Carpal Tunnel Syndrome
The nerves and flexor tendons that run towards the palm of the hand cross an area in the wrist joint called the carpal canal or carpal tunnel. This term is given to what is an anatomical structure that is rather like a pipe which encases the median nerve and the flexor tendons of the hand. The median nerve is essentially responsible for the muscles of the thumb and the sensation on the three fingers on the thumb side. The carpal tunnel is formed in the lower part of the wrist by carpal bones, over which arches a thick band (transverse carpal ligament). On rare occasions, through pathological thickening of the ligament itself or through changes in the tunnel floor, for example following a fracture, there can be a narrowing of the tunnel. However, carpal tunnel syndrome appears to be idiopathic, in other words, appearing without any external cause.
Carpal Tunnel Syndrome Risk Factors
Carpal tunnel syndrome affects considerably more women than men. A favourable condition for its occurrence is a congenital anomaly in that the tunnel itself is relatively narrow in the first place. Certain other underlying diseases or factors also predispose the appearance of carpal tunnel syndrome. Some of these include diabetes, rheumatic diseases, pregnancy, thyroid disease, tendon sheath inflammation, and, among others, fractures to the hand or wrist. The end result is compression damage to the nerve, which leads to the typical complaints the patient describes.
There are characteristic symptoms associated with carpal tunnel syndrome. Initially during the second half of the night there are typical abnormal sensations such as tingling or numbness (paraesthesia) on the three fingers next to the thumb, possibly also in the ball of the thumb, accompanied by pain that may radiate through the forearm. Initially, the pain only appears at night or after certain strenuous activity such as a cycling trip or heavy manual work. As the condition progresses, the symptoms also appear during the day. Permanent paraesthesia occurs and possibly even muscular atrophy (wasting of the muscle) on the ball of the thumb. In many cases the dominant hand is more strongly affected, but dual-sided occurrences of the condition are common.
Apart from the typical signs, we can confirm the diagnosis with a few tests. One of these is a positive Phalen’s test in which the wrist joint is held in a flexed position. After 1-2 minutes, numbness will appear in the thumb side fingers. In addition, the doctor can provoke radiating shooting pains in the finger by tapping on the carpal tunnel (Tinel’s sign). Additionally, a neurologist can measure the nerve conduction velocity and carry out electromyography to judge the extent of the disorder.
The goal of surgery is to eliminate pressure on the nerve and thus prevent its irreversible damage. The success of carpal tunnel surgery depends on how long compression has been applied to the nerve and whether actual irreversible damage already exists. Surgery can be open or endoscopic. In open surgery, the carpal ligament is cut via a 3cm long incision in the palm of the hand. We only perform open surgery as it is the only way to make an assessment of the nerves and other structures within the carpal tunnel. The operation gives the nerve room and releases pressure. Tingling and finger pain usually disappear immediately after surgery. However, if there was severe damage and symptoms in the form of numbness, paralysis or muscle atrophy these will only gradually diminish over a period of weeks and months and sometimes not completely at all. Therefore, we urgently recommend having this surgery early enough.
Carpal tunnel syndrome is one of the nerve compressions syndromes.
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