Volume 15, Number 2, May 1993, pp.37-38,

Cumulative Trauma Disorders: Some Cautions for Conservators

Drawings courtesy of the Knight-Ridder/Tribune Graphics Network

For anyone whose livelihood is dependent on manual dexterity, a problem with the hand is a major threat. It also can be something that is completely unanticipated. Recently, however, the ailment known as Carpal Tunnel Syndrome has been the subject of numerous articles which describe the symptoms as well as explain its occurrence. The incidence of the diagnosis of carpal tunnel syndrome and the frequency of wrist surgery escalated dramatically during the 1980s, and it now accounts for nearly 40% of all worker compensation claims.

Injuries to the arm or wrist are nothing new. There have been cases of tendonitis associated with musicians, writers, athletes both professional and amateur, and many others.

Work-related injuries in the past were more often associated with blue-collar jobs, such as meat-packing, assembly line jobs, or heavy manual labor and construction work. But now, hundreds of thousands of office workers are being disabled in an epidemic of motion-related damage to the hands. Growing numbers of people in jobs that entail constant use of a keyboard are suffering from a form of overuse syndrome. Some try to ignore the symptoms until they can no longer hold a coffee cup, let alone type, while others are banding together to request changes in their office equipment or work pattern. The disorders can sometimes be permanent, and the afflicted people can find themselves forced to change careers. Also known as cumulative trauma disorder, or repetitive stress injury, it was called in a New York Times article "the occupational disease of the 80's." Its occurrence in the field of conservation appears to be relatively uncommon; however, depending upon one's individual work patterns, the potential for developing this ailment seems great.

It is easier to understand the problem if you know the anatomy of the hand and wrist and can visualize the physiology of finger movements. The carpal tunnel, located at the inside center of the wrist, is a narrow tunnel of bone and ligament. A U-shaped cluster of eight bones at the base of the palm forms the rigid floor and the two sides of the tunnel. A very tough ligament lies across the top of the carpal bones, forming the roof of the tunnel. Flexor tendons slide back and forth through the tunnel as the wrist flexes and unflexes and the fingers are used. The median nerve, which conducts sensation from part of the hand up the arm to the central nervous system, also passes through the carpal tunnel. If any of the tendon sheaths become swollen, the median nerve may be compressed and the hand and fingers are affected. This pressure on the median nerve is basically a result of chronic irritation and swelling of the finger flexor tendons inside the wrist. Several specific positions, movements, and hand grips may be responsible.

The signs and symptoms of Carpal Tunnel Syndrome may be divided into three phases: (1) the usual early symptoms of tingling, numbness in the fingers, and later, pain (for some reason the pain is more intense during the night); (2) the later symptoms involve atrophy of the thenar muscles and the loss or impairment of the ability to grasp and pinch; and (3) permanent nerve damage and loss of muscle control that could render the hand almost useless. Before a professional diagnosis, one's instinctive attempt at relief is usually to shake the hand or massage it.

My personal experience began with the feeling of numbness and tingling in the index finger and middle finger of my right hand. I thought that I simply had poor circulation. It was not until I arrived at the point where pain woke me during the night that I went to a neurologist to be examined. Despite the intensity of the pain that it causes, Carpal Tunnel Syndrome involves soft tissue and cannot be measured directly, but it can be measured using objective physical indicators such as electromyography in which nerve conduction across the carpal tunnel is measured. The results are compared with the presumably normal opposite hand. Impingement of the carpal tunnel structures on the affected nerve would be expected to yield an increased nerve conduction time on the affected side. The doctor preceded my examination with an extensive period of questioning about my occupation. After confirming the diagnosis as Carpal Tunnel Syndrome he proceeded to give me emphatic warnings that I must not think that I could continue working while trying to endure discomfort, as I would unquestionably experience further deterioration and the possibility of permanent damage to the nerve. And his last counsel was that if in the end I elected to have surgery, it would be important to go to a hand specialist, not an orthopedist. He suggested that I try to rest my right hand as much as I could, to devise ways to use my left hand more, and to wear a wrist brace at night.

At this point, one might question whether ordinary usage (which is exceptional mostly because of its repetitive nature) could be harmful to a conservator. In the publication Hand Clinics, an article entitled "Cumulative Trauma Disorder of the Upper Limb" quotes numerous studies of the problem of definition. One of them notes that "the human frame varies from person to person...in the size and mechanical relationships of its musculoskeletal structure. The resiliency of this structure and its response to stress and strain varies with health, nutrition and age." What is clear is that awareness of the problem is very important. When detected and intercepted in its early stages, hand and wrist problems are relatively easy to reverse. Experts caution against trying to work in spite of pain, since that will definitely make the injury worse. Try to analyze your working positions, and consider these things now:

When performing a treatment, what is the position of your wrist? The ideal position of the wrist is flat and straight, positioning the hand level with the arm and extended in a straight line out from it. This is not always so simple for a conservator to achieve, but it should be used as a guide and a reminder to be aware.

When you perform frequent repetition of the same action, do you rest your hand often? Experts estimate that hands should be relieved of repetitive motion for at least 15 minutes every two hours. Once we have become conscious of the importance of this, it should be fairly easy to rotate our tasks in a daily schedule so that variety in hand use is achieved.

A further technique which is being taught as physical conditioning is the use of warming-up exercises and stretches.

What about surgery? Surgeons perform an estimated 100,000 operations annually to treat carpal tunnel syndrome. Most articles stress the desirability of trying all other methods of physical conditioning before the last resort of surgery, when more conservative measures seem unable to relieve the problem or when the nerve is becoming scarred or is degenerating. The prospect should give you pause. This quotation is from an article in the January 1992 issue of The American Surgeon: "There has always been some argument as to whom the carpal tunnel syndrome, as a clinical entity, belongs. Hand surgeons, orthopedists, plastic surgeons, and neurosurgeons have engaged in a Rooseveltian battle, when, in actuality, any general surgeon who is familiar with the anatomy and technique can perform surgery after a diagnosis of the syndrome is made."

Well, maybe.

An ounce of prevention is worth a pound of cure.

References

"Epidemic at the Computer: Hand and Arm Injuries," The New York Times; March 3, 1992.

Dobyns, James H.: "Cumulative Trauma Disorder of the Upper Limb," in Hand Clinics, Vol. 7, No. 3, August 1991, pages 587-.

Skandalakis, John E., et al.: "The Carpal Tunnel Syndrome: Part I," The American Surgeon, Volume 58, January 1992.

about the author:

Rosamond Westmoreland, a paintings conservator in private practice in Los Angeles, is a past president of WAAC. She also has worked as a conservator at the National Museum of American Art and the National Portrait Gallery, Smithsonian Institution.