RU2391898C1 - Method of diagnosing trophic nerve function - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to field of medicine, namely to neurology and rehabilitation therapy. Method consists in measurement of electric skin characteristics in zone of autonomous nerve innervation and contralateral side or extremity. Said measurements are carried out by means of device, whose diagnostic electrode diametre is about 1 cm, internal amplifier resistance being 80-100 kOhm. By ratio of electric potentials on affected and contarlateral side asymmetry coefficient (AC) is obtained and conclusion about degree of nerve affection is made: if AC = 1.0 - 1.6 - the nerve is not affected, if AC = 1.7 - 50 - hyposthesia, if AC > 50 - anesthesia.

EFFECT: application of claimed invention allows to reduce diagnostics time, accuracy of method application diagnostics accuracy allows to use it for determining affection degree and recovery dynamics in process of treatment.

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Description

The invention relates to medicine, can be used in neurology and rehabilitation therapy.

Diagnosis of peripheral nerve damage consists of the function of a nerve: motor, sensory and trophic. If objective methods of diagnosis exist for the first two, then only qualitative methods are known for trophic function. Diagnostic methods based on changes in the resistance (electrical conductivity) of the skin are to conduct a weak current. Due to polarization of the skin, the results are distorted and become unreliable.

A known method for the diagnosis of trophic function of nerves, described in the work “Caused skin autonomic potentials: guidelines” (M.N. Odinak, S. A. Kotelnikov, E. B. Shustov. - S. Petersburg, Ivanovo, 1991. - 39 p. .) accepted by us for the closest analogue. In the known method, electrical activity is derived from the sweat glands (electrodermal activity), which changes under the influence of single electrical impulses exceeding the sensitivity threshold. The signal is recorded in the form of a graphic record, which is interpreted depending on the pathology.

The disadvantage of this method is the unreliability of the results, depending on so many reasons (state of the body, room temperature, age, adaptation to the effects of electrical stimuli, distracting thoughts, etc.). Electrode locations are standard. This method can evaluate the general status and pathology of the autonomic nervous system only in certain diseases. The functional state of individual nerves also cannot be reliably evaluated. More often the state of individual nerves is evaluated qualitatively, i.e. there is a defeat or not.

The technical result of the claimed invention is to develop a safe, easy to use method for the diagnosis of trophic function of nerves, which allows to reduce the time of diagnosis. The accuracy of diagnosis when using this method allows you to use it to determine the degree of damage and the dynamics of recovery during treatment.

A method for diagnosing the trophic function of a nerve is proposed, which consists in measuring the electrical characteristics of the skin in the zone of autonomous innervation of the nerve and the contralateral side or limb, characterized in that these measurements are carried out using a device whose diagnostic electrode is about 1 cm in diameter and has an internal resistance of 80-100 kOhm , according to the ratio of electric potentials F on the diseased and contralateral side, they make a conclusion about the degree of nerve damage: with F = 1.0-1.6 - the nerve is not damaged, with F = 1.7-50 - hyposthesia, at F> 50 - anesthesia.

The method is implemented as follows. Electric potentials are recorded on the diseased and contralateral side (limbs) at symmetrical points in the nerve innervation zone, often at the fingertips. The obtained values are compared in the form of a ratio, obtaining an asymmetry coefficient, which is a constant and reliable value. When a nerve is damaged, the electric potential decreases, and the asymmetry coefficient increases (Table 1).

Table 1 No. The degree of nerve damage The value of electric potential, mV The ratio of electrical potentials on the diseased and contralateral side one The nerve is not damaged 200-500 1.0-1.6 2 Hyposthesia for nerve damage (reduced perspiration) 5-200 1.7-50 3 Anesthesia for nerve damage (lack of perspiration) Less than 5 Over 50

A device for detecting a skin electric potential that occurs when the electrode contacts the skin consists of a potential amplifier and a cutaneous electrode acting as a generator of a weak electric current. The skin electrode consists of two plates of dissimilar metals (for example, copper, zinc), separated by a gap of about 1 mm wide. When in contact with the skin, the cutaneous electrode is a biological galvanic cell, with the secret of sweat glands playing the role of the electrolyte. The voltage of the emerging current is up to 0.4 volts, which is less than the physiological action potentials in the tissues of the body. With this voltage, the skin does not change its resistance, so all measurements are reliable. The magnitude of the electric potential depends only on the degree of perspiration. The lower the perspiration, the lower the electrical potential. When a nerve is damaged, its trophic function is violated, including sweating in the zone of autonomous innervation. During nerve regeneration, perspiration is slowly restored.

A method for diagnosing trophic function of nerves provides a quantitative assessment of the degree of damage or regeneration. The examination was conducted in 265 patients with damage to different nerves and in the process of regeneration. A reliable correlation was noted between the dynamics of the ratio of electric potentials and objective diagnostic methods, as well as the sensitive function of nerves. In the process of regeneration, the asymmetry coefficient progressively decreases, reaching normal values.

Consider examples of implementation of the invention.

Example No. 1.

Patient B., 28 years old, was injured in the ulnar and median nerves in the n / a of the forearm. Autoplasty of both nerves has been tested. After 6 months: nail-like deformity of the hand, all types of sensitivity are absent. EMG - 0. The patient underwent mud therapy and interstitial electrical stimulation No. 20. The following dynamics of the cutaneous electric potential on the terminal phalanges of a healthy and diseased hand was determined in the form of an asymmetry coefficient (absolute values do not have practical significance) (Table 2).

table 2 I n. II n. III n. IV n. V n After 6 months p / op. (KA) 500 133 400 571 400 3 0 four 0 After 2 months, canned. treatment 15,2 25 12 thirty 36 After another 2 months, canned. treatment 6.6 6.25 12 11,2 12.5 After 2 g p / op. 1.3 1.8 5 7 6.5

After 2 years, the sensitivity remained in the form of mild hyperesthesia, motor function 20-40% of N (according to EMG).

Example No. 2

Patient X., 40 years old, received a cut in the glass of the ulnar nerve at the level of the wrist joint, according to urgent indications, an operation of the epineural suture of the nerve was performed. After 2 weeks, there is dry skin of the IV-V n., Lack of dilution, EMG - a complete violation of the conductivity of the ulnar nerve. The measurement of skin potential at the fingertips in the form of a SC was as follows (Table 3).

Table 3 I n. II n. III n. IV n. V n 2 weeks after surgery 0.8 one 1,1 28 one hundred 0 After 3 months on the background of treatment 0.8 0.8 0.7 5,4 40 7 months after surgery one one one one 8.3

The trophic function is restored first, then sensitivity, lastly motor. Regression of trophic sensitivity within 1 year did not occur.

Example No. 3

Patient V., 57 years old, was treated with carpal tunnel syndrome and compression of the median nerve. Feeling of numbness, pain in the first three fingers, sensitivity is impaired in the form of hyposthesia, EMG is disturbed up to 40% of the norm. Trophic function was measured in the form of KA of the cutaneous electric potential at the fingertips (Table 4)

Table 4 I n. II n. III n. IV n. V n CA before treatment 2.5 3.3 2,8 2 one After conservative treatment 2.5 9 fourteen 12 one After surgical treatment one 1.7 1,2 1.8 one

An attempt at conservative treatment did not improve (even worsen). The operation of decompression of the nerve. The effect was immediately apparent. Sensitivity and partially muscle function were later restored.

Example No. 4.

Patient Zakharov, 17 years old, was admitted with paresis of the peroneal nerve after an injury. On the back of the foot there is a zone of hyposthesia, the function of the extensors of the foot is absent. Cutaneous electric potential on the back of a healthy and diseased foot in the form of an asymmetry coefficient of 2.5. After conservative treatment for 1 month KA = 1.0, the sensitivity was restored. There is a weak dorsal flexion of the foot.

Thus, the proposed method is an objective quantitative method for the diagnosis of trophic function of the nerve, in addition, it is safe, easy to use and reduces the time of diagnosis. The accuracy of the diagnosis when using this method allows you to use it to determine the degree of damage or regeneration of the nerve.

Claims (1)

A method for diagnosing trophic function of a nerve, which consists in measuring the electrical characteristics of the skin in the area of autonomous innervation of the nerve and the contralateral side or limb, characterized in that these measurements are carried out using a device whose diagnostic electrode diameter is about 1 cm and the internal resistance of the amplifier is 80-100 kOhm , according to the ratio of electric potentials on the diseased and contralateral side, an asymmetry coefficient (KA) is obtained and a conclusion is made on the degree of nerve damage: with KA = 1.0-1.6 - ner not damaged, if KA = 1,7-50 - gipostezii at KA> 50 - anesthesia.