Traumatic lesions of the peripheral nerves is one of the most important problems for doctors of various specialties – neurosurgeons, traumatologists, general surgeons, neuropathologists, physiotherapists, who are contacted by patients with this pathology. Damage to the nerve trunks of the extremities occurs mainly in young and middle-aged people and, if they do not pose a threat to the patient’s life, they often lead to long-term disability, and in many cases to disability.
Timely diagnosis, qualified medical assistance at various stages, timely rational surgical treatment with the use of microsurgical techniques, comprehensive rehabilitation make it possible to return both domestic and professional performance of most of these patients.
Peripheral nerve injuries are divided into open and closed. The first include: cut, chopped, chopped, lacerated, bruised, crushed wounds; to closed ones – concussion, bruise, compression, sprain, rupture and dislocation. From the morphological point of view, a complete and partial anatomical rupture of the peripheral nerve is distinguished.
Nerve damage is manifested by a full or partial block of conduction, which leads to a varying degree of impaired motor, sensory and autonomic function of the nerve. With partial damage to the nerves, irritation symptoms occur in the field of sensitivity and autonomic reactions (hyperpathy, causalgia, hyperkeratosis).
Neuropraxia (Praxis – work, apraxia – inability, inaction) – temporary loss of physiological function – nerve conduction after minor damage. Anatomical changes mainly from the myelin sheaths. Clinically observed mainly motor disorders. From the side of sensitivity, paresthesia is primarily noted. Vegetative disorders are absent or not expressed. Recovery occurs within a few days. This form corresponds to a concussion of the nerve (beyond Doinikov).
Axonotmesis is a more complex form of damage due to compression or extension. The anatomical continuity of the nerve is preserved, but morphologically signs of valerian degeneration appear distal to the site of damage. Neuropraxia and axonotmesis are treated conservatively. Neurotmesis means a complete break of a nerve or severe damage with a rupture of its individual nerve trunks, as a result of which regeneration is impossible without surgical intervention. After a complete break of a nerve in its distal segment, a gradual decomposition of axons, nerve endings and myelin sheaths occurs. The lemocytes surrounding the axon that degenerates participate in the resorption of decay products / Nerve function is restored only after axons regenerating from the central segment of the nerve sprout in the distal direction the entire peripheral segment to the final branches of the damaged nerve and its receptors. The type and degree of nerve damage determines the further treatment tactics: conservative or surgical.
The process of decomposition of nerve fibers, described in 1850 by the French scientist Waller, is now denoted by the term – valerian degeneration. The reverse process – nerve regeneration occurs under the condition that the exact bundles (respectively, sensory and motor) of both segments of the nerve are precisely matched, proceeds rather slowly (at a speed of about 1 mm per day). The process of valerian degeneration begins immediately after a nerve injury and occurs regardless of when the nerve suturing is performed. It is impossible to avoid decomposition of nerve fibers, even if it was possible to cross-link the nerve immediately after damage. The clinical and electrophysiological picture of damage to peripheral nerves significantly depends on the period of time elapsed since the injury. Considering the peculiarities of the course of the Valerian degeneration process, this interval should be divided into two periods: acute and distant.
The acute period of trauma is a period in which not only the manifestations of nerve damage are crucial in the clinical picture, but all the factors of the trauma as a whole: a shock reaction to pain, blood loss, the presence of a secondary infection, mental trauma, etc. The acute period lasts 15 -20 days, at this time, even after a complete rupture, the distal segment retains the possibility of carrying out, so the results of most electrophysiological examination methods in the acute period are uninformative.
The long period of trauma is characterized by the formation of the main pathomorphological changes in nerve fibers caused by valerian degeneration, starting from the third or fourth week after the injury. Given the prognosis In the treatment of nerve damage, it is advisable to divide the distant period into three shorter periods: the early distant – up to four months after the injury (currently the most promising application of the delayed nerve suture), the intermediate (up to 12 months) and the late distant, which begins after of the year. The latter is characterized by the onset of irreversible changes in denervated tissues, the development of contractures and ankylosis of the joints. Reconstructive operations on the nerves in these cases are ineffective. In acute period of injury, the most informative sign of nerve damage is a violation of sensitivity in the innervation zone. Diagnosis with motor and autonomic disorders is not always reliable through concomitant damage to other tissues of the limb and the presence of pain. Medical assistance to victims of nerve injury consists of pain relief and, if necessary, anti-shock measures, in the fight against bleeding and the prevention of infectious complications. In case of combined injuries, appropriate measures to ensure vital functions are additionally taken. The treatment of complete nerve damage during injuries with sharp objects is only surgical. The best treatment results are achieved with adequate surgical treatment on the day of the injury. However, the operation is possible only under certain conditions: the availability of trained specialists, the necessary equipment, including microsurgical instruments, suture material and magnifying optics, proper anesthetic support and the absence of complications from the wound and somatic condition of the patient. Performing operations on the nerve in the absence of the above conditions mainly leads to unsatisfactory consequences, and quite often to additional trauma to the limbs and complications, which can no longer be eliminated even in specialized medical institutions. Therefore, in institutions of a general surgical profile for damage to peripheral nerves, it is enough: to stop bleeding, conduct anti – infection measures and suture the wound with the subsequent referral of the patient to the microsurgery department.
Diagnostics
The diagnosis of nerve damage is based on general clinical findings and electrophysiological findings.
The site of an injury to a limb in the presence of neurological symptoms allows to suspect damage to the peripheral nerve.
The anamnesis significantly allows you to clarify the nature and mechanism of nerve damage. A review of the injured end-localization of the wound allows us to conclude which of the nerves is damaged and to clarify the degree of this damage. The main function of the nerve is conduction. Nerve damage is manifested by a syndrome of complete or partial violation of its function. The degree of its loss is determined by the symptoms of loss of motion, sensitivity and autonomic function of the nerve. Movement disorders with complete damage to the main nerves of the extremities are manifested by a picture of peripheral muscle paralysis (atony, areflexia, atrophy), innervated by nerve branches extending from it distally to the gap. The primary task in examining patients with peripheral nerve damage is the need for accurate diagnosis of the type and degree of nerve damage. Features of the clinical manifestations of motor and sensory disturbances in nerve damage in the acute period make diagnosis difficult. Sensitivity testing is often critical in diagnosing a nerve lesion. Anesthesia in the innervation zone is characteristic of the anatomical rupture of the nerve trunk, or complete dissolution of axons. For a correct assessment of skin sensitivity disorders (pain, temperature, tactile), it should be remembered that immediately after wounding, the zone of loss of sensitivity most corresponds to the zone of nerve innervation, in the future this zone decreases due to overlapping innervation by neighboring nerves. Those zones that are innervated exclusively by one nerve and are not compensated by neighboring nerves by the time line are called autonomous. In the diagnostic, the manifestations of sensitivity disorders in the autonomous zones of nerve innervation are not the most informative.
Autonomous zones are inherent only in the median, ulnar and tibia nerves. Partial nerve injuries are manifested by a decrease in sensitivity and signs of irritation (hyperpathy, paresthesia) in the area of its innervation. Trophic disorders in case of nerve damage are manifested by disorders of perspiration (anhydrosis, hypo-or hyper-hydrosis), immediately after injury by hyperthermia in the innervation zone, followed by a decrease in temperature, a change in hair growth in the form of partial baldness (hypotrichosis), or increased growth (Hypertrichosis), thinning skin, the disappearance of folds on it. The skin acquires a cyanotic hue, the growth of nails is impaired, which become curved, brittle, lose their luster, and thicken. In a later period, often under the influence of mechanical or temperature factors, trophic ulcers occur in places of impaired sensitivity, especially on the tips of the fingers, in the area of the hand, sole, and heel.
Muscles, tendons and ligaments are shortened, drowning, leading to contractures. Trophic disorders are more pronounced with incomplete rupture of the nerve, often accompanied by pain. Helps to clarify the level and type of damage palpation and percussion during the course of the nerve trunk. In the acute period of trauma, when tearing nerve fibers, tapping at the level of damage causes projection pain. At a longer time, palpation reveals a neuroma of the central segment of the damaged nerve. The appearance of pain during palpation and percussion along the peripheral segment of the injured nerve and a characteristic sign of nerve regeneration after suturing (Tinel symptom). Damage to two or more nerves, nerve damage in combination with a bone fracture, dislocation, damage to the great vessels, tendons makes diagnosis and treatment difficult.
Clinic
Ulnar nerve
The ulnar nerve (n. Ulnaris) is mixed. When it is damaged, the retraction of the fifth finger of the brush is observed. In the distant period, the claw-shaped condition of the fingers of the hand is a typical sign. If the ulnar nerve is damaged in the shoulder area, proximal to the departure of its branches to the muscles of the forearm, motor disorders are manifested by the impossibility of bringing the hand, and when it is bent, there is no tendon tension of the ulnar flexor of the hand. For paralysis of the medial part of the deep flexor of the fingers, there is no flexion of the distal part of the phalanges of the IV, V fingers. When placing the palm of the hand on the plane, it is impossible to make scratching movements with these fingers, as well as to part and bring the IV, V fingers, bend their proximal phalanges while straightening the middle and distal fingers, contrast the thumb with the thumb and bring the thumb to the index finger. At the same time, there are cases of pseudo-reduction of the thumb due to the compensatory function of the long flexor of the thumb, which in such cases is accompanied by flexion of the distal phalanx.
Sensitivity disorders are caused by both the level of nerve damage and the expressiveness of the individual characteristics of the autonomous innervation zone. When a nerve is damaged above the departure of its dorsal twig, a violation of sensitivity extends to the medial surface of the fifth finger and adjacent sections of the fourth. An autonomous zone of innervation of the ulnar nerve is the distal phalanx of the fifth finger.
Within the zone of altered sensitivity, sometimes wider sweating disorders and vasomotor disorders are observed. In connection with atrophy of the small muscles of the hand, interosseous spaces sink. Trophic ulcers, as with injuries of the median nerve, are often caused by burns of areas of the skin with impaired sensitivity.
Median nerve
The median nerve (n. Medianus) ~ mixed “contains a large number of sensitive and vegetative fibers. In case of damage at shoulder level, i.e. proximal to the departure of its main branches, the brush takes on a characteristic appearance:
I and II fingers are straightened (hand of the prophet). The flexion of the middle phalanges of the fingers is broken; there is no flexion of the distal phalanges of the I and II fingers. When you try to squeeze the brush into a fist And and
II fingers, to a lesser degree III, remain unbent. Due to paralysis of the radial flexor of the hand, it bends to the elbow side when bent. Despite the paralysis of the muscle, it opposes the thumb, the opposition of this finger is violated only in 2/3 of the injured, the remaining patients and even after a complete anatomical break of the nerve remain And the substitute “fake” finger opposition due to the compensatory function of the deep head of the short flexor of the thumb is innervated ulnar nerve.
Sensitivity disorders in the form of anesthesia in cases of complete cessation of conduction are noted only in the autonomous zone of innervation, which is limited mainly to the distal phalanx of the second finger. With damage to the median nerve, frequent vasomotor-secretory-trophic disorders, which is explained by a large number of vegetative fibers in the nerve.
Radial nerve
The radial nerve (n. Radialis) – mixed, mainly motor. The clinical picture depends on the level of damage and is characterized mainly by a violation of the function of the muscles of the extensors of the hand and fingers. The hand is in pronation, drooping, the fingers in the proximal phalanges are bent. There is completely no extension of the hand and proximal phalanx of the fingers, abduction of the thumb and supination of the forearm. In case of damage to the deep branch of the radial nerve in the forearm, the function of the radial extensor of the hand is preserved, so the patient can extend the hand and draw it away, but cannot extend the fingers and take the thumb away.
The radial nerve does not have a constant autonomous zone of innervation, therefore, a violation of sensitivity on the back of the radial edge of the hand over time due to cross innervation is minimized, or completely disappears.
Musculocutaneous nerve
The main symptoms of nerve damage And impaired function of the biceps of the shoulder, shoulder and beak-shoulder muscles, which is manifested by their atrophy, disappearance of the ajus-laxative reflex and flexion of the forearm in the supination position. Substitutional flexion of the forearm in pronation position may also be observed! due to the reduction of the shoulder-sided muscle, it is innervated by the radial nerve.
Sensitivity loss in case of nerve damage is observed on the outer surface of the forearm, in the area of innervation of the lateral cutaneous nerve of the forearm, U of the muscle-cutaneous nerve branch.
Axillary nerve
Axillary nerve (n. Axillaris) – mixed. When it is damaged, paralysis of the deltoid and pectoral muscles is observed, which is manifested by the inability to raise the shoulder in the frontal plane to a horizontal line. Sensitivity disorders, most often in the form of hypesthesia with hyperpathy, occur on the outer surface of the shoulder – in the zone of innervation of the lateral cutaneous nerve of the shoulder.
Brachial Plexus Damage
The nature of damage to the brachial plexus is very diverse: from slaughter and hemorrhages in the plexus elements to the separation of roots from the spinal cord. With total damage to the brachial plexus, peripheral paralysis of the muscles of the upper limb and the disappearance of all types of sensitivity in the zone of innervation by the plexus nerves are observed. In case of damage to the spinal nerves of Cv-Cyr, forming the upper trunk of the plexus, the function of the musculocutaneous, axillary and partially radial nerves falls out, the so-called I Duchenne-Erb parall develops, in which the arm hangs down along the body, like a flail, does not bend at the elbow joint and does not rise. Movements in the hand and fingers are fully preserved Sensory impairment is manifested by a strip of anesthesia on the outer surface of the shoulder, forearm, and ishti. In case of damage to the spinal nerves, Cvll-Cvlll ma Tl form the lower plexus trunk, the medial cutaneous nerves of the shoulder and forearm, and partly the median, are disturbed. Paralysis of the muscles of the hand and flexors of the fingers develops (lower paralysis of Dejerine-Klump-ke). Sensitivity is impaired by a strip on the inner surface of the shoulder, forearm and hand. With the defeat of the root of Tg to the departure from it of the connecting branches (riv communicantes), a pretty innervation of the eye is disturbed – Horner’s syndrome (ptosis, myosis and enophthalmos) is observed.
Damage to the brachial plexus below the clavicle is characterized by the disappearance of the function of the nerve bundles (lateral, medial and posterior), which is manifested by the symptoms of damage to the corresponding nerves, which of these bundles are formed. The musculocutaneous nerve departs from the lateral bundle, most of the median fibers, from the axillary and radial, the medial bundle forms the ulnar, medial cutaneous nerves of the shoulder and forearm, and partly the median nerve.
Damage to the brachial plexus is one of the most severe manifestations of an injury to the peripheral nervous system. The traction mechanism of damage causes specific surgical tactics and treatment methods.
In injuries of the lower extremities, nerves that form in the lumbosacral plexus (plexus lumbosacralis) are damaged.
Femoral nerve
The femoral nerve (n. Femoralis) is mixed. When a nerve is damaged, paralysis of the quadriceps muscle of the thigh develops, which is manifested by the loss of a knee reflex, the inability to raise a straightened leg, and when trying to stand up, the leg bends at the knee joint.
Sensory impairment is unstable, manifested in the innervation zone of the anterior cutaneous nerve of the thigh, n [hidden] nerve (il saphenus).
The sciatic nerve (n. Ishiadicus) is the mixed, largest nerve in humans. The clinic its damage consists of symptoms of damage to the tibial and common peroneal nerves. Only with a lesion in the gluteal region above the branching of the branches to the semi-membranous, semi-dry-vein and biceps femoris muscles, the bending of the lower leg is disturbed.
Tibial Nerve
Tibial nerve (n. Tibialis) – mixed. If it is damaged at the level of the thigh or the upper third of the leg, the foot is straightened, somewhat retracted outward, the fingers are unbent in the metacarpophalangeal joints and bent in the interphalangeal (claw-shaped state). There is no flexion of the foot and fingers. Achilles reflex is not caused. Anesthesia is observed in the area of the sole and outer edge of the foot, the sole is dry, hot to the touch. With damage to the tibial nerve distal to the middle of the lower leg, the function of the muscles of the foot and sensitivity on the sole are impaired.
For damage to the tibial nerve, pronounced vasomotor and trophic disorders, pain, often a burning character, are characteristic.
Common peroneal nerve
peroneal nerve (n. peroneus communis) ~ ~ mixed. If the nerve is damaged, the foot hangs down, is slightly turned inward, its outer edge is lowered, the tendons on the back of the foot are not contoured, and the fingers are bent. The typical gait is “cock” (so as not to touch the floor with the fingers of the bent foot, patients raise their legs high and first place on the fingers, and then on the entire foot.) Sensory impairment is noted in the anteroposterior surface of the lower third of the leg, back of the foot and fingers.
Additional examination methods. In order to accurately diagnose the level, type and degree of violation of nerve conduction from additional methods, classical electrodiagnostics, determination of the intensity-duration curve during muscle electrostimulation, electroneuromyography, as well as thermometry, remote thermography, capillaroscopy, determination of nerve impulse activity, tissue oxygenation are most widely used. and perspiration; if necessary, muscle biopsy. Classical electrodiagnostics is a study of the reaction of muscle contraction to irritation by a constant and pulsed current with a frequency of 50 Hz, and a pulse duration of 1 ms. It is possible to assess nerve conduction disturbances according to classical electrodiagnostics only 2-3 weeks after the injury, after the completion of the main changes in the nerve fibers during the Valerie degeneration, that is, in the long-term period of the injury. With a complete violation of nerve conduction, irritation with a constant or pulsed current in the projection of the nerve above and below the site of damage does not cause muscle contraction and a complete muscle degeneration reaction (PRP) of the muscles (degeneration) is diagnosed. Electrophysiological research methods can clarify the degree of nerve conduction disturbance, which allows you to pre-determine the type and extent of conservative or surgical treatment. The most informative sign of PRP is the loss of muscle excitability to pulsed current and the preservation of muscle excitability due to direct current irritation. The absence of muscle excitation for all types of current indicates the replacement of muscle fibers with scar tissue (cirrhosis). In case of incomplete violation of the conduction of nerve irritation by pulsed current, the contraction of innervated muscles is weakened. To study the process of nerve regeneration, the classical electrodiagnosis is not informative. Electroneuromyography is a research method that allows you to register the action potential of the nerve and individual groups of muscle fibers, to determine the speed of the impulse in different groups of fibers in different parts of the nerve. This method most fully characterizes the degree of violation of nerve conduction and denervation changes in the muscles, allows you to determine the level of damage and trace the dynamics of the regeneration process. A patient with peripheral nerve damage should be referred to a specialized microsurgical clinic to clarify the diagnosis and surgical treatment.
Treatment
The main method of treating traumatic lesions of the peripheral nerves is surgical.
Neurolysis is the release of a nerve from the tissues surrounding it and causes it to contract (hematoma, scars, bone fragments, bone marrow). The operation is performed by carefully isolating the nerve from the scar tissue surrounding it, and which is then removed, possibly avoiding damage to the epineuria. Internal neurolysis , or endoneurovolgis – the allocation of bundles of the nerve trunk from the intra-neural scars after opening the epineuria, is performed with the aim of decompressing the bundles and clarifying the nature of the damage to the nerve fibers. In order to prevent the formation of new adhesions and scars, the nerve is placed in a new bed prepared from intact tissues, and thorough hemostasis is performed. Stitching a nerve. An indication for nerve crosslinking is complete or partial rupture of a nerve with a significant degree of conduction disturbance. There are primary nerve suturing, which is carried out simultaneously with the primary surgical treatment of the wound, and is delayed, performed 2-4 weeks after the treatment of the wound. An operation microscope, microsurgical instruments, and suture material 6 / 0-10 / 0 are required to perform operations on peripheral nerves at a modern level. When performing epineural stitching, it is necessary to achieve an exact match of the transverse sections of the central and peripheral segments of the crossed nerve trunk. In recent decades, with the development of microsurgery, perineural (interfasicular) stapling is also used to connect the ends of the nerve. A combination of these two stitching techniques is possible . Mapping of beams and suturing is carried out under a microscope. The operation is completed by immobilization of the limb with a plaster cast in a dignity, in which the nerve is subjected to the slightest tension and pressure. The immobilization is maintained for two to three weeks. Autoplasty. In case of nerve damage, accompanied by severe trauma to the nerve trunk with a significant divergence of its ends, spend mizhpuchkovoy plastic. The essence of the operation is that a nerve defect is replaced with one or more graft fragments and stitched with bundles of its ends. As a transplant, the gastrocnemius nerve, medial cutaneous nerves of the shoulder and forearm, the superficial branch of the radial nerve, and the skin branches of the brachial and cervical plexuses are used. If the blood supply to the nerve bed is unsatisfactory, in order to ensure adequate trophic trophism, a plastic defect of vascularized autotransplant can be performed. In cases of intradural separation of the spinal nerve with injuries of the brachial plexus, neurotization of the nerve is possible due to another, less important in functional terms, or due to intercostal nerves. Neurotization consists in the intersection of the donor nerve and stitching of its proximal segment with the distal segment of the injured nerve. It should be remembered that the operation only creates the conditions (but is absolutely necessary) for the restoration of nerve conduction, so further treatment should be aimed at strengthening the regeneration process. In order to maintain optimal conditions for this process, therapeutic gymnastics, massage, electrical stimulation of paralyzed muscles, thermal procedures, as well as medications that increase and optimize metabolism in the nerve cell are prescribed. Such treatment should be long, without long interruptions, until the restoration of limb function. In the more distant period of injury, in addition to nerve surgery, orthopedic correction methods are used, which include eliminating contractures, ensuring a functionally advantageous position of the limb, restoring movements by moving tendons, neurovascular-muscular-neural complexes, or transplanting organs (limb parts).