## 4 Discussion
Contemporary researches show that NMES increases the strength of stimulated muscles, thereby preventing atrophy while waiting for the results of axonal regeneration. A type of electrical muscle stimulation is FES, i.e., functional electrical stimulation, which, using electrodes placed on the damaged muscle, stimulates the sensory and motor fibers of the supplying nerve, thereby supporting the axon's proliferation and reinnervation of the muscle [36; 37]. The proprioceptive neuromuscular facilitation method (PNF), using the patient's exercises against the resistance of the physiotherapist stimulates muscles to contract, and also improves muscle strength and the range of motion of the injured extremity. Additionally, through the phenomenon of the spread of the impulses in the spinal cord neural connections, one can notice an improvement in the parameters of muscle activity on the opposite side [38; 39; 40]. Kinesiotherapy exercises can be used in patients with brachial plexus injuries both as conservative treatment and after surgical reconstructive intervention. In the work of [PERSON] et al. [28] concerning the rehabilitation techniques in the case of brachial plexus injury, they recommend the use of the following: passive, assisted, and active exercises to increase the range of movement, stretching exercises to improve neuromuscular control and improve the elasticity of soft tissues, resistance, and anti-gravity exercises to increase muscle strength and the use of learned exercises in the functional training. To maintain the correct range of motion, it is important to additionally use manual therapy to relax hyperactive muscles, mechanically mobilise the stiff joints, stimulate sensory perception, and reduce pain [41; 42; 43]. The improvement of functional state in the nerves of patients following the brachial plexus paralysis can be considered in the context of [PERSON]'s classification [20]. Neuro-praxia, defined as a conduction block resulting from damage to the myelin sheath, is a type of demyelinating injury. Rehabilitation procedures in this area are limited to mobilisation of the structures surrounding the blocked nerve. For this purpose, the manual therapy described above can be used, focusing on lymphatic drainage and classic massage of the upper extremity [43; 44]. However, [PERSON] et al. [45] proved that the use of electrical stimulation of the nerve immediately after surgical decompression accelerates the process of axon proliferation and, consequently, the reconstruction of myelin sheath. An axonal type of brachial plexus injury, according to [PERSON], can be classified as axonotmesis and neurotmesis. Axonotmesis refers to the disruption of axonal continuity while preserving connective tissue, which allows for potential axonal regrowth and functional recovery. However, in the case of neurotransmission, axonal proliferation is unlikely due to the complete disruption of the nerve structures. Taking the above into account, in the case of axonal damage, rehabilitation procedures should concern the post-operative stage, necessary for the nerve regeneration process [46]. For this purpose, the previously mentioned kinesotherapy exercises, PNF method, or manual therapy can be used. In the literature, many researchers examine the scope of action of electrical nerve stimulation. [PERSON] et al. [47] reported that during electrical stimulation of damaged nerve fibers, through reverse conduction of action potentials to the cell body, intraneuronal cyclic AMP increases, which affects the regulation of genes related to nerve regenerative processes. Additional rehabilitation methods may include the sensory re-education method based on the Homunculus theory, i.e., the representation of the hand in the motor and sensory cortex of the brain. It involves the use of alternative types of stimuli that excite the motor and sensory cortex to rebuild the neuronal network, restoring the proper function of the areas supplied by the damaged peripheral nerve.