Carpal tunnel syndrome (CTS) occurs as a result of compression of the medial nerve where it passes through the carpal tunnel at the wrist. Normal tissue pressure within the tunnel is 7-8 mmHg but CTS can result in pressure above 30 mmHG, which further increases with flexion and extension of the wrist the increase in pressure produces ischemia in the nerve. The increase in pressure produces ischemia in the nerve This results in sensory and motor disturbances in the median nerve distribution of the hand.
Any condition such as edema, inflammation, tumor or fibrosis may cause compression of the median nerve within the carpal tunnel and result in ischemia. The exact cause of CTS is unclear, however conditions that produce inflammation of the carpal tunnel that can contribute to CTS include repetitive use, rheumatoid arthritis, pregnancy, diabetes, trauma, tumor, hypothryoidism, and wrist sprain or fracture. Other causes include congenital narrowing of the tunnel and vitamin B6 deficiency.
Approximately 5 million individuals in the United States are diagnosed with CTS. Most patients are diagnosed between 35 and 55 years of age with prevalence in women. A patient with CTS will initially present with sensory changes and paresthesia along the median nerve distribution in the hand. It may also radiate into the upper extremity, shoulder and neck. Symptoms include night pain, weakness in the hand, muscle atrophy, decreased grip strength, clumsiness, and decreased wrist mobility.
Electromyography and electroneurographic studies can be used to diagnose a motor conduction delay along the median nerve within the carpal tunnel. MRI is sometimes used to identify inflammation of the median nerve, altered tendon or nerve positioning within the tunnel or thickening of the tendon sheath. Physical examination, history and review of the symptoms are extremely important when diagnosing CTS.
Physical therapy management includes splinting, carpal mobilizations, and gentle stretching. An adaptation of the patient's occupation, workplace, leisure activities, and living environment may be necessary. If that fails then the patient may require surgery to release the carpal ligament and decompress the median nerve. Post surgical physical therapy intervention should include the use of moist heat with electrical stimulation, cryotherapy gentle massage, tendon gliding exercises, and active range of motion. A patient should initially avoid wrist flexion and a forceful grasp. After 4 weeks a patient can progress with active wrist flexion, gentle stretching, putting exercises, light progressive resistive exercise, and continued modifications of body mechanics. Radial deviation should be avoided due to the tendency for irritation and inflammation.