30 Postgrad Med J: first published as 10.1136/pgmj.35.399.30 on 1 January 1959. Downloaded from

THE By A. M. WILEY, M.B.E., M.CH., F.R.C.S. Nuffield Orthopaedic Centre, Oxford

In 1947 Russel Brain, Dickson Wright and thenar eminence, the muscles of which in each case Wilkinson produced the original paper describing overhang the structure so that only a very small median compression of the wrist and its portion of it is accessible for direct incision. It is treatment. Credit for drawing the attention of 4 cm. in breadth. surgeons to the carpal tunnel syndrome is largely The ulnar artery crosses this retinaculum on its due to Nissen, although he has written little on the ulnar side, while the thenar branch of the median subject. Kremer, Gilliatt, Golding and Wilson nerve curls around its lower border on the radial (I953) emphasized the vascular side-effects-acro- side and runs upwards and outwards to its muscle paraesthesiae which may accompany median com- mass. pression. The whole tunnel is quite rigid, the nerve is The subject has been taken up principally by packed into the surface of the common palmar neurologists, many of whom hold conflicting views bursa and on flexion of the wrist is angled around Protected by copyright. on the frequency with which this form of peripheral the lower border of the flexor retinaculum. Figs. neuritis is encountered in the upper limb. Vicale i and 2 show the surface anatomy and main and Scarff (I95i), Beck (1954), Growkaest and relations of the flexor retinaculum. Demartin (1954) draw attention to the develop- ment of median neuritis at the wrist during sys- Pathological Features temic disease, and it now seems likely that many Compression of the in the carpal patients previously diagnosed as having brachial tunnel may follow local swelling outside the nerve neuritis or thoracic inlet compression were, in fact, or swelling of the nerve itself. In either case the suffering from carpal compression. As pointed out local effects are the same: temporary ischaemic by Heathfield (I957), it is probable that this syn- neuritis. At operation, under tourniquet, on a drome will shortly align itself along with prolapse proven case of ' carpal compression' the median of the lumbar intervertebral disc as one of the nerve is seen to be narrowed distally (opposite the lower border of the flexor retinaculum) and lying major features of isolated peripheral neuritis. http://pmj.bmj.com/ Since 1947, at this centre, when a median nerve in a bed of synovia which shows some congestion. was first released for symptoms previously labelled There may or may not be evidence of the prime as ' brachial neuritis,' the operation has become a cause of the neuritis-a haematoma, swelling or common one. Indeed, the volume of patients tenosynovitis. requiring' decompression ' justifies the procedure The ischaemic nature of the neuritis is well being performed in out-patients under local illustrated by a brisk local flush, which follows anaesthetic. For this reason it seems opportune release of the tourniquet before closing the wound. to review the anatomy of the area concerned and to This is a flush or flare reaction. on September 27, 2021 by guest. refer to some lesser known pathological and Sunderland (I945) has described the blood clinical features which may not be yet fully supply of the various peripheral . Rich appreciated. perineural and endoneu'ral anastomosis exists on the median nerve. Anatomy The ease with which this network can be tem- Decompression of the carpal tunnel is performed porarily interrupted is shown by the use of the by slitting the roof of the flexor retinaculum. This injection method: 250 c.C. of a radio-opaque is continuous proximally with the deep (investing) medium of fine barium (micropaque) was injected fascia of the forearm and distally with the palmar slowly into the brachial artery of the cadaver of aponeurosis. A palmaris longus tendon, when an elderly female who died of a gastric neoplasm. present, lies superficial to the flexor retinaculum. The wrist joint was acutely flexed during injection. The retinaculum extends from hypothenar to The interruption of neural blood flow is shown January 1959 WILEY: The Carpal Tunnel Syndrome 31 Postgrad Med J: first published as 10.1136/pgmj.35.399.30 on 1 January 1959. Downloaded from

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FIG. i.-Surface anatomy of the flexor retinaculum. FIG. 2.-Dissection of carpal tunnel. The marker is under the thenar nerve. taking place at the lower border of the flexor retinaculum (Fig. 3). This vascular effect is probably unobtainable in the normal wrist, as a simple test on oneself will show. Forced firm as occur in pregnancy and the menopause, may be flexion of the wrist for io minutes or more pro- sufficient to cause local ischaemic neuritis in the http://pmj.bmj.com/ duces slight digital paraesthesiae and a feeling of flexed wrist. stiffness and discomfort, but not median neuritis. More rarery carpal compression may be the Nevertheless, some paraesthesiae do occur and result of a swelling of the peripheral nerve, as illustrate how small a margin exists between sig- may occur in the course of an infectious neuritis nificant and insignificant carpal compression. or follow an acute attack of cervical spondylitis. The tourniquet test of Gilliatt and Wilson (I953) This latter type of effect is important and re- sembles the residual , entirely peripheral in on September 27, 2021 by guest. is merely another method of inciting this potential distribution, which may follow an attack of pro- vascular insufficiency in patients suffering from lapsed lumbar intervertebral disc and may be carpal compression. relieved by Ober's operation of pyriformis These vascular features explain the nature of the tenotomy. paraesthesiae and account for the flushings and Commonly the carpal tunnel syndrome is seen sensation of local heat that may follow and signify in the right hand of heavy manual workers or the end of an attack of neuritis. athletes following an attack of non-specific teno- synovitis, in the right hand of post-menopausal Aetiology women who have more than a fair share of house- Local pressure within the carpal tunnel may work to perform, in patients suffering from rheu- follow contusions, fractures and dislocations around matoid arthritis and in either hand of middle-aged the wrist, acute and chronic tendon and joint in- individuals who have recently had an attack of fections, Even minor tissue fluid exchanges, such cervical spondylitis. POSTGRADUATE MEDICAL JOURNAL January 1959 Postgrad Med J: first published as 10.1136/pgmj.35.399.30 on 1 January 1959. Downloaded from inadvertently flexed and relaxed. Relief is ob- tained by hanging the hand over the side of the bed and this corrects the deformity and improves the vascular supply to the nerve. Sometimes the ' burning' is so intense that the patient plunges his hand into cold water to get relief. The syndrome is to be differentiated from the other causes of in the arm. In particular, as noted previously, median neuritis at the wrist may be an end result of an attack of cervical spondylitis with disc degeneration. A guide to diagnosing in this case is restriction of the neck movements. Another, much rarer, condition is the thoracic inlet syndrome, which tends to affect lower roots of the brachial plexus. Finally, it is worth con- sidering pressure due to ganglia about the wrist in the differential diagnoses of isolated median neuritis. Treatment The results of operation are so good that surgery should not be withheld. It is to be remembered,

.. .. however, that carpal compression is transitory in many patients; for example, in pregnancy and afterProtected by copyright. to the wrist. Some relief may be obtained by splintage of the wrist in the mid position. This is not always convincing and often may be attri- buted to a remission rather than to the splintage. Severe symptoms usually warrant early surgery in any case. The use of hydrocortisone into the carpal tunnel is not recommended. Vitamin B may be ad- ministered to cases of toxic and infective peri- pheral neuritis with developing carpal compression. Surgery is best performed under tourniquet and therefore general anaesthesia. This enables the

surrounding synovia, and particularly the neigh- http://pmj.bmj.com/ bouring reaction, to be studied. Biopsy of the synovial flexor sheaths may be informative in suspected polyarthritis. ..::.: A longitudinal incision is recommended in pre- ference to transverse to enable the entire constrict- ing flexor retinaculum to be divided. The incision FIG. 3.-Shows effect of wrist flexion on neural blood is made on the hypothenar side of the hollow supply. The shaded ridge is the lower border of on September 27, 2021 by guest. the flexor retinaculum. between the thenar and hypothenar muscles to avoid the thenar branch of the median nerve. Symptoms and Signs Illustrative Examples Carpal compression usually presents with sen- Case i. A lieutenant-colonel in the Army sory impairment in the median nerve supply to the Medical Services played tennis every evening hand, less often with actual thenar wasting. until prevented by numbness and tingling of his Frequently the median nerve is tender at the lower right hand. Division of the flexor retinaculum border of the retinaculum and symptoms can be showed chronic non-specific tenosynovitis of the brought on by strongly flexing the wrist or by the wrist. His symptoms were relieved. tourniquet test. Case 2. A housewife had oophorectomies and The symptoms may be episodic, acute or hysterectomy at the age of 40 and thereafter put moderate and are worse at night, when the wrist is on two stones in weight. Two years later she January 1959 WILEY: The Carpal Tunnel Syndrome 33 Postgrad Med J: first published as 10.1136/pgmj.35.399.30 on 1 January 1959. Downloaded from could sleep little from severe nocturnal median- Acknowledgments neuritis. Her symptoms were relieved by carpal My thanks are due to Professor Trueta for decompression and the only abnormality noted at granting me access to his clinical material. operation was slight perineural vascular congestion. BIBLIOGRAPHY Case 3. A widow was running a farm and had had BECK, K. (I954), Deutsche. Z. Nervenheilk, I7I, 31I. several attacks of ' stiff neck ' with residual cervical BRAIN, W. R., WRIGHT, A. D., and WILKINSON, M. (I947), Lancet, i, 277. pain and pain radiating into the right arm and DICK, T. B., and ZADIK, F. R. (IS58), Brit. med. 3., ii, 288. hand. The pain in the right hand persisted GILLIATT, R. W., and WILSON, T. G. (I953), Ibid., ii, 595. following the last attack. Division of the GROWKAEST and DEMARTIN (I954), J. Amer. med. Ass., carpal 155, 635. ligament relieved this pain and appeared to improve KREMER, M., GILLIATT, R. W., GOLDING, J. S. R., and her cervical symptoms. WILSON, T. G. (I953), Lancet, ii, 59o. MARTIN, J. P. (ig95), in Price's 'Textbook of the Practice of Case 4. A Thames bargemaster awoke in his Medicine,' Oxford. NISSEN, K. I. (1952), 3. Bone _t. Surg., 34, 3, 5I4. bunk with a ' crick ' in his neck and thereafter SUNDERLAND, S. (1945), Arch. Neurol. Psychiat. (Chicago), developed such severe pain in the median nerve 53, 9I. VICALE, C. T., and SCARFF, J. E. (Ig9I), Trans. Amer. neurol area of his right palm that he could not control the Ass., 76, I87. tiller. His symptoms were WALSHE, F. M. R. (I95s), 'Diseases of the Nervous System,' relieved by carpal London. decompression and using a Chinese pillow at night. HEATHFIELD, K. W. G. (1957), Lancet, ii, 663. Protected by copyright.


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