Syndrome of the carpel tunnel

The syndrome of the carpel tunnel appears by a numbness or pains at the level of unquestionable consecutive fingers of the hand to the compression of structures nervous and musculo-tendineuse in the Carpel tunnel.

Anatomical recall

The Carpel tunnel is the zone of transition between the Avant-bras and the Main. It is located in the heel of the hand. It forms an inextensible, narrower ostéofibreux procession on this level than with the front armlever or the hand.

This zone represents an arch, delimited by the second line of the bones of the carpus (between the hamulus of the Hamatum and the Trapèze)) and closed with the ventral face by the former annular ligament of the carpus.

Inside this structure, the flexor tendons of the fingers circulate, (the extrinsic ones of the hand: length flexor of the inch and eight surface flexor tendons and major of the four long fingers) and the median Nerve. The artery and the ulnar nerve (cubital) walk on in an independent cabin located on the internal edge: the cabin of Guyon. Flexor Carpi Radialis has its own cabin, inside the concavity of the Trapèze.

When there exists an edema or an inflammatory attack of the sheath of the flexors (Synovite S), it results an increase from it from the pressure intracanalaire involving a compression of the median nerve, responsible for the syndrome. This compression can involve until the irreversible lesion of the nerve.

Description

The symptoms sit on whole or part of the anatomical territory of the median nerve. They prevail on the palmar face of the first three fingers and are sometimes described by the patients like reaching all the hand. The syndrome of the carpel tunnel arises in a bilateral way in more half of the cases.

The syndrome is expressed by tinglings, numbnesses, swarmings or electric shocks. It obliges the patient to mobilize his hand. The patient often says that his hand appears to him inflated, engourdie, deadened, died, that its circulation seems stopped, that it feels awkward. There exists a weakness of the grip inch-index, a reduction in the muscular mass (Amyotrophie) of eminence Thénar (under the inch), a feeling of fingers boudinésL' appearance is usually progressive and the acute form remains rather rare.

Typically, the pains are night, awaking the patient, obliging it to rise (acroparesthésies night). They can appear only in the small hour or be repeated several times in the night. In the course of the day, the pains can be started by certain movements or the maintenance of position: to telephone, read the newspaper, to lead, knit… Practical activities professional or times spare, unusual or usual, but intense, are sometimes at the origin of the appearance of the syndrome.

Causes

There exist multiple supporting factors: traumatisms repeated on the palmar face of the wrist, osseous anomalies covering in the channel, hormonal modifications at the woman, renal Dialysis, obesity (especially at the young patient) etc It seems to exist also a genetic predisposition.

This syndrome generally meets among women.

At the woman, the cause is usually of hormonal nature, therefore this syndrome more frequently reaches the expectant mothers as well as the women close to the menopause. At the man, the cause is quasi exclusively of order mechanical, typically, the workman frequently using a power pick.

The shapes of syndrome of the carpel tunnel of professional origin are numerous in France. This pathology is recognized by the Tableau of occupational disease n°57 of the general scheme.

Diagnosis

The clinical examination finds sometimes disorders vasomoteurs (acrocyanose or blue fingers, sometimes accompanied by pains within the framework of a Syndrome of Raynaud).

There exists a loss of “O” perfect at the time of the opposition of the inch.

The deterioration of the sensitivity of the hand can be detected by a Test of Weber. The percussion of the former face of the carpus can cause swarmings (Signe of Tinel), just as the hyperflection of the wrist (Signe of Phalen). The compression of the wrist with a garrot can cause the appearance of a pain at the end of 30 seconds. The loss of the muscular force can be attested with the Dynamomètre of Jamar.

The electromyogram is used to confirm the attack of the median nerve and makes it possible to appreciate the importance of the nervous lesions. A normal EMG makes it possible as for him to exclude in an almost unquestionable way a severe form of syndrome from the carpel tunnel. It shows an increase in driving latency and reduction in nervous conduction.

The Radiographie of the wrist according to the incidence of the carpel tunnel (hand stuck to the plate, and perpendicular front armlever) makes it possible to appreciate the mechanism of it.

In the more complex forms, one can use the Imagerie by magnetic resonance in case, in particular, of failure of an intervention chirugicale or atypical forms (forms with the effort or extrinsic compression).

The biological assessment does not show anything in particular. It is necessary systematically to seek a diabetes, factor supporting frequent.

Differential diagnosis

most current are the attacks of nervous roots C6-C7, the syndrome of the crossing thoracobrachiale and neuropathies peripheral, syndrome of the round pronator, reached former interosseux nerve.

Treatment

One should not await the complications to treat. When there is loss of the digital sensitivity or muscular cast iron, the nerve is in general severely reached. In the light or moderate forms a medical care, conservative, can be proposed. In the severe forms the surgery appears preferable. The severe forms generally occur in the elderly.

The repetitions are not rare after medical care but are exceptional after surgery.

There do not exist official Frenchwoman or European recommendations for her assumption of responsibility. The only document with type of " recommandations" in 1993 by the American Academy off Neurology was published.

Medical care

The injections of derived cortisones in the channel (infiltrations) are regularly proposed, but of unequal action (Unfortunately, they are more or less limited to 3 per annum).

The drugs associating Diurétique S and antiinflammatoires have only one partial effect.

In the light or moderated forms, a Orthèse of rest of the wrist often makes it possible to calm the numbnesses. It can be carried only the night. This improvement of the symptoms is sometimes of short duration, then obliging to propose the surgery.

The purely mechanical attacks are often professional and can involve a work station or assignment change. When that is possible, it is advised to reduce the repeated microphone-traumatisms, in particular the exposure to the vibrations.

Surgical treatment

It is based on the Neurolyse allowing the release of the median nerve of the structures which compress it. The surgery, in the past to open sky, then maintaining by endoscopy, gives very good performances.

It consists of the section of the former annular ligament of the carpus. The endoscopic technique improves the result in the first three weeks but there do not exist differences significant in the results in the medium and long term. There exists a risk of lesion of the median nerve by endoscopic way which should not be neglected.

A prolonged rest is necessary before the resumption of a demanding manual work. A rehabilitation is useful (handling of a foam ball). The operated subjects complain sometimes about some residual pains, of a light loss of grip strength.

The post-operative continuations are généralements good: 1% of disappointment. There exist however complications: Algodystrophie, infection (in approximately 1% of the cases), repetition. More rarely, a section of one of the nervous branches intended for the inch can occur.

External bonds

Report/ratio on 100 patients in connection with the endoscopic release of the carpel tunnel
canalcarpien.org: Information on the surgery of the hand of the elbow and the shoulder

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