Numbness and tingling is most commonly caused by pressure on a nerve (nerve entrapment). However, circulatory problems can also cause this. If this unexpectantly occurs postoperatively your physician should be notified. Occasionally heart problems or a stroke can present with these symptoms and your medical physian should be made aware. Nerve entrapment (or pressure) can also cause pain and weakness.
Nerves start in the spinal cord and neck and travel under the clavicle (collarbone) through an area called the brachial plexus where they branch and intermingle to form the nerves of the arm. Nerves carry the impulses that supply motor control and sensation to the hand and upper extremity.
Pressure or entrapment anywhere along a nerve (neck, shoulder, forearm or wrist) may cause numbness and tingling in your hand. It is possible to have two or more areas of entrapment (double crush) in the same extremity. Surgery to relieve pressure in one of the areas may not significantly relieve your symptoms if other areas of compression remain. Therefore, your physician will try to localize the area of pressure and determine which location is significant. Consultations with your medical physician, neurologist, rheumatologist, physiatrist and/or spine surgeon may be needed.
Electrophysiologic testing commonly called EMG (electromyogram) consists of an EMG and Nerve conduction study. They are performed by neurologists or physiatrists experienced in this technique. These studies will help your physician make a diagnosis and rule out other problems.
Occasionally MRI or CAT scans will be ordered to identify peripheral nerve compression. They are helpful if a mass or "tumor" is suspected but otherwise usually are not helpful. However, they can be helpful in evaluating the neck area.
The most common areas of nerve compression are median nerve at the wrist (carpal tunnel syndrome) and ulnar nerve compression at the elbow (cubital tunnel syndrome).
Electrodiagnostic studies can be very helpful in evaluating weakness, numbness, tingling, pain as well as fatigue and cramps. The two main procedures used to study nerve and muscle function are the electromyogram (EMG) and nerve conduction study. (NCS) Theses two are often referred to as an EMG. These evaluations are performed by specifically trained physicians usually neurologists or physiatrists.
The nerve conduction study evaluates the speed of conduction of nerve impulses to muscles as well as to skin. Small electrodes are taped to the skin and a brief electric stimulus is applied. This will cause a tingling sensation. The response is then evaluated. The nerve impulse may be conducted normally, at a slow speed or not transmitted at all.
The electrical activity of muscles is evaluated by inserting a fine electrode into the selected muscle. Needle insertion may cause mild, temporary discomfort. The needles are not used for injection and no shocks are administered. The function of the muscle is recorded. This may include muscles of the neck and arm and hand.
The patient does not need to do anything special to prepare form these tests except to keep the skin free of any lotions or emollients on the day of the examination. If you have a bleeding disorder (hemophilia etc) or on blood thinning mediations (i.e. coumadin), or have a cardiac pacemaker, please inform the physician performing the test.
• It requires between 45 to 60 minutes to perform the test.
• There are no restrictions after the test.
• There are no permanent side effects.
• All needles are sterile and therefore there are no risk of disease transmission such as AIDS, HIV, hepatitis, and other infections.