The carpal tunnel of the wrist is a confined space which surrounds the median nerve. The bottom, or dorsal side of the tunnel consists of the wrist bones, while the top, or palmar, side of the tunnel is defined by the transverse carpal ligament. Nestled in this small space are tendons responsible for movement of fingers and the median nerve surrounded by synovial fluid. The median nerve is responsible for sensation in the thumb, index, and middle finger and half of the ring finger on the affected hand, as well as motor function muscles at the base of the thumb that allow the thumb to oppose to the fingers.
Carpal Tunnel Syndrome (CTS) occurs when the median nerve within the tunnel is compressed resulting in a defined set of symptoms. The presentation of these symptoms vary from person to person but commonly include wrist pain. The wrist pain is typically worse at night and frequently causes night time awakening. Numbness, burning and tingling sparing the little finger is often reported, as is clumsiness, reduced grip strength, and weakness. Other, less common symptoms include writer’s cramp, shoulder pain, or even numbness in the third finger alone.
While the causes of CTS are not fully understood, multiple risk factors have been associated with the condition. Swelling in the body may result in an increase in the volume of fluid in the carpal tunnel, causing compression of the median nerve. Pregnancy and Congestive Heart Failure are two conditions associated with CTS for this reason.
Secondly, tumors or other growths can take up space in the carpal tunnel resulting in compression of the median nerve. Even the thickening of the tendons which pass through the carpal tunnel can be significant enough to displace and compress the median nerve. This occurs in some people with arthritis.
Likewise, a fracture of the wrist may change the shape of the carpal tunnel and locally compress the median nerve. Again, arthritis may cause similar alteration in the contours of the carpal tunnel.
Inflammation of the tendon sheaths is the most recognizable factor associated with CTS by the general public. Inflammation may occur with overuse of the wrists, repetitive movements of the wrist, or high force or high pressure movements of the wrist. Occupations and hobbies requiring the use of vibratory instruments are also high risk for CTS.
Conditions such as diabetes or alcoholism, known to have direct cytotoxic effect on nerve cells, can damage the median nerve directly, complicating the other causes of CTS.
Diagnosis of CTS is first and foremost based on a careful history, including the above risk factors and a thorough physical examination, and testing. Electrodiagnostic testing is the cornerstone of the diagnostic work up. Electromyography as illustrated in this video, is used to determine the health of the muscle and nerves in the wrist and hand. In the nerve conduction study, illustrated in this video the function of the median nerve is compared to the function of a similar nerve that does not pass through the carpal tunnel, usually the radial or ulnar nerve. Median nerve conduction velocities are slowed along the wrists and hands of people with CTS. Ultrasound and MRI are useful adjunctive tests to gather additional information if the nerve conduction test is equivocal or negative and a high degree of suspicion exists for CTS. Improvement after an injecting celestone, a corticosteroid, into the wrist may also be used to confirm the diagnosis.
In addition to a careful history of the symptoms described above, an examination will reveal:
- Tinel’s test (thumping the skin over an irritable nerve or wrist crease in this case causes shocks or tingling in the area of distribution of that nerve).
- Phalen s wrist flexion test (with the wrist maximally flexed, symptoms are produced within 60 second).
- Tenderness at the wrist and distal forearm overlying the median nerve.
- Swelling at the distal forearm volar surface.
- Sensation or feeling diminished to all fingers.
- Muscle weakness: Resisted movement or pinching of the thumb to the little finger.
Treatment for CTS depends on the severity of the symptoms and disability and includes both surgical and nonsurgical interventions. Non-surgical interventions may consist of immobilization by hand brace or splinting, ultrasonic therapy, oral steroids, celestone injections, NSAIDS, and workplace modifications, tailored to the individual’s needs.
Surgery is indicated for moderate to severe CTS symptomology, or when CTS is refractory to non-surgical interventions. Surgery for CTS involves cutting the transverse ligament of the carpal tunnel to relieve pressure and alleviate symptoms. It can be done effectively by either the traditional open release procedure, or by the newer endoscopic procedure.
In the traditional open method, a three inch incision is made on the wrist to allow the surgeon to directly visualize the carpal tunnel and surrounding structures, and to allow manipulation with traditionally sized instruments. When the procedure is completed, the wound must be sutured and a splint worn for up to three weeks following. Physical therapy is often needed to complete the healing process, and return to work may be delayed for three months.
In contrast, technological advances have made it possible to release the transverse ligament endoscopically. In Stitchless Endoscopic Carpal Tunnel Release (SECTR) a much smaller incision is made, and with the aid of a tiny camera to visualize the carpal tunnel and surrounding structures, a thin probe is used to divide, or cut, the transverse ligament. Following SECTR no sutures are needed. The wound is bandaged with waterproof material that allows bathing and self care. The scar is smaller, with reduced scar tenderness. Return to light activities is immediate, physical therapy is usually not needed, and most return to strenuous work after a month.
How can Dr. Knight help you with carpal tunnel syndrome?
Dr. Knight has significant experience in the treatment for carpal tunnel syndrome. He will quickly diagnose your problem and make recommendations to resolve your symptoms starting with the most conservative measures.
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