RU2169016C2 - Method for repairing peripheral nerve conductivity in the cases of large-scale anatomic defects - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves nerve trunk defect is substituted with neuroautotransplant. Then, electrodes are implanted in subepineural way into the distal and proximal ends of the nerve. Electric stimulation is carried out using constant electric current changing its direction. Current action duration varies in different directions from 0 to 5 s independently of one another. Current intensity varies from 0 to 250 mcA under 9 V voltage depending on subjective feeling of patient. EFFECT: accelerated treatment course. 5 dwg

Description

 The invention relates to medicine, namely to neurosurgery, microsurgery, neurotraumatology, and is intended for patients with large, 20 cm or more, anatomical defects of the peripheral nerves.

 A known method of treating a peripheral nerve defect by neurolysis, splitting its proximal end into two equal parts according to the size of the defect, cutting off and moving one of the parts to the defect site, applying epineural sutures [1].

 The disadvantage of this method is the use of a healthy area of the nerve to replace the damaged area, which does not fully restore the function of the damaged nerve. It should also be noted that in a known manner restoration of relatively small areas of the damaged nerve is possible.

 A known method of restoring the function of a damaged nerve, including the introduction of drugs into the area of damage and electrical stimulation of the nerve trunk [2].

 However, this method has several disadvantages: in a known manner, it is possible to restore relatively small, up to 8 cm, nerve defects, the electrodes are superimposed on the nerve trunk, which does not guarantee constant and complete contact with the axons of the nerve, moreover, electrode migration is often observed, the special design of the thread electrodes, made of carbon fiber in its properties is not pyrogen-free, the parameters of the electric current are insufficient to restore large, 20 cm or more, nerve defects.

 Closest to the proposed one is a method of treating compression lesions of nerve trunks comprising surgical decompression and electrical stimulation through electrodes implanted in the lesion zone with established threshold values of amplitude, duration and frequency of pulses [3]. A common feature of the proposed method and prototype is the use of electrical stimulation through electrodes implanted in the affected area.

 The disadvantage of this method is the implementation of electrical stimulation by pulsed current (current parameters: amplitude from 1 to V; frequency from 30 to 80 Hz; duration from 0.5 to 0.75 ms), surgical decompression eliminates the compensation of large anatomical defects of the nerves, which does not allow to restore peripheral conductivity.

 The proposed method is aimed at improving treatment results, reducing the duration of treatment.

 According to the proposed method, a peripheral nerve defect is replaced by a nerve autograft taken from n.suralis. Above and below the damage, electro-electrodes made of silver wire with a diameter of 0.1 mm are introduced subepineurally; in the postoperative period (from the first day), they are stimulated by direct electric current that changes its direction. The duration of action in various directions varies from 1 to 5 seconds from each other. The magnitude of the current varies from 0 to 250 μA when the voltage changes from 0 to 9 V.

 The proposed method allows to restore pain and tactile sensitivity starting from 3-5 days of the postoperative period, with the subsequent restoration of all types of sensitivity.

 Fig 1 - Fig. 5 explain the proposed method.

 In FIG. 1 shows a nerve defect before processing the ends of the nerve.

 In FIG. 2 shows a true anatomical defect.

 In FIG. 3 shows a graft from n.suralis laid in a “cable”.

 In FIG. 4 shows the graft at the site of the defect.

 In FIG. 5 shows a reconstructed nerve site with implanted electrodes.

 The proposed method is as follows.

 During surgery, the area of the anatomical defect of the peripheral nerve is exposed (Fig. 1). After excision of the distal and proximal ends of the nerve within the "healthy" tissues determine the true nerve defect. The size of the defect required for replacement may be more than 20 cm (Fig. 2). Makes a neuroautograft (n.suralis) from the lower leg, three times the size of the defect. The collected transplant is divided into three equal parts, laid in the form of a “cable” and fixed with a suture 8/0 thread using an operating microscope (Fig. 3). Then the graft is placed in a prepared bed and hemmed to the central and peripheral ends of the damaged nerve (Fig. 4). Carry out hemostasis. Outside the skin wound, electrodes are subepineurally implanted to the central and peripheral ends of the damaged nerve (Fig. 5). The electrodes are made of silver wire with a diameter of 0.1 mm, as an insulating sheath, use a children's catheter for the smallest intravenous infusion. The electrodes are attached to the skin with two silk sutures behind the "ears" of the catheter and to it with a catgut suture. Alternatively, a silver needle for acupuncture can be used as an electrode. Each wound is sutured. The limb is immobilized.

 In the postoperative period, starting from the first day, twice a day for up to 30 minutes, nerve is stimulated with direct current, which changes its direction. The duration of the current from 1 to 5 seconds. The magnitude of the current strength varies from 0 to 250 μA when the voltage changes from 0 to 9 V, depending on the subjective sensations of the patient in the form of tingling in the area of the graft and distal to it, which ensures the restoration of pain and tactile sensitivity already on the 30th day after the operation. After 10-15 days, depending on the speed of restoration of sensitivity, the electrodes are removed without repeated surgical intervention.

 The proposed method of treatment with experimental clinical radiation was used in 12 patients with peripheral nerve defects from 15 to 20 cm. In all cases, treatment was carried out at a long time after the injury (up to 3 years). In all patients, after treatment, restoration of nerve function was noted.

 Example 1. Patient S., 30 years old, medical history 1319, 1997

 Clinical diagnosis: anatomical defect of the median nerve of the right forearm (15 cm). Post-traumatic mixed flexion contractures of 1-5 fingers of the right hand. Circular saw injury, limitation period - 4 months. It was operated on with the replacement of the defect with a neuroautograft, electrodes were introduced and electrical stimulation was performed. 2 days after electrical stimulation, paresthesia was observed in the innervation zone of the median nerve on the hand and fingers. On the 5th day, restoration of sensitivity on 1-3 fingers to PMPS.

 S. was discharged in satisfactory condition. Control examination after 6 months. The patient works at his previous work, he is satisfied with the result of the operation.

 Example 2. Patient M., 46 years old, medical history 12685, 1997

 Clinical diagnosis: post-traumatic anatomical defect of the ulnar nerve of the right forearm (20 cm). Madelung's disease on the right. Condition after repeated surgical interventions on bones, muscles, nerves. Sick for 4 years. Conservative treatment without defect. At the operation, a defect of the ulnar nerve of the right forearm of 20 cm was diagnosed. A plastic defect was performed with the introduction of electrodes. On the 2nd day of electrical stimulation, the appearance of paresthesia in the zone of innervation of the ulnar nerve was noted.

 On the 10th day, hypesthesia to the base of the nail phalanges. At the end of electrical stimulation, a complete restoration of the function of the ulnar nerve was noted.

Sources of information
1. A.S. N 1806629, IPC A 61 B 17/00, A method for the treatment of a peripheral nerve defect.

 2. A. p. N 1146061, IPC A 61 N 1/36, Method for restoring the function of a damaged peripheral nerve.

 3. RF patent N 2004265, IPC A 61 N 1/36, A method for the treatment of compression lesions of nerve trunks.

Claims (1)

 A method of restoring the conductivity of peripheral nerves with large anatomical defects, including electrical stimulation through electrodes implanted in the lesion zone, characterized in that the nerve defect is replaced by a neutrino autograft, the electrodes are implanted subepineurally at the distal and proximal ends of the affected nerve, and they are stimulated by a constant electric current that changes its direction 1 - 5 s, current 0 - 250 μA at a voltage of 9V.

Images