MEDIAN NERVE COMPRESSION in the CARPAL TUNNEL on September 23, 2021 by Guest
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Postgrad Med J: first published as 10.1136/pgmj.24.271.264 on 1 May 1948. Downloaded from 264 POST GRADUATE MEDICAL JOURNAL May 1946 portant that the physiotherapist should supervise Mrs. G. F., aged 53, housewife. The right and the movements and make sure that the metacarpal left bones were excised in November, I945 (Fig. I). is again moved through a full active range at the She is now very satisfied and has no pain, but new joint. states that her hands are not quite so strong for This treatment is continued until the patient turning taps as previously. The radiographs can return to light work, which is usually a matter taken in January, 1948, show a satisfactory result of four to six weeks. Some patients complain of on 'the right, but on the left a fragment of the pain for longer than this, but others are surpris- trapezium remains in situ (Fig. 5). It is interest- ingly pain free; one started milking cows within ing to note how this fragment has increased in a month of operation. size since the film taken one year after operation (Fig. 6). Results and Case Reports Miss E. W., aged 46, sempstress. Four years of All the patients have been very satisfied with the pain and difficulty in carrying out her work. The results of the operation, and have reported im- right trapezium was excised in April, 1944. She proved function and little or no pain. Removal has been working full time since with no pain. of the trapezium leaves the thumb a little weaker Miss N., aged 58. Symptoms following an in- than the normal, but a full range of movement of jury nine months before. Pain on using. left the metacarpal is regained with no obvious thumb and a marked cystic swelling over the deformity. trapezio-metacarpal joint (Fig. 3). The trapezium Mr. E. B., aged 48, farm worker. Pain and swel- was excised in April, i944. In 1948 she reported ling at the base of the right thumb which he dated that her thumb was quite satisfactory and she from an injury two years before. The right was very pleased that she had undergone the trapezium was excised in April, 1944. He worked operation. full time after this, but attended again in I947, Mr. Q. W., aged 62, retired, is an example of ihe complaining of pain in the left thumb (Fig. 2). results in older patients. He gave a history of in The left trapezium was excised February, 1947. pain over a period of five years. with unsuccessfulby copyright. He was able to do full work inside two months and treatment by physiotherapy. The right trapezium has been doing full farm work since. He states was excised in February, 1947. He now amuses there is no pain and he can do anything. On himself sawing up logs. examination in January, I948, there was a full and painless range of movement with good power in BIBLIOGRAPHY GERVIS, W. H. ('947), Proc. Roy. Soc. Med., 40; 492. both thumbs, but slight crepitus on movement on RAY, M. B. (I933), Proc. Roy. Soc. Med., 27, I93. the right side (Fig. 4). FORESTIER, J. (1927), La Presse Medicale. http://pmj.bmj.com/ MEDIAN NERVE COMPRESSION IN THE CARPAL TUNNEL on September 23, 2021 by guest. Protected By P. H. NEWMAN, D.S.O., M.C., F.R.C.S. Assistant Orthopa dic Surgeon, The Middlesex Hospital, A4sista at Surgeon, Thv Royal National Orthopaedic Hospital- The carpal tunnel is a very confined space. It and the hook of the hamate, and on the lateral has been designed as a trough with a hard floor side, of the tubercle of the scaphoid and the ridge and rigid bony walls in order to protect the im- on the trapezium, have stretched across between portant structures within its confines. But for their peaks a fibrous sheet forming a roof known this anatomical arrangement, it is unlikely that the as the transverse carpal ligament. This is a tough flexor tendons with their delicate sheaths and the structure giving additional protection and acting median nerve could withstand the trauma of re- as a bar to forward prolapse of the structures when current falls on the outstretched hand. The walls, the wrist is in fiexion. which consist on the the medial side of the pisiform The tendons and nerve pass from the loose en- Postgrad Med J: first published as 10.1136/pgmj.24.271.264 on 1 May 1948. Downloaded from May 1948 NEWMAN: Median Nerve Compression in the Carpal Tunnel 265 vironment of the soft tissues ofthe forearm through a directly traumatic nature. Briefly speaking the this bottleneck into the comparative freedom of the changes in order of severity are: palm. As the price of protection from exposure to I. Oedema of nerve without loss of conductivity. danger at this point, they forfeit as it were their 2. Transient paralysis with spontaneous liberty of expansion and freedom of movement recovery. other than that which is essential for the function 3. More severe loss of function with slow of the hand and fingers. There is no place for an recovery after release of pressure. abnormal body or for any hypertrophic process 4. Complete loss of conductivity without the within this tunnel. possibility of recovery, due to total nerve Acute compression of the median nerve at this degeneration. level occurs from forward dislocation of the lunate Recently Brain, Wright and Wilkinson (I947) bone (Fig. i), and may occasionally occur in other have described symptoms of carpal tunnel com- injuries of the carpus with displacement. In a pression of the median nerve arising spontaneously comminuted Colles' fracture a fine spicule of bone in six patients. In no case was there any obvious may project forwards between the flexor tendons encroachment upon the space of the tunnel. The and impinge directly on the median nerve. A patients were all women in the second half of life more insiduous onset of symptoms due to com- and five were occupied in household duties. pression may occur as a result of hypertrophic Experimentally a tambour was placed in the arthritis of the wrist as from an old fracture of the carpal tunnel of a cadaver and it was found that scaphoid (Fig. 2), or even from a malunited Colles' the tension was three times greater when the wrist fracture. In these cases there is some process was extended to a right angle than when flexed to which takes up space within the tunnel and undue the same degree. They point out that the duties pressure falls upon the normal contents. The of a housewife necessitates much work with the tendons derive some protection from their sheaths wrist in the extended position and they consider and do not register symptoms of lateral com- that this, combined with some degeneration in pression unless it be severe. The nerve has no the artery of the nerve, is responsible for the com- by copyright. such sheath, is anchored laterally and is sus- mencement of a vicious circle of oedema and in- ceptible to alteration in pressure. creasing tension. Denny-Brown and Brenner (I944) in two articles have given the results of experiments in which Clinical Types different degrees of pressure were applied to peri- Clinically three types of compression of the pheral nerves. They found that the effect on con- median nerve in the carpal tunnel are found. ductivity of the nerve varies considerably according Firstly, an acute traumatic type associated with to the degree of pressure and the length of time injuries such as anterior dislocation of the lunate during which it is applied. The pressure plate bone; the symptoms recover with replacement of http://pmj.bmj.com/ was i i mm. in length. In one series of experi- bone, provided that this is not delayed too long. ments, if a light pressure of 5 to 7 gm. was applied Secondly, slow compression of the nerve of continuously there was no interference of con- spontaneous onset. Thirdly, slow compression duction, but narrowing of the nerve occurred at secondary to malunion or arthritis in the region. the site of pressure with swelling above and below the site of pressure. An increased pressure of 9 Symptoms and Signs of Slow to io gm. was attended with impairment of motor Compression function within six days and progressed to com- The symptoms are generally those of weakness of on September 23, 2021 by guest. Protected plete paralysis shortly afterwards. If, however, the hand and loss of the power to grip, especially the pressure was continued, the nerve overcame with the thumb. There may be a history of drop- this critical stage and function returned slowly. ping such articles as a cup of tea or saucepan. At the site of pressure, ischaemic and degenerative Tingling or pins and needles are felt over the changes took place, but there was no nerve or median nerve distribution. Pain is common and muscle degeneration distal to this area. extends from the thumb or index finger below, to Continued pressure for several days of 44 gm. the forearm, upper arm or even to the neck above; was followed by complete loss of all conductivity it is worse at night and aggravated by carrying and degeneration of the nerve both distally and for heavy objects. It is sometimes relieved by working some distance proximally. Release of pressure was the fingers and wrist backwards and forwards. not followed by return of function. Compression The following signs may be found in cases of by much greater pressure, e.g.