Evaluation and management of peripheral nerve injury

Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

JOURNAL/nrgr/04.03/01300535-202504000-00033/figure1/v/2024-07-06T104127Z/r/image-tiff Behavioral recovery using (viable) peripheral nerve allografts to repair ablation-type (segmental-loss) peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration. Furthermore, such peripheral nerve allografts undergo immunological rejection by the host immune system. In contrast, peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks, reduced immune responses, and many axons do not undergo Wallerian degeneration. The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study. We hypothesized that polyethylene glycol might have some immune-protective effects, but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery. We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion. Ablation-type sciatic nerve injuries in outbred Sprague-Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts, but peripheral nerve allografts were loose-sutured (loose-sutured polyethylene glycol) with an intentional gap of 1-2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons. Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts, animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively. Other morphological signs of rejection, such as collapsed Schwann cell basal lamina tubes, were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively. Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts. While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts, loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively. MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts, but MHCII expression was modestly lower compared to negative control at 21 days postoperatively. We conclude that, while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts, successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts, and produce recovery of sensory/motor functions and voluntary behaviors. Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.

Towards the development of sensation-enabled skin substitutes

Recent advances in cell and biofabrication technologies have contributed to the development of complex human organs. In particular, several skin substitutes are being generated using tissue engineering and regenerative medicine (TERM) technologies. However, recent studies mainly focus on the restoration of the dermis and epidermis layers rather than the regeneration of a fully functional innervated skin organ. Innervation is a critical step in functional tissue repair which has been overlooked in the current TERM studies. In the current study, we highlight the importance of sensation in the skin as the largest sensory organ in the human body. In large non-healing skin wounds, the skin sensation is severely diminished or completely lost and ultimately lead to chronic pain and wound healing process interruption. Current therapeutics for restoring skin sensation after trauma are limited. Recent regenerative medicine-based studies could successfully induce neural networks in skin substitutes, but the effectiveness of these technologies in enhancing sensory capability needs further investigation.

Outcomes of upper extremity sensory neuromas treated with excision and burial

Background

Upper extremity sensory neuromas can be extremely debilitating leading to pain and dysfunction. Surgical management of neuromas can either be ablative or reconstructive. The primary aim of this study was to examine the outcomes of surgically treated sensory neuromas within the forearm, wrist, and hand with exclusion of digital neuromas.

Methods

A retrospective review was conducted of patients surgically treated for an upper extremity sensory neuroma from a multi-surgeon, single institution database. The types of neuroma, mechanism of injury and the surgical technique utilized for treatment were documented. Patient reported outcomes were collected including resolution of symptoms, pain scores, complications, and need for revision surgery. Averages and proportions were used for analysis.

Results

79 patients were included with mean age of 42.3 years and an average follow-up of 6.7 months. The types of sensory neuromas included 23 dorsal radial sensory, 21 medial antebrachial cutaneous, 15 palmar cutaneous, and 14 dorsal ulnar sensory. Single isolated cases of neuromas were more common (94.9%) than multiple neuromas (5.1%). 67.1% (53/79) of patients experienced pain or hypersensitivity with a mean improvement of 2.0 in the visual analog scale (VAS) following surgery. 6.3% (5/79) required revision surgery, and 82% returned to work in some capacity.

Conclusion

Surgical excision of neuroma and burial into local surrounding tissue can be safely performed with a relatively low reoperation rate. 80% of patients had full resolution or improvement in their symptoms.

Polyethylene Glycol-Fusion Repair of Peripheral Nerve Injuries

Axons successfully repaired with polyethylene glycol (PEG) fusion tecnology restored axonal continuity thereby preventing their Wallerian degeneration and minimizing muscle atrophy. PEG fusion studies in animal models and preliminary clinical trials involving patients with digital nerve repair have shown promise for this therapeutic approach. PEG fusion is safe to perform, and given the enormous potential benefits, there is no reason not to explore its therapeutic potential.

Advanced gene nanocarriers/scaffolds in nonviral-mediated delivery system for tissue regeneration and repair

Tissue regeneration technology has been rapidly developed and widely applied in tissue engineering and repair. Compared with traditional approaches like surgical treatment, the rising gene therapy is able to have a durable effect on tissue regeneration, such as impaired bone regeneration, articular cartilage repair and cancer-resected tissue repair. Gene therapy can also facilitate the production of in situ therapeutic factors, thus minimizing the diffusion or loss of gene complexes and enabling spatiotemporally controlled release of gene products for tissue regeneration. Among different gene delivery vectors and supportive gene-activated matrices, advanced gene/drug nanocarriers attract exceptional attraction due to their tunable physiochemical properties, as well as excellent adaptive performance in gene therapy for tissue regeneration, such as bone, cartilage, blood vessel, nerve and cancer-resected tissue repair. This paper reviews the recent advances on nonviral-mediated gene delivery systems with an emphasis on the important role of advanced nanocarriers in gene therapy and tissue regeneration.

Combat-related peripheral nerve injuries

Active-duty service members (ADSM) and military Veterans represent a population with increased occupational risk for nerve injuries sustained both during training operations and wartime. Mechanisms of war-related nerve injuries have evolved over time, from the musket ball-related traumas described by S.W. Mitchell to complex blast injuries and toxic exposures sustained during Middle East conflicts in the 21st century. Commonly encountered nerve injury etiologies in this population currently include compression, direct trauma, nutritional deficits, traumatic limb amputation, toxic chemical exposures, or blast-related injuries. Expeditious identification and comprehensive, interdisciplinary treatment of combat-associated neuropathies, as well as prevention of these injuries whenever possible is critical to reduce chronic morbidity and disability for service members and to maintain a well-prepared military. However, diagnosis of a combat-associated nerve injury may be particularly challenging due to comorbid battlefield injuries or delayed presentation of neuropathy from military toxic exposures. Advances in imaging for nerve injury, including MRI and ultrasound, provide useful tools to compliment EMG in establishing a diagnosis of combat-associated nerve injury, particularly in the setting of anatomic disruption or edema. Surgical techniques can improve pain control or restoration of function. In all cases, comprehensive interdisciplinary rehabilitation provides the best framework for optimization of recovery. Further work is needed to prevent combat-associated nerve injuries and promote nerve recovery following injury.

Water-circulating probes significantly modify lesion length and axon damage in cooled radiofrequency ablations when compared with similar-sized standard radiofrequency probes in rats

INTRODUCTION

Preclinical research demonstrated water-cooled radiofrequency (CRF) ablations have a significant impact on structural and functional changes compared to standard radiofrequency (SRF) ablations. Clinical procedures utilizing RF to treat chronic pain conditions also show sustained functional outcomes. We hypothesize that the design of the RF probes plays an important role in interventional procedure success, but it remains unclear which specific design features.

METHODS

RF ablations were performed in male Lewis rats (n=51) using multiple-sized probes for CRF (17 Ga/2 mm and 17Ga/4 mm) and SRF (22Ga/5 mm, 18Ga/10 mm and 16Ga/10 mm) to evaluate generator energy output, lesion length, axon damage by histology and nerve function analysis via electromyography. To exclude probe design variables beyond size and remain objective, we tested cooled probes with and without water circulation, which resulted in the CRF probe performing like an SRF probe.

RESULTS

Consistent with our previous findings in smaller probes, CRF large probes delivered more energy (p<0.01) and generated multiple zones of thermal damage in sciatic nerves. When the water-circulating feature was turned off, however, energy output (p<0.001) and lesion length (p<0.05) was significantly reduced. CRF probes with the water circulation also featured significantly more axonal disruption, than larger sized SRF probes (p<0.0001).

CONCLUSIONS

Overall, this data confirms that CRF's water-circulating technology has a greater impact on energy deposition, lesion length and axon damage compared with SRF ablations. Moreover, results suggest that the structural differences between RF modalities cannot be solely attributed to probe size, and it may shed light on its differences in clinical outcomes.

Concentric needle jitter analysis of the genioglossus muscle in patients with motor neuron disease

OBJECTIVES

Difficulty relaxing the genioglossus muscle makes the evaluation of spontaneous activity problematic in patients with motor neuron disease (MND). We performed jitter analysis using conventional disposable concentric needle electrodes (CNEs) of the voluntarily activated genioglossus muscle in patients with and without MND to detect the denervation-reinnervation process.

METHODS

CNE jitter analysis was performed at the genioglossus muscle in 21 MND(+) patients and 22 MND(-) subjects. The jitter analysis was considered abnormal if the jitter values exceeded these limits for the mean consecutive difference (MCD) or the individual MCD in more than 10% of readings.

RESULTS

Seventeen MND(+) patients (81%) had at least three abnormal individual jitter values whereas denervation findings were obtained in eleven of them during the needle electromyographic examination at genioglossus muscle. None of the MND(-) subjects showed CNE jitter abnormality.

CONCLUSION

CNE jitter analysis of genioglossus muscle may provide an useful information that may be suggestive of a diagnosis of MND/ALS.

Ulnar Neuropathy after Distal Radius Fractures - A Case Series and Review of Literature

Background: Ulnar neuropathy after a distal radius fracture is rare and has limited reports in literature. As such, there is no consensus regarding the optimal treatment and management of such injuries. We report our experience with managing these uncommon injuries. Methods: A retrospective review was conducted where patients presenting with ulnar neuropathy after sustaining a distal radius fracture were identified from January 2021 to December 2023 from our hospital database. Results: A total of four patients were identified. All of them underwent surgical fixation for their respective fractures. None of them underwent immediate or delayed exploration and decompression of the ulnar nerve. All patients had clinical improvement at 3 months after their initial injuries. Three patients eventually had resolution of the neuropathy between 5 and 9 months post injury, while one had partial recovery and developed a neuroma but declined surgery due to symptoms minimally affecting work and daily activities. Conclusions: Ulnar neuropathy after distal radius fractures may not be as rare as previously thought. Expectant management of the neuropathy would be a reasonable treatment as long as there is no evidence of nerve discontinuity or translocation and that there is clinical and/or electrodiagnostic improvement at 3-4 months after the initial injury. Level of Evidence: Level IV (Therapeutic).

Real time monitoring peripheral nerve function with ICG and BDA-ICG by NIR-II fluorescence imaging

Neuroanatomical tract tracers are important for studying axoplasmic transport and the complex interconnections of the nervous system. Though traditional fluorescent tracers are widely used, they have several prominent drawbacks when imaging, including low resolutions and low tissue penetrations and inability to be supervised dynamically within a long peripheral nerve during the long term. Here, we explored the potential of ICG as a neural tracer for axoplasmic transport and for the first time demonstrated that ICG could be used to detect transport function within peripheral nerve by near-infrared region II (NIR-II) imaging. On basis of this finding, a novel bi-directional neural tracer biotinylated dextran amine-indocyanine green (BDA-ICG) was prepared and characterized with better long-term stability and higher nerve-to-background ratio than ICG in vivo, and successfully imaged the injured peripheral nerve from the healthy one within 24 h. Our results show that BDA-ICG are promising neural tracers and clinically available dyes with NIR-II emission tail characteristics as ICG.

Electrodiagnostic reporting preferences of referring physicians: An exploratory survey

INTRODUCTION/AIMS

Electrodiagnostic (EDX) studies play a crucial role in the evaluation of patients with peripheral nervous system disorders. Accurate and succinct communication of test results is critical to patient safety and clinical decision-making. The objective of this study was to explore EDX reporting preferences of referring physicians to improve quality of communication and patient care.

METHODS

An online survey was developed, and a purposive sampling strategy was used to recruit physicians in the authors' professional networks. Quantitative and qualitative survey data underwent frequency and thematic analyses, respectively.

RESULTS

There were 40 respondents, including: 21 non-surgical specialists, 12 surgical specialists, and 7 family physicians. Sections rated as most critical were diagnostic impression (97%) and summary/interpretation (72%). Only 18% reported numeric data as critical to their needs, preferring this data to be formatted as bullet points or tables without nerve conduction study waveforms. Regarding the format of the data summary and diagnostic impression sections, the majority of respondents preferred bullet points rather than paragraphs.

DISCUSSION

The results of this exploratory survey suggest that physicians who refer patients for EDX studies prefer reports that emphasize the interpretation of EDX data and a clear diagnostic impression, particularly in bullet point format. This project highlights important preferences and how they compare to recommended reporting guidelines, which may help improve communication and ultimately patient care. Future efforts should explore larger sample sizes with all key stakeholders in the EDX process to better understand reporting styles and preferences with greater nuance and context.

Task force of the Brazilian Society of Otology - evaluation and management of peripheral facial palsy

OBJECTIVE

To review key evidence-based recommendations for the diagnosis and treatment of peripheral facial palsy in children and adults.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on peripheral facial palsy were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 main parts: (1) Evaluation and diagnosis of facial palsy: electrophysiologic tests, idiopathic facial palsy, Ramsay Hunt syndrome, traumatic peripheral facial palsy, recurrent peripheral facial palsy, facial nerve tumors, and peripheral facial palsy in children; and (2) Rehabilitation procedures: surgical decompression of the facial nerve, facial nerve grafting, surgical treatment of long-term peripheral facial palsy, and non-surgical rehabilitation of the facial nerve.

CONCLUSIONS

Peripheral facial palsy is a condition of diverse etiology. Treatment should be individualized according to the cause of facial nerve dysfunction, but the literature presents better evidence-based recommendations for systemic corticosteroid therapy.

Increasing Awareness of Complications of Nerve Injury Following Shoulder Surgery: Preventing Delays in Referral and Treatment

BACKGROUND

Nerve injuries remain a challenging complication after shoulder surgery. While most resolve spontaneously, some require surgical intervention. This study describes the characteristics of patients sustaining nerve injuries following shoulder surgery, evaluates referral patterns to nerve surgeons, and characterizes nerve surgeries performed and their outcomes. Increased awareness of these injuries allows patients and providers to be better informed regarding the appropriate management when these complications occur.

METHODS

A retrospective review of referrals with nerve injuries following shoulder surgery between 2007 and 2015 was performed. The final analysis included 65 patients. Data reviewed included demographics, procedure and anesthesia type, and diagnosis of nerve injury. Time to referral to nerve surgeon and proportional changes in the Disabilities of the Arm, Shoulder, and Hand (DASH) scores were determined. Outcomes were categorized as failed, partially successful, and successful based on final follow-up.

RESULTS

Patients were referred following arthroscopic shoulder surgeries (35.4%), shoulder arthroplasties (24.6%), open shoulder procedures (21.5%), and combined open and arthroscopic procedures (18.5%). The mean time to referral was 7.6 months. Nerve injuries involved brachial plexus (33) and individual and multiple peripheral nerve branches (23 and 7, respectively). Twenty-five (38%) nerve injuries demonstrated spontaneous recovery. Thirty-five patients underwent surgical intervention, of which 27 were successful, 3 were partially successful, and 3 failed.

CONCLUSIONS

This is the largest series of patients with iatrogenic nerve injury following shoulder surgeries to date. Our data demonstrate a lack of timely referral to nerve surgeons, especially after arthroscopy. There continues to be a variable injury pattern even among similar surgeries. Despite this, timely surgical intervention, when indicated, can lead to favorable outcomes.

Enhancing neuroinduction activity of PLCL-based nerve conduits through native epineurium integration

Autologous nerve grafts have been considered the gold standard for peripheral nerve grafts. However, due to drawbacks such as functional loss in the donor area and a shortage of donor sources, nerve conduits are increasingly being considered as an alternative approach. Polymer materials have been widely studied as nerve repair materials due to their excellent processing performance. However, their limited biocompatibility has restricted further clinical applications. The epineurium is a natural extra-neural wrapping structure. After undergoing decellularization, the epineurium not only reduces immune rejection but also retains certain bioactive components. In this study, decellularized epineurium (DEP) derived from the sciatic nerve of mammals was prepared, and a bilayer nerve conduit was created by electrospinning a poly (l-lactide-co-ε-caprolactone) (PLCL) membrane layer onto the outer surface of the DEP. Components of the DEP were examined; the physical properties and biosafety of the bilayer nerve conduit were evaluated; and the functionality of the nerve conduit was evaluated in rats. The results demonstrate that the developed bilayer nerve conduit exhibits excellent biocompatibility and mechanical properties. Furthermore, this bilayer nerve conduit shows significantly superior therapeutic effects for sciatic nerve defects in rats compared to the pure PLCL nerve conduit. In conclusion, this research provides a novel strategy for the design of nerve regeneration materials and holds promising potential for further clinical translation.

Traumatic and iatrogenic sciatic nerve injury in 38 dogs and 10 cats: Clinical and electrodiagnostic findings

BACKGROUND

Reports describing sciatic nerve injuries (SNI) and their outcome are scarce in veterinary medicine.

HYPOTHESIS

Describe the causes of traumatic and iatrogenic SNI and evaluate which clinical and electrodiagnostic findings predict outcome.

ANIMALS

Thirty-eight dogs and 10 cats with confirmed SNI referred for neurologic and electrodiagnostic evaluation.

METHODS

Clinical and electrodiagnostic examination results, including electromyography (EMG), motor nerve conduction studies, muscle-evoked potential (MEP), F-waves, sensory nerve conduction studies, and cord dorsum potential (CDP), were retrospectively evaluated. Quality of life (QoL) was assessed based on owner interviews.

RESULTS

Surgery (42%) and trauma (33%) were the most common causes of SNI; in dogs, 24% were caused by bites from wild boars. Ability to flex and extend the tarsus was significantly associated with positive outcome in dogs. Mean time from onset of clinical signs until electrodiagnostic evaluation was 67 ± 65 (range, 7-300) days and 65 ± 108 (range, 7-365) days for dogs and cats, respectively. A cut-off amplitude of 1.45 mV for compound motor action potentials (CMAP) was predictive of positive outcome in dogs (P = .01), with sensitivity of 58% and specificity of 100%.

CONCLUSIONS AND CLINICAL IMPORTANCE

Clinical motor function predicts recovery better than sensory function. Electrodiagnostic findings also may play a role in predicting the outcome of SNI. Application of the proposed CMAP cut-off amplitude may assist clinicians in shortening the time to reassessment or for earlier suggestion of salvage procedures. Owners perceived a good quality of life (QoL), even in cases of hindlimb amputation.

Enhancing nerve regeneration in infraorbital nerve injury rat model: effects of vitamin B complex and photobiomodulation

Orofacial nerve injuries may result in temporary or long-term loss of sensory function and decreased quality of life in patients. B vitamins are required for DNA synthesis and the repair and maintenance of phospholipids. In particular, vitamins B1, B6, and B12 are essential for neuronal function. Deficiency in vitamin B complex (VBC) has been linked to increased oxidative stress, inflammation and demyelination. Photobiomodulation (PBM) has antioxidant activity and is neuroprotective. In addition, a growing literature attests to the positive effects of PBM on nerve repair. To assess the effect of PBM and VBC on regenerative process we evaluated the expression of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), myelin basic protein (MBP), laminin and neurofilaments (NFs) using Western blotting to identify regenerative pattern after chronic constriction injury of the infraorbital nerve (CCI IoN) treated by PBM, VBC or its combination. After CCI IoN, the rats were divided into six groups naive, sham, injured (CCI IoN), treated with photobiomodulation (904 nm, 6.23 J/cm2, CCI IoN + PBM), treated with VBC (containing B1, B6 and B12) 5 times, CCI IoN + VBC) and treated with PBM and VBC (CCI IoN + VBC + PBM). The treatments could revert low expression of BDNF, MBP and laminin. Also reverted the higher expression of neurofilaments and enhanced expression of NGF. PBM and VBC could accelerate injured infraorbital nerve repair in rats through reducing the expression of neurofilaments, increasing the expression of BDNF, laminin and MBP and overexpressing NGF. These data support the notion that the use of PBM and VBC may help in the treatment of nerve injuries. This finding has potential clinical applications.

NaV1.7 targeted fluorescence imaging agents for nerve identification during intraoperative procedures

Surgeries and trauma result in traumatic and iatrogenic nerve damage that can result in a debilitating condition that approximately affects 189 million individuals worldwide. The risk of nerve injury during oncologic surgery is increased due to tumors displacing normal nerve location, blood turbidity, and past surgical procedures, which complicate even an experienced surgeon's ability to precisely locate vital nerves. Unfortunately, there is a glaring absence of contrast agents to assist surgeons in safeguarding vital nerves. To address this unmet clinical need, we leveraged the abundant expression of the voltage-gated sodium channel 1.7 (NaV1.7) as an intraoperative marker to access peripheral nerves in vivo, and visualized nerves for surgical guidance using a fluorescently-tagged version of a potent NaV1.7-targeted peptide, Tsp1a, derived from a Peruvian tarantula. We characterized the expression of NaV1.7 in sensory and motor peripheral nerves across mouse, primate, and human specimens and demonstrated universal expression. We synthesized and characterized a total of 10 fluorescently labeled Tsp1a-peptide conjugates to delineate nerves. We tested the ability of these peptide-conjugates to specifically accumulate in mouse nerves with a high signal-to-noise ratio in vivo. Using the best-performing candidate, Tsp1a-IR800, we performed thyroidectomies in non-human primates and demonstrated successful demarcation of the recurrent laryngeal and vagus nerves, which are commonly subjected to irreversible damage. The ability of Tsp1a to enhance nerve contrast during surgery provides opportunities to minimize nerve damage and revolutionize standards of care across various surgical specialties.

Nano-pulling stimulates axon regeneration in dorsal root ganglia by inducing stabilization of axonal microtubules and activation of local translation

Introduction

Axonal plasticity is strongly related to neuronal development as well as regeneration. It was recently demonstrated that active mechanical tension, intended as an extrinsic factor, is a valid contribution to the modulation of axonal plasticity.

Methods

In previous publications, our team validated a the "nano-pulling" method used to apply mechanical forces to developing axons of isolated primary neurons using magnetic nanoparticles (MNP) actuated by static magnetic fields. This method was found to promote axon growth and synaptic maturation. Here, we explore the use of nano-pulling as an extrinsic factor to promote axon regeneration in a neuronal tissue explant.

Results

Whole dorsal root ganglia (DRG) were thus dissected from a mouse spinal cord, incubated with MNPs, and then stretched. We found that particles were able to penetrate the ganglion and thus become localised both in the somas and in sprouting axons. Our results highlight that nano-pulling doubles the regeneration rate, and this is accompanied by an increase in the arborizing capacity of axons, an accumulation of cellular organelles related to mass addition (endoplasmic reticulum and mitochondria) and pre-synaptic proteins with respect to spontaneous regeneration. In line with the previous results on isolated hippocampal neurons, we observed that this process is coupled to an increase in the density of stable microtubules and activation of local translation.

Discussion

Our data demonstrate that nano-pulling enhances axon regeneration in whole spinal ganglia exposed to MNPs and external magnetic fields. These preliminary data represent an encouraging starting point for proposing nano-pulling as a biophysical tool for the design of novel therapies based on the use of force as an extrinsic factor for promoting nerve regeneration.

Animal models in peripheral nerve transection studies: a systematic review on study design and outcomes assessment

Aim: Peripheral nerve injury regeneration studies using animal models are crucial to different pre-clinical therapeutic approaches efficacy evaluation whatever the surgical technique explored. Materials & methods: A 944 articles systematic review on 'peripheral nerve injury in animal models' over the last 9 years was carried out. Results: It was found that 91% used rodents, and only 9% employed large animals. Different nerves are studied, with generated gaps (10,78 mm) and methods applied for regeneration evaluation uniformed. Sciatic nerve was the most used (88%), followed by median and facial nerves (2.6%), significantly different. Conclusion: There has not been a significant scale-up of the in vivo testing to large animal models (anatomically/physiologically closer to humans), allowing an improvement in translational medicine for clinical cases.

CC Chemokine Family Members' Modulation as a Novel Approach for Treating Central Nervous System and Peripheral Nervous System Injury-A Review of Clinical and Experimental Findings

Despite significant progress in modern medicine and pharmacology, damage to the nervous system with various etiologies still poses a challenge to doctors and scientists. Injuries lead to neuroimmunological changes in the central nervous system (CNS), which may result in both secondary damage and the development of tactile and thermal hypersensitivity. In our review, based on the analysis of many experimental and clinical studies, we indicate that the mechanisms occurring both at the level of the brain after direct damage and at the level of the spinal cord after peripheral nerve damage have a common immunological basis. This suggests that there are opportunities for similar pharmacological therapeutic interventions in the damage of various etiologies. Experimental data indicate that after CNS/PNS damage, the levels of 16 among the 28 CC-family chemokines, i.e., CCL1, CCL2, CCL3, CCL4, CCL5, CCL6, CCL7, CCL8, CCL9, CCL11, CCL12, CCL17, CCL19, CCL20, CCL21, and CCL22, increase in the brain and/or spinal cord and have strong proinflammatory and/or pronociceptive effects. According to the available literature data, further investigation is still needed for understanding the role of the remaining chemokines, especially six of them which were found in humans but not in mice/rats, i.e., CCL13, CCL14, CCL15, CCL16, CCL18, and CCL23. Over the past several years, the results of studies in which available pharmacological tools were used indicated that blocking individual receptors, e.g., CCR1 (J113863 and BX513), CCR2 (RS504393, CCX872, INCB3344, and AZ889), CCR3 (SB328437), CCR4 (C021 and AZD-2098), and CCR5 (maraviroc, AZD-5672, and TAK-220), has beneficial effects after damage to both the CNS and PNS. Recently, experimental data have proved that blockades exerted by double antagonists CCR1/3 (UCB 35625) and CCR2/5 (cenicriviroc) have very good anti-inflammatory and antinociceptive effects. In addition, both single (J113863, RS504393, SB328437, C021, and maraviroc) and dual (cenicriviroc) chemokine receptor antagonists enhanced the analgesic effect of opioid drugs. This review will display the evidence that a multidirectional strategy based on the modulation of neuronal-glial-immune interactions can significantly improve the health of patients after CNS and PNS damage by changing the activity of chemokines belonging to the CC family. Moreover, in the case of pain, the combined administration of such antagonists with opioid drugs could reduce therapeutic doses and minimize the risk of complications.

Advancing Peripheral Nerve Regeneration: 3D Bioprinting of GelMA-Based Cell-Laden Electroactive Bioinks for Nerve Conduits

Peripheral nerve injuries often result in substantial impairment of the neurostimulatory organs. While the autograft is still largely used as the "gold standard" clinical treatment option, nerve guidance conduits (NGCs) are currently considered a promising approach for promoting peripheral nerve regeneration. While several attempts have been made to construct NGCs using various biomaterial combinations, a comprehensive exploration of the process science associated with three-dimensional (3D) extrusion printing of NGCs with clinically relevant sizes (length: 20 mm; diameter: 2-8 mm), while focusing on tunable buildability using electroactive biomaterial inks, remains unexplored. In addressing this gap, we present here the results of the viscoelastic properties of a range of a multifunctional gelatin methacrylate (GelMA)/poly(ethylene glycol) diacrylate (PEGDA)/carbon nanofiber (CNF)/gellan gum (GG) hydrogel bioink formulations and printability assessment using experiments and quantitative models. Our results clearly established the positive impact of the gellan gum on the enhancement of the rheological properties. Interestingly, the strategic incorporation of PEGDA as a secondary cross-linker led to a remarkable enhancement in the strength and modulus by 3 and 8-fold, respectively. Moreover, conductive CNF addition resulted in a 4-fold improvement in measured electrical conductivity. The use of four-component electroactive biomaterial ink allowed us to obtain high neural cell viability in 3D bioprinted constructs. While the conventionally cast scaffolds can support the differentiation of neuro-2a cells, the most important result has been the excellent cell viability of neural cells in 3D encapsulated structures. Taken together, our findings demonstrate the potential of 3D bioprinting and multimodal biophysical cues in developing functional yet critical-sized nerve conduits for peripheral nerve tissue regeneration.

Three Useful Tips and Tricks for Intraoperative Nerve Stimulation

Disposable handheld nerve stimulators are widely used in peripheral nerve surgery. Such devices stimulate a motor nerve or the motor component of a mixed nerve by applying electrical current to the proximal region, targeting the main nerve trunk. This stimulation then travels along the motor nerve, reaching the distal end to control the corresponding muscle(s). In this study, the authors demonstrate three useful tips and tricks for handheld nerve stimulation during targeted muscle reinnervation and peripheral nerve surgery. The three tips are (1) identification of proximal muscle contraction by retrograde electrical stimulation of a distal sensory nerve; (2) graded stimulation for identifying motor nerves within fibrotic scarred tissue beds or parallel to the major motor/mixed nerve of interest; and (3) proximal stimulation for validation of adequate post-targeted muscle reinnervation coaptation(s).

Occupational Nerve Injuries due to Metallic Foreign Bodies: A Case Series of Eighteen Patients

Introduction

Peripheral nerve injuries (PNIs) remain an important health problem. PNIs mostly affect young men as this age group is mostly involved in road traffic accidents and other injuries at workplace. PNI can occur from foreign bodies like metal chips while working in industries using lathe machines. Among PNI's, injuries to the ulnar nerve, the brachial plexus and the median nerve are the most frequent lesions encountered.

Materials and methods

This presentation is on a series of 18 cases of nerve injuries among industrial workers located from finger level up to the arm excluding the brachial plexus due to metallic foreign bodies entering while operating lathe machines over a period of two years with patients being followed-up over a one year period.

Results

Mean age in this series was 31.3 years with age range 16-40 years and all were males. Two patients had more than one nerve involvement and one patient had associated vascular injury. All the patients showed functional improvement. Most common nerve injured was median nerve. Most common site for nerve injury was forearm. Combined lesions most commonly involved the ulnar and median nerves.

Conclusion

Social cost of traumatic peripheral nerve injuries is significant since it has a higher incidence in young, previously healthy, and economically active people.

The fabrication of the chitosan-based bioink for in vitro tissue repair and regeneration: A review

The repair and regeneration of the injured tissues or organs is a major challenge for biomedicine, and the emerging 3D bioprinting technology as a class of promising techniques in biomedical research for the development of tissue engineering and regenerative medicine. Chitosan-based bioinks, as the natural biomaterials, are considered as ideal materials for 3D bioprinting to design and fabricate the various scaffold due to their unique dynamic reversibility and fantastic biological properties. Our review aims to provide an overview of chitosan-based bioinks for in vitro tissue repair and regeneration, starting from modification of chitosan that affect these bioprinting processes. In addition, we summarize the advances in chitosan-based bioinks used in the various 3D printing strategies. Moreover, the biomedical applications of chitosan-based bioinks are discussed, primarily centered on regenerative medicine and tissue modeling engineering. Finally, current challenges and future opportunities in this field are discussed. The combination of chitosan-based bioinks and 3D bioprinting will hold promise for developing novel biomedical scaffolds for tissue or organ repair and regeneration.

B-Mode ultrasound imaging in diagnosing carpal tunnel syndrome: an auxiliary diagnostic tool for hand surgeons

Objective

The purpose of this article is to explore the effectiveness of B-Mode ultrasound as an auxiliary diagnostic tool for carpal tunnel syndrome (CTS). It aims to demonstrate the advantages of B-Mode ultrasound, including its non-invasive nature and its ability to provide real-time imaging, in localizing nerve compression and predicting postoperative outcomes.

Methods

The study included 40 patients who were subjected to preoperative B-ultrasonography. The approach focused on evaluating the consistency of B-Mode ultrasound results with intraoperative findings. It also assessed the importance of employing standardized imaging techniques and emphasized the need for cooperation between hand surgeons and sonographers for accurate diagnosis.

Results

B-Mode ultrasound findings in the study were consistent with intraoperative observations, indicating its reliability. Additionally, B-Mode ultrasound was able to identify other anatomical abnormalities within the carpal canal that may contribute to CTS symptoms, such as persistent median arteries, median nerve bifurcation, and space-occupying lesions like cysts and tumors.

Conclusion

The article concludes that B-Mode ultrasound should be considered a valuable supplementary diagnostic tool for CTS, particularly in instances where clinical signs and electrophysiological studies do not offer clear results. However, it should not replace established diagnostic methods for CTS.

Comprehensive Development of a Cellulose Acetate and Soy Protein-Based Scaffold for Nerve Regeneration

BACKGROUND

The elaboration of biocompatible nerve guide conduits (NGCs) has been studied in recent years as a treatment for total nerve rupture lesions (axonotmesis). Different natural polymers have been used in these studies, including cellulose associated with soy protein. The purpose of this report was to describe manufacturing NGCs suitable for nerve regeneration using the method of dip coating and evaporation of solvent with cellulose acetate (CA) functionalized with soy protein acid hydrolysate (SPAH).

METHODS

The manufacturing method and bacterial control precautions for the CA/SPAH NGCs were described. The structure of the NGCs was analyzed under a scanning electron microscope (SEM); porosity was analyzed with a degassing method using a porosimeter. Schwann cell (SCL 4.1/F7) biocompatibility of cell-seeded nerve guide conduits was evaluated with the MTT assay.

RESULTS

The method employed allowed an easy elaboration and customization of NGCs, free of bacteria, with pores in the internal surface, and the uniform wall thickness allowed manipulation, which showed flexibility; additionally, the sample was suturable. The NGCs showed initial biocompatibility with Schwann cells, revealing cells adhered to the NGC structure after 5 days.

CONCLUSIONS

The fabricated CA/SPAH NGCs showed adequate features to be used for peripheral nerve regeneration studies. Future reports are necessary to discuss the ideal concentration of CA and SPAH and the mechanical and physicochemical properties of this biomaterial.

Nerve Transfer Surgery in Acute Flaccid Myelitis: Prognostic Factors, Long-Term Outcomes, Comparison With Natural History

BACKGROUND

Nerve transfer surgery is sometimes offered to patients with acute flaccid myelitis (AFM). The objectives of this study were to evaluate surgical efficacy, assess which clinical and neurophysiological data are valuable for preoperative planning, and report long-term outcomes.

METHODS

This is a single-center, retrospective case series of patients with AFM who received nerve transfer surgery. All patients had preoperative electromyography and nerve conduction studies (EMG/NCS). Matched control muscles that did not receive nerve transfer surgery were defined in the same cohort.

RESULTS

Ten patients meeting inclusion criteria received a total of 23 nerve transfers (19 upper extremity, four lower extremity). The mean age at symptom onset was 3.8 years, surgery was 0.5 to 1.25 years after diagnosis, and mean follow-up was 2.3 years (range 1.3 to 4.5 years). Among muscles with preoperative strength Medical Research Council (MRC) grade 0, muscles receiving nerve transfers performed significantly better than those that did not (MRC grade 2.17 ± 0.42 vs 0 ± 0, respectively, P = 0.0001). Preoperative EMG/NCS predicted worse outcomes in recipient muscles with more abundant acute denervation potentials (P = 0.0098). Donor nerves found to be partially denervated performed equally well as unaffected nerves. Limited data suggested functional improvement accompanying strength recovery.

CONCLUSIONS

Nerve transfer surgery is an effective strategy to restore strength for patients with AFM with persistent, severe motor deficits. Postoperative outcomes in patients with complete paralysis are better than the natural history of disease. This study demonstrates the utility of preoperative clinical and electrophysiological data in guiding patient selection for nerve transfer surgery.

Surgery for mononeuropathies

Advancement in microsurgical techniques and innovative approaches including greater use of nerve and tendon transfers have resulted in better peripheral nerve injury (PNI) surgical outcomes. Clinical evaluation of the patient and their injury factors along with a shift toward earlier time frame for intervention remain key. A better understanding of the pathophysiology and biology involved in PNI and specifically mononeuropathies along with advances in ultrasound and magnetic resonance imaging allow us, nowadays, to provide our patients with a logical and sophisticated approach. While functional outcomes are constantly being refined through different surgical techniques, basic scientific concepts are being advanced and translated to clinical practice on a continuous basis. Finally, a combination of nerve transfers and technological advances in nerve/brain and machine interfaces are expanding the scope of nerve surgery to help patients with amputations, spinal cord, and brain lesions.

Functional outcome of tardy ulnar nerve palsy manifests after 25 years due to nonunion of lateral epicondyle left humerus treated by ulnar nerve transposition: A case report

INTRODUCTION

Tardy ulnar nerve palsy is a chronic clinical condition characterized by delayed-onset ulnar neuropathy.

CASE PRESENTATION

Male 36 years old with 5 years clawing left ring and little finger, weakness of intrinsic muscle and grip, and paresthesia on ulnar nerve distribution. There was a history of elbow trauma 30 years ago. The radiological finding is a non-union of the lateral condyle without significant valgus. Intraoperatively, an intact ulnar nerve was discovered with no significant fibrous tissue. The author performed anterior transposition of the ulnar nerve. After 6 months, there is improvement in power and sensibility, with the quick dash score decreasing from 18 to 6.

DISCUSSION

Any increase in a valgus deformity at the elbow joint would lead to stretching of the nerve resulting in neuropraxia. On this case we found there is slight valgus deformity, but there is malunion of lateral epicondyle that causes incongruency of elbow joint that will lead to chronic impingement ulnar nerve. The patient work as officer working in front of computer typing for hours and sometimes lifting heavy objects. These activities irritate ulnar nerve on incongruent joint which causes tardy ulnar nerve palsy. The treatment of choice is ulnar nerve transposition.

CONCLUSION

The treatment of choice is anterior ulnar transposition. Any condition that impairs the anatomical structure of the elbow joint can cause ulnar nerve palsy. From this case, we also learn that it is not necessary to correct bone deformity or stabilize the non-union condyle if there is no significant deformity.

Exploring Schwann Cell Behavior on Electrospun Polyhydroxybutyrate Scaffolds with Varied Pore Sizes and Fiber Thicknesses: Implications for Neural Tissue Engineering

The placement of a polymeric electrospun scaffold is among the most promising strategies to improve nerve regeneration after critical neurotmesis. It is of great interest to investigate the effect of these structures on Schwann cells (SCs), as these cells lead nerve regeneration and functional recovery. The aim of this study was to assess SC viability and morphology when cultured on polyhydroxybutyrate (PHB) electrospun scaffolds with varied microfiber thicknesses and pore sizes. Six electrospun scaffolds were obtained using different PHB solutions and electrospinning parameters. All the scaffolds were morphologically characterized in terms of fiber thickness, pore size, and overall appearance by analyzing their SEM images. SCs seeded onto the scaffolds were analyzed in terms of viability and morphology throughout the culture period through MTT assay and SEM imaging. The SCs were cultured on three scaffolds with homogeneous smooth fibers (fiber thicknesses: 2.4 μm, 3.1 μm, and 4.3 μm; pore sizes: 16.7 μm, 22.4 μm, and 27.8 μm). SC infiltration and adhesion resulted in the formation of a three-dimensional network composed of intertwined fibers and cells. The SCs attached to the scaffolds maintained their characteristic shape and size throughout the culture period. Bigger pores and thicker fibers resulted in higher SC viability.

Repair and regeneration of peripheral nerve injuries that ablate branch points

The peripheral nervous system has an extensive branching organization, and peripheral nerve injuries that ablate branch points present a complex challenge for clinical repair. Ablations of linear segments of the PNS have been extensively studied and routinely treated with autografts, acellular nerve allografts, conduits, wraps, and nerve transfers. In contrast, segmental-loss peripheral nerve injuries, in which one or more branch points are ablated so that there are three or more nerve endings, present additional complications that have not been rigorously studied or documented. This review discusses: (1) the branched anatomy of the peripheral nervous system, (2) case reports describing how peripheral nerve injuries with branched ablations have been surgically managed, (3) factors known to influence regeneration through branched nerve structures, (4) techniques and models of branched peripheral nerve injuries in animal models, and (5) conclusions regarding outcome measures and studies needed to improve understanding of regeneration through ablated branched structures of the peripheral nervous system.

[Choosing the right imaging for the diagnostics and assessment of the course of peripheral nerve injuries]

BACKGROUND

Nerve injuries are a frequent problem in routine clinical practice and require intensive interdisciplinary care.

OBJECTIVE

The current status of imaging to confirm the diagnosis of nerve injuries is described. The role of high-resolution ultrasound and magnetic resonance imaging (MRI) in the diagnostics and follow-up of peripheral nerve injuries is elaborated.

MATERIAL AND METHODS

Review of the current state of imaging to confirm the diagnosis of nerve injuries.

RESULTS

Depending on the suspected site of damage, the primary domain of magnetic resonance (MR) imaging (MR neurography) is injuries in the region of the spine, nerve roots, brachial plexus and lumbar plexus, pelvis and proximal thigh. In contrast, in other peripheral nerve lesions of the extremities the advantages of high-resolution nerve ultrasound in a dynamic setting predominate. The MR neurography is indicated here, especially in the frequent bottleneck syndromes and only in very isolated and selected cases.

CONCLUSION

In addition to a correct anatomical assignment, the timely decision for a possible intervention and the appropriate concomitant treatment are an important basis for a favorable prognosis of nerve injuries. Imaging techniques should therefore be used early in the diagnostics and follow-up controls of peripheral nerve injuries.

Neural Mobilization for Reducing Pain and Disability in Patients with Lumbar Radiculopathy: A Systematic Review and Meta-Analysis

Lumbar radiculopathy causes lower back and lower extremity pain that may be managed with neural mobilization (NM) techniques. This meta-analysis aims to evaluate the effectiveness of NM in alleviating pain and reducing disability in patients with lumbar radiculopathy. We hypothesized that NM would reduce pain and improve disability in the lumbar radiculopathy population, leveraging the statistical power of multiple studies. Electronic databases from their inception up to October 2023 were searched for randomized controlled trials (RCTs) that explored the impact of NM on lumbar radiculopathy. Our primary outcome measure was the alteration in pain intensity, while the secondary one was the improvement of disability, standardized using Hedges' g. To combine the data, we employed a random-effects model. A total of 20 RCTs comprising 877 participants were included. NM yielded a significant reduction in pain intensity (Hedges' g = -1.097, 95% CI = -1.482 to -0.712, p < 0.001, I2 = 85.338%). Subgroup analyses indicated that NM effectively reduced pain, whether employed alone or in conjunction with other treatments. Furthermore, NM significantly alleviated disability, with a notable effect size (Hedges' g = -0.964, 95% CI = -1.475 to -0.453, p < 0.001, I2 = 88.550%), particularly in chronic cases. The findings provide valuable insights for clinicians seeking evidence-based interventions for this patient population. This study has limitations, including heterogeneity, potential publication bias, varied causal factors in lumbar radiculopathy, overall study quality, and the inability to explore the impact of neural pathology on NM treatment effectiveness, suggesting opportunities for future research improvements.

Potential Application of Orofacial MSCs in Tissue Engineering Nerve Guidance for Peripheral Nerve Injury Repair

Injury to the peripheral nerve causes potential loss of sensory and motor functions, and peripheral nerve repair (PNR) remains a challenging endeavor. The current clinical methods of nerve repair, such as direct suture, autografts, and acellular nerve grafts (ANGs), exhibit their respective disadvantages like nerve tension, donor site morbidity, size mismatch, and immunogenicity. Even though commercially available nerve guidance conduits (NGCs) have demonstrated some clinical successes, the overall clinical outcome is still suboptimal, especially for nerve injuries with a large gap (≥ 3 cm) due to the lack of biologics. In the last two decades, the combination of advanced tissue engineering technologies, stem cell biology, and biomaterial science has significantly advanced the generation of a new generation of NGCs incorporated with biological factors or supportive cells, including mesenchymal stem cells (MSCs), which hold great promise to enhance peripheral nerve repair/regeneration (PNR). Orofacial MSCs are emerging as a unique source of MSCs for PNR due to their neural crest-origin and easy accessibility. In this narrative review, we have provided an update on the pathophysiology of peripheral nerve injury and the properties and biological functions of orofacial MSCs. Then we have highlighted the application of orofacial MSCs in tissue engineering nerve guidance for PNR in various preclinical models and the potential challenges and future directions in this field.

Second Harmonic Generation Microscopy as a Novel Intraoperative Assessment of Rat Median Nerve Injury

PURPOSE

Nerves that are functionally injured but appear macroscopically intact pose the biggest clinical dilemma. Second Harmonic Generation (SHG) Microscopy may provide a real-time assessment of nerve damage, with the ultimate goal of allowing surgeons to accurately quantify the degree of nerve damage present. The aim of this study was to demonstrate the utility of SHG microscopy to detect nerve damage in vivo in an animal model.

METHODS

Ten Sprague-Dawley rats were anesthetized and prepared for surgery. After surgical exposure and using a custom-made stretch applicator, the right median nerves were stretched by 20%, corresponding to a high strain injury, and held for 5 minutes. The left median nerve served as a sham control (SC), only being placed in the applicator for 5 minutes with no stretch. A nerve stimulator was used to assess the amount of stimulation required to induce a flicker and contraction of the paw. Nerves were then imaged using a multiphoton laser scanning microscope.

RESULTS

Immediately after injury (day 0), SHG images of SC median nerves exhibited parallel collagen fibers with linear, organized alignment. In comparison with SC nerves, high strain nerves demonstrated artifacts indicative of nerve damage consisting of wavy, undulating fibers with crossing fibers and tears, as well as a decrease in the linear organization, which correlated with an increase in the mean stimulation required to induce a flicker and contraction of the paw.

CONCLUSIONS

Second Harmonic Generation microscopy may provide the ability to detect an acute neural stretch injury in the rat median nerve. Epineurial collagen disorganization correlated with the stimulation required for nerve function.

CLINICAL RELEVANCE

In the future, SHG may provide the ability to visualize nerve damage intraoperatively, allowing for better clinical decision-making. However, this is currently a research tool and requires further validation before translating to the clinical setting.

Nerve regeneration using decellularized tissues: challenges and opportunities

In tissue engineering, the decellularization of organs and tissues as a biological scaffold plays a critical role in the repair of neurodegenerative diseases. Various protocols for cell removal can distinguish the effects of treatment ability, tissue structure, and extracellular matrix (ECM) ability. Despite considerable progress in nerve regeneration and functional recovery, the slow regeneration and recovery potential of the central nervous system (CNS) remains a challenge. The success of neural tissue engineering is primarily influenced by composition, microstructure, and mechanical properties. The primary objective of restorative techniques is to guide existing axons properly toward the distal end of the damaged nerve and the target organs. However, due to the limitations of nerve autografts, researchers are seeking alternative methods with high therapeutic efficiency and without the limitations of autograft transplantation. Decellularization scaffolds, due to their lack of immunogenicity and the preservation of essential factors in the ECM and high angiogenic ability, provide a suitable three-dimensional (3D) substrate for the adhesion and growth of axons being repaired toward the target organs. This study focuses on mentioning the types of scaffolds used in nerve regeneration, and the methods of tissue decellularization, and specifically explores the use of decellularized nerve tissues (DNT) for nerve transplantation.

Pigment epithelium-derived factor enhances peripheral nerve regeneration through modulating oxidative stress and stem cells: An experimental study

Peripheral nerve injury is common and negatively affects an individual's quality of life. Drugs used for peripheral nerve regeneration should aim to eliminate symptoms such as neuropathic pain and have therapeutic effects. In recent studies, pigment epithelium-derived factor (PEDF) has been considered an essential therapeutic agent because of its potential neuroprotective properties. In this study, we aimed to investigate the efficacy of locally applied PEDF for peripheral nerve regeneration. Twenty-four Wistar albino male rats were used. The study groups included Injury (n = 12) and Injury+PEDF (n = 12). An injury model was created by applying 50 N pressure to the right sciatic nerves in groups, and 10 μg/kg local PEDF was injected into the Injury+PEDF group. After 28 days of recovery, functional tests and stereological, immunohistochemical, and biochemical analyses were performed. A significant difference was found between the Injury and Injury+PEDF groups in amplitude, whereas no difference was found in latency. The number of myelinated axons and the myelinated axon area increased significantly in the Injury+PEDF group, while no statistically significant difference was found in myelin sheath thickness. Superoxide dismutase, catalase, and glutathione peroxidase activities were increased by PEDF, whereas they were suppressed in mesenchymal stem cells. PEDF exerts functional, quantitative, and antioxidative effects on sciatic nerve injury during neuroregeneration. In addition, when oxidative stress parameters were examined, it was seen that PEDF reduced oxidative stress following sciatic nerve injury.

Regenerative Strategies in Treatment of Peripheral Nerve Injuries in Different Animal Models

BACKGROUND

Peripheral nerve damage mainly resulted from traumatic or infectious causes; the main signs of a damaged nerve are the loss of sensory and/or motor functions. The injured nerve has limited regenerative capacity and is recovered by the body itself, the recovery process depends on the severity of damage to the nerve, nowadays the use of stem cells is one of the new and advanced methods for treatment of these problems.

METHOD

Following our review, data are collected from different databases "Google scholar, Springer, Elsevier, Egyptian Knowledge Bank, and PubMed" using different keywords such as Peripheral nerve damage, Radial Nerve, Sciatic Nerve, Animals, Nerve regeneration, and Stem cell to investigate the different methods taken in consideration for regeneration of PNI.

RESULT

This review contains tables illustrating all forms and types of regenerative medicine used in treatment of peripheral nerve injuries (PNI) including different types of stem cells " adipose-derived stem cells, bone marrow stem cells, Human umbilical cord stem cells, embryonic stem cells" and their effect on re-constitution and functional recovery of the damaged nerve which evaluated by physical, histological, Immuno-histochemical, biochemical evaluation, and the review illuminated the best regenerative strategies help in rapid peripheral nerve regeneration in different animal models included horse, dog, cat, sheep, monkey, pig, mice and rat.

CONCLUSION

Old surgical attempts such as neurorrhaphy, autogenic nerve transplantation, and Schwann cell implantation have a limited power of recovery in cases of large nerve defects. Stem cell therapy including mesenchymal stromal cells has a high potential differentiation capacity to renew and form a new nerve and also restore its function.

Can the electrically stimulated manual muscle test differentiate upper from lower motor neuron injury in persons with acute SCI?

OBJECTIVE

To determine if the motor response on the stimulated manual muscle test (SMMT) in muscles with a grade 0 motor score on the manual muscle test (MMT) can differentiate lower motor neuron (LMN) from upper motor neuron (UMN) injury based on the presence of spontaneous activity (SA) with needle EMG.

DESIGN

Prospective Study.

PARTICIPANTS/METHODS

Twenty-one subjects with acute traumatic cervical SCI.

METHODS

An upper extremity International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) evaluation was completed on all subjects. A needle EMG and an electrically stimulated manual muscle test (SMMT) were completed on all key upper extremity muscles with a MMT motor score of zero.

RESULTS

The MMT, SMMT and Needle EMG were done on 77 muscles. The SMMT motor score was 0 on 10 muscles and >1 on 67 muscles. The needle EMG identified spontaneous activity (SA) in 55/77 muscles. Seventy percent (7/10) of the muscles with MMT and SMMT motor score of zero demonstrated SA on EMG. Seventy-two percent (48/67) of the muscles with MMT motor score = 0 and SMMT motor score ≥1 demonstrated SA on EMG.

CONCLUSION

In our study, 70% of the muscles with a SMMT motor response of zero and 72% of the muscles with a SMMT motor response greater than or equal to one demonstrated SA on EMG. The use of the SMMT as a clinical measure to differentiate LMN from UMN integrity may be limited when applied.

Mesencephalic astrocyte-derived neurotrophic factor promotes axonal regeneration and the motor function recovery after sciatic nerve injury

Peripheral nerve injuries have common clinical problems that are often accompanied by sensory and motor dysfunction and failure of axonal regeneration. Although various therapeutic approaches have been attempted, full functional recovery and axonal regeneration are rarely achieved in patients. In this study, we investigated the effects of recombinant adeno-associated virus (AAV) of mesencephalic astrocyte-derived neurotrophic factor (AAV-MANF) or placental growth factor (AAV-PlGF) transduced into mesenchymal stem cells (hMSC-MANF and hMSC-PlGF), which were then transplanted using human decellularized nerves (HDN) into sciatic nerve injury model. Our results showed that both AAV-MANF and AAV-PlGF were expressed in MSCs transplanted into the injury site. Behavioral measurements performed 2, 4, 6, 8, and 12 weeks after injury indicated that MANF facilitated the rapid and improved recovery of sensory and motor functions than PlGF. In addition, immunohistochemical analysis was used to quantitatively analyze the myelination of neurofilaments, Schwann cells, and regrowth axons. Both hMSC-MANF and hMSC-PlGF increased axon numbers and immunoreactive areas of axons and Schwann cells compared with the hMSC-GFP group. However, hMSC-MANF significantly improved the thickness of axons and Schwann cells compared with hMSC-PlGF. G-ratio analysis also showed a marked increase in axon myelination in axons thicker than 2.0 μm treated with MANF than that treated with PlGF. Our study suggests that transplantation of hMSC transduced with AAV-MANF has a potential to provide a novel and efficient strategy for promoting functional recovery and axonal regeneration in peripheral nerve injury.

Imaging diagnosis in peripheral nerve injury

Peripheral nerve injuries (PNIs) can be caused by various factors, ranging from penetrating injury to compression, stretch and ischemia, and can result in a range of clinical manifestations. Therapeutic interventions can vary depending on the severity, site, and cause of the injury. Imaging plays a crucial role in the precise orientation and planning of surgical interventions, as well as in monitoring the progression of the injury and evaluating treatment outcomes. PNIs can be categorized based on severity into neurapraxia, axonotmesis, and neurotmesis. While PNIs are more common in upper limbs, the localization of the injured site can be challenging. Currently, a variety of imaging modalities including ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) and positron emission tomography (PET) have been applied in detection and diagnosis of PNIs, and the imaging efficiency and accuracy many vary based on the nature of injuries and severity. This article provides an overview of the causes, severity, and clinical manifestations of PNIs and highlights the role of imaging in their management.

Median neuropathy after multiple punctures of the forearm for catheterization: A case report

BACKGROUND

Neuropathy may occur at some sites after catheterization for close examination of cardiac disease. Although the radial artery is considered a relatively uncom-plicated site for catheterization, the radial artery and median nerve are in relatively close proximity, with the risk of median nerve injury depending on the angle of puncture. The purpose of this study was to report the outcomes of surgery performed for conservative therapy-resistant median neuropathy following forearm catheterization.

CASE SUMMARY

A 50-year-old woman experienced palsy from the right thumb to the radial side of the ring finger after catheterization from the radial artery of the right forearm. Paresthesia developed at the same site and a positive tinel-like sign was seen for the median nerve area at the high level of the puncture site. Nerve conduction study showed reduced compound muscle action potentials and loss of sensory nerve action potentials. Symptoms did not improve despite pharmacotherapy and the patient gradually developed flexion restrictions of the index and middle fingers. Median nerve injury and associated flexor tendon adhesion was diagnosed, and the patient was referred for surgery at 3 mo after injury. When the same area was opened, no injury to the median nerve epithelium was obvious, but the area of the positive tinel-like sign was highly adherent to surrounding tissue and to the flexor digitorum superficialis of the index and middle fingers. The surgery was terminated with adequate adhesion release. Rehabilitation was initiated postoperatively, improving neurological symptoms and range of motion of the fingers. Six months after surgery, the patient returned to daily activities without discomfort.

CONCLUSION

This case provides the appropriate diagnosis and treatment for a suspected peripheral nerve injury.

Consensus for management of sacral fractures: from the diagnosis to the treatment, with a focus on the role of decompression in sacral fractures

BACKGROUND

There is no evidence in the current literature about the best treatment option in sacral fracture with or without neurological impairment.

MATERIALS AND METHODS

The Italian Pelvic Trauma Association (A.I.P.) decided to organize a consensus to define the best treatment for traumatic and insufficiency fractures according to neurological impairment.

RESULTS

Consensus has been reached for the following statements: When complete neurological examination cannot be performed, pelvic X-rays, CT scan, hip and pelvis MRI, lumbosacral MRI, and lower extremities evoked potentials are useful. Lower extremities EMG should not be used in an acute setting; a patient with cauda equina syndrome associated with a sacral fracture represents an absolute indication for sacral reduction and the correct timing for reduction is "as early as possible". An isolated and incomplete radicular neurological deficit of the lower limbs does not represent an indication for laminectomy after reduction in the case of a displaced sacral fracture in a high-energy trauma, while a worsening and progressive radicular neurological deficit represents an indication. In the case of a displaced sacral fracture and neurological deficit with imaging showing no evidence of nerve root compression, a laminectomy after reduction is not indicated. In a patient who was not initially investigated from a neurological point of view, if a clinical investigation conducted after 72 h identifies a neurological deficit in the presence of a displaced sacral fracture with nerve compression on MRI, a laminectomy after reduction may be indicated. In the case of an indication to perform a sacral decompression, a first attempt with closed reduction through external manoeuvres is not mandatory. Transcondylar traction does not represent a valid method for performing a closed decompression. Following a sacral decompression, a sacral fixation (e.g. sacroiliac screw, triangular osteosynthesis, lumbopelvic fixation) should be performed. An isolated and complete radicular neurological deficit of the lower limbs represents an indication for laminectomy after reduction in the case of a displaced sacral fracture in a low-energy trauma associated with imaging suggestive of root compression. An isolated and incomplete radicular neurological deficit of the lower limbs does not represent an absolute indication. A worsening and progressive radicular neurological deficit of the lower limbs represents an indication for laminectomy after reduction in the case of a displaced sacral fracture in a low-energy trauma associated with imaging suggestive of root compression. In the case of a displaced sacral fracture and neurological deficit in a low-energy trauma, sacral decompression followed by surgical fixation is indicated.

CONCLUSIONS

This consensus collects expert opinion about this topic and may guide the surgeon in choosing the best treatment for these patients.

LEVEL OF EVIDENCE

IV.

TRIAL REGISTRATION

not applicable (consensus paper).

Serum neurofilament light chain measurements following nerve trauma

BACKGROUND

Optimal functional recovery following peripheral nerve injuries (PNIs) is dependent upon early recognition and prompt referral to specialist centres for appropriate surgical intervention. Technologies which facilitate the early detection of PNI would allow faster referral rates and encourage improvements in patient outcomes. Serum Neurofilament light chain (NfL) measurements are cheaper to perform, easier to access and interpret than many conventional methods used for nerve injury diagnosis, such as electromyography and/or magnetic resonance imaging assessments, but changes in serum NfL levels following traumatic PNI have not been investigated. This pre-clinical study aimed to determine whether serum NfL levels can: (1) detect the presence of a nerve trauma and (2) delineate between different severities of nerve trauma.

METHODS

A rat sciatic nerve crush and common peroneal nerve crush were implemented as controlled animal models of nerve injury. At 1-, 3-, 7- and 21-days post-injury, serum samples were retrieved for analysis using the SIMOA® NfL analyser kit. Nerve samples were also retrieved for histological analysis. Static sciatic index (SSI) was measured at regular time intervals following injury.

RESULTS

Significant 45-fold and 20-fold increases in NfL serum levels were seen 1-day post-injury following sciatic and common peroneal nerve injury, respectively. This corresponded with an eightfold higher volume of axons injured in the sciatic compared to the common peroneal nerve (p < .001). SSI measurements post-injury revealed greater reduction in function in the sciatic crush group compared with the common peroneal crush group.

CONCLUSIONS

NfL serum measurements represent a promising method for detecting traumatic PNI and stratifying their severity. Clinical translation of these findings could provide a powerful tool to improve the surgical management of nerve-injured patients.

Clinical evaluation of the perception of post-trauma paresthesia in the mandible, using a biomimetic material: A preliminary study in humans

There is a great effort from numerous research groups in the development of materials and therapeutic strategies for the functional recovery of patients who have suffered peripheral nerve injuries (PNI). In an article in vivo, the formation of a nerve bridge was observed, reconnecting the distal and proximal stumps, in the sciatic nerve of rats, indicating the effective participation of the biomaterial in the recovery of peripheral nerve injuries. For the current pilot study, 15 cases of multiple fractures of the mandible, with involvement of the inferior alveolar nerve (IAN) were selected and studied: JC (control cases) n = 6 with conventional treatment, and JT (treated cases) n = 9, with the use of biomimetic biomaterial. The evaluation of the return to sensitivity was measured through a self-assessment, where the patients assigned scores from 0 to 10, where zero (0) represented the complete absence of sensitivity and ten (10) the normality of the perception of local sensitivity. Patients were evaluated from the preoperative period to the 360th day. The statistical results obtained by the t-Student, Shapiro-Wilk normality and non-parametric One-Way ANOVA tests indicated statistically significant differences (p < 0.005; 0.005 e 0.5 respectively), between the two treatments, which were reflected in the clinical results observed, we also calculate the size of the effect represented by ϵ², calculated by Cohen's d. The results indicate a great difference between the treatments performed,ϵ² = 1.00. In the 6 cases followed up in the JC group, four remained with a significant deficit until the end of the evaluations and two indicated the remission of the lack of sensitivity in this period. In the JT group, in 28 days, all cases indicated complete remission of the lack of sensitivity with healing concentration. In one of the cases where there was a complete rupture of the mental nerve, the (score-10) was observed in 60 days. The observed results indicate the existence of a statistical significance between the groups and an important relationship when using the biomimetic biomaterial during the recovery of the perception of sensitivity in polytraumatized patients, compatible with the results observed in laboratory animals, which may indicate its clinical feasibility in the reduction of sequelae in PNI.

Challenges in Nerve Repair and Reconstruction

Peripheral nerve injuries may substantially impair a patient's function and quality of life. Despite appropriate treatment, outcomes often remain poor. Direct repair remains the standard of care when repair is possible without excessive tension. For larger nerve defects, nerve autografting is the gold standard. However, a considerable challenge is donor site morbidity. Processed nerve allografts and conduits are other options, but evidence supporting their use is limited to smaller nerves and shorter gaps. Nerve transfer is another technique that has seen increasing popularity. The future of care may include novel biologics and pharmacologic therapy to enhance regeneration.

Functional attachment of primary neurons and glia on radiopaque implantable biomaterials for nerve repair

Repairing peripheral nerve injuries remains a challenge, even with use of auxiliary implantable biomaterial conduits. After implantation the location or function of polymeric devices cannot be assessed via clinical imaging modalities. Adding nanoparticle contrast agents into polymers can introduce radiopacity enabling imaging using computed tomography. Radiopacity must be balanced with changes in material properties impacting device function. In this study radiopaque composites were made from polycaprolactone and poly(lactide-co-glycolide) 50:50 and 85:15 with 0-40 wt% tantalum oxide (TaOx) nanoparticles. To achieve radiopacity, ≥5 wt% TaOx was required, with ≥20 wt% TaOx reducing mechanical properties and causing nanoscale surface roughness. Composite films facilitated nerve regeneration in an in vitro co-culture of adult glia and neurons, measured by markers for myelination. The ability of radiopaque films to support regeneration was driven by the properties of the polymer, with 5-20 wt% TaOx balancing imaging functionality with biological response and proving that in situ monitoring is feasible.

Stem cell-derived extracellular vesicle-based therapy for nerve injury: A review of the molecular mechanisms

Recent evidence suggests that stem cell therapy has beneficial effects on nerve damage. These beneficial effects were subsequently found to be exerted in part in a paracrine manner by the release of extracellular vesicles. Stem cell-secreted extracellular vesicles have shown great potential to reduce inflammation and apoptosis, optimize the function of Schwann cells, regulate genes related to regeneration, and improve behavioral performance after nerve damage. This review summarizes the current knowledge on the effect of stem cell-derived extracellular vesicles on neuroprotection and regeneration along with their molecular mechanisms after nerve damage.

Diagnostic Considerations in Compressive Neuropathies

Peripheral nerve compression of the upper extremity is a common pathology often necessitating surgical intervention, much is known, but much more is left to understand. For the more common pathologies, carpal tunnel syndrome, cubital tunnel syndrome, and ulnar tunnel syndrome, research and clinical efforts directed toward standardization and reduction of resource use have been attempted with varied success. Diagnosis of many of these syndromes is largely based on a proper history and physical examination. Electrodiagnostic studies continue to have value, but proportionally less than previous decades. In addition, emerging technologies, including magnetic resonance neurography, novel ultrasound evaluation techniques, and ultrasound-guided diagnostic injections, are beginning to demonstrate their ability to add value to the diagnostic algorithm, particularly when less common compressive neuropathies are present and/or the diagnosis is in question.