Injury of peripheral nerves: symptoms, treatment

Injury of peripheral nerves is, in the opinion of different authors, from 1.5 to 3.5% of the total traumatism in peacetime, and on loss of ability to work it occupies one of the first places and often leads to severe disability of patients in almost 65% of cases.

Surgery of injuries and diseases of the peripheral nervous system as a section of regenerative neurosurgery is extremely important in our time, primarily due to the increase in injuries, including domestic, road traffic, and gunshot nerve injuries, with an increase in the number of lesions of peripheral nerves, combined , as well as iatrogenic lesions. At the same time, many patients with injuries and diseases of the peripheral nervous system do not always receive timely and qualified medical care, which leads to their persistent disability (according to various data in 28-75% of cases). The overwhelming majority of these patients are persons of a young able-bodied age.

[1], [2], [3], [4], [5], [6]

What causes peripheral nerve injury?

Trauma of nerves on the upper limbs arises in the lower third of the forearm and hand (almost 55% of all lesions of the upper limb), with about 20% of them accompanied by injuries of several nerves. Damage in the axillary region and upper third of the shoulder, accounting for only 6% of all injuries, is often (almost half the time) accompanied by damage to two or more nerves. For the lower extremity, the area of risk is the region of the lower third of the thigh - the upper third of the shin, which accounts for almost 65% of all peripheral nerves.

Until now, the generally accepted uniform classification of peripheral nerve injury has not been developed. The vast majority of classifications of injuries of peripheral nerve trunks differ significantly both in form and in content from the classification schemes of other injuries, for example, the musculoskeletal system.

The nature of peripheral nerve injury:

• household;
• production;
• fighting;
• transport;
• iatrogenic.

Symptoms of nerve injury

When a neurologic examination reveals characteristic of nerve injury symptoms:

• Disturbances of sensitivity (from anesthesia in the corresponding zone of innervation with complete damage to the nerve trunk, to hyposthenic or paresthesia with partial injuries).

Scheme of assessment of sensitivity disorder:

1. S0 - anesthesia in the autonomous zone of innervation;
2. S1 - undefined pain sensations;
3. S2 - hyperpathy;
4. S3 - hypoesthesia with decreased hyperpathy;
5. S4 - moderate hypoesthesia without hyperpathy;
6. S5 normal pain sensitivity

• Violations of muscle strength (in the form of development of peripheral paresis and paralysis, respectively, innervation of the nerve).

Scheme of evaluation of muscular strength

1. M0 - absence of muscle contractions (paralysis);
2. M1 - weak muscle contractions without convincing signs of movements in the joints;
3. M2 - movement provided that the weight of the limb is removed;
4. MZ - movement with overcoming the weight of the limb;
5. M4 - movement with the overcoming of a certain resistance;
6. M5 - complete clinical recovery.

• Violations of trophism of muscles and skin in the area of the damaged nerve.

In a number of cases, with peripheral nerve injury, the pain syndrome is determined (the morbidity of the nerve trunk itself with irradiation into the zone of its innervation, the presence of the Tynel symptom - the pain of the shooting character with irradiation along the nerve trunk during poklachivanii at the site of injury, and sometimes the development of complex pain syndromes as amputation pain syndrome or complex regional pain syndrome of the 2nd type with development of causalgia). Quite often, the pain syndrome is accompanied by partial damage to the nerves, especially the medial and tibial portion of the sciatic nerve.

Among injuries of the peripheral nerves, a special group of degree of severity, peculiarities of the clinic and treatment, is occupied by injuries of the brachial plexus. Most often they are caused by traction of nerve trunks, for example, when falling from a motorcycle, with dislocations in the shoulder joint, etc. One of the first descriptions of the clinical picture of damage to the brachial plexus belongs to II. Pirogov, "The Beginning of Military Surgery" (1866), Duchenn (1872) described the damage to the upper primary trunk of the brachial plexus, and Erb (1874) described this type of injury in more detail and on the basis of a clinic and electrophysiological study came to the conclusion that the most frequent The place of rupture in such cases is the site at the junction of C5-C6 spinal nerves (Erba point). To damage the brachial plexus according to the Duchesne-Erba type (mainly the dysplastic, axillary, muscular-cutaneous and partially radial nerves), the paresis or paralysis of the muscles of the shoulder girdle and shoulder is most characteristic with the relatively preserved function of the muscles of the forearm and hand and sensitivity disturbance in the C5 innervation zone -C6.

Symptoms of damage to the lower trunk were described by Dejerine-Klumpke (1885), first noting that Horner's syndrome is associated with damage to the first thoracic spinal nerve or its sympathetic branches. In contrast to the upper type, damage to the brachial plexus of the type Dejcrine-Klumpke (mainly a violation of the function of the ulnar and median nerves) is characterized by paresis and paralysis of the muscles in the distal limbs (forearm, hand) and sensitivity disorders in the innervation zone C7, C8-Th1.

In addition to these classic types, a total variant of damage to the brachial plexus is isolated.

There are several levels of damage to the brachial plexus:

• I level - preganglionic damage of the roots of the brachial plexus;
• Level II - spinal nerve damage:
  • with pronounced retrograde changes right up to the anterior horns of the spinal cord;
  • with minor retrograde changes;
• III level - damage to trunks, bundles or long branches of the brachial plexus.

Diagnosis of peripheral nerve injury

Diagnosis of nerve injury is based on a comprehensive examination, including: patient complaints, anamnesis with mandatory clarification of the circumstances of the injury, a thorough examination of the patient and the injury site (the probability of damage to the nerve trunk taking into account the injury topic), neurologic examination and additional research methods.

Among the methods of additional diagnostics of damage to the peripheral nerves, electrophysiological methods play a leading role. The most informative methods for the study of the function of the neuromuscular apparatus are the investigation of evoked potentials (PN) of nerves and muscles, electroneuromyography (ENMG), intramuscular electromyography (EMG), registration of somatosensory evoked potentials (SSVP), called sympathetic skin potentials. To assess the motor function of the nerve, indicators such as the latent period, the amplitude of the M-response (the potential that appears in the muscle with electric stimulation of the motor nerve), the speed of excitation (SPV) are used. To assess the sensitivity function of peripheral nerves, the method of determining SLE with antidromic or orthodromic stimulation is used.

Radiography of bones is performed in case of suspicion of fractures, compression of the nerve with a callus or a metal plate, in the presence of dislocations. In addition, the use of this method is justified to clarify the degree of consolidation of bone fragments, which in most cases determines conservative and surgical tactics.

MRI as a highly informative method of research is used only in some diagnostically complex cases of lesions of the brachial and lumbosacral plexus, sciatic nerve and in the process of differential diagnosis with lesions of the spine and the other brain. For diagnosis, MRI is extremely informative in comparison with other methods, because it allows you to visualize the spinal roots directly, to identify traumatic meningocele, resulting from the detachment of roots from the spinal cord, the degree of severity of the atrophic process of the spinal cord, and to evaluate the state of the muscles that are innervated by individual nerves or plexuses in general.

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Treatment of peripheral nerve injury

Rendering assistance to victims with a trauma of peripheral nerves render stage by stage. At the stage of emergency medical care for patients with peripheral nerve injury, the Organization's standard of care is the urgent transportation of the victim to a medical institution (trauma centers, traumatology, surgical departments, departments of polytrauma). Optimal for isolated injuries of peripheral nerves is the hospitalization of the patient immediately in a specialized microsurgical or neurosurgical department.

The main activities that should be carried out at the stage of emergency medical care:

1. Inspection and evaluation of the nature and extent of damage, including related injuries.
2. Assessment of the general condition of the victim.
3. Stop bleeding.
4. Immobilization of the damaged limb (limbs).
5. In the presence of indications - the introduction of painkillers, carrying out anti-shock and resuscitation measures.

In case of difficulties with carrying out a neurological examination, trauma to the peripheral nerves should be suspected if there are: damage to the main vessels, motorcycle trauma (damage to the brachial plexus), fractures of the pelvic bones and collarbone.

In non-core medical institutions perform neurosurgical interventions on peripheral nerves inappropriate. At this stage, it is necessary to exclude concomitant lesions; establish a preliminary diagnosis; carry out resuscitation in anti-shock activities; prevent the development of infectious complications (performing primary surgical treatment, prescribing antibacterial therapy); to intervene to definitively stop bleeding and immobilize fractures; in the case of closed peripheral nerve and plexus injuries, appoint restorative treatment and ensure regular (at least 1 time every 2-4 years) electroneuromyographic monitoring of the quality of recovery of the neuromuscular system.

In the profile neurosurgical hospitals it is necessary to transport patients without disturbance of breathing and with stable hemodynamics. In specialized microsurgical or neurosurgical hospitals, a detailed assessment of the neurological condition should be made, neurological lesions of the peripheral nerve and / or plexus should be determined, an ENMG performed to assess the degree of loss of function and a detailed determination of the level of closed lesion. After the examination it is necessary to establish a diagnosis that would reflect the nature, type and level of damage, the type and localization of concomitant lesions, neurological symptoms, complications.

Surgical treatment for peripheral nerve injury should be carried out as quickly as the patient's condition allows. To avoid technical errors at the stage of surgical treatment of traumatic injuries of peripheral nerves, a number of conditions are necessary, without which surgical intervention on nerve trunks is contraindicated (the presence of a specialist who possesses the skills of microsurgical techniques with perfect knowledge of topographic anatomy of peripheral nerves, capable of providing accurate diagnosis of the nature, degree and the level of nerve damage, the presence of microsurgical equipment, tools, suture mater yla, apparatus for the intraoperative electrode for gnostics).

In the case of open damage to the peripheral nerves, nerve stitching during the initial surgical treatment (PXO) is optimal if the above conditions exist for this. In the absence of these conditions, surgical intervention should be performed as soon as possible (preferably up to two weeks or, in extreme cases, within the first month after injury).

With closed lesions, early referral of patients to specialized medical institutions, intensive conservative recovery treatment and constant monitoring in dynamics with mandatory ENMG control are advisable. In the absence of signs of recovery of the nerve function for 4-6 weeks or in case of ineffective restoration against intensive therapy in the period of 3-6 months (depending on the clinic and ENMG data) surgical intervention in the specialized department is recommended.

With isolated damage to the peripheral nerves and plexuses, as a rule, there are no difficulties in diagnosing and the quality of care for patients depends entirely on determining the optimal tactics of treatment and its technical support. Compliance with the basic conditions when providing care to patients with nerve injuries allows us to solve the issue of surgical treatment at the optimal time - the first 14 days (or even the first 12 hours) with open injuries and 1-3 months with closed peripheral nerve injuries. At the same time, the most adequate should be considered help in the conditions of specialized microsurgical and neurosurgical departments.

With combined injuries of peripheral nerves, the quality of care for a patient depends on the type of lesion and the severity of the patient's condition. When closed fractures of bones and dislocations with simultaneous damage to the peripheral nerve are shown:

1. With closed repositioning (repositioning) - regenerative therapy, observation and ENMG in dynamics. In the absence of signs of restoration of nerve function (ineffective recovery) with intensive restorative treatment, surgical intervention in a specialized department at a time of 1-3 months (depending on the clinic and ENMG data) is indicated.
2. With open repositioning (repositioning) - revision of the nerve during the operation with subsequent tactics, depending on the operational findings. With damages of the tendons and nerves, one-step reconstructive surgical intervention should be considered optimal in order to restore the integrity of these anatomical structures. With damages of nerves and vessels it is also desirable to carry out a one-stage reconstructive surgical intervention.

Such patients should be taken to specialized departments and operated as soon as possible, first of all, to restore the normal circulation of the limb. The question of intervention on the peripheral nerves in this case should be solved depending on the complexity of the operative intervention, its duration and the somatic state of the patient.

Complex, primarily in the diagnostic plan, a group of patients with peripheral joint injuries are faithful to patients who need urgent medical care for their vital indications. These are victims who, in addition to injuries of the plexus and individual nerve trunks, have injuries to the skull and brain, internal organs, major blood vessels, multiple fractures of the bones. They need reanimation assistance both at the site of the event and during the evacuation. The NOR page in this case has the timely transportation of such victims to specialized medical institutions in accordance with the localization of the dominant damage. And the initial period of treatment for patients in this group is mainly carried out with resuscitation measures. The accompanying trauma of plexuses and individual neural trunks usually attracts little attention of physicians and therefore is often not diagnosed. However, even a diagnosed nerve injury can not be performed because of the severity of the condition of the patients. Optimal is the hospitalization of such patients in the departments or hospitals of polytrauma under the supervision of experienced specialists of various qualifications, including neurosurgeons.

Another complex group of victims are patients with iatrogenic lesions of peripheral nerves. Given that most of these patients need urgent specialized care due to the possibility of developing irreversible changes in nerve trunks, along with preventive measures and mandatory neurological alertness of medical personnel, it is advisable to send these patients to specialized neurosurgical institutions as soon as possible.

Contraindications to neurosurgical intervention in peripheral nerve injuries:

• shock, impaired breathing and cardiovascular system;
• development of infectious complications on the site of injury or suspected surgical access.
• absence of conditions for performing surgical interventions on peripheral nerves,

Absolute indications for neurosurgical intervention are;

• open injuries of peripheral nerves with complete impairment of function;
• closed lesions as a result of fractures of bones, if an open reposition is performed (it is necessary to audit the corresponding nerve trunk);
• injection injuries of peripheral nerves with aggressive medicinal preparations (calcium chloride, cordiamin);
• a progressive decrease in the function of the nerve trunk in the case of increasing edema, compression, or hematoma.

Relative indications for neurosurgical intervention are:

• damage to the peripheral nerves, which are accompanied by a partial loss of their function;
• injection injuries of peripheral nerves with non-aggressive medications;
• iatrogenic closed injuries of peripheral nerves;
• traction and other closed traumatic injuries of peripheral nerves;
• damage to the peripheral nerves, which are accompanied by a significant defect (mainly for the purpose of performing reconstructive orthopedic interventions);
• trauma of peripheral nerves as a result of electric injury.

Operations with nerve injuries

The main requirement for surgical access is the possibility of a sufficient view of the nerve at the level of damage in the proximal and distal directions. This makes it possible to freely manipulate on the nerve trunk, to correctly assess the nature and size of the lesion and to perform a sufficient intervention in the future. Operative access should be as much as possible atraumatic and be carried out with observance of regularities of an arrangement of power lines and a line of the Langer. It should not be carried out directly above the projection line of the nerve trunk, so that later the rough scars are not formed, which in addition to the cosmetic defect entails secondary compression of the nerve trunk.

When the nerve trunk is compressed, neurolysis is performed (excision of tissues that cause compression of the nerve or its fibers). If the anatomic integrity of the nerve is disturbed, it must be cross-linked. In this case, it is possible to cross-link the epineurium (epineural seam), the epineurium with the seizure of the perineurium (epineurial suture), or perform the seam of individual septic fibers (fascicullus suture),

If it is impossible to compare the ends of the damaged seal by mobilization, moving to another anatomical bed, etc., one resorts to performing autoplasty (a segment of another nerve trunk is sutured between the ends of the damaged nerve, using low-value donor nerves, for example, the gastrocnemius nerve). If it is impossible to restore the integrity of the damaged nerve trunk, one resorts to neuroticization (sewing the distal end of the damaged nerve with the proximal end of the other nerve, the function of which can be sacrificed to ensure the functioning of the muscles innervated by the damaged nerve trunk).

The main requirements for both the suture and the other trunk are the most accurate alignment of the ends, taking into account the fascicular structure of the nerve and the absence of tension (seam retention by the 7/0 thread).

Detailed neurological examination after intervention in patients who have nerve trauma should be performed at least once every 4 weeks. Upon completion of neurosurgical treatment, the patient is transferred to the rehabilitation or neurology department.