Carpal tunnel syndrome is a compression—ischemic lesion of the median nerve in the carpal (carpal) canal. It is manifested by pain, decreased sensitivity and paresthesia in the area of the palmar surface of the I–IV fingers, some weakness and awkwardness when moving the brush, especially when a gripping movement of the thumb is necessary. The diagnostic algorithm includes a neurologist’s examination, electrophysiological testing, biochemical blood examination, radiography, ultrasound, CT or MRI of the wrist area. Treatment is mainly conservative — anti-inflammatory, decongestant, analgesic, physiotherapy. When it fails, an operative dissection of the carpal ligament is shown. The prognosis is favorable, provided that the treatment measures are timely.
ICD 10
G56.0 Carpal tunnel syndrome
General information
Carpal tunnel syndrome (carpal tunnel syndrome) is compression and ischemia of the median nerve with a decrease in the volume of the carpal canal in which it passes, passing from the forearm to the hand. In neurology, it refers to the so-called tunnel syndromes. The carpal canal is located at the base of the hand from its palmar surface, formed by the bones of the wrist and the transverse ligament stretched over them. Passing through it, the median nerve exits to the palm. The tendons of the flexor muscles of the fingers also pass through the channel under the trunk of the median nerve. On the hand, the median nerve innervates the muscles responsible for the abduction and opposition of the thumb, flexion of the proximal phalanges of the index and middle fingers, extension of the middle and distal phalanges of the same fingers. Sensitive branches provide superficial sensitivity of the skin of the tenor (elevation of the thumb), the palmar surface of the first three and half of the 4th finger, the rear of the distal and middle phalanges of the 2nd and 3rd fingers. In addition, the median nerve carries out autonomic innervation of the hand.
Causes
Carpal tunnel syndrome occurs in any pathological processes that lead to a decrease in the volume of the canal. The tendency to the disease may be due to congenital narrowness or structural features of the canal. So, women have a narrower carpal canal, and carpal tunnel syndrome occurs in them much more often than in men.
One of the reasons for the narrowing of the carpal canal is a wrist injury: a bruise, a fracture of the wrist bones, a dislocation in the wrist joint. At the same time, the volume of the canal may decrease not only due to bone displacement, but also due to post-traumatic edema. Due to excessive bone growth, a change in the ratio of anatomical structures forming the carpal canal is observed in the case of acromegaly. Carpal tunnel syndrome can develop against the background of inflammatory diseases (synovitis, tendovaginitis, rheumatoid arthritis, deforming osteoarthritis, acute and chronic arthritis, tuberculosis of the joints, gout) and tumors (lipomas, hygromas, chondromas, synoviomas) of the wrist area. The cause of carpal syndrome may be excessive swelling of tissues, which is noted during pregnancy, renal insufficiency, endocrine pathology (hypothyroidism, menopause, condition after ovariectomy, diabetes mellitus), oral contraception.
Chronic inflammatory process in the area of the carpal canal is possible with constant traumatization associated with professional activities involving multiple flexion-extension of the hand, for example, pianists, cellists, packers, carpenters. A number of authors suggest that prolonged daily work on the computer keyboard can also provoke carpal tunnel syndrome. However, statistical studies have not revealed significant differences between the incidence among keyboard workers and the average incidence of the population.
Compression of the median nerve primarily leads to a disorder of its blood supply, i.e. to ischemia. At the beginning, only the sheath of the nerve trunk suffers, as the compression increases, pathological changes affect the deeper layers of the nerve. The function of sensory fibers is disrupted first, then motor and vegetative fibers. Long-term ischemia leads to degenerative changes in nerve fibers, replacement of nerve tissue with connective tissue elements and, as a consequence, persistent loss of the function of the median nerve.
Carpal tunnel syndrome symptoms
Carpal tunnel syndrome manifests with pain and paresthesia. Patients note numbness, tingling, “lumbago” in the palm area and in the first 3-4 fingers of the hand. The pain often spreads upwards to the inner surface of the forearm, but can go downwards from the wrist to the fingers. Nocturnal pain attacks are characteristic, forcing patients to wake up. The intensity of pain and the severity of numbness decrease when rubbing the palms, lowering the hands down, shaking or waving them in a lowered state. Carpal syndrome can be bilateral in nature, but the dominant hand is more often and more severely affected.
Over time, along with sensory impairments, there are difficulties with brush movements, especially those that require the exciting participation of the thumb. It is difficult for patients with an affected hand to hold a book, draw, hold on to the upper handrail in transport, hold a mobile phone near their ear, drive a car for a long time, etc. There is an inaccuracy and discoordination of brush movements, which is described by patients as if “everything falls out of their hands”. The disorder of the autonomic function of the median nerve is manifested by a feeling of “swelling of the hand”, its cooling or, conversely, a feeling of an increase in temperature in it, increased sensitivity to cold, paleness or hyperemia of the skin of the hand.
Diagnostics
Neurological examination reveals an area of hypesthesia corresponding to the zone of innervation of the median nerve, a slight decrease in strength in the muscles innervated by the median nerve, vegetative changes in the skin of the hand (skin color and temperature, its marbling). Additional tests are carried out that reveal: the symptom of Phalaen is the occurrence of paresthesia or numbness in the hand during its passive flexion—extension for a minute, the symptom of Tinel is tingling in the hand that occurs when tapping in the carpal canal area. Accurate data on the topic of the lesion can be obtained using electromyography and electroneurography.
In order to study the genesis of carpal syndrome, a blood test for RP, blood biochemistry, radiography of the wrist joint and hand, ultrasound of the wrist joint, CT of the wrist joint or MRI, if indicated, its puncture is performed. It is possible to consult an orthopedist or traumatologist, endocrinologist, oncologist. It is necessary to differentiate carpal tunnel syndrome from radial nerve neuropathy, ulnar nerve neuropathy, upper limb polyneuropathy, vertebrogenic syndromes caused by cervical spondyloarthrosis and osteochondrosis.
Carpal tunnel syndrome treatment
The basis of therapeutic tactics is the elimination of the causes of narrowing of the carpal canal. These include the reduction of dislocations, immobilization of the hand, correction of endocrine and metabolic disorders, relief of inflammation and reduction of tissue swelling. Conservative therapy is carried out by a neurologist, if necessary, together with other specialists. The issue of surgical treatment is decided with a neurosurgeon.
Conservative methods of therapy are reduced to immobilization of the affected hand with a splint for a period of about 2 weeks, anti-inflammatory, analgesic, decongestant pharmacotherapy. NSAIDs are used (ibuprofen, indomethacin, diclofenac, naproxen, etc.), in severe cases, they resort to the appointment of glucocorticosteroids (hydrocortisone, prednisone), with severe pain syndrome, therapeutic blockades of the wrist area are performed with the introduction of local anesthetics (lidocaine). Decongestant therapy is carried out with the help of diuretics, mainly furosemide. A positive effect is provided by vitamin therapy with gr. V preparations, mud treatment, electrophoresis, ultraphonophoresis, compresses with dimethyl sulfoxide. Vascular therapy with pentoxifylline, nicotinic acid allows to reduce ischemia of the median nerve. After achieving clinical improvement, physical therapy, hand massage, and myofascial hand massage are recommended to restore nerve function and strength in the muscles of the hand.
If conservative measures are ineffective, carpal syndrome requires surgical treatment. The operation consists in dissecting the transverse ligament of the wrist. It is performed on an outpatient basis using endoscopic techniques. With significant structural changes in the area of the carpal canal due to the impossibility of using endoscopic techniques, the operation is performed in an open way. The result of the intervention is an increase in the volume of the carpal canal and the removal of compression of the median nerve. 2 weeks after the operation, the patient can already perform hand movements that do not require a significant load. However, it takes several months to fully restore the brush.
Prognosis and prevention
With timely complex treatment, carpal tunnel syndrome, as a rule, has a favorable prognosis. However, about 10% of compression cases do not respond to even the most optimal conservative treatment and require surgery. The best postoperative prognosis is in cases that are not accompanied by complete loss of sensitivity and atrophy of the hand muscles. In most cases, a month after the operation, the function of the brush is restored by about 70%. However, awkwardness and weakness can be noted after a few months. In some cases, there is a recurrence of carpal syndrome.
Prevention consists in the normalization of working conditions: adequate workplace equipment, ergonomic organization of the workflow, change of activities, the presence of breaks. Preventive measures also include the prevention and timely treatment of injuries and diseases of the wrist area.