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Surgical and Radiologic Anatomy : SRA Sep 2023The current cadaveric case series evaluates the coracobrachialis muscle morphology, the related musculocutaneous nerve origin, course, and branching pattern, as well as...
PURPOSE
The current cadaveric case series evaluates the coracobrachialis muscle morphology, the related musculocutaneous nerve origin, course, and branching pattern, as well as associated adjacent neuromuscular variants.
MATERIALS AND METHODS
Twenty-seven (24 paired and 3 unpaired) cadaveric arms were dissected to identify the coracobrachialis possible variants with emphasis on the musculocutaneous nerve course and coexisted neural variants.
RESULTS
Four morphological types of the coracobrachialis were identified: a two-headed muscle in 62.96% (17/27 arms), a three-headed in 22.2% (6/27), a one-headed in 11.1% (3/27), and a four-headed in 3.7% (1 arm). A coracobrachialis variant morphology was identified in 37.04% (10/27). A three-headed biceps brachii muscle coexisted in 23.53% (4/17). Two different courses of the musculocutaneous nerve were recorded: 1. a course between coracobrachialis superficial and deep heads (in cases of two or more heads) (100%, 24/24), and 2. a medial course in case of one-headed coracobrachialis (100%, 3/3). Three neural interconnections were found: 1. the lateral cord of the brachial plexus with the medial root of the median nerve in 18.52%, 2. the musculocutaneous with the median nerve in 7.41% and 3. the radial with the ulnar nerve in 3.71%. Duplication of the lateral root of the median nerve was identified in 11.1%.
CONCLUSIONS
The knowledge of the morphology of the muscles of the anterior arm compartment, especially the coracobrachialis variant morphology and the related musculocutaneous nerve variable course, is of paramount importance for surgeons. Careful dissection and knowledge of relatively common variants play a significant role in reducing iatrogenic injury.
Topics: Humans; Arm; Musculocutaneous Nerve; Brachial Plexus; Median Nerve; Muscle, Skeletal; Cadaver
PubMed: 37464221
DOI: 10.1007/s00276-023-03207-7 -
Journal of Biomedical Research Sep 2023The current study aims to ascertain the anatomical feasibility of transferring the contralateral S1 ventral root (VR) to the ipsilateral L5 VR for treating unilateral...
The current study aims to ascertain the anatomical feasibility of transferring the contralateral S1 ventral root (VR) to the ipsilateral L5 VR for treating unilateral spastic lower limb paralysis. Six formalin-fixed (three males and three females) cadavers were used. The VR of the contralateral S1 was transferred to the VR of the ipsilateral L5. The sural nerve was selected as a bridge between the donor and recipient nerve. The number of axons, the cross-sectional areas and the pertinent distances between the donor and recipient nerves were measured. The extradural S1 VR and L5 VR could be separated based on anatomical markers of the dorsal root ganglion. The gross distance between the S1 nerve root and L5 nerve root was 31.31 (± 3.23) mm in the six cadavers, while that on the diffusion tensor imaging was 47.51 (± 3.23) mm in 60 patients without spinal diseases, and both distances were seperately greater than that between the outlet of S1 from the spinal cord and the ganglion. The numbers of axons in the S1 VRs and L5 VRs were 13414.20 (± 2890.30) and 10613.20 (± 2135.58), respectively. The cross-sectional areas of the S1 VR and L5 VR were 1.68 (± 0.26) mm and 1.08 (± 0.26) mm , respectively. In conclusion, transfer of the contralateral S1 VR to the ipsilateral L5 VR may be an anatomically feasible treatment option for unilateral spastic lower limb paralysis.
PubMed: 37750309
DOI: 10.7555/JBR.37.20230068 -
Anesthesiology Dec 2023Continuous nerve block with ropivacaine is commonly performed after repair surgery for traumatic peripheral nerve injuries. After peripheral nerve injury,...
BACKGROUND
Continuous nerve block with ropivacaine is commonly performed after repair surgery for traumatic peripheral nerve injuries. After peripheral nerve injury, tetrodotoxin-resistant voltage-gated sodium channel Nav1.8 is upregulated and contributes to macrophage inflammation. This study investigated whether ropivacaine promotes peripheral nerve regeneration through Nav1.8-mediated macrophage signaling.
METHODS
A sciatic nerve transection-repair (SNT) model was established in adult Sprague-Dawley rats of both sexes. The rats received 0.2% ropivacaine or 10 μM Nav1.8-selective inhibitor A-803467 around the injured site or near the sacrum for 3 days. Nerve regeneration was evaluated using behavioral, electrophysiologic, and morphological examinations. Moreover, myelin debris removal, macrophage phenotype, Nav1.8 expression, and neuropeptide expression were assessed using immunostaining, enzyme-linked immunosorbent assay, and Western blotting.
RESULTS
Compared to the SNT-plus-vehicle group, the sensory, motor, and sensory-motor coordination functions of the two ropivacaine groups were significantly improved. Electrophysiologic (mean ± SD: recovery index of amplitude, vehicle 0.43 ± 0.17 vs. ropivacaine 0.83 ± 0.25, n = 11, P < 0.001) and histological analysis collectively indicated that ropivacaine significantly promoted axonal regrowth (percentage of neurofilament 200 [NF-200]-positive area: vehicle 19.88 ± 2.81 vs. ropivacaine 31.07 ± 2.62, n = 6, P < 0.001). The authors also found that, compared to the SNT-plus-vehicle group, the SNT-plus-ropivacaine group showed faster clearance of myelin debris, accompanied by significantly increased macrophage infiltration and transition from the M1 to M2 phenotype. Moreover, ropivacaine significantly attenuated Nav1.8 upregulation at 9 days after sciatic nerve transection (vehicle 4.12 ± 0.30-fold vs. ropivacaine 2.75 ± 0.36-fold, n = 5, P < 0.001), which coincided with the increased expression of chemokine ligand 2 and substance P. Similar changes were observed when using the selective Nav1.8 channel inhibitor A-803467.
CONCLUSIONS
Continuous nerve block with ropivacaine promotes the structural and functional recovery of injured sciatic nerves, possibly by regulating Nav1.8-mediated macrophage signaling.
Topics: Male; Female; Rats; Animals; Ropivacaine; Rats, Sprague-Dawley; Peripheral Nerve Injuries; Axons; Nerve Regeneration; Sciatic Nerve; Macrophages
PubMed: 37669448
DOI: 10.1097/ALN.0000000000004761 -
Pain Oct 2023Dorsal root ganglia (DRG) neurons have been well described for their role in driving both acute and chronic pain. Although nerve injury is known to cause transcriptional...
Dorsal root ganglia (DRG) neurons have been well described for their role in driving both acute and chronic pain. Although nerve injury is known to cause transcriptional dysregulation, how this differs across neuronal subtypes and the impact of sex is unclear. Here, we study the deep transcriptional profiles of multiple murine DRG populations in early and late pain states while considering sex. We have exploited currently available transgenics to label numerous subpopulations for fluorescent-activated cell sorting and subsequent transcriptomic analysis. Using bulk tissue samples, we are able to circumvent the issues of low transcript coverage and drop-outs seen with single-cell data sets. This increases our power to detect novel and even subtle changes in gene expression within neuronal subtypes and discuss sexual dimorphism at the neuronal subtype level. We have curated this resource into an accessible database for other researchers ( https://livedataoxford.shinyapps.io/drg-directory/ ). We see both stereotyped and unique subtype signatures in injured states after nerve injury at both an early and late timepoint. Although all populations contribute to a general injury signature, subtype enrichment changes can also be seen. Within populations, there is not a strong intersection of sex and injury, but previously unknown sex differences in naïve states-particularly in Aβ-RA + Aδ-low threshold mechanoreceptors-still contribute to differences in injured neurons.
Topics: Mice; Female; Male; Animals; RNA-Seq; Neuralgia; Sensory Receptor Cells; Mechanoreceptors; Peripheral Nerve Injuries; Ganglia, Spinal
PubMed: 37318015
DOI: 10.1097/j.pain.0000000000002934 -
Nature Methods Nov 2023We develop soft and stretchable fatigue-resistant hydrogel optical fibers that enable optogenetic modulation of peripheral nerves in naturally behaving animals during...
We develop soft and stretchable fatigue-resistant hydrogel optical fibers that enable optogenetic modulation of peripheral nerves in naturally behaving animals during persistent locomotion. The formation of polymeric nanocrystalline domains within the hydrogels yields fibers with low optical losses of 1.07 dB cm, Young's modulus of 1.6 MPa, stretchability of 200% and fatigue strength of 1.4 MPa against 30,000 stretch cycles. The hydrogel fibers permitted light delivery to the sciatic nerve, optogenetically activating hindlimb muscles in Thy1::ChR2 mice during 6-week voluntary wheel running assays while experiencing repeated deformation. The fibers additionally enabled optical inhibition of pain hypersensitivity in an inflammatory model in TRPV1::NpHR mice over an 8-week period. Our hydrogel fibers offer a motion-adaptable and robust solution to peripheral nerve optogenetics, facilitating the investigation of somatosensation.
Topics: Mice; Animals; Optical Fibers; Optogenetics; Hydrogels; Motor Activity; Sciatic Nerve; Locomotion
PubMed: 37857906
DOI: 10.1038/s41592-023-02020-9 -
Ulusal Travma Ve Acil Cerrahi Dergisi =... Dec 2023This study aimed to compare the analgesic efficacy of the femoral nerve block (FNB) with that of the pericapsular nerve group (PENG) block in the lateral decubitus... (Comparative Study)
Comparative Study Randomized Controlled Trial
Comparison of pericapsular nerve group block and femoral nerve block in spinal anesthesia position analgesia for proximal femoral fractures in geriatric patients: a randomized clinical trial.
BACKGROUND
This study aimed to compare the analgesic efficacy of the femoral nerve block (FNB) with that of the pericapsular nerve group (PENG) block in the lateral decubitus position for spinal anesthesia in geriatric hip fracture surgery.
METHODS
Patients aged ≥65 years scheduled to undergo hip fracture surgery for proximal femur fractures with an American Society of Anesthesiologists physical status of class I-IV and body mass index of 18-40 kg/m2 were included in the study. The PENG block or FNB was performed 20 min before positioning for spinal anesthesia. Lateral position, hip flexion, and lumbar spine flexion pain were evaluated during spinal anesthesia.
RESULTS
Sixty patients completed the study. The median pain scores for lateral positioning were 2 (0-4) and 2.5 in the PENG and FNB groups, respectively (P=0.001). The median pain scores during hip flexion were 1 (0-4) and 2.5 in the PENG and FNB groups, respectively (P<0.001). The median pain score during lumbar flexion was 1 (0-4) and 2.0 in the PENG and FNB groups, respectively (P=0.001). The two groups did not show a significant difference in the quality of the spinal anesthesia position (P>0.05).
CONCLUSION
Pre-operative PENG block is more effective in reducing the pain associated with spinal anesthesia position than FNB in geriatric hip fractures. Both blocks had a similar effect on posture quality and the number of spinal interventions.
Topics: Aged; Humans; Analgesia; Anesthesia, Spinal; Femoral Nerve; Hip Fractures; Pain; Pain, Postoperative; Proximal Femoral Fractures
PubMed: 38073453
DOI: 10.14744/tjtes.2023.33389 -
Science Advances Jul 2023The blood circulation is considered the only way for the orally administered nanoparticles to enter the central nervous systems (CNS), whereas non-blood route-mediated...
The blood circulation is considered the only way for the orally administered nanoparticles to enter the central nervous systems (CNS), whereas non-blood route-mediated nanoparticle translocation between organs is poorly understood. Here, we show that peripheral nerve fibers act as direct conduits for silver nanomaterials (Ag NMs) translocation from the gut to the CNS in both mice and rhesus monkeys. After oral gavage, Ag NMs are significantly enriched in the brain and spinal cord of mice with particle state however do not efficiently enter the blood. Using truncal vagotomy and selective posterior rhizotomy, we unravel that the vagus and spinal nerves mediate the transneuronal translocation of Ag NMs from the gut to the brain and spinal cord, respectively. Single-cell mass cytometry analysis revealed that enterocytes and enteric nerve cells take up significant levels of Ag NMs for subsequent transfer to the connected peripheral nerves. Our findings demonstrate nanoparticle transfer along a previously undocumented gut-CNS axis mediated by peripheral nerves.
Topics: Animals; Mice; Silver; Central Nervous System; Spinal Cord; Peripheral Nerves; Nanostructures
PubMed: 37418525
DOI: 10.1126/sciadv.adg2252 -
Anatomical Science International Sep 2023This study aimed to elucidate the origin, course, and distribution of the branches of the posterior femoral cutaneous nerve, considering the segmental and dorsoventral...
This study aimed to elucidate the origin, course, and distribution of the branches of the posterior femoral cutaneous nerve, considering the segmental and dorsoventral compositions of the sacral plexus, including the pudendal nerve. The buttocks and thighs of five cadavers were analyzed bilaterally. The branches emerged from the sacral plexus, which was divided dorsally to ventrally into the superior gluteal, inferior gluteal, common peroneal, tibial, and pudendal nerves. It descended lateral to the ischial tuberosity and comprised the thigh, gluteal, and perineal branches. As for the thigh and gluteal branches, the dorsoventral order of those originating from the sacral plexus corresponded to the lateromedial order of their distribution. However, the dorsoventral boundary was displaced at the inferior margin of the gluteus maximus between the thigh and gluteal branches. The perineal branch originated from the ventral branch of the nerve roots. In addition, the pudendal nerve branches, which ran medially to the ischial tuberosity, were distributed in the medial part of the inferior gluteal region. These branches should be distinguished from the gluteal branches; the former should be classified as the medial inferior cluneal nerves and the latter as the lateral ones. Finally, the medial part of the inferior gluteal region was distributed by branches of the dorsal sacral rami, which may correspond to the medial cluneal nerves. Thus, the composition of the posterior femoral cutaneous nerve is considered necessary when considering the dorsoventral relationships of the sacral plexus and boundaries of the dorsal and ventral rami.
Topics: Humans; Lumbosacral Plexus; Thigh; Muscle, Skeletal; Buttocks; Cadaver
PubMed: 37017904
DOI: 10.1007/s12565-023-00721-x -
Korean Journal of Radiology Nov 2023Magnetic resonance neurography (MRN) is increasingly used to visualize peripheral nerves in vivo. However, the implementation and interpretation of MRN in the brachial... (Review)
Review
Magnetic resonance neurography (MRN) is increasingly used to visualize peripheral nerves in vivo. However, the implementation and interpretation of MRN in the brachial and lumbosacral plexi are challenging because of the anatomical complexity and technical limitations. The purpose of this article was to review the clinical context of MRN, describe advanced magnetic resonance (MR) techniques for plexus imaging, and list the general categories of utility of MRN with pertinent imaging examples. The selection and optimization of MR sequences are centered on the homogeneous suppression of fat and blood vessels while enhancing the visibility of the plexus and its branches. Standard 2D fast spin-echo sequences are essential to assess morphology and signal intensity of nerves. Moreover, nerve-selective 3D isotropic images allow improved visualization of nerves and multiplanar reconstruction along their course. Diffusion-weighted and diffusion-tensor images offer microscopic and functional insights into peripheral nerves. The interpretation of MRN in the brachial and lumbosacral plexi should be based on a thorough understanding of their anatomy and pathophysiology. Anatomical landmarks assist in identifying brachial and lumbosacral plexus components of interest. Thus, understanding the varying patterns of nerve abnormalities facilitates the interpretation of aberrant findings.
Topics: Humans; Magnetic Resonance Imaging; Imaging, Three-Dimensional; Lumbosacral Plexus; Magnetic Resonance Spectroscopy
PubMed: 37899521
DOI: 10.3348/kjr.2023.0150 -
Biomedical Engineering Online Dec 2023It is difficult to create intuitive methods of controlling prosthetic limbs, often resulting in abandonment. Peripheral nerve interfaces can be used to convert motor...
BACKGROUND
It is difficult to create intuitive methods of controlling prosthetic limbs, often resulting in abandonment. Peripheral nerve interfaces can be used to convert motor intent into commands to a prosthesis. The Extraneural Spatiotemporal Compound Action Potentials Extraction Network (ESCAPE-NET) is a convolutional neural network (CNN) that has previously been demonstrated to be effective at discriminating neural sources in rat sciatic nerves. ESCAPE-NET was designed to operate using data from multi-channel nerve cuff arrays, and use the resulting spatiotemporal signatures to classify individual naturally evoked compound action potentials (nCAPs) based on differing source fascicles. The applicability of this approach to larger and more complex nerves is not well understood. To support future translation to humans, the objective of this study was to characterize the performance of this approach in a computational model of the human median nerve.
METHODS
Using a cross-sectional immunohistochemistry image of a human median nerve, a finite-element model was generated and used to simulate extraneural recordings. ESCAPE-NET was used to classify nCAPs based on source location, for varying numbers of sources and noise levels. The performance of ESCAPE-NET was also compared to ResNet-50 and MobileNet-V2 in the context of classifying human nerve cuff data.
RESULTS
Classification accuracy was found to be inversely related to the number of nCAP sources in ESCAPE-NET (3-class: 97.8% ± 0.1%; 10-class: 89.3% ± 5.4% in low-noise conditions, 3-class: 70.3% ± 0.1%; 10-class: 52.5% ± 0.3% in high-noise conditions). ESCAPE-NET overall outperformed both MobileNet-V2 (3-class: 96.5% ± 1.1%; 10-class: 84.9% ± 1.7% in low-noise conditions, 3-class: 86.0% ± 0.6%; 10-class: 41.4% ± 0.9% in high-noise conditions) and ResNet-50 (3-class: 71.2% ± 18.6%; 10-class: 40.1% ± 22.5% in low-noise conditions, 3-class: 81.3% ± 4.4%; 10-class: 31.9% ± 4.4% in high-noise conditions).
CONCLUSION
All three networks were found to learn to differentiate nCAPs from different sources, as evidenced by performance levels well above chance in all cases. ESCAPE-NET was found to have the most robust performance, despite decreasing performance as the number of classes increased, and as noise was varied. These results provide valuable translational guidelines for designing neural interfaces for human use.
Topics: Humans; Rats; Animals; Median Nerve; Cross-Sectional Studies; Neural Networks, Computer; Sciatic Nerve; Evoked Potentials
PubMed: 38062509
DOI: 10.1186/s12938-023-01181-0