Why are my fingers numb? Part 2


NUMBNESS AND WEAKNESS in the hands of motorcycle riders is common, and usually due to nerves being compressed somewhere between the neck and fi ngers. There are three major nerves that supply sensation to the hand and fi ngers: the median, ulnar and radial. The median and ulnar nerves supply sensation to the palm and fi ngers: those surfaces in contact with the motorcycle’s handlebar controls. Carpal tunnel syndrome is compression of the median nerve at the wrist. The median nerve supplies sensation to the thumb, index fi nger, long fi nger and thumb side of the ring fi nger—areas critical for dexterity. The median nerve enters the carpal tunnel at the level of the wrist. The canal is made of unyielding bone on three sides and a thick ligament (like leather) enclosing the canal. Patients have excessive pressure within the carpal tunnel, but the actual cause is not always clear. The fi nal pathway associated with all nerve compression syndromes is thought to be diminished microcirculation within the nerve, leading to loss of nerve function. Patients often experience these progressively worse symptoms over several years, if left untreated: 1. Nighttime numbness and tingling. Shaking the hand helps it go away. 2. Daytime numbness that comes and goes. Often worse after intense gripping activities. 3. Numbness that remains present all day and night 4. Muscle atrophy and loss of dexterity. The goal of treatment is to reverse the progressive deterioration and to prevent irreversible nerve damage. The diagnosis is made when the history of the symptoms and the physical exam both fi t. Since wrist fl exion causes the pressure to rise within the carpal canal and most people sleep with their wrists fl exed, a simple diagnostic is wearing a splint at night to keep the wrist straight. If the symptoms improve, the diagnosis is supported. Nerve tests that measure the electrical conduction speed and the voltage of the nerve can also be done. This also helps serve as a baseline to know how bad the nerve is before surgical treatment. Surgery involves dividing the transverse carpal ligament so that it springs open and heals as a bigger tunnel. There are several methods, all of which can be very successful, and none have shown any superiority in hand function after three months of recovery. The surgery is generally 10-20 minutes and causes little pain. Treatment can typically be planned at a convenient time for the patient. The median nerve seems to recover function in proportion to how poorly it was functioning before surgery. Fortunately, even in severe cases, the pain associated with the carpal tunnel often improves directly after surgery and patients often report sleeping better. In severe cases, numbness may take months to improve, but this is not guaranteed. MCN Dr. Cary Tanner is a surgeon, chairman of the board at Fresno Surgical Hospital and medical director of Summit Surgery Center. MCNEWS.COM Ride Better I MCN 41 Why Are My Fingers Numb? Part 2 MATTERS HEALTH > By Cary Tanner, M.D. WITH ANY SURGERY involving palm incisions, tenderness generally lasts up to 12 weeks, but contact against the palm will not hurt the nerve. Desensitization activities can be done independently, to help postoperative palm tenderness. Formal therapy is rarely required and it’s often best to ignore the fact that surgery was performed. Keep the wound clean until the sutures are out (one week post-op). Soap and water can run over the incisions, but the wound should not be immersed in water. Some surgeons recommend a removable wrist splint for a few weeks after surgery, but patients can be quite functional without the splint, so this does not impair the recovery rate. Most manual-labor patients can return to work at six weeks. Office workers can return to work the day following surgery. Low-impact riding can be started within a few weeks. Flat-track and road racers are usually competitive within a month. Motocross racers will usually return to full-capacity riding in eight weeks.