Carpal tunnel syndrome (CTS)

Definition

Carpal tunnel syndrome is a compression-ischemic lesion of the median nerve in the carpal canal. It is manifested by pain, decreased sensitivity, and paresthesias in the area of the palm surface of the I-IV fingers, as well as some weakness and awkwardness in hand movements, especially when a grasping movement of the thumb is required. The diagnostic algorithm includes an examination by a neurologist, electrophysiologic testing, blood biochemical testing, radiography, ultrasound, CT, or MRI of the wrist region. Treatment is mainly conservative. With its failure, surgical dissection of the carpal ligament is recommended. The prognosis is favorable, provided that treatment measures are timely. 

General information

Carpal tunnel syndrome – compression and ischemia of the median nerve with a decrease in the carpal tunnel volume where it passes from the forearm to the hand. In neurology, it belongs to the so-called tunnel syndromes. The carpal tunnel is located at the base of the hand on its palmar surface, formed by the carpal bones and the transverse ligament stretched over them. Passing through it, the median nerve exits to the palm. In the channel under the trunk of the median nerve also pass the tendons of the finger flexor muscles.

On the other hand, the median nerve innervates the muscles responsible for the abduction and contraction of the thumb, flexion of the proximal phalanges of the index and middle fingers, and extension of the middle and distal phalanges of the same fingers. Sensory branches provide superficial sensitivity of the skin of the tenor (thumb eminence), the palmar surface of the first three and half of the 4th finger, and the back of the distal and middle phalanges of the 2nd and 3rd fingers. In addition, the median nerve provides autonomic innervation of the hand.

Causes of carpal tunnel syndrome

Carpal tunnel syndrome occurs with any pathologic processes that lead to a decrease in the volume of the canal. The tendency to the disease may be due to congenital narrowness or peculiarities of the canal structure. For example, women have a narrower carpal tunnel, and carpal tunnel syndrome occurs in them much more often than in men.

One of the causes of carpal tunnel narrowing is wrist trauma: contusion, fracture of the wrist bones, and dislocation in the wrist joint. In this case, the volume of the canal may decrease not only due to bone displacement but also due to posttraumatic edema. The change in the ratio of anatomical structures forming the carpal canal caused by excessive bone growth is observed in cases of acromegaly. Carpal tunnel syndrome can develop against the background of inflammatory diseases (synovitis, tendovaginitis, rheumatoid arthritis, deforming osteoarthritis, acute and chronic arthritis, joint tuberculosis, gout) and tumors (lipomas, hygromas, chondromas, synoviomas) of the wrist region. The cause of carpal tunnel syndrome can be excessive swelling of tissues, which is noted in pregnancy, renal failure, endocrine pathology (hypothyroidism, menopause, the state after ovariectomy, diabetes mellitus), and oral contraception.

Chronic inflammation in the carpal tunnel area is possible with constant traumatization associated with occupational activities involving repeated flexion-extension of the hand, such as pianists, cellists, packers, and carpenters. Several authors suggest prolonged daily computer keyboard work may also provoke carpal tunnel syndrome. However, statistical studies have not found significant differences between the incidence among keyboard workers and the average incidence in the population.

Symptoms of carpal tunnel syndrome

Carpal tunnel syndrome is manifested by pain and paresthesias. Patients note numbness and tingling in the palm area and in the hand’s first 3-4 fingers. The pain often extends upward to the inner surface of the forearm but can go downward from the wrist to the fingers. Nocturnal pain attacks are characteristic, forcing patients to wake up. The intensity of the pain and the severity of numbness are reduced by rubbing the palms, putting the hands down, shaking, or waving them in a lowered state. Carpal tunnel syndrome can be bilateral, but the dominant hand is more often and more severely affected.

Over time, along with sensory impairments, there are difficulties in hand movements, especially those requiring the grasping involvement of the thumb. The affected hand makes it difficult for patients to hold a book, draw, hold on to the overhead rail in transportation, hold a cell phone near the ear, drive a car for long periods, etc. There is inaccuracy and discoordination of hand movements, described by patients as “everything falls out of their hands.” Disorder of the autonomic function of the median nerve is manifested by a sensation of “swelling of the hand,” its coldness, or, on the contrary, a feeling of increased temperature in it, increased sensitivity to cold, pallor, or hyperemia of the skin of the hand.

Diagnosis of carpal tunnel syndrome

Neurological examination reveals an area of hypoesthesia corresponding to the innervation zone of the median nerve, a slight decrease in strength in the muscles innervated by the median nerve, autonomic changes in the skin of the hand (color and temperature of the skin, its marbling). Additional tests are carried out, which reveal Phalen’s symptom – paresthesias or numbness in the hand during its passive flexion-extension for a minute; Tinel’s symptom – tingling in the hand, occurring when tapping in the area of the carpal tunnel. Accurate data on the topography of the lesion can be obtained by electromyography and electroneurography.

To study the genesis of carpal tunnel syndrome, a blood test for rheumatoid factor, blood biochemical test, radiography of the wrist joint and hand, ultrasound of the wrist joint, CT scan of the wrist joint, or MRI, if indicated – its puncture. Possible consultation with an orthopedist or traumatologist, endocrinologist, or oncologist. Carpal tunnel syndrome should be differentiated from radial nerve neuropathy, ulnar nerve neuropathy, polyneuropathy of the upper extremities, vertebrogenic syndromes due to cervical spondyloarthritis and osteochondrosis.

Treatment of carpal tunnel syndrome

The treatment tactics are based on eliminating the causes of carpal tunnel narrowing. This includes correcting dislocations, immobilizing the hand, correcting endocrine and metabolic disorders, managing inflammation, and reducing tissue swelling. If necessary, a neurologist, in conjunction with other specialists, carries out conservative therapy. The question of surgical treatment is decided by a neurosurgeon.

Conservative treatment methods are reduced to immobilizing the affected hand with a splint for about two weeks, anti-inflammatory, analgesic, and anti-edema drug therapy. NSAIDs are used, in severe cases resort to the appointment of corticosteroids; in severe pain syndrome, therapeutic blockades of the wrist area with the introduction of local anesthetics. Reducing ischemia of the median nerve allows vascular therapy with pentoxifylline and nicotinic acid. After clinical improvement, physiotherapy and hand massage are recommended to restore nerve function and strength in the hand muscles.

If conservative measures are ineffective, carpal tunnel syndrome requires surgical treatment. The surgery consists of dissecting the transverse ligament of the wrist. It is performed on an outpatient basis using endoscopic techniques. If there are significant structural changes in the carpal tunnel area due to the impossibility of using the endoscopic technique, the operation is performed openly. The intervention increases the volume of the carpal tunnel and the removal of compression of the median nerve. In 2 weeks after the operation, the patient can perform movements with the hand that do not require significant load. However, it takes several months for the hand to recover fully.

All these treatment options are available in more than 990 hospitals worldwide (https://doctor.global/results/diseases/carpal-tunnel-syndrome-cts). For example, Carpal tunnel surgery can be done in 40 clinics across Germany for an approximate price of $3.9 K (https://doctor.global/results/europe/germany/all-cities/all-specializations/procedures/carpal-tunnel-surgery). 

Prognosis and prevention of carpal tunnel syndrome

With timely, comprehensive treatment, carpal tunnel syndrome usually has a favorable prognosis. However, about 10% of cases of compression do not succumb to even the most optimal conservative treatment and require surgery. The best postoperative prognosis has cases not accompanied by complete loss of sensation and atrophy of the hand muscles. In most cases, about 70% of hand function is restored one month after surgery. However, awkwardness and weakness may be noted several months later. Recurrence of carpal tunnel syndrome can occur in some cases.

Prevention consists of normalizing working conditions: adequate workplace equipment, ergonomic organization of the work process, change of activities, and the presence of breaks. Preventive measures also include prevention and timely treatment of injuries and diseases of the wrist area.