Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion Injuries: Case Series and Literature Review

Introduction: Brachial plexus avulsion (BPA) injuries commonly occur secondary to motor vehicle collisions, usually in the young adult population. These injuries are associated with significant morbidity, and up to 90% of patients suffer from deafferentation pain. Neuromodulation procedures can be efficacious in the treatment of refractory neuropathic pain, although the treatment of pain due to BPA can be challenging. Dorsal root entry zone (DREZ) lesioning is a classical and effective neurosurgical technique which has become underutilized in treating refractory root avulsion pain.Methods: A systematic review of the different technical nuances, procedural efficacy, and complication profiles regarding DREZ lesioning for BPA injuries in the literature is included. We also present an institutional case series of 7 patients with BPA injuries who underwent DREZ lesioning.Results: In the literature, 692 patients were identified to have undergone DREZ lesioning for pain related to BPA. In 567 patients, the surgery was successful in reducing pain intensity by over 50% in comparison to baseline (81.9%). Complications included transient motor deficits (11%) and transient sensory deficits (11%). Other complications including permanent disability, cardiovascular complications, infections, or death were rare (<1.9%). In our case series, all but one patient achieved >50% reduction in pain intensity, with the mean pre-operative pain of 7.9 ± 0.63 (visual analog scale) reduced to 2.1 ± 0.99 at last follow-up (p < 0.01).Conclusion: Both the literature and the current case series demonstrate excellent pain severity reduction following DREZ ablation for deafferentation pain secondary to BPA.

MiR-615 Agomir Encapsulated in Pluronic F-127 Alleviates Neuron Damage and Facilitates Function Recovery After Brachial Plexus Avulsion

Brachial plexus avulsion (BPA) is a devastating traumatic peripheral nerve injury complicated with paralysis of the upper extremity. We previously reported that leucine-rich repeat and immunoglobulin-like domain-containing NOGO receptor-interacting protein 1 (LINGO-1) has a potent role in inhibiting neuron survival and axonal regeneration after the central nervous system (CNS) damage and miR-615 is a potential microRNA (miRNA) negatively regulated LINGO-1. However, the effect of miR-615 in BPA remains to be elucidated. Accumulating evidence indicates that pluronic F-127 (PF-127) hydrogel could serve as a promising vehicle for miRNA encapsulation. Thus, to further explore the potential role of hydrogel-miR-615 in BPA-reimplantation, the present study established the BPA rat model and injected miR-615 agomir encapsulated by PF-127 hydrogel into the reimplantation site using a microsyringe. In this study, results indicated that hydrogel-miR-615 agomir effectively alleviated motoneuron loss by LINGO-1 inhibition, promoted musculocutaneous nerve regeneration and myelination, reduced astrocytes activation, promoted angiogenesis and attenuated peripheral amyotrophy, leading to improved motor functional rehabilitation of the upper extremity. In conclusion, our findings demonstrate that miR-615-loaded PF-127 hydrogel may represent a novel therapeutic strategy for BPA treatment.

MiR-615 Agomir Encapsulated in Pluronic F-127 Alleviates Neuron Damage and Facilitates Function Recovery after Brachial Plexus Avulsion

Brachial plexus avulsion(BPA)is a devastating traumatic peripheral nerve injury complicated with paralysis of the upper extremity. We previously reported that leucine-rich repeat and immunoglobulin-like domain-containing NOGO receptor-interacting protein 1 (LINGO-1) has a potent role in inhibiting neuron survival and axonal regeneration after central nervous system (CNS) damage and miR-615 is a potential microRNA (miRNA) negatively regulated LINGO-1. However, the effect of miR-615 in BPA remains to be elucidated. Accumulating evidence indicates that pluronic F-127 (PF-127) hydrogel could serve as a promising vehicle for miRNA encapsulation. Thus, to further explore the potential role of hydrogel-miR-615 in BPA-reimplantation, the present study established the BPA rat model and injected miR-615 agomir encapsulated by PF-127 hydrogel into the reimplantation site using a microsyringe. In this study, results indicated that hydrogel-miR-615 agomir effectively alleviated motoneuron loss by LINGO-1 inhibition, promoted musculocutaneous nerve regeneration and myelination, reduced astrocytes activation, promoted angiogenesis and attenuated peripheral amyotrophy, leading to improved motor functional rehabilitation of the upper extremity. In conclusion, our findings demonstrate that miR-615-loaded PF-127 hydrogel may represent a novel therapeutic strategy for BPA treatment.

Microarray Analysis of Potential Biomarkers for brachial plexus avulsion caused neuropathic pain

Nerve injury-induced neuropathic pain remains a challenging clinical problem due to a lack of satisfactory treatment. Pain after BPA (Brachial Plexus Avulsion) is resistant to most traditional pain relief treatments due to the lack of understanding of the cellular or molecular mechanism of pain development. The present study aimed to investigate the expression of mRNA in the brachial plexus avulsion neuropathic pain model and analyze biological functions. Sprague-Dawley rats were treated with complete brachial plexus avulsion. An animal behavior test was carried out to distinguish the pain group from the control group. In this study, a microarray mRNA assay and reverse transcriptase quantitative polymerase chain reaction (RT-PCR) was conducted. The whole blood was collected from two groups for Microarray mRNA analysis. The predicted mRNA targets were studied by gene ontology analysis and pathway analysis. The PIK3CB, HRAS, and JUN genes were verified by RT-PCR. In total, differentially expressed genes(DEGs) were identified between individuals with or without neuropathic pain (case and control), and A biological processes were enriched. We identified 3 targeted mRNAs, including PIK3CB, HRAS, and JUN, which may be potential biomarkers for BPA-caused NP. The results showed that PIK3CB, HRAS, and JUN gene expression was increased in the control group but decreased in the neuropathic pain group. The PIK3CB gene was part of the Neurotrophin signaling pathway. The function of the HRAS gene was synergetic in the aspect of axon guidance and the Neurotrophin signaling pathway. The JUN gene participates in axon regeneration. These results suggest that PIK3CB, HRAS, and JUN genes might become potential biomarkers for the prediction of and new targets for the prevention and treatment of neuropathic pain after BPA. These findings indicate that mRNA expression changes in the blood may play an important role in the development of NP after BPA, which is of theoretical and clinical importance for future research and clinical-treatment strategies.

Dramatic Response to Lidocaine Infusion for Pain from Brachial Plexus Avulsion Injury

BACKGROUND: Traumatic brachial plexus avulsion injury (tBPI) can cause a severe chronic pain syndrome that is very difficult to treat. Though lidocaine has been shown to be effective for other pain syndromes, effectiveness in tBPI has not previously been reported. CASE REPORT: A 55-year-old man with tBPI had severe pain and minimal relief with numerous analgesic agents. He was able to access intravenous lidocaine as he was being treated at a cancer center, and had a sustained response to 7 mg/kg given over an hour. CONCLUSION: There is potential for a single bolus intravenous lidocaine infusion to provide good pain control sustained over many months in patients with traumatic brachial plexus injury. An adequate serum concentration of lidocaine is required for analgesic effect. If initial doses of lidocaine are tolerated but ineffective, higher doses may still be beneficial. KEY WORDS: Brachial plexus avulsion, lidocaine, lignocaine, pain management, palliative care, therapeutics, trauma