Nerve damage of the extremities: causes, symptoms, diagnosis, treatment

ICD-10 code

• S44. Injury of nerves at shoulder girdle and arm level.
• S54. Injury of nerves at forearm level.
• S64. Injury of nerves at wrist and hand level.
• S74. Injury of nerves at hip and thigh level.
• S84. Injury of nerves at leg level.
• S94. Injury of nerves at ankle and foot level.

What causes nerve damage to the extremities?

Damage to the peripheral nerves of the extremities occurs in 20-30% of victims of road accidents, industrial injuries and sports. Most authors agree that the most common are the forearm, with paresis of the fibers of the median nerve going to the flexors of the fingers. All small muscles of the hand are paralyzed, possibly the long flexors of the fingers. Skin sensitivity is impaired on the ulnar side of the shoulder, forearm and hand (in the zones of the ulnar and median nerves). Horner's syndrome (ptosis, miosis and enophthalmos) is detected when the functions of the cervical sympathetic nerve are lost.

Damage to individual trunks of the brachial plexus, as well as its total damage, can also occur with closed injuries.

In cases of complete brachial plexus paresis, the upper limb hangs along the body, is moderately edematous, cyanotic, without signs of muscle function. Sensitivity is absent up to the level of the shoulder joint.

Injuries to the long thoracic nerve ( _C5 - _C7 )

Occurs when pulling up on the arms, as a result of pressure from a heavy backpack in mountain climbers, etc. The consequence is paresis of the anterior serratus muscle. When trying to raise the arms forward, the patient's medial edge of the scapula (winged scapula) moves away. There are no sensitivity disorders.

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Injuries to the axillary nerve ( _C5 - _C6 )

The cause of the injury is shoulder dislocations, less commonly fractures of the surgical neck of the shoulder. It is characterized by paresis of the deltoid and teres minor muscles, resulting in impaired abduction and external rotation of the shoulder. Sensitivity is lost along the outer surface of the proximal shoulder (a palm's width).

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Subscapular nerve injuries ( _C4 - _C6 )

The causes of occurrence and dysfunction are the same as with damage to the axillary nerve. They arise as a result of paresis of the supraspinatus and infraspinatus muscles. Sensitivity is not affected.

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Injuries to the musculocutaneous nerve ( _C5 - _C7 )

Isolated injuries are rare, more often the musculocutaneous nerve is injured with other nerves of the plexus. They cause paralysis of the biceps brachii, and in higher lesions - the coracobrachialis and brachialis muscles, which causes weakness in flexion and supination of the forearm and a slight decrease in sensitivity along the radial side of the forearm.

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Radial nerve injuries ( _C5 - _C8 )

Radial nerve injuries are the most common type of upper limb nerve injury, occurring as a result of gunshot wounds and closed fractures of the shoulder. The clinical picture depends on the level of injury.

• When the nerve is damaged at the level of the upper third of the shoulder, paralysis of the triceps brachii muscle (no extension of the forearm) and the disappearance of the reflex from its tendon are detected. Sensitivity is lost along the back of the shoulder.
• When the nerve is damaged at the level of the middle third of the shoulder, the most well-known clinical picture occurs, characterized by paresis of the extensors of the hand ("drooping hand"), it becomes impossible to extend the hand, the main phalanges of the fingers, abduct the first finger, and supination is impaired. Skin sensitivity is impaired on the back of the forearm and the radial half of the back of the hand (not always with clear boundaries), more often in the area of the main phalanges of the first, second and half of the third finger.

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Median Nerve Injuries

The cause is gunshot wounds to the shoulder, cut wounds to the distal part of the palmar surface of the forearm and wrist fold.

When the nerve is damaged at the shoulder level, it becomes impossible to bend the wrist and fingers, clench the fist, oppose the first finger, or pronate the wrist. Rapidly developing thenar atrophy gives the wrist a peculiar appearance ("monkey paw"). Sensitivity is impaired along the radial half of the palmar surface of the wrist and the first three and a half fingers on the back - the middle and terminal phalanges of the second and third fingers. Pronounced autonomic disorders appear: vascular reaction of the skin, changes in sweating (usually increased), keratoses, increased nail growth, causalgia with a positive "wet rag" symptom: wetting the wrist reduces burning pain.

When the nerve is damaged below the branches that go to the pronators, the clinical picture changes. It is manifested only by a violation of the opposition of the first finger, but sensory disorders are the same as with damage at the shoulder level.

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Ulnar Nerve Injuries

They are encountered in fractures of the humeral condyle, incised wounds of the forearm and wounds at the level of the wrist joint. The ulnar nerve mainly innervates the small muscles of the hand, therefore, when it is damaged, adduction of the 1st and 5th fingers, adduction and spreading of the fingers, extension of the nail phalanges, especially the 4th and 5th fingers, and opposition of the 1st finger disappear. The developed hypothenar atrophy gives the hand a characteristic appearance ("claw hand"). Sensitivity is lost on the ulnar half of the hand, as well as on one and a half fingers of the palmar side and two and a half fingers of the dorsal side.

Femoral Nerve Injuries

Damage to the femoral nerve occurs with fractures of the pelvis and femur. Damage to the femoral nerve causes paralysis of the quadriceps and sartorius muscles; extension of the lower leg becomes impossible. The knee reflex disappears. Sensitivity is impaired along the anterior surface of the thigh (anterior cutaneous femoral nerve) and the anterointernal surface of the lower leg (subcutaneous nerve).

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Sciatic nerve injuries (L ₄ -S ₃ )

Damage to this largest nerve trunk is possible with various injuries at the level of the pelvis and hip. These are gunshot wounds, stab wounds, fractures, dislocations, stretches and compressions. The clinical picture of the injury consists of symptoms of damage to the tibial and peroneal nerves, with damage to the latter having more pronounced manifestations and always coming to the fore. The simultaneous detection of signs of dysfunction of the tibial nerve indicates an injury to the sciatic nerve.

Peroneal nerve injuries (L ₄ -S ₂ )

The most common cause of isolated damage to the peroneal nerve is trauma to the head of the fibula, where it is closest to the bone. The main symptoms are: drooping of the foot and its outer edge ("equine foot"); active dorsiflexion and pronation of the foot are impossible due to paresis of the peroneal muscles. Skin sensitivity is absent along the anterolateral surface of the lower third of the leg and on the dorsum of the foot.

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Tibial nerve injuries

Occurs with fractures of the tibia and other mechanical injuries in the area of the nerve. The shutdown of innervation leads to the loss of the function of flexion of the foot and toes, its supination. Walking on toes becomes impossible. The Achilles reflex disappears. Sensitivity is impaired on the posterior-outer surface of the shin, the outer edge and the entire plantar surface of the foot and toes.

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General principles of treatment of nerve damage of the extremities

Treatment of limb nerve damage should be comprehensive and should begin from the moment of diagnosis. Conservative and surgical treatment are distinguished. This division is conditional, since after surgery, the entire arsenal of conservative means is used to help restore innervation.

Conservative treatment of nerve damage to the extremities

They start with immobilization of the limb in a functionally advantageous position with the maximum possible exclusion of the effect of gravity on the injured one, if the damage to the nerve trunk is located in the proximal part of the limb (shoulder girdle, shoulder, thigh). Immobilization serves as a means of preventing contractures in a vicious position. Its use is mandatory, since in case of closed injuries the prognosis and treatment time are extremely difficult to predict. Immobilization in the form of plaster and soft tissue (snake or sling) bandages also prevents the limb from drooping. An upper limb left without fixation droops downwards as a result of gravity, overstretching the paralyzed muscles, vessels and nerves, causing secondary changes in them. Excessive traction can cause neuritis of previously undamaged nerves.

Medicinal stimulation of the neuromuscular system is prescribed according to the following scheme:

• injections of monophosphate 1 ml subcutaneously and bendazole 0.008 orally 2 times a day for 10 days;
• then, for 10 days, the patient receives injections of 0.06% neostigmine methylsulfate solution, 1 ml intramuscularly;
• then the 10-day course of monophosphate and microdoses of bendazole is repeated again.

Physiofunctional treatment is prescribed in parallel. It begins with UHF on the injury area, then pain-relieving physiotherapy procedures are used (electrophoresis of procaine, DDT, "Luch", laser). Subsequently, they switch to treatment aimed at preventing and resolving the cicatricial-adhesive process: electrophoresis of potassium iodide, phonophoresis of hyaluronidase, paraffin, ozokerite, mud. Longitudinal galvanization of nerve trunks and electrical stimulation of muscles in a state of paresis are very useful. These procedures prevent degeneration of nerves and muscles, contractures, and reduce edema. The use of active and passive therapeutic exercises, massage, water procedures, and hyperbaric oxygenation is mandatory.

It is known that nerve regeneration and growth do not exceed 1 mm per day, so the treatment process lasts for months and requires persistence and patience from both the patient and the doctor. If there are no clinical and electrophysiological signs of improvement within 4-6 months of treatment, surgical treatment should be used. If conservative treatment does not produce results within 12-18, maximum 24 months, there is no hope for restoration of the damaged nerve functions. It is necessary to switch to orthopedic treatment methods: muscle transplantation, arthrodesis in a functionally advantageous position, arthrorisis, etc.

Surgical treatment of nerve damage to the extremities

Surgical treatment of damage to the nerves of the extremities is indicated in the following cases.

• In open injuries that allow primary nerve suturing.
• If there is no effect from conservative treatment carried out for 4-6 months.
• If paralysis develops 3-4 weeks after the fracture.

In case of open injuries of the extremities, primary nerve suturing can be performed in cases where the wound is supposed to be tightly sutured after the primary surgical treatment. Otherwise, surgical treatment should be delayed for up to 3 weeks or up to 3 months or more. In the first case, we are talking about early delayed intervention, in the second - about late. If damage to bones and blood vessels is detected, then osteosynthesis must first be performed, then suturing of the vessels, and then neurorrhaphy.

The primary suture of the nerve is made after its mobilization, cutting off the damaged ends with a razor, preparing the bed, bringing together and contacting the "refreshed" surfaces. Atraumatic needles with thin threads (No. 00) are used to apply 4-6 knotted sutures behind the epineurium, trying to avoid compression of the nerve and its twisting along the axis. After suturing the wound, a plaster immobilization (splint) is applied in a position that facilitates bringing the ends of the nerve together for 3 weeks. The operated patient undergoes a full range of conservative treatment for damage to the nerves of the extremities.