Carpal tunnel syndrome


Most common focal peripheral neuropathy, secondary to compression of the median nerve at the wrist.

One of the most common nerve entrapments in the upper extremity.

Swelling of any of the nine tendons within the carpal tunnel can increase compartmental pressure and compress the median nerve, causing the symptoms that are characteristic of carpal tunnel syndrome,

Carpal tunnel symptoms include tingling and pain in the fingers or hand and numbness in the thumb, the second and third digits, and the radial half of the fourth digit.

Nonspecific tenosynovitis is the most common cause of carpal tunnel syndrome.

Nerve conduction studies are the recognized diagnostic standard for carpal tunnel syndrome.

Affects approximately 3% of adults and three times more common in women than men.

Approximately one in 10 people develop carpal tunnel syndrome.

Incidence is approximately 2.3 per 100 person years, in adults.

Studies have shown the prevalence of CTS symptoms in the general population about 14.4% with a electrodiagnostically confirmed disease prevalence of 2.7 to 4.9%.

Mean age at diagnosis 45-50 years.

Often takes longer than one year before seeking medical attention.

Typical symptoms include numbness, pain in the median nerve distribution of thumb, index and middle fingers and radial half of the ring finger, and weakness with opposition.

Pain, numbness, and tingling in the distribution of the median nerve.

Symptoms are usually worse at night.

Pain may radiate to the forearm, elbow and shoulder.

Symptoms may awaken patients or progress to persistent numbness.

Characteristic physical examination may show decreased median nerve sensation, thenar muscle wasting or weakness, and provocation of symptoms by holding firm pressure on the carpal tunnel, holding a 90° flex wrist position for 20-30 seconds and firmly and repeatedly tapping at the carpal tunnel.

If severe, thenar muscle atrophy and decreased strength may develop.

Both hands are often affected.

Carpal tunnel syndrome affects three times more women than men.

Higher risk with obesity and diabetes.

People engaged in repetitive tasks such as computer or mouse use, excessive force or gripping, and occupations associated with hand tasks that include vibration have a higher prevalence of CTS.

People most at risk for carpal tunnel syndrome are those who assemble parts, clean, sew, or work in meat, poultry and fish packing.

Heavy computer work — up to 7 hours a day — does not increase the risk of carpal tunnel syndrome.

More than a quarter million surgeries for carpal tunnel syndrome are performed in the U.S. each year.

The wrist bones form the floor of the carpal tunnel and the roof is formed by the transverse carpal ligament.

The transverse carpal ligament attaches to the radial side of the wrist to the trapezium and scaphoid bones, while it connects on the ulnar side to the hamate and pisiform bones.

The transverse carpal ligament maintains the carpal arch giving the palm its concave appearance.

The transverse ligament serves as a pulley for the flexor tendons.

Within the carpal tunnel is the median nerve and the nine flexor tendons to the fingers and thumb.

At the level of the wrist the median nerve is primarily a sensory nerve.

The median nerve has one motor branch, the recurrent median nerve, that innervates the thumb muscles.

The median nerve supplies sensory nerves to the thumb, index finger, the long finger and the radial side of the ring finger.

Diagnosis is reinforced by the Phalen test where flexing the dorsum of the hands against themselves with wrist flexion and Tinel’s test percussing the carpal area near the base of the thumb producing typical symptoms.

The Phalen’s maneuver asks the patient to hold the wrist in forced flexion for 30 to 60 seconds.

The Phalen’s maneuver can increase pressure on the carpal tunnel and further irritate the median nerve, causing abnormal sensations that include burning, tingling, or numbness in the thumb or in the second or third digits.

Assess the patient for Tinel’s sign by firmly percussing the median nerve

Tinel’s sign is present if the patient reports tingling, “pins and needles,” or any other signs of paresthesia, such as a shooting sensation in the thumb or the second or third digits.

The sensitivity of Tinel’s sign for carpal tunnel syndrome is 36% and the specificity is 75%.

The Durkan’s test is performed by compressing the carpal tunnel for up to 30 seconds with the thumb

The onset of pain, tingling, or any abnormal sensation in the median nerve distribution constitutes a positive test result.

The Phalen’s test will be positive in more than 90% of cases while the Tinel’s test will be positive in 50% of cases.

A nerve conduction test of the compressed median nerve is an objective definitive test demonstrating the delay of the nerve conduction across the wrist which can be quantitative and titrated for severity of the neuropathy and response to treatment.

Electrodiagnostic testing is often done in the evaluation of the carpal tunnel syndrome and can help rule out central causes of pain in the hand as in cervical radiculopathies or in polyneuropathies.

Ultrasound can assess median nerve compression by visualizing variations in the nerve diameter.

Treatment may involve changing activities, splinting, anti-inflammatory agents and surgery.

Splinting can produce some relief, but it is of usual modest nature and transient in most patients with severe CTS.

There is no consensus for the treatment of mild to moderate CTS.

A Cochrane review revealed the duration of benefit of local corticosteroid injections and the effect on mild to moderate CTS appear to be temporary with unclear benefits beyond one month

Recent studies suggest that the benefit of local corticosteroid injections may last up to 10 weeks, and some studies up to one year with reduced need for surgical treatment at one year.

Subfasccial corticosteroid soft tissue injections has a response rate which is quite good at 10 weeks post injection, but symptoms recur in 73-81% subsequently.

Use of subcutaneous corticosteroids repetitively can weaken the tissues and increase risk of tendon rupture.

Ultrasound is an acceptable alternative treatment for patients with mild to moderate symptoms.

First line nonoperative treatments include avoiding activities that provoke symptoms, and nighttime wrist neutral immobilization.

Neurodynamic mobilization with exercises that stretch and facilitate nerve gliding is associated with subjective improvement in symptoms.

Nighttime splinting is associated with improved outcomes compared with no treatment.

Acupuncture, laser therapy, therapeutic ultrasound have poor quality evidence for improvement.

Surgery is associated with symptom improvement than non-surgical management.

Open carpal tunnel release is performed through an incision in the palm by transacting the transverse carpal ligament, and decompressing the median nerve.

Endoscopic carpal tunnel release is associated with the faster return to work at three months, higher satisfaction rates, higher transient nerve injuries, lower rates of scat related complications and no difference in permanent nerve injuries compared with open carpal tunnel release.

Complications of surgical intervention include: hypertrophic or painful scars, infection, treatment failure with symptom recurrence in 7 to 25% of cases, injury to the median nerve in 0.21% of cases or nearby neurovascular structures 0.3 to 0.1%.

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