Carpal tunnel syndrome and repetitive strain injury

Carpal tunnel syndrome (CTS) is the scourge of the modern workplace. The median nerve becomes entrapped as it passes through the wrist, causing weakness, clumsiness, pain or numbness in the hand. Often associated with repeated or sustained activity of the fingers or hands, its incidence has risen sharply with the advent of the keyboard-based office and now affects 10 per cent of the work force (National Underwriter, 1985; 89: 15).

It is more common in middle-aged women, particularly those taking the Pill and in those going through the menopause, and is more likely to occur after arm trauma or in pregnancy, rheumatoid arthritis, severe hypothyroidism or acromegaly (overproduction of growth hormone making certain bones larger), or with haemodialysis.

As with a ‘frozen shoulder’, CTS may be associated with a systemic disorder such as chronic pulmonary disease, leukaemia, multiple myeloma, sarcoidosis or diabetes. There may be pain in the forearm, neck, shoulder and upper arm. Symptoms and pain occur mostly at night and are more pronounced in the morning.

Lithium treatment can cause CTS as a side-effect.

Although orthodox medical treatment involves a wrist-splint to reduce movement and steroid injections, these may only provide temporary relief. However, there are a number of tried-and-tested alternative treatments.

About 80 per cent of sufferers have low levels of vitamin B6. Many double-blind studies have established that B6 supplementation (up to 100 mg/day) can relieve all symptoms of CTS in such patients (Proc Natl Acad Sci, 1982; 79: 7494-8; Am J Clin Nutr, 1979; 32: 2040-6; Res Commun Clin Path Pharm, 1977; 17: 165-7; Clin Chem, 1982; 28: 721; Nutr Rep Int, 1986; 34: 1031-40).

One major cause of CTS are drugs that lower levels of vitamin B6 (such as the antirheumatoid penicillamine and the antituberculous isoniazid), excessive protein intake and oral contraceptives. Such patients should increase foods containing B6, avoid foods containing yellow dyes (which lower B6), use another form of contraception and limit protein consumption to 50 g/day (Murray M, Pizzorno J, Encyclopaedia of Natural Medicine, Rocklin, CA: Prima Publishing, 1990: 190). However, only take high doses of B6 with the supervision of an experienced practitioner as chronic megadoses (over 100 mg daily) may cause a sensory neuropathology.

For patients who don’t respond to vitamin B6 (about 20 per cent), the anti-inflammatory effects of the proteolytic enzyme bromelain, from the common pineapple (Ananas comosus), may help alleviate the pain.

A proven potent naturopathic remedy consists of applying a poultice made from turmeric mixed with slaked lime (Ind J Exp Biol, 1972; 10: 235-6).

In homoeopathy, Dichapetalum thunbergh D6 is highly recommended (Allg Homoeop Zeit, 1960; 24: 127-30).

Local acupuncture treatment may be counterproductive in CTS and repetitive strain injuries (Gascoigne S, The Manual of Conventional Medicine for Alternative Practitioners, vol I, Richmond, Surrey: Jigme Press, 1993: 207) as those with this chronic condition have a weakness of Qi or Blood which, in Oriental medicine, suggests a need for constitutional treatment.

In herbal medicine, only Harpagophytum procumbens (grapple plant or Devil’s claw) has been extensively studied (Weiss RF et al., Ausserschulische Methoden bei rheumatischen Erkrankungen, Heidelberg: E Fischer Verlag, 1981). Only the storage roots (tubers) of the plant contain antirheumatoid agents, but the popular demand for this wild South African plant has led to the selling of the whole root structure. Thus, users may now be taking herbs with no antirheumatoid effects whatsoever (Weiss RF, Herbal Medicine, Gothenburg: Ab Arcanum, 1988: 266-7).

The most consistent work on CTS and repetitive strain injury has been done by osteopathic practitioners. In 1971, D.I. Abramson et al. showed that a decreased blood supply to a nerve alters conduction (J Appl Physiol, 1971; 30: 636-42). N.J. Larson suggested that upper thoracic vertebral dysfunction altered the blood supply to the upper extremities, and S. Sunderland showed that lymphatic and venous congestion contributed to CTS (J Am Osteo Assoc, 1972; 72: 94-100; J Neurol Neurosurg Psychiatr, 1976; 39: 615).

In 1973, A. Upton and A.J. McComas postulated the ‘double-crush syndrome’, which hypothesised that single neural-axon damage leads to a greater susceptibility to damage elsewhere on the nerve. K. Nemoto later demonstrated that single-point compression of the dog sciatic nerve failed to produce conduction loss, but two-point compressions – at both proximal and distal points on the nerve – did block conduction in half of the animals (Nippon Sea Gakkai Zasshi, 1983; 57: 1773-86).

Finally, by analysing 1000 cases of CTS, L.C. Hurst and colleagues conclusively showed that the second point of compression in CTS – the wrist lesion being the first – is cervical arthritis (J Hand Surg, 1985; 10: 202). This provided an explanation for the frequent involvement of the neck.

In short, osteopathic treatment needs to focus on the vertebrae in the lower neck as well as on the wrists when dealing with a patient with CTS.

To diagnose CTS, osteopaths now either use Phalen’s test (maximum flexing of the wrist for 60 seconds) or attempt to elicit (by tapping gently with the reflex hammer over the course of the injured nerve) Tinel’s sign, pain or tingling in the distribution of the nerve. The ‘double-crush syndrome’ may also explain why wrist splints and cortisone injections produce such notoriously short-lived or unreliable results.

Harald Gaier

Harald Gaier is a registered homoeopath, naturopath and osteopath.

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