The study of the features of regeneration of traumatically damaged peripheral nerve using different options for connecting its proximal and distal segments remains an open problem for modern practical neurosurgery. The effectiveness of microsurgical techniques has a direct impact on the outcome of the recovery of the injured peripheral nerve, both at the level of structural nerve regeneration and muscle reinnervation, and functional recovery of the limb. For a long time, microsurgical repair of the injured peripheral nerve was performed by several microsuture techniques (epi- and perineural sutures). But this approach, although considered the gold standard in nerve microsurgery, has its disadvantages. First, this neurorrhaphy requires a high technical level of performance. Second, suturing involves additional injury to the nerve stumps. Third, decreased nerve stumps adhesion can decelerate regenerative processes and the strength of nerve neurorrhaphy. To avoid these difficulties and disadvantages, it is proposed to use additional adhesive substrates in the area of the suture of the damaged peripheral nerve, such as hydrogels based on polyethylene glycol and fibrin. In our study, we hypothesized that the use of adhesives (hydrogels) will simplify the microsurgical repair of the damaged nerve, improve the recovery process or not interfere with it. In order to obtain evidence, experimental studies were performed on laboratory animals (80 white outbred male rats weighing 250 ± 25 g, aged 5-6 months). The research algorithm consisted of modeling traumatic damage to the peripheral nerve and assessment of regenerative processes in the dynamics. The full cross-section of the sciatic nerve at the level of the upper third was chosen as the model of the experiment. All experimental rats had section of a sciatic nerve and were further divided into 3 main groups: 1) group with epineural suture (ES) – nerve stumps were connected by 4-6 epineural sutures; 2) group with the use of polyethylene glycol hydrogel (PEG) – nerve stumps were combined with hydrogel, but additionally performed 2 fixating epineural sutures; 3) group using fibrin glue (FG) – nerve stumps were combined with fibrin glue, but additionally performed 2 fixating epineural sutures. The following groups were selected as control groups: 1) intact rats; 2) sham-operated rats (accessed the sciatic nerve without neurotomy); 3) rats with complete neurotomy of the nerve (sciatic nerve was left without connecting the nerve stumps). To analyze the dynamics of recovery processes, three terms were chosen – 14, 30 and 60 day. Research methods: a) functional test – «Walking track analysis» with Sciatic Functional Index (SFI) – a widely used indicator of the condition of the limb in assessing the effectiveness of recovery of the damaged nerve; b) ENMG – the level of neuromuscular recovery was assessed by the parameters of the amplitude of the M-response, the latent period of the M-response and the speed of nerve excitation; c) histological methods – studied the regeneration of nerve fibers through the suture area into the distal nerve segment, morphometrically assessed the number of regenerated myelinated nerve fibers in the distal nerve segment, studied the morphological changes of muscle fibers in denervated muscles, histochemically and morphometrically evaluated fibrosis processes in denervated muscles; d) molecular biological methods – revealed the presence and level of activity of matrix metalloproteinase-9 in muscles, to study the processes of muscle hypotrophy and fibrosis during denervation. Statistical methods and correlation analysis were used to establish the intergroup difference and determine the most effective method of connecting the stumps of the crossed sciatic nerve.
