Long-Term Outcome of Brachial Plexus Reimplantation After Complete Brachial Plexus Avulsion Injury

Anatomical damages in the spinal nerve roots and the spinal cord after brachial plexus injury: descriptive study from a cohort of consecutive patients who underwent DREZ-lesioning for pain-practical implications

BACKGROUND

Systematic descriptions of anatomical damage after brachial plexus injury (BPI) at the intradural level have been scarcely reported in detail. However, considering these damages, not only in the spinal nerve roots but also in the spinal cord itself, is crucial in determining the appropriate surgical approach to restore upper limb function and address refractory pain. Therefore, the authors present a descriptive study focusing on intradural findings observed during microsurgical DREZ-lesioning.

METHODS

This study enrolled 19 consecutive patients under the same protocol. Microsurgical observation through exposure of C4 to Th1 medullary segments allowed to describe the lesions in spinal nerve roots, meninges, and spinal cord. Electrical stimulation of the ventral roots checked the muscle responses.

RESULTS

Extensive damage was observed among the 114 explored roots (six roots per patient), with only 21 (18.4%) ventral (VR) and 17 (14.9%) dorsal (DR) roots retaining all rootlets intact. Damage distribution varied, with the most frequent impairments in C6 VRs (18 patients) and the least in Th1 VRs (14 patients), while in all the 19 patients for the C6 DRs (the most frequently impaired) and in 14 patients for Th1 DRs (the less impaired). C4 roots were found damaged in 12 patients. Total or partial avulsions affected 63.3% and 69.8% of DRs and VRs, respectively, while 15.8% and 14.0% of the 114 DRs and VRs were atrophic, maintaining muscle responses to stimulation in half of those VRs. Pseudomeningoceles were present in 11 patients but absent in 46% of avulsed roots. Adhesive arachnoiditis was noted in 12 patients, and dorsal horn parenchymal alterations in 10.

CONCLUSIONS

Knowledge of intradural lesions post-BPI helps in guiding surgical indications for repair and functional neurosurgery for pain control.

Prospect of Mesenchymal Stem Cells in Enhancing Nerve Regeneration in Brachial Plexus Injury in Animals: A Systematic Review

Objectives

Brachial plexus injuries (BPI), although rare, often results in significant morbidity. Stem cell was thought to be one of BPI treatment modalities because of their nerve-forming regeneration potential. Although there is a possibility for the use of mesenchymal stem cells as one of BPI treatment, it is still limited on animal studies. Therefore, this systematic review aimed to analyze the role of mesenchymal stem cells in nerve regeneration in animal models of brachial plexus injury.

Method

This study is a systematic review with PROSPERO registration number CRD4202128321. Literature searching was conducted using keywords experimental, animal, brachial plexus injury, mesenchymal stem cell implantation, clinical outcomes, electrophysiological outcomes, and histologic outcomes. Searches were performed in the PubMed, Scopus, and ScienceDirect databases. The risk of bias was assessed using SYRCLE's risk of bias tool for animal studies. The data obtained were described and in-depth analysis was performed.

Result

Four studies were included in this study involving 183 animals from different species those are rats and rabbits. There was an increase in muscle weight and shortened initial onset time of muscle contraction in the group treated with stem cells. Electrophysiological results showed that mesenchymal stem cells exhibited higher (Compound muscle action potential) CMAP amplitude and shorter CMAP latency than control but not better than autograft. Histological outcomes showed an increase in axon density, axon number, and the formation of connections between nerve cells and target muscles.

Conclusion

Mesenchymal stem cell implantation to animals with brachial plexus injury showed its ability to regenerate nerve cells as evidenced by clinical, electrophysiological, and histopathological results. However, this systematic study involved experimental animals from various species so that the results cannot be uniformed, and conclusion should be drawn cautiously.

Transhumeral amputation in brachial plexus lesion patients: A multicenter case series

BACKGROUND

A flail limb can be the result of a traumatic complete brachial plexus lesion. Some patients prefer retaining the flail limb, however some patients feel that a flail limb negatively affects daily life. In these circumstances an elective amputation is sometimes elected, however long-term follow-up, with respect to satisfaction and function is unknown. The aim of this study is to evaluate the long-term outcome of this rare and life changing operation.

MATERIALS AND METHODS

8 patients with a transhumeral amputation performed in 2 specialized medical centers were included. Postoperatively, the functional- and psychological outcome and the quality of life were evaluated with standardized patient reported outcome measures (PROMs; DASH, SIP-68, EQ-5D-5L and HADS).

RESULTS

After a median of 9.4 (range 7.5 - 12.8) years follow-up, 7 patients (88%) stated that they would undergo the operation again and were satisfied with the results. At latest follow-up the median DASH score was 37.3 (range 8.3-61.7), the median SIP-68 score was 6.5 (range 0-43) and the median HADS score was 3.0 (range 0-14) for anxiety and 3.0 (range 1-19) for depression. In the EQ-5D-5L patients had most difficulties in self-care, usual activities and pain/discomfort. The median overall health status was 69 (range 20-95).

DISCUSSION

With the right indication a transhumeral amputation is a reasonable option for traumatic complete brachial plexus lesion with satisfying long-term results.

LEVEL OF EVIDENCE

IV, multicenter case series.

Acetylglutamine facilitates motor recovery and alleviates neuropathic pain after brachial plexus root avulsion in rats

BACKGROUND

Brachial plexus root avulsion (BPRA), a disabling peripheral nerve injury, induces substantial motoneuron death, motor axon degeneration and denervation of biceps muscles, leading to the loss of upper limb motor function. Acetylglutamine (N-acetyl-L-glutamine, NAG) has been proven to exert neuroprotective and anti-inflammatory effects on various disorders of the nervous system. Thus, the present study mainly focused on the influence of NAG on motor and sensory recovery after BPRA in rats and the underlying mechanisms.

METHODS

Male adult Sprague Dawley (SD) rats were subjected to BPRA and reimplantation surgery and subsequently treated with NAG or saline. Behavioral tests were conducted to evaluate motor function recovery and the mechanical pain threshold of the affected forelimb. The morphological appearance of the spinal cord, musculocutaneous nerve, and biceps brachii was assessed by histological staining. Quantitative real-time PCR (qRT‒PCR) was used to measure the mRNA levels of remyelination and regeneration indicators in myocutaneous nerves. The protein levels of inflammatory and pyroptotic indicators in the spinal cord anterior horn were measured using Western blotting.

RESULTS

NAG significantly accelerated the recovery of motor function in the injured forelimbs, enhanced motoneuronal survival in the anterior horn of the spinal cord, inhibited the expression of proinflammatory cytokines and pyroptosis pathway factors, facilitated axonal remyelination in the myocutaneous nerve and alleviated atrophy of the biceps brachii. Additionally, NAG attenuated neuropathic pain following BPRA.

CONCLUSION

NAG promotes functional motor recovery and alleviates neuropathic pain by enhancing motoneuronal survival and axonal remyelination and inhibiting the pyroptosis pathway after BPRA in rats, laying the foundation for the use of NAG as a novel treatment for BPRA.

Neurophysiological Evaluation of Neural Transmission in Brachial Plexus Motor Fibers with the Use of Magnetic versus Electrical Stimuli

The anatomical complexity of brachial plexus injury requires specialized in-depth diagnostics. The clinical examination should include clinical neurophysiology tests, especially with reference to the proximal part, with innovative devices used as sources of precise functional diagnostics. However, the principles and clinical usefulness of this technique are not fully described. The aim of this study was to reinvestigate the clinical usefulness of motor evoked potential (MEP) induced by a magnetic field applied over the vertebrae and at Erb's point to assess the neural transmission of brachial plexus motor fibers. Seventy-five volunteer subjects were randomly chosen to participate in the research. The clinical studies included an evaluation of the upper extremity sensory perception in dermatomes C5-C8 based on von Frey's tactile monofilament method, and proximal and distal muscle strength by Lovett's scale. Finally, 42 healthy people met the inclusion criteria. Magnetic and electrical stimuli were applied to assess the motor function of the peripheral nerves of the upper extremity and magnetic stimulus was applied to study the neural transmission from the C5-C8 spinal roots. The parameters of compound muscle action potential (CMAP) recorded during electroneurography and MEP induced by magnetic stimulation were analyzed. Because the conduction parameters for the groups of women and men were comparable, the final statistical analysis covered 84 tests. The parameters of the potentials generated by electrical stimulus were comparable to those of the potentials induced by magnetic impulse at Erb's point. The amplitude of the CMAP was significantly higher following electrical stimulation than that of the MEP following magnetic stimulation for all the examined nerves, in the range of 3-7%. The differences in the potential latency values evaluated in CMAP and MEP did not exceed 5%. The results show a significantly higher amplitude of potentials after stimulation of the cervical roots compared to potentials evoked at Erb's point (C5, C6 level). At the C8 level, the amplitude was lower than the potentials evoked at Erb's point, varying in the range of 9-16%. We conclude that magnetic field stimulation enables the recording of the supramaximal potential, similar to that evoked by an electric impulse, which is a novel result. Both types of excitation can be used interchangeably during an examination, which is essential for clinical application. Magnetic stimulation was painless in comparison with electrical stimulation according to the results of a pain visual analog scale (3 vs. 5.5 on average). MEP studies with advanced sensor technology allow evaluation of the proximal part of the peripheral motor pathway (between the cervical root level and Erb's point, and via trunks of the brachial plexus to the target muscles) following the application of stimulus over the vertebrae.

Cervical selective nerve root injection alleviates chronic refractory pain after brachial plexus avulsion: a case report

Background

Intractable chronic pain, as well as motor, sensory, and autonomic neuropathy, significantly reduces the quality of life of brachial plexus avulsion (BPA) patients. We report the successful application of cervical selective nerve root injection (CSNRI) in a patient with BPA.

Case presentation

A 40-year-old man had been diagnosed with complete left BPA due to a motorcycle accident and underwent intercostal nerve transplantation at the age of 18 years and had been experiencing pain ever since. His pain increased after fracture of the left humerus, and he was referred to our pain management clinic. As his exacerbated pain was suspected to be due to peripheral nerve hypersensitivity, we performed repetitive ultrasound-guided CSNRI (3 mL of 1% mepivacaine of each) targeted C5 and 6 intervertebral foramina, and his symptoms gradually improved.

Conclusions

Repetitive CSNRI may help diagnose and treat BPA-associated peripheral neuropathic pain, even in patients diagnosed with BPA.

Reversal of neuropathic pain is associated with corticostriatal functional reorganization after nerve repair in the spared nerve injury model

ABSTRACT

Following surgical repair after peripheral nerve injury, neuropathic pain diminishes in most patients but can persist in a small proportion of cases, the mechanism of which remains poorly understood. Based on the spared nerve injury (SNI), we developed a rat nerve repair (NR) model, where a delayed reconstruction of the SNI-injured nerves resulted in alleviating chronic pain-like behavior only in a subpopulation of rats. Multiple behavioral measures were assayed over 11-week presurgery and postsurgery periods (tactile allodynia, pain prick responses, sucrose preference, motor coordination, and cold allodynia) in SNI (n = 10), sham (n = 8), and NR (n = 12) rats. All rats also underwent resting-state functional magnetic resonance imaging under anesthesia at multiple time points postsurgery, and at 10 weeks, histology and retrograde labeling were used to calculate peripheral reinnervation. Behavioral measures indicated that at approximately 5 weeks postsurgery, the NR group separated to pain persisting (NR persisting, n = 5) and recovering (NR recovering, n = 7) groups. Counts of afferent nerves and dorsal root ganglion cells were not different between NR groups. Therefore, NR group differences could not be explained by peripheral reorganization. By contrast, large brain functional connectivity differences were observed between NR groups, where corticolimbic reorganization paralleled with pain recovery (repeated-measures analysis of variance, false discovery rate, P < 0.05), and functional connectivity between accumbens and medial frontal cortex was related both to tactile allodynia (nociception) and to sucrose preference (anhedonia) in the NR group. Our study highlights the importance of brain circuitry in the reversal of neuropathic pain as a natural pain-relieving mechanism. Further studies regarding the therapeutic potentials of these processes are warranted.

The impact of different exercise protocols on rat soleus muscle reinnervation and recovery following peripheral nerve lesion and regeneration

Background: Incomplete functional recovery following traumatic peripheral nerve injury is common, mainly because not all axons successfully regenerate and reinnervate target muscles. Exercise can improve functional outcomes increasing the terminal sprouting during the muscle reinnervation. However, exercise is not a panacea per se. Indeed, the type of exercise adopted dramatically impacts the outcomes of rehabilitation therapy. To gain insight into the therapeutic effects of different exercise regimens on reinnervation following traumatic nerve lesion, we evaluated the impact of different clinically transferable exercise protocols (EPs) on metabolic and functional muscle recovery following nerve crush.

Methods: The reinnervation of soleus muscle in adult nerve-crushed rats was studied following 6 days of different patterns (continuous or intermittent) and intensities (slow, mid, and fast) of treadmill running EPs. The effects of EPs on muscle fiber multiple innervation, contractile properties, metabolic adaptations, atrophy, and autophagy were assessed using functional and biochemical approaches.

Results: Results showed that an intermittent mid-intensity treadmill EP improves soleus muscle reinnervation, whereas a slow continuous running EP worsens the functional outcome. However, the mid-intensity intermittent EP neither enhanced the critical mediators of exercise-induced metabolic adaptations, namely, PGC-1α, nor improved muscle atrophy. Conversely, the autophagy-related marker LC3 increased exclusively in the mid-intensity intermittent EP group.

Conclusion: Our results demonstrated that an EP characterized by a mid-intensity intermittent activity enhances the functional muscle recovery upon a nerve crush, thus representing a promising clinically transferable exercise paradigm to improve recovery in humans following peripheral nerve injuries.

Long-Term Suppression of c-Jun and nNOS Preserves Ultrastructural Features of Lower Motor Neurons and Forelimb Function after Brachial Plexus Roots Avulsion

Brachial plexus root avulsions cause debilitating upper limb paralysis. Short-term neuroprotective treatments have reported preservation of motor neurons and function in model animals while reports of long-term benefits of such treatments are scarce, especially the morphological sequelae. This morphological study investigated the long-term suppression of c-Jun- and neuronal nitric oxide synthase (nNOS) (neuroprotective treatments for one month) on the motor neuron survival, ultrastructural features of lower motor neurons, and forelimb function at six months after brachial plexus roots avulsion. Neuroprotective treatments reduced oxidative stress and preserved ventral horn motor neurons at the end of the 28-day treatment period relative to vehicle treated ones. Motor neuron sparing was associated with suppression of c-Jun, nNOS, and pro-apoptotic proteins Bim and caspases at this time point. Following 6 months of survival, neutral red staining revealed a significant loss of most of the motor neurons and ventral horn atrophy in the avulsed C6, 7, and 8 cervical segments among the vehicle-treated rats (n = 4). However, rats that received neuroprotective treatments c-Jun JNK inhibitor, SP600125 (n = 4) and a selective inhibitor of nNOS, 7-nitroindazole (n = 4), retained over half of their motor neurons in the ipsilateral avulsed side compared. Myelinated axons in the avulsed ventral horns of vehicle-treated rats were smaller but numerous compared to the intact contralateral ventral horns or neuroprotective-treated groups. In the neuroprotective treatment groups, there was the preservation of myelin thickness around large-caliber axons. Ultrastructural evaluation also confirmed the preservation of organelles including mitochondria and synapses in the two groups that received neuroprotective treatments compared with vehicle controls. Also, forelimb functional evaluation demonstrated that neuroprotective treatments improved functional abilities in the rats. In conclusion, neuroprotective treatments aimed at suppressing degenerative c-Jun and nNOS attenuated apoptosis, provided long-term preservation of motor neurons, their organelles, ventral horn size, and forelimb function.

Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion: A Comprehensive Literature Review

Dorsal root entry zone (DREZ) lesioning is a neurosurgical procedure that aims to relieve severe neuropathic pain in patients with brachial plexus avulsion by selectively destroying nociceptive neural structures in the posterior cervical spinal cord. Since the introduction of the procedure over 4 decades ago, the DREZ lesioning technique has undergone numerous modifications, with a variety of center- and surgeon-dependent technical differences and patient outcomes. We have reviewed the literature to discuss reported methods of DREZ lesioning and outcomes.

Clinical outcomes report in different brachial plexus injury surgeries: a systematic review

Brachial plexus injury is a lesion that results in loss of function of the arm, and there are multiple ways of surgically approaching its treatment. Controlled trials that compare all surgical repair strategies and their clinical outcomes have not been performed. A systematic review was conducted to identify all articles that reported clinical outcomes in different surgeries (nerve transfer, nerve graft, neurolysis, end-to-end, multiple interventions, and others). Advanced search in PubMed was performed using the Mesh terms "brachial plexus injury" as the main topic and "surgery" as a subtopic, obtaining a total of 2153 articles. The clinical data for eligibility extraction was focused on collecting motor, sensory, pain, and functional recovery. A statistical analysis was performed to find the superior surgical techniques in terms of motor recovery, through the assessment of heterogeneity between groups, and of relationships between surgery and motor recovery. The frequency and the manner in which clinical outcomes are recording were described. The differences that correspond to the demographics and procedural factors were not statistically significant among groups (p > 0.05). Neurolysis showed the highest proportion of motor recovery (85.18%), with significant results between preoperative and post-operative motor assessment (p = 0.028). The proportion of motor recovery in each group according to the surgical approach differed significantly (X² = 82.495, p = 0.0001). The motor outcome was the most reported clinical outcome (97.56%), whereas the other clinical outcomes were reported in less than 15% of the included articles. Unexpectedly, neurolysis, a technique displaced by new surgical alternatives such as nerve transfer/graft, demonstrated the highest proportion of motor recovery. Clinical outcomes such as pain, sensory, and functional recovery were infrequently reported. These results introduce the need to re-evaluate neurolysis through comparative clinical trials, as well as to standardize the way in which clinical outcomes are reported.

A Quantitative Systematic Review of Clinical Outcome Measure Use in Peripheral Nerve Injury of the Upper Limb

BACKGROUND

Peripheral nerve injury (PNI) is common, leading to reduced function, pain, and psychological impact. Treatment has not progressed partly due to inability to compare outcomes between centers managing PNI. Numerous outcome measures exist but there is no consensus on which outcome measures to use nor when.

OBJECTIVE

To perform a systematic review in order to describe and classify outcome measures used in PNI.

METHODS

A search of Ovid Medline, Ovid Embase, Allied and Complementary Medicine Database (AMED), and CENTRAL (Cochrane Clinical Trials) was conducted. Randomized control trials (RCTs), cohort studies, and case-controlled and case series (≥5 participants) published from inception of the database until 2019 investigating adult patients with a traumatic upper limb PNI in which an outcome measurement was utilized were included.

RESULTS

A total of 96 studies were included (15 RCTs, 8 case-control studies, 18 cohort studies, 5 observational studies, and the remainder were case series or retrospective reviews). A total of 56 individual outcome measures were identified, utilized across 28 different countries and 7097 patients. Ten core domains were defined: sensory subjective, sensory objective, motor subjective, motor objective, sensorimotor function, psychology and well-being, disability, quality of life, pain and discomfort, and neurotrophic measures.

CONCLUSION

Lack of consensus on outcome measure use hinders comparison of outcomes between nerve injury centers and the development of novel treatments. Development of a core outcome set will help standardize outcome reporting, improve translation of novel treatments from lab to clinical practice, and ensure future research in PNI is more amenable to systematic review and meta-analysis.

Impaired Limb Functional Outcome of Peripheral Nerve Regeneration Is Marked by Incomplete Recovery of Paw Muscle Atrophy and Brain Functional Connectivity in a Rat Forearm Nerve Repair Model

Skilled sensorimotor deficit is an unsolved problem of peripheral nerve injury (PNI) led by limb trauma or malignancies, despite the improvements in surgical techniques of peripheral nerve anastomosis. It is now accepted that successful functional recovery of PNI relies tremendously on the multilevel neural plasticity from the muscle to the brain. However, animal models that recapitulate these processes are still lacking. In this report, we developed a rat model of PNI to longitudinally assess peripheral muscle reinnervation and brain functional reorganization using noninvasive imaging technology. Based on such model, we compared the longitudinal changes of the rat forepaw intrinsic muscle volume and the seed-based functional connectivity of the sensorimotor cortex after nerve repair. We found that the improvement of skilled limb function and the recovery of paw intrinsic muscle following nerve regeneration are incomplete, which correlated with the functional connectivity between the primary motor cortex and dorsal striatum. Our results were highly relevant to the clinical observations and provided a framework for future investigations that aim to study the peripheral central sensorimotor circuitry underlying skilled limb function recovery after PNI.

Upregulation of JHDM1D-AS1 alleviates neuroinflammation and neuronal injury via targeting miR-101-3p-DUSP1 in spinal cord after brachial plexus injury

BACKGROUND

Neuroinflammation in the spinal cord following acute brachial plexus injury (BPI) remains a vital cause that leads to motor dysfunction and neuropathic pain. In this study, we aim to explore the role of long non-coding RNA JHDM1D antisense 1 (JHDM1D-AS1) in mediating BPI-induced neuroinflammation and neuronal injury.

METHODS

A total brachial plexus root avulsion (tBPRA) model in adult rats and IL-1β-treated motor neuron-like NSC-34 cells and LPS-treated microglia cell line BV2 were conducted for in vivo and in vitro experiments, respectively. The expressions of JHDM1D-AS1, miR-101-3p and DUSP1, p38, NF-κB, TNF-α, IL-1β, and IL-6 were detected by RT-PCR and western blot seven days after tBPI. Immunohistochemistry (IHC) was used to detect neuronal apoptosis. CCK8 assay, Tunel assay and LDH kit were used for the detection of neuronal injury. The targeted relationships between JHDM1D-AS1 and miR-101-3p, miR-101-3p and DUSP1 were verified by RNA immunoprecipitation (RIP) and dual-luciferase reporter gene assay.

RESULTS

We found significant downregulated expression of JHDM1D-AS1 and DUSP1 but upregulated expression of miR-101-3p in the spinal cord after tBPI. Overexpression of JHDM1D-AS1 had a prominent neuroprotective effect by suppressing neuronal apoptosis and microglial inflammation through reactivation of DUSP1. Further exploration revealed that JHDM1D-AS1 may act as a competitive endogenous RNA targeting miR-101-3p, which bound on the 3'UTR of DUSP1 mRNA. In addition, overexpression of miR-101-3p could reverse the neuroprotective effects of JHDM1D-AS1 upregulation by blocking DUSP1.

CONCLUSIONS

JHDM1D-AS1 exerted neuroprotective and anti-inflammatory effects in a rat model of tBPI by regulating miR-101-3p/DUSP1 axis.

Enhanced regeneration and reinnervation following timed GDNF gene therapy in a cervical ventral root avulsion

Avulsion of spinal nerve roots is a severe proximal peripheral nerve lesion. Despite neurosurgical repair, recovery of function in human patients is disappointing, because spinal motor neurons degenerate progressively, axons grow slowly and the distal Schwann cells which are instrumental to supporting axon extension lose their pro-regenerative properties. We have recently shown that timed GDNF gene therapy (dox-i-GDNF) in a lumbar plexus injury model promotes axon regeneration and improves electrophysiological recovery but fails to stimulate voluntary hind paw function. Here we report that dox-i-GDNF treatment following avulsion and re-implantation of cervical ventral roots leads to sustained motoneuron survival and recovery of voluntary function. These improvements were associated with a twofold increase in motor axon regeneration and enhanced reinnervation of the hand musculature. In this cervical model the distal hand muscles are located 6,5 cm from the reimplantation site, whereas following a lumber lesion this distance is twice as long. Since the first signs of muscle reinnervation are observed 6 weeks after the lesion, this suggests that regenerating axons reached the hand musculature before a critical state of chronic denervation has developed. These results demonstrate that the beneficial effects of timed GDNF-gene therapy are more robust following spinal nerve avulsion lesions that allow reinnervation of target muscles within a relatively short time window after the lesion. This study is an important step in demonstrating the potential of timed GDNF-gene therapy to enhance axon regeneration after neurosurgical repair of a severe proximal nerve lesion.

Network-centric medicine for peripheral nerve injury: Treating the whole to boost endogenous mechanisms of neuroprotection and regeneration

Peripheral nerve injuries caused by accidents may lead to paralysis, sensory disturbances, anaesthesia, and lack of autonomic functions. Functional recovery after disconnection of the motoneuronal soma from target tissue with proximal rupture of axons is determined by several factors: motoneuronal soma viability, proper axonal sprouting across inhibitory zones and elongation toward specific muscle, effective synapse contact rebuilding, and prevention of muscle atrophy. Therapies, such as adjuvant drugs with pleiotropic effects, that promote functional recovery after peripheral nerve injury are needed. Toward this aim, we designed a drug discovery workflow based on a network-centric molecular vision using unbiased proteomic data and neural artificial computational tools. Our focus is on boosting intrinsic capabilities of neurons for neuroprotection; this is in contrast to the common approach based on suppression of a pathobiological pathway known to be associated with disease condition. Using our workflow, we discovered neuroheal, a combination of two repurposed drugs that promotes motoneuronal soma neuroprotection, is anti-inflammatory, enhances axonal regeneration after axotomy, and reduces muscle atrophy. This drug discovery workflow has thus yielded a therapy that is close to its clinical application.

Standard neurophysiological studies and motor evoked potentials in evaluation of traumatic brachial plexus injuries - A brief review of the literature

PURPOSE

Traumatic damage to the brachial plexus is associated with temporary or permanent motor and sensory dysfunction of the upper extremity. It may lead to the severe disability of the patient, often excluded from the daily life activity. The pathomechanism of brachial plexus injury usually results from damage detected in structures taking origin in the rupture, stretching or cervical roots avulsion from the spinal cord. Often the complexity of traumatic brachial plexus injury requires a multidisciplinary diagnostic process including clinical evaluation supplemented with clinical neurophysiology methods assessing the functional state of its structures. Their presentation is the primary goal of this paper.

METHODS

The basis for the diagnosis of brachial plexus function is a clinical examination and neurophysiology studies: electroneurography (ENG), needle electromyography (EMG), somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) assessing the function of individual brachial plexus elements.

CONCLUSIONS

The ENG and EMG studies clarify the level of brachial plexus damage, its type and severity, mainly using the Seddon clinical classification. In contrast to F-wave studies, the use of the MEPs in the evaluation of traumatic brachial plexus injury provides valuable information about the function of its proximal part. MEPs study may be an additional diagnostic in confirming the location and extent of the lesion, considering the pathomechanism of the damage. Clinical neurophysiology studies are the basis for determining the appropriate therapeutic program, including choice of conservative or reconstructive surgery which results are verified in prospective studies.