Local injection for Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is a medical condition due to compression of the median nerve as it travels through the wrist at the carpal tunnel. The main symptoms are pain, numbness, and tingling, in the thumb, index finger, middle finger, and the thumb side of the ring fingers. Symptoms typically start gradually and during the night. Pain may extend up the arm. Weak grip strength may occur and after a long period of time the muscles at the base of the thumb may waste away. In more than half of cases both sides are affected.

Risk factors include obesity, repetitive wrist work, pregnancy, and rheumatoid arthritis. There is tentative evidence that hypothyroidism increases the risk. Diabetes mellitus is weakly associated with CTS. The use of birth control pills does not affect the risk. Types of work that are associated include computer work, work with vibrating tools, and work that requires a strong grip. Diagnosis is suspected based on signs, symptoms, and specific physical tests and may be confirmed with electrodiagnostic tests. If muscle wasting at the base of the thumb is present, the diagnosis is likely. Being physically active can decrease the risk of developing CTS. Symptoms can be improved by wearing a wrist splint or with corticosteroid injections.

Signs and Symptoms

People with CTS experience numbness, tingling, or burning sensations in the thumb and fingers, in particular the index and middle fingers and radial half of the ring finger, because these receive their sensory and motor function (muscle control) from the median nerve. Ache and discomfort can possibly be felt more proximally in the forearm or even the upper arm. Less-specific symptoms may include pain in the wrists or hands, loss of grip strength, and loss of manual dexterity.

Some suggest that median nerve symptoms can arise from compression at the level of the thoracic outlet or the area where the median nerve passes between the two heads of the pronator teres in the forearm, although this is debated.

Numbness and paresthesias in the median nerve distribution are the hallmark neuropathic symptoms (NS) of carpal tunnel entrapment syndrome. Weakness and atrophy of the thumb muscles may occur if the condition remains untreated, because the muscles are not receiving sufficient nerve stimulation. Discomfort is usually worse at night and in the morning.

Diagnosis

A combination of described symptoms, clinical findings, and electrophysiological testing may be used. CTS work up is the most common referral to the electrodiagnostic lab. Historically, diagnosis has been made with the combination of a thorough history and physical examination in conjunction with the use of electrodiagnostic (EDX) testing for confirmation. Additionally, evolving technology has included the use of ultrasonography in the diagnosis of CTS.

Numbness in the distribution of the median nerve, nocturnal symptoms, thenar muscle weakness/atrophy, positive Tinel's sign at the carpal tunnel, and abnormal sensory testing such as two-point discrimination have been standardized as clinical diagnostic criteria by consensus panels of experts. Pain may also be a presenting symptom, although less common than sensory disturbances.

Electrodiagnostic testing (electromyography and nerve conduction velocity) can objectively verify the median nerve dysfunction. Normal nerve conduction studies, however, do not exclude the diagnosis of CTS. Clinical assessment by history taking and physical examination can support a diagnosis of CTS. If clinical suspicion of CTS is high, treatment should be initiated despite normal electrodiagnostic testing.

Prevention

Suggested healthy habits such as avoiding repetitive stress, work modification through use of ergonomic equipment (mouse pad, taking proper breaks, using keyboard alternatives (digital pen, voice recognition, and dictation), and have been proposed as methods to help prevent carpal tunnel syndrome. The potential role of B-vitamins in preventing or treating carpal tunnel syndrome has not been proven.

There is little or no data to support the concept that activity adjustment prevents carpal tunnel syndrome. The evidence for wrist rest is debated.

Stretches and isometric exercises will aid in prevention for persons at risk. Stretching before the activity and during breaks will aid in alleviating tension at the wrist. Place the hand firmly on a flat surface and gently press for a few seconds to stretch the wrist and fingers. An example for an isometric exercise of the wrist is done by clenching the fist tightly, releasing and fanning out fingers. None of these stretches or exercises should cause pain or discomfort.

Biological factors such as genetic predisposition and anthropometric features had significantly stronger causal association with carpal tunnel syndrome than occupational/environmental factors such as repetitive hand use and stressful manual work. This suggests that carpal tunnel syndrome might not be preventable simply by avoiding certain activities or types of work/activities.

Treatment

Generally accepted treatments include: physiotherapy, steroids either orally or injected locally, splinting, and surgical release of the transverse carpal ligament. Limited evidence suggests that gabapentin is no more effective than placebo for CTS treatment. There is insufficient evidence for therapeutic ultrasound, yoga, acupuncture, low level laser therapy, vitamin B6, and exercise. Change in activity may include avoiding activities that worsen symptoms.

The American Academy of Orthopedic Surgeons recommends proceeding conservatively with a course of nonsurgical therapies tried before release surgery is considered. A different treatment should be tried if the current treatment fails to resolve the symptoms within 2 to 7 weeks. Early surgery with carpal tunnel release is indicated where there is evidence of median nerve denervation or a person elects to proceed directly to surgical treatment. Recommendations may differ when carpal tunnel syndrome is found in association with the following conditions: diabetes mellitus, coexistent cervical radiculopathy, hypothyroidism, polyneuropathy, pregnancy, rheumatoid arthritis, and carpal tunnel syndrome in the workplace.

Splints & Braces

The importance of wrist braces and splints in the carpal tunnel syndrome therapy is known, but many people are unwilling to use braces. In 1993, The American Academy of Neurology recommend a non-invasive treatment for the CTS at the beginning (except for sensitive or motor deficit or grave report at EMG/ENG): a therapy using splints was indicated for light and moderate pathology. Current recommendations generally don't suggest immobilizing braces, but instead activity modification and non-steroidal anti-inflammatory drugs as initial therapy, followed by more aggressive options or specialist referral if symptoms do not improve.

Many health professionals suggest that, for the best results, one should wear braces at night and, if possible, during the activity primarily causing stress on the wrists.

Corticosteroids

Corticosteroid injections can be effective for temporary relief from symptoms while a person develops a long-term strategy that fits their lifestyle. This form of treatment is thought to reduce discomfort in those with CTS due to its ability to decrease median nerve swelling. The use of ultrasound while performing the injection is more expensive but leads to faster resolution of CTS symptoms. The injections are done under local anesthesia. This treatment is not appropriate for extended periods, however. In general, local steroid injections are only used until more definitive treatment options can be used. Corticosteroid injections do not appear to be very effective for slowing disease progression.

Surgery

Release of the transverse carpal ligament is known as "carpal tunnel release" surgery. It is recommended when there is static (constant, not just intermittent) numbness, muscle weakness, or atrophy, and when night-splinting or other conservative interventions no longer control intermittent symptoms. The surgery may be done with local or regional anesthesia with or without sedation, or under general anesthesia. In general, milder cases can be controlled for months to years, but severe cases are unrelenting symptomatically and are likely to result in surgical treatment.

Surgery is more beneficial in the short term to alleviate symptoms (up to six months) than wearing an orthotic for a minimum of 6 weeks. However, surgery and wearing a brace resulted in similar symptom relief in the long term (12–18 month outcomes).