of female grocery checkers respondents reported to have at least one of the four primary symptoms described in the survey. In addition, the researchers found checkers using electronic scanners reporting significantly more symptoms than did those not using scanners. The highest reported rate of symptoms in the study was for the age group 35 to 49 years. The investigators concluded that as many as 400,000 female grocery checkers in the U.S. may evidence one or more symptoms of CTS.

Table 1 contains a list of occupations known to be high risk for CTS and the number of persons employed in such jobs as reported in the 1986 Occupational Outlook Handbook (US Dept. of Labor, 1986).

Taking only 30% of the workers listed in Table 1, a potential sample of 1,726,000 rehabilitation clients results. Thirty (30) per cent is a somewhat conservative number, considering that the survey by Margolis and Kraus (1987) found a 62.5% prevalence rate in their sample.

Schenck (1988) cites a study of 400 hand surgeons who, collectively reported performing 26,000 CTS operations per year.

These data would suggest that general caseload counselors can expect to be serving a large number of clients with carpal tunnel syndrome in the future.

Diagnostic Methods

Symptoms of CTS include numbness and pain (Berkow, (1987). First is a numbness of the hand, termed paraesthesia. The numbness usually begins in the thick muscle just below the thumb, termed the thenar muscle, affecting primarily the dominant hand. There also may be pain in this same area as well as in the wrist and the forearm. Frequently, such pain occurs at night during sleep, becoming excruciating, but is alleviated somewhat by shifting the position of the wrist or arm.

                             TABLE 1
OCCUPATIONS POTENTIALLY AT RISK FOR CARPAL TUNNEL
                       SYNDROME
         Occupation                    Number Employed*
         Computer operator             241,000
         Data Key Entry Operator       324,000
         Mail Handlers                 317,000
         Statistics Clerk              93,000
         Grocery Checker               1,902,000
         Typist                        991,000
         Carpenter                     932,000
         Musician                      192,000
         Barber                        94,000
         Cosmetologist                 524,000
         Electronic Assembler          144,000
* Source:  U.S. Department of Labor[USDL] (1986) Occupational
Outlook Handbook

The three most frequently used diagnostic tests for CTS are (a) tapping the median nerve to elicit a tingling responses (termed Tinel's test), (b) putting the back of the hands together while acutely flexing the wrists for one minute (termed Phalen's tests), and (c) electromyographic studies (Schenck, 1989). Green (1988) states that CTS may be diagnosed through the presence of decreased sensibility in the distribution of the median nerve and atrophy of the thenar muscle, both of which signify advanced stages of CTS. Other diagnostic indicators are reduced sensation and/or pain upon wrist flexion, sensitivity to the tapping of the median nerve and objective sensory mapping of the areas innervated by the median nerve. According to Green (1988), electromyographic studies are necessary in order to differentiate CTS from thoracic nerve conditions or compression of the lower cervical nerve roots. Seror (1988) reviewed the validity of Phalen's test for the presence of CTS. Phalen's test consists of having the person fully flex the wrist for 60 seconds. If positive, the person experiences pain and/or paresthesia along the median nerve innervations usually experienced at night or during over-use of the hand. In Seror's study, 34% of the subjects with CTS had a negative test, while 20% of the controls reported false positive results. Seror concluded that in large groups of persons, Phalen's test is effective; however, in individual cases, Phalen's test results must always be accompanied by electrophorus test results.

Intervention Methods

There are several non-medical as well as medical procedures for alleviating the pain and discomfort associated with Carpal Tunnel Syndrome. Several of the non-medical strategies are often listed as preventive techniques.

Non-Medical Methods

There are several procedures a client can do to reduce the complications of CTS. According to Buchiagnani (1989), a person can reduce their liquid intake, since water retention increases the discomfort, frequency and pain of CTS. This is particularly true of pregnant women who develop CTS. Buchiagnani states that in most cases where the patient is pregnant, the symptoms of CTS disappear after delivery of the child.

If the individual works in an occupation requiring repetitive and rapid hand movements, the following strategies may reduce a client's discomfort (Krames Communications, 1987):

(1) Keep the wrist in a neutral position whenever possible and avoid flexing the hand (hand bent downward) or extending the hand (hand pulled upward).

(2) Use the whole hand and all fingers to grasp an object when possible. Placing a large amount of pressure on the thumb and index finger increases the pressure in the carpal tunnel.

(3) Minimize repetitive motions, if possible. Avoid holding an object in the same position for an extended period of time.

(4) By whatever method, give the hands frequent rest during heavy activity periods. This may entail alternating easy and hard tasks, switching hands or rotating work activities.

(5) Reduce the speed and force with which a task is done when possible. Reducing speed with which a task is done affords rest for the wrist during peak activities.

Medical Methods

Medical procedures for treatment of Carpal Tunnel Syndrome usually involve splinting, medication, and/or surgery (Krames Communications, 1987; Payan, 1988; Schenck, 1989).

Splints

There are two types of splinting procedures used for CTS. The first is termed night splinting and assists in keeping the hand in a neutral position while the client is sleeping. The second type is termed occupational splinting and involves customizing a client's splint to the type of work the client does. The major function of both types of splints is to reduce unnecessary flexing or extending the wrist.

Medication

Medication for CTS includes diuretics, vitamins, non-steroid anti-inflammatory drugs as well as steroid injections (Krames Communications, 1987). Diuretics and Vitamin B-6 appear to be the most conservative type of medication, while anti-inflammatory and steroid drugs are usually reserved for more intractable cases. Payan (1988) cautioned against the use of steroid injections due to the many adverse side effects of the procedure. Greene (1988) states that this procedure should only be used when the condition is temporary, such as in pregnancy.

Surgery

Operative procedures for CTS vary (Greene, 1988). Schenck (1989) states that the major purpose of any surgical procedure for CTS is to lengthen the thick, transverse ligament which crosses at the base of the hand. This procedure provides more room in the carpal tunnel. Post-operatively, care is taken to separate the transverse ligament from the median nerve in order to reduce the risk of further scarring and other complications (Schenck, 1989).

Implications for Rehabilitation

CTS will have implications for vocational rehabilitation counselors in terms of the impact on their caseloads and in-service training. In addition, counselors will need to acquaint themselves with referral sources for medical restoration services in their respective communities. Finally, knowledge of job modification procedures for persons desiring to return to their former occupation after rehabilitation for CTS will be a must for the counselor serving CTS clientele.

Since the body of knowledge about restoration procedures is steadily growing (Payan, 1988; Greene, 1988; Buchiagnani, 1989; Nau, et al. 1988) counselors should avail themselves of in-service training on various aspects of CTS. Training is needed in the identification of CTS symptoms, medical and allied health management of CTS rehabilitation, ergonomics and job modification, and transfer of skills for clients who cannot return to their preinjury jobs.

Even though CTS has been known for some time, patients receiving treatment for this disorder are frequently unsatisfied with the results of their treatment (Payan, 1988). Therefore, it is important for the rehabilitation counselor to be familiar with the sources for rehabilitative procedures for CTS within his/her community. For example, in the authors' local community there are three orthopedic groups who are knowledgeable of the medical management of CTS, as well as several surgeons who are recognized for their expertise in surgery for CTS, there are two rehabilitation clinics for post-operative care, several orthopedic appliance suppliers and one clinic providing work hardening services. With such knowledge, the counselor will be in a position to advise clients who are uncertain about locating such services.

Rehabilitation of job-related CTS and the prevention of the syndrome often involve some type of job modification. Such modifications are best done after the appearance of the first symptoms of CTS, but should always be made if a client returns to a repetitive job task after medical rehabilitation procedures have been rendered. These modifications may include:

(a) tool grip redesign to remove pressure from the thumb and forefinger; or

(b) Seating arrangement redesign to assure a straight posture, feet touching the floor, and situating keyboarding instruments to minimize wrist flexion and extension.

The Americans with Disabilities Act of 1990 (ADA), with its repeated reference to "reasonable accommodations," will place greater emphasis on job site modification (Commerce clearing House, 1990). Counselors and vocational evaluators will be making decisions such as whether a client with CTS would be able to return to a job and what job site modifications would need to be made for that client. Many of the ideas behind such job modifications come from "ergonomics studies" (Raniere, 1989; Sullivan, 1989). To many rehabilitation professionals, ergonomic studies will seem very similar to job analysis. To a degree, however, ergonomics makes greater use of physical measures of efficient/inefficient, destructive/non-destructive use of the body in meeting job demands.

Summary

Vocational rehabilitation professionals will be serving more clients with CTS in the very near future. Rehabilitation professionals need to be aware of the causes, the interventions for and the prevention of CTS. Clients coming to vocational rehabilitation for services because of CTS will, more than likely have well developed job skills and work experience. The rehabilitation program should involve job modification or re-training for positions not requiring rapid, repetitive hand motions. With the increasing number of service jobs involving hand and wrist motions, clients with Carpal Tunnel Syndrome will become a significant part of the rehabilitation counselor's caseloads.

References

Beck, L. (1989). Good materials handling is good ergonomics. Modern Materials Handling, 55-59.

Belsole, R.J., & Greeley, J.M. (1988). Surgeon's acute carpal tunnel syndrome: an occupational hazard. Journal of Florida Medical Association. 75:(6), 369-370.

Berkow, R. (Ed.) (1987) The Merck manual of diagnosis and therapy. 15th Ed. Rahway, N.J.: Merck, Sharpe & Dohme Laboratories

Buchagnani, J., Neurosurgeon, Memphis, TN. Personal communication 1989.

Center for Disease Control (1989). Occupational disease surveillance: carpal tunnel syndrome. Morbidity and Mortality Weekly Report. 38(28), 485-488.

Commerce Clearing House (1990) Americans with disabilities act: Law and explanation. Chicago: Commerce Clearing House.

Goodgold, J. Peripheral neuropathies. In Stolow, W.C. & Clowers, M.R. (Eds.) Handbook of severe disabilities. Washington, D.C.: Rehabilitation Services Administration, 1981.

Green, D.P. (1988) Operative hand surgery. (Vol. 2). New York: Churchill and Livingston.

Krames Communications (1987) Carpal tunnel syndrome: Relieving the pressure in your wrist. Daly City, CA: Krames Communication

Luchetti, R., Shoenhuber, R. & Landi, A. Assessment of sensory nerve conduction in carpal tunnel syndrome before, during and after surgery. Journal of Hand Surgery. 13(4), 386-389.

Mallory, M. & Bradford, H. (January 19, 1989). An invisible workplace hazard gets harder to ignore. Business Week, 92-93.

Nau, H.E., Lange, B., & Lange, S. (1988) Prediction of outcome of decompression for carpal tunnel syndrome. Journal of Hand Surgery 13, (4), 391-394.

Nicholas, J.J. (1981) Rheumatic Disease. In W.C. Stolov & M.R. Clowers (Eds.) Handbook of Severe Disability (189-204). Washington, D.C.: Rehabilitation Services Administration.

Payan, J. (1988) Editorial: The carpal tunnel syndrome: Can we do better? Journal of Hand Surgery. 13(4), 365-367.

Raniere, T.M. (1989) Prevention of cumulative trauma injuries. AAOHN Journal 37:(6), 221-225.

Schenck, R.R. (1989) Carpal tunnel syndrome: The new industrial epidemic'. AAOHN Journal 37(6), 226-231.

Seror, P. (1988). Phalen's test in the diagnosis of carpal tunnel syndrome. Journal of Hand Surgery, 13(4), 383-385.

Stedman, T.L. (1988) Stedman's medical dictionary. (24th ed.). New York: Williams and Wilkins.

Sullivan, M. (1989) Video display terminal health concerns. AAOHN Journal 37(7), 254-257.

U.S. Department of Labor. (1986). Occupational outlook handbook. [1986-87 ed.] Washington, D.C.