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Handbook of Clinical Neurology 2024The femoral and obturator nerves both arise from the L2, L3, and L4 spinal nerve roots and descend into the pelvis before emerging in the lower limbs. The femoral... (Review)
Review
The femoral and obturator nerves both arise from the L2, L3, and L4 spinal nerve roots and descend into the pelvis before emerging in the lower limbs. The femoral nerve's primary function is knee extension and hip flexion, along with some sensory innervation to the leg. The obturator nerve's primary function is thigh adduction and sensory innervation to a small area of the medial thigh. Each may be injured by a variety of potential causes, many of them iatrogenic. Here, we review the anatomy of the femoral and obturator nerves and the clinical features and potential etiologies of femoral and obturator neuropathies. Their necessary investigations, including electrodiagnostic studies and imaging, their prognosis, and potential treatments, are discussed in this chapter.
Topics: Humans; Obturator Nerve; Peripheral Nervous System Diseases; Femoral Nerve; Femoral Neuropathy
PubMed: 38697739
DOI: 10.1016/B978-0-323-90108-6.00007-7 -
Current Opinion in Neurology Oct 2023The purpose if this review is to provide an overview of the available data on the use of nerve ultrasound for the diagnosis and follow-up of peripheral neuropathies. (Review)
Review
PURPOSE OF REVIEW
The purpose if this review is to provide an overview of the available data on the use of nerve ultrasound for the diagnosis and follow-up of peripheral neuropathies.
RECENT FINDINGS
During the last decade, nerve ultrasound has been established as a complementary tool for the evaluation of morphological changes mostly for immune-mediated polyneuropathies. Through the development of ultrasound protocols for evaluation of disease-specific sites, nerve ultrasound has proven to be a practical, widely available, reproducible diagnostic tool with no relevant contraindications.
SUMMARY
Cross-sectional area, echogenicity, morphology of the individual nerve fascicles, thickness of the epineurium, vascularization and mobility of the nerve are the main parameters evaluated with nerve ultrasound in polyneuropathies. Patients with typical chronic inflammatory demyelinating polyneuropathy show multifocal nerve enlargements easily visible on the upper extremities and the brachial plexus, whereas its variants show focal nerve enlargements. On the other hand, axonal neuropathies including diabetic neuropathy present with isolated nerve enlargement mostly in compression sites.
Topics: Humans; Follow-Up Studies; Polyneuropathies; Polyradiculoneuropathy, Chronic Inflammatory Demyelinating; Ultrasonography; Diabetic Neuropathies; Peripheral Nerves
PubMed: 37382111
DOI: 10.1097/WCO.0000000000001183 -
Journal of Materials Chemistry. B Nov 2023Peripheral nerve injuries are common and can cause catastrophic consequences. Although peripheral nerves have notable regenerative capacity, full functional recovery is... (Review)
Review
Peripheral nerve injuries are common and can cause catastrophic consequences. Although peripheral nerves have notable regenerative capacity, full functional recovery is often challenging due to a number of factors, including age, the type of injury, and delayed healing, resulting in chronic disorders that cause lifelong miseries and significant financial burdens. Fluorescence imaging, among the various techniques, may be the key to overcome these restrictions and improve the prognosis because of its feasibility and dynamic real-time imaging. Intraoperative dynamic fluorescence imaging allows the visualization of the morphological structure of the nerve so that surgeons can reduce the incidence of medically induced injury. Axoplasmic transport-based neuroimaging allows the visualization of the internal transport function of the nerve, facilitating early, objective, and accurate assessment of the degree of regenerative repair, allowing early intervention in patients with poor recovery, thereby improving prognosis. This review briefly discusses peripheral nerve fluorescent dyes that have been reported or could potentially be employed, with a focus on their role in visualizing the nerve's function and anatomy.
Topics: Humans; Peripheral Nerves; Peripheral Nerve Injuries; Optical Imaging
PubMed: 37846619
DOI: 10.1039/d3tb01927f -
International Journal of Molecular... Nov 2023No matter what treatment is used after nerve transection, a complete cure is impossible, so basic and clinical research is underway to find a cure. As part of this... (Review)
Review
No matter what treatment is used after nerve transection, a complete cure is impossible, so basic and clinical research is underway to find a cure. As part of this research, autophagy is being investigated for its role in nerve regeneration. Here, we review the existing literature regarding the involvement and significance of autophagy in peripheral nerve injury and regeneration. A comprehensive literature review was conducted to assess the induction and role of autophagy in peripheral nerve injury and subsequent regeneration. Studies were included if they were prospective or retrospective investigations of autophagy and facial or peripheral nerves. Articles not mentioning autophagy or the facial or peripheral nerves, review articles, off-topic articles, and those not written in English were excluded. A total of 14 peripheral nerve studies that met these criteria, including 11 involving sciatic nerves, 2 involving facial nerves, and 1 involving the inferior alveolar nerve, were included in this review. Studies conducted on rats and mice have demonstrated activation of autophagy and expression of related factors in peripheral nerves with or without stimulation of autophagy-inducing factors such as rapamycin, curcumin, three-dimensional melatonin nerve scaffolds, CXCL12, resveratrol, nerve growth factor, lentinan, adipose-derived stem cells and melatonin, basic fibroblast growth factor, and epothilone B. Among the most studied of these factors in relation to degeneration and regeneration of facial and sciatic nerves are LC3II/I, PI3K, mTOR, Beclin-1, ATG3, ATG5, ATG7, ATG9, and ATG12. This analysis indicates that autophagy is involved in the process of nerve regeneration following facial and sciatic nerve damage. Inadequate autophagy induction or failure of autophagy responses can result in regeneration issues after peripheral nerve damage. Animal studies suggest that autophagy plays an important role in peripheral nerve degeneration and regeneration.
Topics: Rats; Mice; Animals; Peripheral Nerve Injuries; Melatonin; Prospective Studies; Retrospective Studies; Peripheral Nerves; Sciatic Nerve; Nerve Regeneration; Autophagy
PubMed: 38003409
DOI: 10.3390/ijms242216219 -
Journal of the Peripheral Nervous... Jul 2023Action potential propagation along myelinated axons depends on the geometry of the myelin unit and the division of the underlying axon to specialized domains. The latter... (Review)
Review
Action potential propagation along myelinated axons depends on the geometry of the myelin unit and the division of the underlying axon to specialized domains. The latter include the nodes of Ranvier (NOR), the paranodal junction (PNJ) flanking the nodes, and the adjacent juxtaparanodal region that is located below the compact myelin of the internode. Each of these domains contains a unique composition of axoglial adhesion molecules (CAMs) and cytoskeletal scaffolding proteins, which together direct the placement of specific ion channels at the nodal and juxtaparanodal axolemma. In the last decade it has become increasingly clear that antibodies to some of these axoglial CAMs cause immune-mediated neuropathies. In the current review we detail the molecular composition of the NOR and adjacent membrane domains, describe the function of different CAM complexes that mediate axon-glia interactions along the myelin unit, and discuss their involvement and the underlying mechanisms taking place in peripheral nerve pathologies. This growing group of pathologies represent a new type of neuropathies termed "nodopathies" or "paranodopathies" that are characterized by unique clinical and molecular features which together reflect the mechanisms underlying the molecular assembly and maintenance of this specialized membrane domain.
Topics: Humans; Ranvier's Nodes; Axons; Myelin Sheath; Neuroglia; Peripheral Nerves
PubMed: 37272548
DOI: 10.1111/jns.12568 -
Current Opinion in Anaesthesiology Oct 2023To summarize the recent literature describing and comparing novel motor-sparing peripheral nerve block techniques for hip and knee surgery. This topic is relevant... (Review)
Review
PURPOSE OF REVIEW
To summarize the recent literature describing and comparing novel motor-sparing peripheral nerve block techniques for hip and knee surgery. This topic is relevant because the number of patients undergoing same day discharge after hip and knee surgery is increasing. Preserving lower extremity muscle function is essential to facilitate early physical therapy for these patients.
RECENT FINDINGS
Distal peripheral nerve blocks may allow for preserved quadriceps motor strength and comparable analgesia to traditional techniques. However, few studies in hip and knee populations include strength or function as primary outcomes. For hip surgeries, studies have failed to show analgesic differences between regional blocks and periarticular infiltration. Similarly for knee arthroplasty in the absence of periarticular infiltration, recent evidence suggests adding combinations of blocks (ACB plus iPACK or genicular nerve blocks) may balance pain control and early ambulation.
SUMMARY
The use of motor-sparing peripheral nerve block techniques enables early ambulation, adequate pain control, and avoidance of opioid-related side effects facilitating outpatient/ambulatory lower extremity surgery. Further studies of these techniques for continuous peripheral nerve block catheters are needed to assess if extended blockade continues to provide motor-sparing and opioid-sparing benefits.
Topics: Humans; Analgesics, Opioid; Pain, Postoperative; Anesthesia, Conduction; Nerve Block; Peripheral Nerves; Anesthetics, Local
PubMed: 37552001
DOI: 10.1097/ACO.0000000000001287 -
Med (New York, N.Y.) Aug 2023While peripheral nerve stimulation (PNS) has shown promise in applications ranging from peripheral nerve regeneration to therapeutic organ stimulation, clinical...
BACKGROUND
While peripheral nerve stimulation (PNS) has shown promise in applications ranging from peripheral nerve regeneration to therapeutic organ stimulation, clinical implementation has been impeded by various technological limitations, including surgical placement, lead migration, and atraumatic removal.
METHODS
We describe the design and validation of a platform technology for nerve regeneration and interfacing: adaptive, conductive, and electrotherapeutic scaffolds (ACESs). ACESs are comprised of an alginate/poly-acrylamide interpenetrating network hydrogel optimized for both open surgical and minimally invasive percutaneous approaches.
FINDINGS
In a rodent model of sciatic nerve repair, ACESs significantly improved motor and sensory recovery (p < 0.05), increased muscle mass (p < 0.05), and increased axonogenesis (p < 0.05). Triggered dissolution of ACESs enabled atraumatic, percutaneous removal of leads at forces significantly lower than controls (p < 0.05). In a porcine model, ultrasound-guided percutaneous placement of leads with an injectable ACES near the femoral and cervical vagus nerves facilitated stimulus conduction at significantly greater lengths than saline controls (p < 0.05).
CONCLUSION
Overall, ACESs facilitated lead placement, stabilization, stimulation, and atraumatic removal, enabling therapeutic PNS as demonstrated in small- and large-animal models.
FUNDING
This work was supported by K. Lisa Yang Center for Bionics at MIT.
Topics: Animals; Swine; Transcutaneous Electric Nerve Stimulation; Sciatic Nerve; Ultrasonography; Nerve Regeneration
PubMed: 37339635
DOI: 10.1016/j.medj.2023.05.007 -
Nature Feb 2024Guillain-Barré syndrome (GBS) is a rare heterogenous disorder of the peripheral nervous system, which is usually triggered by a preceding infection, and causes a...
Guillain-Barré syndrome (GBS) is a rare heterogenous disorder of the peripheral nervous system, which is usually triggered by a preceding infection, and causes a potentially life-threatening progressive muscle weakness. Although GBS is considered an autoimmune disease, the mechanisms that underlie its distinct clinical subtypes remain largely unknown. Here, by combining in vitro T cell screening, single-cell RNA sequencing and T cell receptor (TCR) sequencing, we identify autoreactive memory CD4 cells, that show a cytotoxic T helper 1 (T1)-like phenotype, and rare CD8 T cells that target myelin antigens of the peripheral nerves in patients with the demyelinating disease variant. We characterized more than 1,000 autoreactive single T cell clones, which revealed a polyclonal TCR repertoire, short CDR3β lengths, preferential HLA-DR restrictions and recognition of immunodominant epitopes. We found that autoreactive TCRβ clonotypes were expanded in the blood of the same patient at distinct disease stages and, notably, that they were shared in the blood and the cerebrospinal fluid across different patients with GBS, but not in control individuals. Finally, we identified myelin-reactive T cells in the nerve biopsy from one patient, which indicates that these cells contribute directly to disease pathophysiology. Collectively, our data provide clear evidence of autoreactive T cell immunity in a subset of patients with GBS, and open new perspectives in the field of inflammatory peripheral neuropathies, with potential impact for biomedical applications.
Topics: Humans; Autoimmunity; Biopsy; CD8-Positive T-Lymphocytes; Guillain-Barre Syndrome; HLA-DR Antigens; Immunodominant Epitopes; Myelin Sheath; Peripheral Nerves; Peripheral Nervous System Diseases; Receptors, Antigen, T-Cell; Th1 Cells; T-Lymphocytes, Cytotoxic; Immunologic Memory
PubMed: 38233524
DOI: 10.1038/s41586-023-06916-6 -
International Journal of Molecular... Oct 2023Appropriate animal models, mimicking conditions of both health and disease, are needed to understand not only the biology and the physiology of neurons and other cells... (Review)
Review
Appropriate animal models, mimicking conditions of both health and disease, are needed to understand not only the biology and the physiology of neurons and other cells under normal conditions but also under stress conditions, like nerve injuries and neuropathy. In such conditions, understanding how genes and different factors are activated through the well-orchestrated programs in neurons and other related cells is crucial. Knowledge about key players associated with nerve regeneration intended for axonal outgrowth, migration of Schwann cells with respect to suitable substrates, invasion of macrophages, appropriate conditioning of extracellular matrix, activation of fibroblasts, formation of endothelial cells and blood vessels, and activation of other players in healthy and diabetic conditions is relevant. Appropriate physical and chemical attractions and repulsions are needed for an optimal and directed regeneration and are investigated in various nerve injury and repair/reconstruction models using healthy and diabetic rat models with relevant blood glucose levels. Understanding dynamic processes constantly occurring in neuropathies, like diabetic neuropathy, with concomitant degeneration and regeneration, requires advanced technology and bioinformatics for an integrated view of the behavior of different cell types based on genomics, transcriptomics, proteomics, and imaging at different visualization levels. Single-cell-transcriptional profile analysis of different cells may reveal any heterogeneity among key players in peripheral nerves in health and disease.
Topics: Rats; Animals; Endothelial Cells; Rats, Wistar; Peripheral Nerves; Diabetic Neuropathies; Schwann Cells; Nerve Degeneration; Nerve Regeneration; Axons; Peripheral Nerve Injuries; Diabetes Mellitus
PubMed: 37894921
DOI: 10.3390/ijms242015241 -
PM & R : the Journal of Injury,... Nov 2023Nerve pain frequently develops following amputations and peripheral nerve injuries. Two innovative surgical techniques, targeted muscle reinnervation (TMR) and... (Review)
Review
OBJECTIVE
Nerve pain frequently develops following amputations and peripheral nerve injuries. Two innovative surgical techniques, targeted muscle reinnervation (TMR) and regenerative peripheral nerve interfaces (RPNI), are rapidly gaining popularity as alternatives to traditional nerve management, but their effectiveness is unclear.
LITERATURE SURVEY
A review of literature pertaining to TMR and RPNI pain results was conducted. PubMed and MEDLINE electronic databases were queried.
METHODOLOGY
Studies were included if pain outcomes were assessed after TMR or RPNI in the upper or lower extremity, both for prophylaxis performed at the time of amputation and for treatment of postamputation pain. Data were extracted for evaluation.
SYNTHESIS
Seventeen studies were included, with 14 evaluating TMR (366 patients) and three evaluating RPNI (75 patients). Of these, one study was a randomized controlled trial. Nine studies had a mean follow-up time of at least 1 year (range 4-27.6 months). For pain treatment, TMR and RPNI improved neuroma pain in 75%-100% of patients and phantom limb pain in 45%-80% of patients, averaging a 2.4-6.2-point reduction in pain scores on the numeric rating scale postoperatively. When TMR or RPNI was performed prophylactically, many patients reported no neuroma pain (48%-100%) or phantom limb pain (45%-87%) at time of follow-up. Six TMR studies reported Patient-Reported Outcomes Measurement Information System (PROMIS) scores assessing pain intensity, behavior, and interference, which consistently showed a benefit for all measures. Complication rates ranged from 13% to 31%, most frequently delayed wound healing.
CONCLUSIONS
Both TMR and RPNI may be beneficial for preventing and treating pain originating from peripheral nerve dysfunction compared to traditional techniques. Randomized trials with longer term follow-up are needed to directly compare the effectiveness of TMR and RPNI with traditional nerve management techniques.
Topics: Humans; Phantom Limb; Amputation, Surgical; Neurosurgical Procedures; Neuroma; Peripheral Nerves; Muscles; Muscle, Skeletal; Randomized Controlled Trials as Topic
PubMed: 36965013
DOI: 10.1002/pmrj.12972