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Chapter 6. Peripheral nerve injury Traumatic injuries of the peripheral nervous system (PNS) make, in opinion of different authors from 1.5 to 3.5 % of general traumatism of peace-time connected with loss of the ability to work they occupy one of the first places and often result in heavy incapacitation of patients in up to 65 % of cases. Surgery of injuries and diseases of the peripheral nervous system as a section of Restorative neurosurgery acquires an extraordinarily great important now, foremost, in connection with the growth of traumatism, including, transport, household injuries and gunshot damages of nerves, with the icrease of the number of iatrogenic damages of peripheral nerves. At the same time, plenty of patients with traumas and diseases of the peripheral nervous system not always get timely and skilled medicare, that results in persistent incapacitation of this contingent of patients (according to different data in 29–75 % of cases). The overwhelming majority of such patients is made by persons of a young able to work age. Most of damages of nerves of upper extremities arise in the area of a lower 1/3 of a forearm and hand (almost 55 % of all injuries of the upper extremity), at that about 20 % of them is accompanied with injuries of some nerves. Damages in the axillary region and upper 1/3 of the shoulder making only 6 % of all damages, quite often (practically in half of cases) are accompanied with damages of two and more nerves. For the lower extremity a “risk area” is the area of the lower onethird of a thigh – the upper 1/3 of a shin which makes almost 65 % of all damages of peripheral nerves. There are different classifications of damages of peripheral nerves. The overwhelming majority of classifications of traumas of trunks of peripheral nerves differ considerably in both the forms and contents from classifications of other wounds, for example of the locomotorium. Character of trauma
• • • • •
household injuries; work injury (factory accident); battle; transport; iatrogenic
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Classification of damages of peripheral nerves: Open damages 1. Cut, stab, lacerated, chopped, contused, bite
Closed damages Concussion, contusion, compression, distension, dislocation, combined (e.g. compression-traction and others) Isolated damages
2. Gunshot (missile, fragment, shot, perforated, blind, gutter) Isolated damages Combined wounds of nerves with damage of: – bones; – vessels; – tendons
Combined damages of nerves: – with the fracture of bones – with dislocation – with damage of vessels – with a massive contusion of muscles (surrounding tissues)
Combined damages of peripheral nerves Damage with a tourniquet Burns: – by electric current; – thermal
Ischemic damages Chemical damages Cold damages Forms of damage
By morphological signs (intraoperatively): – a complete anatomic interruption; – a partial anatomic interruption (with a lateral partial damage); – with almost a complete anatomic interruption; – intratruncal damages (hematomas, foreign bodies,intratruncal neuromas and others) with almost a complete anatomic interruption
1. Functional block of conductivity 2. Neurotmesis A total severance or disruption of the entire nerve fiber, which includes an axon (or long dendrite), myelin sheath (if existence), schwann cells, endoneurium. Neurotmesis may be partial or complete. 3. Axonotmesis – type A (damage of membranes of separate axons); – type B (anatomical damage of separate fascicles) 4. Neuropraxia The temporary interruption of conduction without loss of axonal continuity. In neurapraxia there is a physiologic block of nerve conduction in the affected axons.
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Damage of peripheral nerves is diagnosed on the basis of a complex checkup including: complaints of the patient, anamnesis with the obligatory taking into consideration the circumstances of injury, examination of the patient and sites of damage (the probability of damage of the nervous trunk is estimated taking into account the topics of damage), neurological examination and additional methods of investigation. At a neurological examination they reveal the symptoms characteristic for peripheral damage can be reveal: 1. Disorders of sensitiveness (from anaesthesia directly in the area of innervation at a complete damage of the nervous stem to hyposthesia or paresthesia at partial damages). The scheme of estimation of disorder of sensitiveness according to the Modified Seddon (Seddon HJ, 1975): S0 – anaesthesia in the autonomous area of innervation; S1 – the uncertain pain feelings; S2 – hyperpathy; S3 – hypesthesia with the diminishing of hyperpathy; S4 – moderate hypesthesia without hyperpathy; S5 – normal algesthesia. 2. Disorder of the muscle strength (as the development of peripheral paresises and paralyses according to the innervation of the given nerve). The scheme of estimation of muscular strength according to the Modified British Medical Research Counsil Scale (2008): M0 – the absence of muscle contractions (paralysis); M1 – weak muscle constructions without convincing signs of motions in joints; M2 – motions under the condition of removal of the extremity weight; M3 – motions on the assumption of elimination of the extremity weight; M4 – motions with overcoming of certain resistance; M5- a complete clinical renewal. 3. Disturbances of trophic function of muscles and skin in the area of the damaged nerve. In a number of cases at damages of peripheral nerves a pain syndrome is determined (painfulness of the nervous trunk itself with irradiation into the area of its innervation, the presence of Tinel ‘s symptom – a pain of shooting nature with irradiation along the nervous trunk at knocking in the site of damage and, sometimes, the development of complicated pain syndromes as amputation pain syndrome or complex regional pain syndrome of the 2nd type with the development of causalgia). Quite often, the pain syndrome accompanies
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partial damages of nerves, especially of a median one and of the tibial portion of the sciatic nerve. Among damages of peripheral nerves the brachial plexus injury is a special type of trauma taking into consideration the degree of severity, features of clinical presentation, treatment and outcomes. Most often, it is caused by the traction of nervous trunk, for example, at falling down from a motorcycle, at dislocations in the brachial joint etc. One of the first descriptions of the clinical picture of damage of the brachial plexus belongs to M. I. Pirogov who described it in “Principles of the military field surgery” (1866). G. Duchenne (1872) described the damage of the upper primary trunk of the brachial plexus, and W. Erb (1874) described in detail this type of damage and on the basis of clinic and electro-physiological investigation came to the conclusion, that the most frequent site of fracture in such cases is the area on the joint of C5–C6 spinal nerves (Erb’s point). Of the damage of the brachial plexus after Duchenne – Erb’s type (mainly dysfunction of subclavicular, axillary, musculocutaneous and, partly, radial nerves) the most characteristic are paresis or paralysis of muscles of the brachial girdle and shoulder at relatively safe functions of muscles of forearm and hand and disturbance of sensitiveness in the area of innervation of C5–C6. The scheme of estimation of the pain syndrome
4 scores
Extraordinarily severe spontaneous pains, often with a burning shade, paresthesias, which do not subside without medical aid, spread over the nearby areas and is generalized; the patient is in an analgetic pose, any motor activity is impossible, sleep is sharply disturbed. Drastic analgetics, including drugs, do not help, considerable disorders of psychics are noted
3 scores
Severe pains limiting the activity of the patient or sleeping. An effect from taking drastic analgetics is marked. Can be disorders of psychics
2 scores
Severe pains, preventing from everyday activity of the patient and resulting in disordering the formula of sleep. Pains can subside or are considerably diminished at taking ordinary analgetics
1 score
Spontaneous pains are absent. Pain, as a rule, is short-term, does not require taking analgetics, does not affet sleep and daily activity of the patient. Appearance of provoked not sharp pains is only possible in special conditions
0 scores
The absence of spontaneous and provoked pain
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The clinical picture of damage of the lower trunk was described by A. DejerineKlumpke (1885) who was the first who noted that Horner’s syndrome is related to the damage of the first thoracic spinal nerve or its sympathic branches. Unlike the upper type, the damage of the brachial plexus of Dejerine – Klumpke’s type (mainly dysfunction of the ulnar and median nerves) is characterized by paresises and paralyses of muscles in the distal parts of an extremity (forearm, hand) and dysaesthesia in the area of innervation of C7, С8–Th1. Besides these classic types, there is a total variant of damage of the brachial plexus. The levels of damage of the brachial plexus
(Fig. 48):
Level I – a preganglionic damage of the roots of the brachial plexus; Level II – a damage of spinal nerves: – with apparent retrograde changes up to the anterior horns of the spinal cord; – with slight retrograde changes. Level III – damage of the trunks, fascicles or long branches of the brachial plexus. Among methods of additional diagnostics of damages of peripheral nerves, electro-physiological methods play a leading role. The most informative methods of investigation of the function of the neuromuscular apparatus are investigations of the generated potentials (GP) of nerves and muscles, electroneuromyography (ENMG), intramuscular electromyography (EMG), registration of the somatosensory generated potentials (SSGP), generated sympathetic cutaneous potentials (GSCP). For the estimation of the motor function of the nerve such indexes as the latent period, amplitude of M-answer (the potential arising in a muscle at the electric irritation of the motorius), speed of performing excitation (SPE) can be used. For the estimation of the function of the sensitiveness of peripheral nerves the method of the determination of SPE at antidromic or orthodromic stimulation is widely used. Roentgenography of bones is informative in cases of suspicion of fractures, compression of nerve by a bone callus or a metal plate, or dislocations of bones. In addition, the application of this method is justified for the specification of the degree of consolidation of fragments of bones, that determines the conservative and surgical tactics in most cases. MRI as a highly informiative method of investigation is only used in some diagnostically complicated cases of damages of the brachial plexus, lumbosacral plexuses, a sciatic nerve and in differential diagnostics with damages of the spine and spinal cord. For diagnostics MRI has an exceptional self-descriptiveness in
Peripheral nerve injury
1 – n. dorsales scapulae 2 – n. musculocutaneus 3 – n. axillaris 4 – n. radialis 5 – n. medianus 6 – n. pectoralis 7 – n. ulnaris 8 – n. cutaneus brachii med. 9 – n. cutaneus antebrachii med. 10 – nn. intercostales 11 – nn. intercostales 12 – n. thoracic
C4 C5
С5
1 C6
Upper type Lower type
C7
С5 С6 С7
2 С4 С5 С6 С5 С6 С5 С6 С7 С8 Т1 С5 С6 С7 С8 Т1
12 C8
Т1
3 8
4 6
5
123
7 С5 С6 Т1 С8 Т1 С7 С8
С8 Т1
Т2
Т1
11 9
Т1
10 Т1 Т2
Т2
III
II
I
Fig. 48. A schematic picture of the main types of damage of the brachial plexus: level I – the preganglionic level; II – damage of spinal nerves (the postganglionic level); III – damage of the trunks and branches of the brachial plexus
comparison with other methods, as it allows to visualize spinal roots immediately, to reveal traumatic meningocele, being formed as a result of tearing away of roots from the spinal cord, the degree of the apparency of the atrophic process of the spinal cord, as well as to estimate the state of muscles which are innervated by separate nerves or plexuses. Also the ultrasound examination of periferal nerves, muscles, joints, ligaments can be used for diagnostics and intraoperative control and navigation. Providing help for patients with trauma of peripheral nerves is performed stageby-stage. At the stage of urgent medical aid for patients with trauma of peripheral
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nerves, the standard of the organization of help is an urgent transportation of the patient to the hospitals (traumatological, surgical, and polytrauma departments). In isolated damages of peripheral nerves the hospitalization of the patient at once to a specialized microsurgical or neurosurgical department is optimal. Thy basic measures which should be taken at the stage of the urgent medical aid: 1. Examination and estimation of the origin and degree of damage, including concomitant damages. 2. Estimation of the general condition of the patient. 3. Arrest of bleeding. 4. Immobilization of the damaged extremity (extremities). 5. In the presence of indications – introduction of anaesthetics, taking antishock and reanimation measures. In case of the appearance of difficulties with performing a neurological examination, trauma of peripheral nerves one should suspect, if there are: damages of main vessels, motorcycle trauma (damage of the brachial plexus), fractures of the pelvic bones and a clavicle. In nonspecialized hospitals it is inexpedient to perform neurosurgical interventions on peripheral nerves. At this stage it is necessary to exclude concomitant damages; to make a preliminary diagnosis; to carry out reanimation and antishock measures; to prevent the development of infectious complications (implementation of the primary surgical processing, appointment of antibacterial therapy); to perform intervention with the purpose of the final arrest of bleeding and immobilization of fractures; in case of closed damages of peripheral nerves and plexuses, to appoint a restoration treatment and provide a regular (not rarer than 1 time in 2–4 weeks) electroneuromyographic control over the quality of renewal of function of the neuromuscular apparatus. It is necessary to transport patients to specialized neurosurgical departments without the disturbance of breathing and at a stable hemodynamics. In specialized microsurgical and neurosurgical department it is necessary to perform a detailed estimation of the neurological state, to define the neurological level of damage of the peripheral nerve and/or plexuses, to carry out electroneuromyography with the purpose of estimation of the degree of the loss of the function and detailed determination of the level of closed damages. After checkup, it is necessary to make a diagnosis which would represent the nature, type and level of damage, type and localization of concomitant damages, neurological symptomatology, complications. Operative treatment at the trauma of peripheral nerves needs to be performed so quickly as it allows the state of the patient. To avoid technical errors at the stage
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of surgical treatment of traumatic damages of peripheral nerves, the presence of a number of conditions is needed, without the account of which surgical intervention on nerve trunks is contraindicated (the presence of the specialist which possess the skills of microsurgical technique with the perfect knowledge of topographical anatomy of peripheral nerves, able to provide exact diagnostics of the nature, degree and level of damage of the nerve, the presence of microsurgical equipment, tooling, suture material, the apparatus for the intraoperative electrodiagnosis). In case of open damages of peripheral nerves the suturing the nerve during performing the primary surgical processing (PSP), if for this there are aforementioned conditions is optimal. In the absence of these conditions, operative intervention must be performed in the earliest possible terms (desirably up to two weeks or, during the first month after a trauma). At closed damages expedient is an early direction of patients to specialized hospitals, carrying out intensive conservative treatment and permanent obserbance in dynamics with the obligatory electroneuromyography (ENMG)-control. In case of the absence of signs of renewal of the function of the nerve during 4–6 weeks, or at an ineffective renewal against the background of intensive therapy during 3–6 months (depending on a clinics and information of ENMG) surgical intervention in a specialized department is recommended. At isolated damages of peripheral nerves and plexuses, as a rule, complications in making diagnosis are absent and the quality of providing help for patients depends on the determination of an optimal tactics of treatment and its technical providing. The observation of basic condition at providing help for patients with damages of PNS allows to solve the problem of surgical treatment in optimal terms – the first 14 days (or even first 12 hours) at the open damages and 1–3 months at closed damages of peripheral nerves. At that, the most adequate should be considered help in the conditions of specialized microsurgical and neurosurgical departments. In combined damages of peripheral nerves the quality of providing help for a patient depends on the type of damage and severity of the state of the patient. At closed fractures of bones and dislocations with simultaneous damage of the peripheral nerve, the indications are the foolows: 1. At closed reposition (reduction) is restorative therapy, observation and ENMG in dynamics. In case of the absence of signs of renewal of the function of the nerve (an ineffective renewal) at intensive restoration treatment surgical interference is indicated in a specialized department during 1–3 months (depending on a clinic and findings of ENMG). 2. At open reposition (reduction) – the revision of the nerve during the operation with the subsequent tactics depending on the operation findings.
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At damages of tendons and nerves the optimal one-stage plastic surgical intervention with the purpose of renewal of the integrity of the indicated anatomic structures should be regard. At damages of nerves and vessels it is also desirable to perform onestage plastic surgical intervention. Patients with such damages must be delivered to specialized departments and operated as quickly as possible, above all things, with the purpose of renewal of the normal blood circulation of the extremity. The problem of intervention on peripheral nerves in this case must be solved depending on the complexity of the operative interference, its duration and the somatic state of the patient. Complicated, above all things, in a diagnostic plan, the group of patients with combined damages of peripheral nerves is made by patients who need an urgent medical aid by life-saving indications. These are patients in, whom peripheral nerves injuries are both with damages of the skull and cerebrum, inner organs, main blood vessels, multiple fractures of bones. They need reanimation help both on spot and during evacuation. Of great importance in this case is a timely transporting of such patients to specialized medical clinics in accordance with the localization of the dominant damage. In the initial period of treatment of the patient of this group, reanimation measures are mainly taken. The concomitant trauma of plexuses and separate nervous trunks usually attracts little attention of doctors, and therefore is often not diagnosed. However, even diagnosed damages of PNS can not be operated on because of the severity of the state of patients. Optimal is hospitalization of such patients to departments or hospitals of polytrauma under the observation of experienced specialists of a different qualification, including neurosurgeons. One more difficult group of patients are patients with iatrogenic damages of peripheral nerves. Taking into account that most of these patients need an urgent specialized aid because of the possibility of the development of irreversible changes in nerve trunks, along with prophylactic measures and obligatory neurological suspicion of the medical staff, expedient hospitalization of these patients to specialized neurosurgical departments as early as possible is obligatory. Absolute indications to neurosurgical treatment are:
• open damages of peripheral nerves with a complete dysfunction; • closed damages as a result of fractures of bones, if an open reposition is performed (it is necessarily to revise a corresponding nerve trunk); • injection damages of peripheral nerves by "aggressive" solutions (Chloride calcium, Cordiaminum); • progressing decrease of the function of the nerve trunk in case of increasing edema, compression or hematoma.
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Relative indications for a neurosurgical intervention are:
• damages of peripheral nerves which are accompanied with a partial loss of their function; • injection damages of peripheral nerves by "non-aggressive" solutions; • iatrogenic closed damages of peripheral nerves; • traction and other closed traumatic damages of peripheral nerves; • damages of peripheral nerves which are accompanied with their considerable defect (mostly with the purpose of the implementation of plastic orthopedic interventions); • damage of peripheral nerves as a result of electrotrauma. Contraindications to neurosurgical intervention at damages of peripheral nerves:
• shock, disturbances of breathing and cardiovascular system; • development of infectious complications at the site of the wound or supposed surgical approach; • absence of terms for the implementation of operative interventions on peripheral nerves.
Surgical tactics The main demand of a surgical approach is the possibility of a sufficient review of the nerve at the level of damage in the proximal and distal directions. It enables to manipulate freely on the nerve trunk, to estimate correctly the nature and volume of damage and perform a sufficient in volume intervention in future. An operative approach must be maximally non-traumatic and performed with the observance of the pattern of the location of lines of force and Langer’s lines. It should not be carried out immediately above the projection line of the nerve trunk, lest rough scars should be formed in future, that, besides a cosmetic defect, entails the secondary compression of the nerve trunk. At the compression of the nerve trunk, neurolysis is performed (excision of tissues causing the compression of the nerve or its fibres). At the disturbance of the anatomic integrity of the nerve, it is necessary to carry out suturing the nerve. At that suturing is possible behind the epineurium (an epineural suture), behind the epineurium with the capture of the perineurium (an epeperineural suture), or to perform the suturing of separate nervous fibres (a fascicular suture; Fig. 49).
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1
2
3
Fig. 49. Types of sutures of the nerve trunk: 1 – an epiperineural suture; 2 – a fascicular suture; 3 – interfascicular autoplasty of the nerve trunk
In case of impossibility to confront the ends of the damaged nerve by imobilization, displacement to another anatomic bed etc., it is possible to performe autoplasty (a piece of another nerve trunk which is stitched between the ends of the damaged nerve. At that nerves-donors of minor importance are used, for example, the gastrocnemius nerve). At the impossibility to recover the integrity of the damaged nerve trunk, can be done neurotization (suturing the distal end of the damaged nerve with the proximal end of another nerve, function of which can be sacrified for providing the functioning of muscles innervated by the damaged nerve trunk; Fig. 50). The main demands of sutures of the nerve trunk is a maximally exact confrontation of the ends of nerves taking into account the fascicular structure of the nerve and the absence of tension (keeping the suture with a thread 7/0). A detailed neurological examination after the operation is necessary to perform later one time in 4 weeks. Upon the completion of neurosurgical treatment, the patient is transferred to the department of rehabilitation or general neurology.
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n. facialis n. facialis
n. hypoglossus Fig. 50. The schematic picture of neurotization of the facial nerve with the using of the descending branch of the n. hypoglossus
Control queStIonS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
What are the reasons of traumatic damages of peripheral nerves? Name possible reasons of iatrogenic damages of peripheral nerves? Classification of traumatic injuries of peripheral nerves. Classification of traumatic injuries of the brachial plexus. What is the most frequent localization of traumatic damages of peripheral nerves? Clinical signs of damage of the radial nerve. What are the optimal terms of surgical treatment of traumatic damages of peripheral nerves? What volume of aid is provided for patients with open damages of peripheral at the pre-admission stage. Indications for surgical treatment of birth injury of the brachial plexus. The volume of an urgent aid in open damages of peripheral nerves. Enumerate the possible operations in traumatic injuries of peripheral nerves. Principles of restorative treatment of outcomes of damage of peripheral nerves in the postoperative period. Types of pain syndromes in traumatic damages of peripheral nerves.
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14. Providing an urgent aid for patients with open and closed damages of the peripheral nervous system. 15. Rehabilitation of patients with traumatic damages of peripheral nerves. 16. Pain syndromes. Trigeminal nerve neuralgia. Treatment.
taSkS Task 1.
In a patient, there was revealed a fragmental fracture of the left shoulder on the border of the middle and lower one-third. The volume of motions in the hand is not disturbed. After the operation of osteosynthesis, the left hand dangled, the patient cannot unbend the hand, fingers, abduct the thumb. Make the diagnosis, apply auxiliary methods of investigation, the medical tactics. Task 2.
A patient was hospitalized to the district hospital with a cut wound of the inner surface of the middle 1/3 of the right forearm. The injuries of the ulner artery, median and ulner nerves were diagnosed. What symptoms will be observed in the patient? Name the volume of the primary surgical aid, define the futher medical tactics. task 3.
A patient was hospitalized to the surgical department of the central district hospital with a cut wound of the inner surface of the median 1/3 of the right forearm. There is observed an intensive bleeding from the wound, at the neurological checkup it has been established: the hand looks like a “clawhand”, the flexion of IV and V fingers are absent, opposition of V finger, bringing together and separating of fingers, anesthesia of the palmar surface of III–V fingers. They assume damage of the ulnar artery and ulnar nerve. Define the volume of the primary surgical aid and further medical tactics. task 4.
At work a detail from the workbench damaged a left thigh of a worker. After trauma the patient cannot extend the leg at the knee, than appeared the loss of sensitivity along the frontal surface of the thigh and inner surface of the left lower leg. What nerve has suffered? What is the tactics of the checkup and treatment of the patient. task 5.
In a 9-year-old child there was a cut wound along the external surface of the upper onethird of the right lower leg after which the foot “dangled”. Define the nature of damage and medical tactics.