What is carpal tunnel syndrome?
Carpal tunnel syndrome or ‘median nerve compression’ is a painful condition that develops as a result of excess pressure on a nerve (median nerve) as it travels into the wrist through the narrow passageway.
Median nerve of arm carries sensation from thumb, index finger, middle finger and a part of the ring finger to the brain and controls the movement of some important hand muscle. This nerve arises from the brachial plexus which is formed by the joining of many nerve roots exiting the spine in the neck region. Median nerve runs down the forearm and passes through a narrow tunnel like passageway (carpal tunnel) on the palm side of the wrist. Your pain specialist can further explain the anatomical details to help you understand the condition better.
What causes carpal tunnel syndrome?
CTS may affect one or both hands. Those, who are involved in jobs requiring repetitive movement of the wrist such as construction workers, manufacturers etc. are more likely to be diagnosed with CTS. Women are three times more likely to have CTS and the prevalence, severity increases with age. Some studies have observed a peak incidence between the age of 45 and 59 years and a second peak between 75 and 84 years. In most cases it is difficult to pinpoint the cause as to why this condition develops although many predisposing factors have been identified and these include:
- Fluid retention from pregnancy especially in 3rd trimester
- Thyroid dysfunction
- Autoimmune disorders such as rheumatoid arthritis
- Fractures or trauma to the wrist
- Repeated over extension of the wrist or movement such as typing, working on computers for more than 20 hours/ week
- Hereditary factors and conditions such as polyneuropathy (where multiple nerves are affected)
What are the symptoms of carpal tunnel syndrome?
In the early stage the symptoms may be intermittent and only at night. As the condition advances these may become constant with development of wasting and weakness of hand muscles. The common symptoms include
- Numbness, burning, tingling, shock like sensation, pain in the ring, middle, index fingers and the thumb.
- Affected individuals often have disturbed sleep with urge to shake out their hand to obtain relief from symptoms.
- Provocation of symptoms by sustained hand or arm positions especially those involving arm elevation and wrist flexion as while holding a phone. Provocation may also be more noticeable after repetitive actions of the hand or wrist.
- Clumsiness and weakness of hand with difficulty performing simple tasks like buttoning clothes & opening jars.
- Losing grip over things/ difficulty to hold objects firmly in hand due to weakness.
- Burning sensation/ pain may involve forearm, upper arm.
How is carpal tunnel syndrome diagnosed?
Your doctor will take a careful history and perform examination of your hand, arm, shoulders and neck. The sensation and movements of the hand may also be evaluated. The doctor may also hold, bend your wrist in a flexed position to check if this increases/ brings on your symptoms as this position further narrows the space for the nerve temporarily.
He/she may request for investigations such as electrodiagnostic studies (nerve conduction studies and electromyography) and ultrasound. Electrodiagnostic studies can help determine severity and prognosis. Plain X-ray may be useful if bone or joint disease/ structural abnormalities are suspected. Magnetic Resonance Imaging is useful in picking up rare pathological causes of CTS such as ganglion or bony deformity and these can have bearing on the surgical plan.
How is carpal tunnel syndrome treated?
Management of CTS depends on the severity of symptoms. In mild to moderate cases your doctor may recommend the conservative approach which should result in improvement in a few weeks time. This includes
Splinting or bracing – Wearing a splint or brace will keep you from moving or bending the wrist while you rest. One study has shown that using a neutral wrist splint is twice as likely to give symptom relief compared to a splint in extension position. This modality, in combination with other treatment modalities, can be especially useful in pregnancy. However not everyone is able to get accustomed to the splint.
Physical therapy – There is some evidence that physical therapy techniques are effective CTS treatments. Multiple sessions from specialist physiotherapists and treatment modalities include carpal bone mobilization, therapeutic ultrasound and nerve glide exercises.
Oral medications – Oral steroids have shown to improve symptoms for limited time but are less effective than local injections with more side effects. Anti-inflammatory medications (NSAIDS) and diuretics have questionable benefits. Similarly research studies show that vitamin B-6 supplementation has a negligible therapeutic effect.
Ultrasound-guided local injections
This involves injecting local anaesthetics and a small dose of steroid close to the problem site under ultrasound guidance. Ultrasound helps to ensure accuracy and minimises the risk of complications. One study has estimated the risk of serious complication with these injections as less than 0.1%. There is evidence suggesting that the local injection is effective for more than one month in patients with mild to moderate carpal tunnel syndrome and delays the need for surgery at one year. Some studies have demonstrated improvement lasting 10 weeks to more than one year. This option can help manage the symptoms, avoiding the need for surgery. Certain cases may require a repeat injection for more effective symptom control. Wrist injections may help to relieve inflammation of the affected nerves and the fibrous sheath and fasten the healing process.
This option is suitable for patients with severe carpal tunnel syndrome or when symptoms have not improved after four to six months of conservative therapy. It is an effective option and can provide a lasting relief in 70 to 90 % of cases. The procedure involves release of pressure by placing a cut on the fibrous sheath, which will provide more space for the median nerve to pass through.