## 1 Introduction  
Traumatic brachial plexus injuries (tBPIs) can be characterized by different mechanisms, elongation, and avulsion amongst the most burdensome, which is very often invalidating for the patient, with a huge impact on the quality of life [1]. In addition to magnetic resonance imaging (MRI), the extent of the lesion can be accurately described within the neurapraxia, axonotness, or neurotmesis phenomena by the use of different clinical and electrophysiological instruments [2]. Electromyography (EMG) provides useful information about the early degeneration processes that occur, as well as the proper moment for surgical intervention. This depends on the spontaneous and uncoordinated muscle activity that can be recorded from the recent denervated muscle territories, as a result of the muscle fiber's hyper sensibility to acetylcholine, but also during the rehabilitation period after surgery [2,3]. Needle EMG can, in a positive scenario, provide information about motor unit action potential (MUAP) recruitment [2]. The measurement of the sensory nerve action potential (SNAP) can also provide useful data about the possible reinnervation that is taking place at a specific moment [1]. Recording a low amplitude compound muscle action potential (CMAP) is a much better predictor of the reinnervation process [1,2]. In tBPIs, neurotization is the procedure of choice, when possible (dependent on the extent of atrophy of the muscle: less atrophy, the better the outcomes). The transfer of a healthy nerve to the damaged one facilitates reinnervation [2,3]. Functional MRI has already proven the remodeling of sensory-motor cortical areas in peripheral nerve impairment [2]. The phenomenon of neuroplasticity, especially after surgery, can be assessed by early electric activity measurable by transcranial magnetic stimulation (TMS) and recording of motor evoked potential (MEP), especially by evidence of its improved latencies following motor rehabilitation-induced facilitation. The modulation of cortical reorganization mechanisms correlates with the amelioration of the motor deficit, as appreciated by the use of the standardized British Medical Research Council's score (MRC) [2,4,5]. Among the brachial plexus (BP), the nerves that originate from the C5-C6 roots tend to be less affected by avulsion and, therefore, especially in paraganglion lesions, they are better candidates for neurotization, with good results in restoring elbow flexion [2,6]. On the other hand, a lesion with a higher extent (up to multilevel C5-T1 origin, and possible avulsions) is more challenging, and multiple surgical procedures are often required with less spectacular results over time [7,8]. The Oberlin procedure, described by [PERSON] in 1994, realizes motor nerve graphon transfer from the ulnar nerve to the biceps muscle (musculocutaneous nerve), with good recovery of elbow flexion [9]. It is useful in a variety of cases, from simple C5-C6 preganglionic lesions to many complex cases (along with other neurotization interventions over the years). As well as other surgical procedures, EMG can assess results in a period of 3-4 to 6 months, depending on the complexity of the case [2,4]. Sometimes, even in early stages, EMG can provide a favorable prognosis by evidence of a decrease in spontaneous pathological activity (such as fibrillation potentials), correlated with an increase in the number of MUAP [2,4]. Original techniques, such as direct coaptation in C5-C6-C7 roots in a spinal tangential traumatic lesion can result in good recovery of elbow flexion at 6 months after surgery [10]. Physical therapy (PT) neurorehabilitation treatment for tBPIs is focused on returning the limb to its previous level of function and preventing potential disability. The goals of PT rehabilitation are pain control through electrotherapy, increase muscle strength and endurance, restore coordination, maintain range of motion, and control edema [1]. Our study relies on the use of neuromuscular electrical stimulation (NEMS) and proprioceptive neuromuscular facilitation (PNF).