Carpal tunnel syndrome occurs when the median nerve, which runs from the forearm into the hand, becomes compressed or squeezed at the wrist. The median nerve controls sensation to the thumb, index, middle, and part of the ring finger. It also controls the muscle at the base of the thumb. The carpal tunnel – a narrow, rigid passageway of ligament and bones at the base of the hand – contains the median nerve and tendons that flex the fingers. Sometimes thickening from irritated tendons or other swelling narrows the tunnel and causes the median nerve to be compressed. The result may be pain, weakness, or numbness in the hand and wrist, sometimes radiating up the arm.
Carpal tunnel syndrome is the result of a combination of factors that increase pressure on the median nerve in the carpal tunnel. Most commonly the disorder is due to a congenital predisposition – the carpal tunnel is simply smaller in some people than in others. Women are three times more likely than men to develop carpal tunnel syndrome. Other contributing factors include certain medical conditions such as diabetes, hypothyroidism, or rheumatoid arthritis. Working in an assembly line, and using vibrating tools can cause the disease. Pregnant women commonly develop this syndrome which usually resolves after delivery.
Symptoms usually start gradually with tingling, burning, or numbness in the thumb, index, and middle fingers. The symptoms often first appear at night, since many people sleep with flexed wrists. Affected individuals may wake up feeling the need to “shake out” the hand or wrist. As symptoms worsen, people might feel tingling during the day. Decreased grip strength may make it difficult to form a fist, grasp small objects, or perform other manual tasks. In chronic and/or untreated cases, the muscles at the base of the thumb may waste away.
Diagnosis is accomplished first by a detailed history. Important considerations include the anatomic distribution of symptoms, timing and duration of symptoms, presence or absence of night symptoms, activities that worsen symptoms, and presence of other medical conditions such as diabetes or thyroid disorders. A thorough physical exam will look for things like loss of sensation, irritability of the nerve with direct tapping or bending of the wrist, and muscle weakness or atrophy. Entrapment of the nerve at more proximal locations like the forearm and neck should be ruled out as well. Nerve Conduction Studies and Electromyography can assess how well the nerve transmits electrical signals down the arm. These tests are used to confirm a diagnosis and give objective information about the stage or severity of the disease. They can also be used to rule out problems in other areas such as the neck.
Non-operative treatment involves changing patterns of wrist and hand use to reduce pressure on the nerve. Identifying and treating underlying medical causes such as diabetes or thyroid disorders is essential. Wearing a splint at night that keeps the wrist from bending is often successful. Injection of corticosteroids into the carpal tunnel can be helpful. Modifications to a patient’s workplace environment or schedule can be therapeutic and preventative.
Patients who have failed an adequate trial of non-operative treatment are candidates for surgery. Carpal tunnel release is one of the most common and most successful surgical procedures in orthopedics. It involves cutting the band of tissue laying directly on top of the nerve called the transverse carpal ligament to reduce pressure. Two techniques exist:
Open release surgery, the traditional procedure used to correct carpal tunnel syndrome, consists of making an incision up to 2 inches in the wrist and then cutting the transverse carpal ligament to enlarge the carpal tunnel.
Endoscopic surgery may allow faster functional recovery and less postoperative discomfort than traditional open release surgery. The surgeon makes a much smaller incision at the wrist, inserts a camera with a retractable knife blade, and cuts the transverse carpal ligament while observing the tissue on a video screen
Both options are outpatient procedures and take 10-15 minutes to complete. A post-operative splint is not required and the patient goes home with a soft dressing. Patients are encouraged to gently move the wrist and fingers immediately after surgery. Most people can return to full activities within 1-3 weeks
Ellis O’Neal Cooper, MD is board certified in both hand surgery and orthopedic surgery. Dr Cooper practices at Orthopedic Specialists of Louisiana in Shreveport. To schedule an evaluation with Dr. Cooper, please visit: orthopedicspecialistsla.com or call: 866.759.9679.