1.Spinal Pain: From Neoplastic to Parasitic
Philippine Journal of Pathology 2026;(75th PSP Research Competition Abstracts):1-
Introduction:
Spinal cord schistosomiasis can masquerade as an intramedullary tumor when it involves the conus medullaris or lower thoracic cord.
Eggs transported via the valveless vertebral (Batson) venous plexus provoke a
granulomatous inflammatory response, producing mass-like lesions on MRI.
Because clinical presentation overlaps with neoplastic or inflammatory spinal
diseases, the diagnosis often requires histopathologic confirmation.
Case Description:
A 26-year-old male experienced sudden severe back pain
initially thought to be due to a manifestation of symptoms from a bad fall from
when the patient was just 5 years old. The patient was assessed through MRI with
contrast yielding a 1 x 1.6 x 4.1 cm mass at the distal lumbar area involving the
conus medullaris. Histopathological examination revealed the spinal tumor to
be schistosomiasis with chronic inflammation.
Discussion:
Spinal neuroschistosomiasis, overall, is rare with a 1-4%
incidence among people with systemic schistosomiasis. Even among medullary
schistosomiasis, 0.7% were lumbosacral and not necessarily involving the conus
medullaris. Spinal cord schistosomiasis is most commonly due to Schistosoma
mansoni or haematobium and can masquerade as an intramedullary tumor but
epidemiological and microscopic data point toward Schistosoma japonicum to be
the more likely causative agent for this case. The clinical presentation of spinal
neuroschistosomiasis of the conus medullaris is non-specific and may overlap
with more common spinal pathologies presenting as a subacute myelopathy,
clinically.
Conclusion
The case highlights the necessity of heightened suspicion for
spinal tumors among patients from schistosoma-endemic areas, advocating early
diagnosis and management.
Schistosomiasis
;
Spinal Cord Diseases
2.EGR2 maintains neuropathic pain by promoting microglial phagocytosis.
Caiyun XI ; Jianxi ZHANG ; Zhifeng HUANG ; Liqiong HE ; Kailu ZOU ; Xiaoping XU ; Qulian GUO ; Bei SUN ; Changsheng HUANG
Journal of Central South University(Medical Sciences) 2025;50(4):586-601
OBJECTIVES:
Neuropathic pain (NP) is one of the most common forms of chronic pain, yet current treatment options are limited in effectiveness. Peripheral nerve injury activates spinal microglia, altering their inflammatory response and phagocytic functions, which contributes to the progression of NP. Most current research on NP focuses on microglial inflammation, with relatively little attention to their phagocytic function. Early growth response factor 2 (EGR2) has been shown to regulate microglial phagocytosis, but its specific role in NP remains unclear. This study aims to investigate how EGR2 modulates microglial phagocytosis and its involvement in NP, with the goal of identifying potential therapeutic targets.
METHODS:
Adult male Sprague-Dawley (SD) rats were used to establish a chronic constriction injury (CCI) model of the sciatic nerve. Pain behaviors were assessed on days 1, 3, 7, 10, and 14 post-surgery to confirm successful model induction. The temporal and spatial expression of EGR2 in the spinal cord was examined using real-time quantitative PCR (RT-qPCR), Western blotting, and immunofluorescence staining. Adeno-associated virus (AAV) was used to overexpress EGR2 in the spinal cord, and behavioral assessments were performed to evaluate the effects of EGR2 modulation of NP. CCI and lipopolysaccharide (LPS) models were established in animals and microglial cell lines, respectively, and changes in phagocytic activity were measured using RT-qPCR and fluorescent latex bead uptake assays. After confirming the involvement of microglial phagocytosis in NP, AAV was used to overexpress EGR2 in both in vivo and in vitro models, and phagocytic activity was further evaluated. Finally, eukaryotic transcriptome sequencing was conducted to screen differentially expressed mRNAs, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses to identify potential downstream effectors of EGR2.
RESULTS:
The CCI model successfully induced NP. Following CCI, EGR2 expression in the spinal cord was upregulated in parallel with NP development. Overexpression of EGR2 via spinal AAV injection enhanced microglial phagocytic activity and increased pain hypersensitivity in rats. Both animal and cellular models showed that CCI or LPS stimulation enhanced microglial phagocytosis, which was further amplified by EGR2 overexpression. Transcriptomic analysis of spinal cord tissues from CCI rats overexpressing EGR2 revealed upregulation of numerous genes associated with microglial phagocytosis and pain regulation. Among them, Lag3 emerged as a potential downstream target of EGR2.
CONCLUSIONS
EGR2 contributes to the maintenance of NP by enhancing microglial phagocytosis in the spinal dorsal horn.
Animals
;
Microglia/metabolism*
;
Phagocytosis/physiology*
;
Rats, Sprague-Dawley
;
Neuralgia/physiopathology*
;
Early Growth Response Protein 2/metabolism*
;
Male
;
Rats
;
Spinal Cord/metabolism*
;
Sciatic Nerve/injuries*
3.Noggin alleviates neuropathic pain by regulating microglial polarization and remodeling iron homeostasis via a STAT3-dependent pathway.
Wenjuan ZHANG ; Lin YANG ; Ran ZHANG
Journal of Central South University(Medical Sciences) 2025;50(4):602-614
OBJECTIVES:
Pain sensitization, as a core feature of neuropathic pain (NP), is closely associated with inflammatory imbalance within the central nervous system. To investigate the effects of intrathecal injection of noggin (NOG) on mechanical hypersensitivity, microglial (MG) activation and polarization, and iron metabolism in a spinal nerve ligation (SNL)-induced rat model of NP, and to explore the role of signal transducer and activator of transcription 3 (STAT3) in MG phenotypic transformation.
METHODS:
Sixty-six Sprague-Dawley (SD) rats were randomly divided into 3 groups: Sham, SNL, and SNL+NOG. Paw withdrawal threshold (PWT) was assessed using von Frey filaments. Western blotting and real-time polymerase chain reaction (RT-PCR) were used to detect spinal cord expression of MG activation marker CD11b, STAT3, phosphorylated STAT3 (p-STAT3), M1 polarization markers [CD86, CD32, interleukin (IL)-1β], tumor necrosis factor-alpha (TNF-α), and CC chemokine receptor 2 (CCR2), M2 markers [CD204, CD163, CX3C chemokine receptor 1 (CX3CR1), IL-10, and arginase-1 (ARG-1)], and iron metabolism-related proteins including ferroportin (FPN, gene: SLC40A1), hepcidin (gene: HAMP), transferrin receptor (gene: TFRC), and divalent metal transporter 1 (DMT-1, gene: SLC11A2). p-STAT3 localization in MGs was visualized via immunofluorescence. In vitro, primary MGs were divided into Control, bone morphogenetic protein-4 (BMP4), and BMP4+Stattic (STAT3 inhibitor) groups to examine the effects of STAT3 inhibition on MG activation, polarization, and iron regulation.
RESULTS:
In vivo, compared with the Sham group, the SNL and SNL+NOG groups exhibited significantly decreased PWT (P<0.05), elevated spinal CD11b and p-STAT3 protein levels (all P<0.05), increased M1 markers (CD86, CD32, IL-1β, TNF-α, and CCR2) (all P<0.05), and decreased M2 markers (CD204 protein; mRNA of CD204, ARG-1) (all P<0.05). Hepcidin protein and mRNA levels of HAMP, SLC11A2, and TFRC were significantly elevated, while FPN protein and SLC40A1 mRNA were reduced (all P<0.05). Compared to SNL alone, the SNL+NOG group showed increased PWT, decreased CD11b, p-STAT3, and M1 marker expression (except TNF-α), increased M2 marker expression, reduced hepcidin and HAMP levels, and increased FPN and SLC40A1 expression (all P<0.05). In vitro, BMP4 treatment increased CD11b, STAT3, p-STAT3, CD86, and hepcidin levels, while reducing CD204 and FPN (all P<0.05). Inhibition STAT3 with Stattic reversed these changes (all P<0.05).
CONCLUSIONS
NOG alleviates SNL-induced NP by antagonizing the STAT3 signaling pathway, thereby rebalancing microglial polarization and restoring iron metabolism.
Animals
;
Neuralgia/drug therapy*
;
Rats, Sprague-Dawley
;
Microglia/cytology*
;
STAT3 Transcription Factor/metabolism*
;
Rats
;
Iron/metabolism*
;
Male
;
Signal Transduction/drug effects*
;
Carrier Proteins/therapeutic use*
;
Homeostasis/drug effects*
;
Spinal Cord/metabolism*
4.Mechanisms of spinal microglia and astrocytes in exercise-induced analgesia.
Shuang HU ; Haojun YOU ; Jing LEI
Journal of Central South University(Medical Sciences) 2025;50(8):1455-1464
Exercise-induced analgesia (EIA) refers to the elevation of pain thresholds and reduction in sensitivity to noxious stimuli achieved through exercise training. As a non-pharmacological treatment strategy, exercise therapy has demonstrated positive effects on both acute and chronic pain. Increasing evidence indicates that modulation of glial cell activity is an important mechanism underlying analgesia. Spinal glial cells contribute to the development and maintenance of pathological pain by promoting pain signal transmission through inflammatory responses and synaptic remodeling. Exercise can differentially regulate microglia and astrocyte activity, inhibiting multiple inflammatory signaling pathways, such as P2X4/P2X7 purinergic receptors, brain-derived neurotrophic factor (BDNF)/phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR), interleukin (IL)-6/Janus kinase (JAK) 2/signal transducer and activator of transcription 3 (STAT3), p38-mitogen-activated protein kinases (MAPK), and Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB), thereby reducing the release of pro-inflammatory cytokines, decreasing inflammatory and nociceptive hypersensitivity, and alleviating pathological pain. This review also summarized the effects of different exercise intensities, durations, and frequencies on glial cell responses in order to provide a theoretical foundation for optimizing exercise-based interventions for pathological pain conditions.
Humans
;
Microglia/metabolism*
;
Astrocytes/metabolism*
;
Exercise/physiology*
;
Signal Transduction
;
Analgesia/methods*
;
Spinal Cord/cytology*
;
Exercise Therapy
;
Pain Management/methods*
;
Animals
;
Brain-Derived Neurotrophic Factor/metabolism*
5.Effect of moxibustion at "Shenque" (CV8) on the expression of BDNF and c-fos in the urinary control brain regions of rats with neurogenic bladder after spinal cord injury.
Han YU ; Yuanbo FU ; Huilin LIU ; Yuzhuo ZHANG ; Yutong NI ; Qingdai LI ; Yi XU
Chinese Acupuncture & Moxibustion 2025;45(5):638-645
OBJECTIVE:
To observe the effects of moxibustion at "Shenque" (CV8) on urodynamics and the expression of brain-derived neurotrophic factor (BDNF) and immediate early gene (c-fos) in pontine micturition center (PMC), periaqueductal gray (PAG), medial prefrontal cortex (mPFC) of neurogenic bladder (NB) rats after spinal cord injury.
METHODS:
Twenty-four SPF female SD rats were randomly divided into a sham-operation group (6 rats) and a modeling group (18 rats). In the modeling group, T9 complete spinal cord transection method was used to establish a neurogenic detrusor overactivity model, and the 12 rats with successful modeling were randomized into a model group and a moxibustion group, with 6 rats in each group. The rats in the moxibustion group were treated with ginger/salt-insulated moxibustion at "Shenque" (CV8), and 4 consecutive moxa cones were delivered in one intervention. Moxibustion was operated once daily and for 14 days. After intervention completion, the urodynamic indexes of rats in each group were detected. Fluorescence quantitative PCR was used to detect the mRNA expression of BDNF and c-fos in PMC, PAG and mPFC in rats. Western blot was used to detect the protein expression of BDNF and c-fos in PMC, PAG and mPFC.
RESULTS:
The rats in the sham-operation group did not show phasic detrusor contraction during bladder filling. Compared with the model group, the frequency and amplitude of the phasic detrusor contraction were reduced 5 min before urine leakage in the rats of the moxibustion group (P<0.05), and the duration of the first phasic detrusor contraction during bladder filling was prolonged (P<0.05). Compared with the sham-operation group, the mRNA and protein expression of BDNF and c-fos in PMC, PAG and mPFC increased in the model group (P<0.05). Compared with the model group, the mRNA and protein expression of BDNF and c-fos in PMC, PAG and mPFC decreased in the moxibustion group (P<0.05).
CONCLUSION
Moxibustion at "Shenque" (CV8) can improve the phasic contraction during bladder filling in NB rats after spinal cord injury, possibly by down-regulating the mRNA and protein expression of BDNF and c-fos in PMC, PAG, and mPFC.
Animals
;
Moxibustion
;
Female
;
Rats
;
Brain-Derived Neurotrophic Factor/metabolism*
;
Rats, Sprague-Dawley
;
Acupuncture Points
;
Spinal Cord Injuries/metabolism*
;
Urinary Bladder, Neurogenic/etiology*
;
Proto-Oncogene Proteins c-fos/metabolism*
;
Humans
;
Urinary Bladder/physiopathology*
;
Brain/metabolism*
;
Urination
6.Acupuncture and moxibustion combined with umbilical therapy for 30 cases of anxiety and depression in patients with neurogenic bladder after spinal cord injury.
Dongli WANG ; Xueqian WANG ; Rui WANG ; Youzhi HAO ; Weiwei QIAO ; Chao LI ; Yinping ZUO
Chinese Acupuncture & Moxibustion 2025;45(7):923-926
OBJECTIVE:
To observe the clinical effect of acupuncture and moxibustion combined with umbilical therapy on anxiety and depression in patients with neurogenic bladder (NB) after spinal cord injury (SCI).
METHODS:
Thirty cases of NB after SCI with anxiety and depression were selected and treated with acupuncture and moxibustion combined with umbilical therapy. Acupuncture was applied at Baihui (GV20), Yintang (GV24+), Sanyinjiao (SP6), Shenmen (HT7), Hegu (LI4), Taichong (LR3), once a day, continuous treatment for 4 weeks. Ginger moxibustion was applied at the bladder meridian of foot taiyang and governor vessel, once a day, continuous treatment for 4 weeks. In treatment of umbilical therapy, Chaihu (Radix Bupleuri), Yujin (Radix Curcumae), Rougui (Cortex Cinnamomi) were ground and mixed with the same amount of honey, put into the application, and the application was placed on the navel after filling the navel with fine salt, once a day for 4 weeks. Hamilton anxiety scale (HAMA) score, Hamilton depression scale (HAMD) score, urodynamic indexes (maximum urinary flow rate [Qmax], maximum detrusor pressure [Pdet-max], residual urine volume [RUV]), neurogenic bladder symptom score (NBSS), urinary symptom distress scale (USDS) score were compared before and after treatment, and the clinical efficacy was evaluated.
RESULTS:
After treatment, the scores of HAMA, HAMD, NBSS, USDS and RUVwere lower than those before treatment (P<0.05), and Qmax and Pdet-max were higher than those before treatment (P<0.05). The total effective rate was 93.3 (28/30).
CONCLUSION
Acupuncture and moxibustion combined with umbilical therapy can effectively relieve anxiety and depression symptoms, improve urination disorders in patients with NB after SCI.
Humans
;
Moxibustion
;
Male
;
Female
;
Adult
;
Middle Aged
;
Acupuncture Therapy
;
Spinal Cord Injuries/psychology*
;
Depression/etiology*
;
Anxiety/etiology*
;
Urinary Bladder, Neurogenic/etiology*
;
Young Adult
;
Aged
;
Combined Modality Therapy
;
Acupuncture Points
7.Effect of ultrasound-guided foraminal electroacupuncture on spinal cord injury based on the Wnt/β-catenin signaling pathway.
Weixian WU ; Bin CHEN ; Jing LIU ; Li WANG ; Feizhen CHEN ; Yanling WU
Chinese Acupuncture & Moxibustion 2025;45(10):1442-1449
OBJECTIVE:
To observe the effects of ultrasound-guided foraminal electroacupuncture on neuronal apoptosis and motor function in rats with spinal cord injury (SCI), and to explore the potential underlying mechanisms.
METHODS:
Thirty-six SPF-grade Sprague-Dawley rats were randomly assigned to a sham operation group, a model group, and an ultrasound-guilded electroacupuncture group (electroacupuncture group), with 12 rats in each group. In the sham operation group, the spinal cord was exposed and then the incision was sutured without contusion. In the other two groups, SCI models were established using a modified Allen's impact method. On days 1, 3, 7, and 14 after modeling, the electroacupuncture group received electroacupuncture intervention at the T9/T10 and T10/T11 intervertebral foramen under ultrasound guidance, avoiding spinal cord injury. Stimulation parameters were dense-disperse wave at 2 Hz/100 Hz and 1-2 mA for each session. Following interventions on days 1, 3, 7, and 14, the Basso-Beattie-Bresnahan (BBB) score was assessed; the inclined plane test was used to assess hindlimb grip strength in rats. After the intervention, HE staining was used to observe spinal cord morphology; TUNEL staining was used to detect neuronal apoptosis; ELISA was used to measure the serum levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor-alpha (TNF-α); Western blot was used to analyze the protein expression of Wnt-4, β-catenin, c-Myc, Bax, Bcl-2, and NeuN in spinal tissue; quantitative real-time PCR was used to detect the mRNA expression of Wnt-4, β-catenin, c-Myc, Bax, Bcl-2, and NeuN.
RESULTS:
Compared with the sham operation group, the model group showed significantly reduced BBB scores (P<0.05), and reduced inclined plane angles (P<0.05) at all time points. Compared with the model group, the electroacupuncture group exhibited increased BBB scores on days 3, 7, and 14 (P<0.05), and higher inclined plane angles on days 1, 3, 7, and 14 (P<0.05). Compared with the sham operation group, the model group showed disorganized spinal cord structure with increased inflammatory cells and necrotic neurons, higher number of apoptotic neurons in spinal tissue (P<0.05), elevated serum IL-6, IL-1β, and TNF-α levels (P<0.05), increased protein and mRNA expression of Wnt-4, β-catenin, c-Myc, and Bax (P<0.05), and decreased protein and mRNA expression of Bcl-2 and NeuN in spinal tissue (P<0.05). Compared with the model group, the electroacupuncture group had fewer inflammatory cells and apoptotic neurons in spinal tissue (P<0.05), reduced serum IL-6, IL-1β, and TNF-α levels (P<0.05), increased protein and mRNA expression of Wnt-4, β-catenin, Bcl-2, and NeuN (P<0.05), and decreased protein and mRNA expression of c-Myc and Bax in spinal tissue (P<0.05).
CONCLUSION
Ultrasound-guided foraminal electroacupuncture could improve motor function in rats with SCI, potentially by regulating the expression of molecules related to the Wnt-4/β-catenin signaling pathway to inhibit neuronal apoptosis and inflammatory responses.
Animals
;
Electroacupuncture/methods*
;
Spinal Cord Injuries/physiopathology*
;
Rats, Sprague-Dawley
;
Rats
;
Wnt Signaling Pathway
;
Male
;
Humans
;
Female
;
beta Catenin/metabolism*
;
Apoptosis
;
Ultrasonography
;
Tumor Necrosis Factor-alpha/genetics*
;
Spinal Cord/metabolism*
8.Automatic brain segmentation in cognitive impairment: Validation of AI-based AQUA software in the Southeast Asian BIOCIS cohort.
Ashwati VIPIN ; Rasyiqah BINTE SHAIK MOHAMED SALIM ; Regina Ey KIM ; Minho LEE ; Hye Weon KIM ; ZunHyan RIEU ; Nagaendran KANDIAH
Annals of the Academy of Medicine, Singapore 2025;54(8):467-475
INTRODUCTION:
Interpretation and analysis of magnetic resonance imaging (MRI) scans in clinical settings comprise time-consuming visual ratings and complex neuroimage processing that require trained professionals. To combat these challenges, artificial intelligence (AI) techniques can aid clinicians in interpreting brain MRI for accurate diagnosis of neurodegenerative diseases but they require extensive validation. Thus, the aim of this study was to validate the use of AI-based AQUA (Neurophet Inc., Seoul, Republic of Korea) segmentation software in a Southeast Asian community-based cohort with normal cognition, mild cognitive impairment (MCI) and dementia.
METHOD:
Study participants belonged to the community-based Biomarker and Cognition Study in Singapore. Participants aged between 30 and 95 years, having cognitive concerns, with no diagnosis of major psychiatric, neurological or systemic disorders who were recruited consecutively between April 2022 and July 2023 were included. Participants underwent neuropsychological assessments and structural MRI, and were classified as cognitively normal, with MCI or with dementia. MRI pre-processing using automated pipelines, along with human-based visual ratings, were compared against AI-based automated AQUA output. Default mode network grey matter (GM) volumes were compared between cognitively normal, MCI and dementia groups.
RESULTS:
A total of 90 participants (mean age at visit was 63.32±10.96 years) were included in the study (30 cognitively normal, 40 MCI and 20 dementia). Non-parametric Spearman correlation analysis indicated that AQUA-based and human-based visual ratings were correlated with total (ρ=0.66; P<0.0001), periventricular (ρ=0.50; P<0.0001) and deep (ρ=0.57; P<0.0001) white matter hyperintensities (WMH). Additionally, volumetric WMH obtained from AQUA and automated pipelines was also strongly correlated (ρ=0.84; P<0.0001) and these correlations remained after controlling for age at visit, sex and diagnosis. Linear regression analyses illustrated significantly different AQUA-derived default mode network GM volumes between cognitively normal, MCI and dementia groups. Dementia participants had significant atrophy in the posterior cingulate cortex compared to cognitively normal participants (P=0.021; 95% confidence interval [CI] -1.25 to -0.08) and in the hippocampus compared to cognitively normal (P=0.0049; 95% CI -1.05 to -0.16) and MCI participants (P=0.0036; 95% CI -1.02 to -0.17).
CONCLUSION
Our findings demonstrate high concordance between human-based visual ratings and AQUA-based ratings of WMH. Additionally, the AQUA GM segmentation pipeline showed good differentiation in key regions between cognitively normal, MCI and dementia participants. Based on these findings, the automated AQUA software could aid clinicians in examining MRI scans of patients with cognitive impairment.
Humans
;
Cognitive Dysfunction/pathology*
;
Magnetic Resonance Imaging/methods*
;
Male
;
Middle Aged
;
Female
;
Aged
;
Artificial Intelligence
;
Software
;
Dementia/diagnostic imaging*
;
Aged, 80 and over
;
Adult
;
Singapore
;
Neuropsychological Tests
;
Brain/pathology*
;
Cohort Studies
;
Gray Matter/pathology*
;
Southeast Asian People
9.Illness duration-related developmental trajectory of progressive cerebral gray matter changes in schizophrenia.
Xin CHANG ; Zhihuan YANG ; Yingjie TANG ; Xiaoying SUN ; Cheng LUO ; Dezhong YAO
Journal of Biomedical Engineering 2025;42(2):293-299
In different stages of schizophrenia (SZ), alterations in gray matter volume (GMV) of patients are normally regulated by various pathological mechanisms. Instead of analyzing stage-specific changes, this study employed a multivariate structural covariance model and sliding-window approach to investigate the illness duration-related developmental trajectory of GMV in SZ. The trajectory is defined as a sequence of brain regions activated by illness duration, represented as a sparsely directed matrix. By applying this approach to structural magnetic resonance imaging data from 145 patients with SZ, we observed a continuous developmental trajectory of GMV from cortical to subcortical regions, with an average change occurring every 0.208 years, covering a time window of 20.176 years. The starting points were widely distributed across all networks, except for the ventral attention network. These findings provide insights into the neuropathological mechanism of SZ with a neuroprogressive model and facilitate the development of process for aided diagnosis and intervention with the starting points.
Humans
;
Schizophrenia/pathology*
;
Gray Matter/pathology*
;
Magnetic Resonance Imaging
;
Disease Progression
;
Male
;
Female
;
Brain/pathology*
;
Cerebral Cortex/pathology*
;
Adult
10.A simulation study of nerve fiber activation in the lumbar segment under kilohertz-frequency transcutaneously spinal cord stimulation.
Qi XU ; Xinru LI ; Zhixin LU ; Yongchao WU
Journal of Biomedical Engineering 2025;42(2):300-307
Clinical trials have demonstrated that kilohertz-frequency transcutaneous spinal cord stimulation (TSCS) can be used to facilitate the recovery of sensory-motor function for patients with spinal cord injury, whereas the neural mechanism of TSCS is still undetermined so that the choice of stimulation parameters is largely dependent on the clinical experience. In this paper, a finite element model of transcutaneous spinal cord stimulation was used to calculate the electric field distribution of human spinal cord segments T 12 to L 2, whereas the activation thresholds of spinal fibers were determined by using a double-cable neuron model. Then the variation of activation thresholds was obtained by varying the carrier waveform, the interphase delay, the modulating frequency, and the modulating pulse width. Compared with the sinusoidal carrier, the usage of square carrier could significantly reduce the activation threshold of dorsal root (DR) fibers. Moreover, the variation of activation thresholds was no more than 1 V due to the varied modulating frequency and decreases with the increased modulating pulse width. For a square carrier at 10 kHz modulated by rectangular pulse with the frequency of 50 Hz and the pulse width of 1 ms, the lowest activation thresholds of DR fibers and dorsal column fibers were 27.6 V and 55.8 V, respectively. An interphase delay of 5 μs was able to reduce the activation thresholds of the DR fibers to 20.1 V. The simulation results can lay a theoretical foundation on the selection of TSCS parameters in clinical trials.
Humans
;
Spinal Cord Stimulation/methods*
;
Nerve Fibers/physiology*
;
Finite Element Analysis
;
Spinal Cord/physiology*
;
Computer Simulation
;
Spinal Cord Injuries/physiopathology*
;
Lumbosacral Region
;
Lumbar Vertebrae
;
Transcutaneous Electric Nerve Stimulation/methods*
;
Models, Neurological

Result Analysis
Print
Save
E-mail