Carpal tunnel syndrome

Carpal tunnel syndrome (CTS, synonyms include: carpal tunnel syndrome, CTS, Medianuskompressionssyndrom, as a symptom Brachialgia paresthetica nocturna ) is a term used in medicine and refers to a compression syndrome of the median nerve in the wrist. Women are about three times more frequently affected than men.

Typical initial symptom are occurring pain or discomfort that can radiate from the hand in the entire arm. Later, the pain usually occurs increasingly on the day, in the advanced stage it can lead to a muscle in the area of ​​the thenar eminence, weakness when gripping and a reduction of touch. Mild forms of carpal tunnel syndrome can be treated conservatively, in severe cases, surgical treatment must be carried out.

• 5.1 Conservative
• 5.2 Operational 5.2.1 anesthesia
• 5.2.2 Open surgical technique
• 5.2.3 Endoscopic surgical technique

• 6.1 Open surgical technique
• 6.2 Endoscopic surgical technique
• 6.3 Long-Term Results

Anatomy

The carpal tunnel is a tunnel-like connective tissue, firmly enclosed tube from the forearm to the hand on the palmar ( palm side ) of the wrist. The "floor" and the side walls of the tunnel formed by the carpal bones ( a part of the bony hand bones ), while the "roof" of a broad band, the flexor retinaculum, is formed, which stretches out transversely between the carpal bones. The tunnel runs - along with nine flexor tendons (four each of the superficial and deep Fingerbeugers as well as that of the long Daumenbeugers ) - the median nerve, which controls, among other things, the movements of the fingers and the thumb, sensations re-register and meets autonomic functions by the hand.

Causes

By a narrowing of the carpal tunnel of the nerve is damaged. In most cases, carpal tunnel syndrome occurs in pre-existing relative anatomical narrowness, where a tissue swelling is added by a mechanical overload, inflammation or systemic diseases.

Dispose to carpal tunnel syndrome

• Constitutional narrowness of carpal tunnel
• Work hand usually more affected (two-sided occurrence but is frequent)
• Manual work
• Pregnancy
• Kidney damage
• Wrist or distal forearm fractures and scarring
• Diabetes mellitus
• Tenosynovitis of the digital flexor
• Prolonged muscular profile of the long finger flexors
• Underactive thyroid (hypothyroidism)
• Chronic Polyarthritis
• Acromegaly
• Infections in the hand area
• Increased venous pressure, as the shunt arm in dialysis patients
• Alcohol abuse
• Amyloidosis

Symptoms

Typical initial symptom is pain occurring ( Brachialgia nocturnal ) or discomfort ( asleep, pins and needles ), which may radiate into the entire arm with a focus in the coverage area of the median nerve of the hand diffuse. First, the symptoms occur during and especially after wrist stress on such as after physical work or when riding a bicycle. Later, however, there is also no apparent cause for nocturnal symptoms. Finally, the complaints also occur increasingly on the day and it comes through a pressure damage to nerve fibers (through the narrowing in the carpal tunnel ) to a muscle supplied by the median nerve of the hand muscles, clearly visible in the area of ​​the thenar eminence.

Patients get a first primarily occurring in the morning, but later continued weakness in the grab. It is not uncommon also to autonomic disorders, for example, trophic and vascular disorders.

If the nerve damage progresses, there is an increase in the weakness of the typical hand muscles and reduction of touch in a circumscribed area of ​​the skin. In particular, by loss of function of the thumb there is a disability. On the other hand, can be but at this stage the pain after, as well as the pain fibers are destroyed.

Status

The fine motor skills and sensitivity are reduced, affected are the first three fingers corresponding to the area supplied by the median nerve with a Hyp and paraesthesia of the three radial ( thumb or spoke- side ) fingertips and atrophy of the thenar muscles in the advanced stage.

Often the carpal tunnel ( carpal tunnel ) is sensitive to pressure and light percussion ( Tinel's sign). In hyperextension ( or strong flexion) of the wrist it comes to the typical abnormal sensations in the sensitive area supplied by the median nerve ( Phalen's sign). The Medianuskompressionstest is positive in about one minute.

Diagnostics

Even though medical history and physical examination findings are often characteristic of carpal tunnel syndrome, only the measurement of nerve conduction velocities can help confirm the diagnosis. It is the motor conduction time ( " distal motor latency " ) of the median nerve measured between the stimulation at the wrist and the innervated by this nerve thenar muscles. As normal values ​​are < 4.2 ms. However, the standard values ​​depend on the chosen technology and are not necessarily of the examiner to examiner the same. Therefore, should always be measured in both hands side comparison and the values ​​obtained with the corresponding values ​​of the ulnar nerve are compared. Typically, in the presence of carpal tunnel syndrome and the sensitive nerve conduction velocity of the median nerve between the forefinger or middle finger middle joint and wrist is slower than the sensitive nerve of the measured to compare the ulnar nerve of the same hand ( it is in the healthy for both nerves at about 48 m / s). It often turns out that electrophysiologically already (albeit smaller ) are on a symptom-free counter hand to find unusual values ​​. An answer to the question of whether there is a (temporary ) blockage of nerve conduction ( neurapraxia ) or even to an actual nerve fiber destruction ( axonotmesis ), can only provide electromyography.

When a discrepancy between examination findings and found measured values, the measurement of the sensory nerve can be done by appeal to the finger and dissipation both in the palm of the hand and the other side of the carpal tunnel to measure the conduction velocity selectively in the area of ​​the carpal tunnel. A comparison of the responses of the median nerve and ulnar nerve after ring finger stimulus may be useful for diagnosis.

If no comparative measurements are made, the hands should be warm enough in the measurements of nerve conduction velocities, since the rate per ° C to about 2 m / s is slower. The ideal measurement temperature is 34 ° C.

Due to the compression by the retinaculum it comes to a narrowly localized swelling ( Pseudoneurom ) of the median nerve at the Karpaltunneleingang. This can be assessed with an ultrasound examination. The nerve cross sectional area is measured at several points. Specialized hand surgery centers may thus provide a reliable diagnosis, so that in conjunction with a corresponding clinical symptoms on the (often painful ) Measurement of nerve conduction can be omitted in most cases already. In addition, other, in this context, but important pathological changes can be detected such as tendonitis in the ultrasound examination, a long muscle bellies or medium arteries.

Differential diagnosis, especially damage to the cervical spine into consideration that lead to an irritation of the spinal cord or spinal nerve roots of ( Cervicobrachialsyndrom, especially nerve root C6). Even with these diseases may radiate down to the wrist pain and discomfort over the arm. In individual cases, disease or a compression syndrome of arterial vessels can trigger appropriate complaints. It should therefore not be dispensed with a key of the radial pulse and a comparative measurement of blood pressure in both arms in the investigation.

Therapy

Conservative

In the early stages of carpal tunnel syndrome, a conservative treatment be tried. Found a history of a severe mechanical, repetitive overloading, so you can bring an improvement in the absence of the symptom -inducing activity. Wearing special night splints or even the creation of shaped support organizations that are offered by the medical stores for the day, the discomfort, at least for a time long can eliminate or mitigate. An alternative to conventional night splint are tracks that open the carpal tunnel by this are stretched and thereby extending the transverse bands. This process reduces the pressure on the nerves, causing the pain softens and allows the healing of inflammation.

As supportive therapy or alternative analgesic and anti-inflammatory medications can be used, such as non-steroidal anti-inflammatory drugs or local infiltration of corticosteroids into the carpal tunnel. Also apply cold therapy to reduce inflammatory activity or heat therapy to improve circulation.

In the context of pregnancy, the symptoms ease after birth can be expected.

If conservative treatment is unsuccessful, then, in order to avoid permanent damage done surgery.

Operational

The procedure can be performed on an outpatient basis in the rule.

Anesthesia

The procedure is performed under regional anesthesia. A stunning the whole arm is required so that the tourniquet required for the operation is tolerated better. It can be performed as axillary block or intravenous regional anesthesia. To prepare the tourniquet, the blood is " wrapped " with a tightening bandage from the arm, the back flow of blood is prevented by a tourniquet. For intravenous regional anesthesia, pain freedom of the whole arm is then by filling the veins with a local anesthetic causes. When subaxillären regional anesthesia for the arm pulling nerves are anesthetized in the armpit.

Only in exceptional cases is a general anesthetic into consideration.

Open surgical technique

The surgeon operates from the outside with a direct view of the surgical field with optical magnification. The required about 1.5 to 3 cm long skin incision is located in the palm, without touching the natural creases of the palm touching and disturbing. Possible alternative is a " short-cut " just distal to the wrist crease, a more distally located "mini- incision " or a double cut. These procedures remain the more experienced surgeon reserved.

The principle of operation is the complete transection of the flexor retinaculum, the bond which spans the carpal bones and the carpal tunnel volar upward limited. The band ends soft apart and the carpal tunnel widens. The nerve recovers in the sequence, if the damage has not passed too long through the carpal tunnel, through the pressure relief achieved. Contrary to earlier practice measures are displayed directly on the nerve only in rare, very special circumstances.

The surgery is one of the most common operations for a hand surgeon takes a few minutes and is very safe, that involve minimal complication rate. Typical problems are occasional scars complaints that require Abhärtungsbehandlung, a power reduction of the gross strength over a few months and as a very rare complication - as with all hand surgeries - the formation of a reflex sympathetic dystrophy ( Sudecksche disease). A plaster treatment is in the technique with a short cut in the palm of the hand is no longer necessary, however in Germany in many places still common. The scar is usually after 6 months almost invisible healed the period of incapacity, depending on activity a few days to several weeks.

Endoscopic surgical technique

The surgeon works endoscopically, ie from the inside, only with instrumental visibility of the surgical field. The endoscopic procedures have neither advantages nor disadvantages unique compared to open techniques. The operation results are generally comparable to those of the open operation, even in comparison to the mini- incision. The higher patient satisfaction with an uncomplicated course and the lower scar pain in endoscopic procedures are possibly a higher rate of complications or poorer long-term results and a higher rate of recurrence compared with open surgery than with.

Consequences of surgery and complications

The success of treatment depends essentially on the duration and extent of previous nerve injury. In uncomplicated cases the carpal tunnel release fixes all problems immediately, eliminating pain and discomfort at night. If already have passed numbness, paresthesia and / or muscle weakness, can not be considered in any case of immediate or complete disappearance.

The general risks of surgical intervention (eg, bleeding, infection, swelling, or injury to nerves and blood vessels) have become rare. In exceptional cases it may be independent of the chosen surgical technique to a lengthy, come take a very painful bone decalcification and / or soft tissue swelling, joint stiffness also may result ( dystrophy ).

Open surgical technique

Too small incisions in the skin increase the risk of incomplete Retinakulumspaltungen and damage to the median nerve and its branches, but also of the ulnar nerve. A routine opening of the connective tissue around the nerve ( epineurotomy ) is at Ersteingriffen not necessary, an operational division of the individual nerve bundles ( interfascicular neurolysis ) leads to poorer results and is not displayed. The representation of the branch that controls the movement of the ball of the thumb is not routinely required but caution is advised when atypical departure or standard versions. A removal of the mucous membrane ( synovectomy ) is also not be required routinely but only when striking pathological changes such as with increased mucous formation or inflammatory rheumatic mucosal inflammation ( synovitis ) and amyloidosis in dialysis patients. Removal of the palmaris longus tendon should be done only with subsequent autologous transplantation. Atypical muscles or tendons within the carpal tunnel can be removed in each case. A reconstruction of the retinaculum (eg by a Z-plasty ) to improve grip strength after surgery is judged contradictory.

Endoscopic surgical technique

The often smaller surgical wound caused significantly less scar problems, compared to open surgical technique to be reckoned with but with a slightly higher complication rate.

Above all, there is a danger of injury to the median nerve, in particular a small side branch that leads to the thumb. An incomplete opening of the carpal tunnel sometimes leads to that later need surgery again. Occasionally, there is also the need to switch from one endoscopically begun to open surgery because of bleeding or the anatomy is unclear.

Long-term results

In a follow-up, mean age of 13 were of 113 patients, the "open" in Massachusetts / USA were operated on, 74 % completely free of symptoms (80 % of women and only 59 % of men) and 88 % satisfied or very satisfied. Only twice (1.8%) had to be performed reoperation. All patients without comorbidities were completely symptom-free, while the result was the poorer, the more comorbidities were present. Especially with diabetes, neuropathy, rheumatoid arthritis and osteoarthritis function and satisfaction were postoperative rare good to very good.

Follow-up treatment

Cotton federation or an association with mild compression in the wound area without constriction is required for a few days. A short-term immobilization of the wrist by a rail is not required and is at the discretion of the surgeon. If necessary, can be a pain medication. Postoperative cold packs can relieve pain. Special " scars albums" are not required, at best, an oleaginous ointment for scar treatment are recommended.

An early functional treatment with self- motion exercises of the fingers with no or low load on the first postoperative day prevents a Handödem and finger stiffness. Avoid a wrist splint and early exercise treatment lead to earlier use of the hand in daily life and at work.