A COMPRESSIVE NERVE DISORDER – SOMETIMES ALSO KNOWN AS A PINCHED OR TRAPPED NERVE – OCCURS when the pressure around a part of a nerve causes it to malfunction. Strength and feeling in the hands depends on healthy nerves. En route to the hand, the nerves pass through narrow areas at the elbow and wrist where they are vulnerable to being “pinched”.
Compressive nerve disorders can arise through external factors – such as when you rest your elbows on a table too frequently or when a leg cast or brace is ill-fitted – or as a result of the patient’s own body putting pressure on a nerve. Known as entrapment neuropathy, this usually happens as a result of tissue swelling or thickening at tight points along the pathway of a nerve. Individuals with certain medical conditions such as diabetes, thyroid problems, renal failure, gout and rheumatoid arthritis are also at increased risk of developing compressive nerve disorders as these disorders tend to either induce swelling or reduce general blood flow throughout the body.
Carpal tunnel syndrome is the most common compressive nerve disorder. In this condition, the median nerve (a nerve that runs through the shoulder and down the arm, all the way tot he fingers) is compressed at the wrist, causing numbness and pain in the thumb, index, middle and ring fingers. Theses symptoms are usually worse on waking in the morning or at night, and may be aggravated by holding on to an object too tightly or for too long.
In especially severe cases of carpal tunnel syndrome, the thumb muscles eventually shrink and weaken, making it difficult for the patient to do any sort of fine manipulation with the thumb. Activities such as picking up a coin or doing up a button become extraordinarily difficult, and the patient may feel especially clumsy when doing anything with his thumbs. Unfortunately, it is rarely possible to prevent compressive nerve disorders as they tend to arise from a combination of factors. Attention to proper ergonomics of the neck and upper limb may, however, decrease the risk of compressive nerve disorders from developing or worsening, as will avoiding holding things like mobile phones or tablets in the same position for overly long periods of time. Try not to keep your elbow and wrists flexed for too long, and always take a break every hour to stretch your neck, arms and legs when working at a desk.
Mild or early compression may be treated through a combination of non-sterioidal anti-inflammatory drugs, splints and regular exercises. Injections near the site of compression may provide relief.
A more definitive cure can be achieved through surgical decompression of the nerve, either through traditional “open” surgery or endoscopic means. Compared to open surgery, endoscopic nerve decompression by a qualified hand surgeons had much less postoperative pain and faster return to full function. In most cases, the hand can be used the very next day for light daily activities. The scar is much smaller and hardly visible.
Although slight pain and weakness may be noticed in the hand after decompression, this does not usually last for more than a month or two. The relief from the constant sensation of pins and needles – a common sign of compressive nerve disorder – is on the other hand rapid and almost always permanent. Full sensory function and strength usually returns within another few months.
Dr. Kevin Yip, Orthopaedic Specialist
