Injury Pain Research Articles

One-Step Cartilage Repair of Full-Thickness Knee Chondral Lesions Using a Hyaluronic Acid-Based Scaffold Embedded With Bone Marrow Aspirate Concentrate: Long-term Outcomes After Mean Follow-up Duration of 14 Years.

One-step cell-based techniques of cartilage repair that lead to restoration of durable chondral tissue and long-term maintenance of joint function are cost-effective and ideal for routine use. To examine the long-term clinical outcomes, after a mean follow-up duration of 14 years, of cartilage repair in the knee using a hyaluronic acid-based scaffold in association with bone marrow aspirate concentrate (HA-BMAC) and to evaluate the effect of age, lesion characteristics, and associated treatments on the outcome of this cartilage repair method. Case series; Level of evidence, 4. Patients were followed prospectively for a mean duration of 14.0 years after undergoing treatment of knee full-thickness articular cartilage injury using HA-BMAC. Clinical evaluation consisted of the patient-reported scoring tools of the visual analog scale and the Knee injury and Osteoarthritis Outcome Score, which were completed preoperatively and at the time of final follow-up. A total of 26 patients with a mean age of 48.3 years (17 male, 9 female) and median chondral lesion size of 6.6 cm2 (range, 1-27 cm2) were followed prospectively. There were 3 treatment failures, and 1 patient who underwent medial compartment unicompartmental arthroplasty 12 years after HA-BMAC treatment of patellar chondral injury. Of the 22 remaining patients, after a mean final follow-up duration of 14.0 years (range, 12-16 years), the median visual analog scale score of 0.6 was significantly decreased from the preoperative median score of 5.0 (P < .001). The median Knee injury and Osteoarthritis Outcome Score Pain (92), Symptoms (86), Activities of Daily Living (96), Sports (85), and Quality of Life (88) subscale values were all increased compared with the preoperative scores (P≤ .001). There was no correlation of clinical outcome score and body mass index. One-step cartilage repair of full-thickness chondral defects in the knee using an HA-BMAC led to successful long-term clinical outcomes and maintenance of joint junction after a mean follow-up duration of 14 years. Long-term clinical success in active, nonobese patients has been uniformly demonstrated across a wide range of patient ages and lesion types, including cases of multicompartment involvement, treatment of associated conditions, and large or bipolar chondral lesions.

Adherence to Physical Activity Guidelines in Manual Wheelchair Users With Spinal Cord Injury and the Association With Shoulder Pain.

The aim of the study is to investigate the association between adherence to spinal cord injury-specific physical activity guidelines in manual wheelchair users with spinal cord injury and shoulder pain prevalence. This is a cross-sectional analysis of the SwiSCI Community Survey 2022 data, assessing aerobic activity and muscle strength training adherence in manual wheelchair users with spinal cord injury and shoulder pain prevalence. Logistic regression analysis was used to identify the association between meeting the physical activity guidelines and shoulder pain. Low adherence to aerobic activity and strength training guidelines are observed, with 46% and 64% of the study sample not meeting the respective guidelines. The low adherence to physical activity guidelines contrasts with the general Swiss population from which around 75% is physically active for more than 2.5 hrs a week. Manual wheelchair users present a high prevalence of shoulder pain (40%) and nonadherence to aerobic guidelines in the study sample correlates with 1.55-1.97 higher odds of having shoulder pain. Aerobic activity adherence is associated with lower shoulder pain prevalence, emphasizing its potential for injury prevention. Overall, the presented findings necessitate further longitudinal studies and interventions for a comprehensive understanding and effective management of shoulder pain in manual wheelchair users with spinal cord injury.

The Holistic MAP to Athletic Wellness: A Narrative Review

You can’t use an old map to explore a new world. —Albert Einstein We are at a fork in the evolutionary road to athletic wellness. While elite athletes are achieving unsurpassed magnificence in strength, endurance, power, and skill, much of our population is experiencing a devolution from poor lifestyle choices that negatively influence both human and planetary health. The alarming descent to a lesser state of collective health puts most of our sedentary population at greater risk of injury, disease, dysfunction, and chronic pain. The father of sports medicine, Herodicus, was the first known physician to recommend exercise for the treatment of disease, recognizing its powerful influence on quality of life and health span. Athletic participation is linked with improved physical and mental health, as well as reduced obesity, disability, and disease. However, sports may also result in physical, psychological, social, athletic, professional, and financial repercussions.1 The international scientific community has rallied with tremendous research over the past decades to promote sustainable athletic participation and healthy active living. While tremendous efforts have been launched to engage in this challenging endeavor, a significant problem remains due to the multifactorial nature of athletic injuries. The full potential for body-mind-spirit resilience and wellness is achieved through the balance of all interdependent components, considering all possible biological, psychological, social, and spiritual factors influencing each athlete to establish an individualized, holistic mindset, agility, and personalization (MAP) approach toward injury-free sports and active living.

Emotional awareness and expression difficulties in relation to pain experiences in people with brain injury and chronic pain: preliminary investigation

ABSTRACT Objectives Preliminary examination of emotional awareness/expression relationships with pain in people with traumatic brain injury (TBI) and chronic pain (CP) and exploration of psychological factors as mediators or moderators of these relationships. Methods Cross-sectional study in adults (N = 59) with chronic TBI and CP using Toronto Alexithymia Scale-20 Difficulty Identifying and Describing Feelings subscales; Ambivalence over Emotional Expressiveness Questionnaire; Emotional Approach Coping Scale; PROMIS Pain Intensity and Pain Interference scales, Michigan Body Map (pain widespreadness); headache frequency; Pain Catastrophizing Scale; Brief Symptom Inventory-18 (psychological distress), and Post-traumatic Stress Checklist-Civilian. Results Difficulty Identifying Feelings was positively associated with pain intensity, pain interference, and headache frequency. Difficulty Describing Feelings was positively correlated with pain interference and headache frequency. Emotional Approach Coping was inversely correlated with headache frequency. Emotional awareness/expression relationships with pain outcomes were mediated by Pain Catastrophizing; Difficulty Describing Feelings relationships with Pain Interference and headache frequency were mediated by psychological distress; and Difficulty Describing Feelings associations with Pain Interference were mediated by post-traumatic stress. No moderators were identified. Conclusion These preliminary findings suggest that emotional awareness/expression is linked to pain in adults with TBI and CP, which may be connected via pain catastrophizing and psychological distress. If longitudinal studies with larger samples produce similar findings, researchers should explore training emotional awareness/expression for possible pain management after TBI.

Small-molecule natural product sophoricoside reduces peripheral neuropathic pain via directly blocking of NaV1.6 in dorsal root ganglion nociceptive neurons.

Peripheral neuropathic pain poses a significant global health challenge. Current drugs for peripheral neuropathic pain often fall short in efficacy or come with severe side effects, emphasizing the critical need for the development of highly effective and well-tolerated alternatives. Sophoricoside (SOP) is a nature product-derived isoflavone that possesses various pharmacological effects on inflammatory and neuropathy diseases. Here, in this study, analgesic effect was investigated by intrathecally administration of SOP/vehicle to spared nerve injury (SNI) or paclitaxel-induced peripheral neuropathic pain (PINP) rodent models, and mechanical allodynia was measured in Von Frey tests. Ipsilateral L4-L6 dorsal root ganglia (DRG) were used for protein expression. In silico molecular docking analysis was applied for assessing compound-target binding affinity. Primary cultured DRG neurons were utilized to investigate SOP's effect on veratridine-triggered nociceptor activities and its selective inhibition of voltage-gated sodium channels subtype 1.6 (NaV1.6). The results showed SOP treatment alleviated mechanical allodynia in SNI and PINP rodent models (paw withdrawal threshold after 1 h of injection: SNI-vehicle: 1.385 ± 0.338 g; SNI-SOP: 9.963 ± 2.029 g, P < 0.001; PINP-vehicle: 5.040 ± 0.985 g; PINP-SOP: 8.287 ± 3.812 g, P = 0.004). SOP presented effects on both inhibiting veratridine-triggered nociceptor activities (oscillatory population: vehicle: 39.9 ± 7.3%; SOP: 30.7 ± 9.8%, P = 0.021) and selectively blocking NaV1.6 in DRG sensory neurons. Molecular docking analysis indicated direct binding between SOP and NaV1.6, leading to its endocytosis in DRG Sensory Neurons. In conclusion, SOP alleviated nociceptive allodynia induced by peripheral nerve injury via selectively blocking of NaV1.6 in DRG nociceptive neurons. we highlight its potential as an analgesic and elucidate its mechanism involving NaV1.6 endocytosis. This research opens avenues for exploring the analgesic effects of SOP and its potential impact on neuropathic pain therapy.

Bedside Neuromodulation of Persistent Pain and Allodynia with Caloric Vestibular Stimulation.

Caloric vestibular stimulation (CVS) is a well-established neurological diagnostic technique that also induces many phenomenological modulations, including reductions in phantom limb pain (PLP), spinal cord injury pain (SCIP), and central post-stroke pain. We aimed to assess in a variety of persistent pain (PP) conditions (i) short-term pain modulation by CVS relative to a forehead ice pack cold-arousal control procedure and (ii) the duration and repeatability of CVS modulations. The tolerability of CVS was also assessed and has been reported separately. We conducted a convenience-based non-randomised single-blinded placebo-controlled study. Thirty-eight PP patients were assessed (PLP, n = 8; SCIP, n = 12; complex regional pain syndrome, CRPS, n = 14; non-specific PP, n = 4). Patients underwent 1-3 separate-day sessions of iced-water right-ear CVS. All but four also underwent the ice pack procedure. Analyses used patient-reported numerical rating scale pain intensity (NRS-PI) scores for pain and allodynia. Across all groups, NRS-PI for pain was significantly lower within 30 min post-CVS than post-ice pack (p < 0.01). Average reductions were 24.8% (CVS) and 6.4% (ice pack). CRPS appeared most responsive to CVS, while PLP and SCIP responses were less than expected from previous reports. The strongest CVS pain reductions lasted hours to over three weeks. CVS also induced substantial reductions in allodynia in three of nine allodynic CRPS patients, lasting 24 h to 1 month. As reported elsewhere, only one patient experienced emesis and CVS was widely rated by patients as a tolerable PP management intervention. Although these results require interpretative caution, CVS was found to modulate pain relative to an ice pack control. CVS also modulated allodynia in some cases. CVS should be examined for pain management efficacy using randomised controlled trials.

The effectiveness of effriction and frirage massage therapy in reducing pain in knee injuries: a comprehensive review of 1-month and 2-month injuries duration

The purpose of this study was to compare the effectiveness of effriction and frirage massage therapy methods in reducing pain in knee injuries. A total of 64 participants (Male, BMI = 21.48 kg/m2, Age ± SD = 24,07 ± 2.72), who were classified by 1-month and 2-month injury duration, underwent various therapy regimens with 10-minute and 15-minute treatment durations. The data collection instrument used the NPRS scale. The results of the analysis showed that the effriction intervention significantly reduced knee pain in injuries with a history of 1 month and 2 months, with a consistent reduction in pain at both 10 and 15 minute durations (p-value = 0.000). In contrast, frirage interventions also showed a reduction in pain, but their effectiveness varied; A significant reduction in pain was only observed at a 10-minute duration for a 1-month history injury (p-value = 0.041) and at a 15-minute duration for a 2-month history injury (p-value = 0.028). There was no significant reduction in pain in frirage with a duration of 10 minutes for 2 months of injury and a duration of 15 minutes for 1 month of injury. Overall, the effriction technique is more effective than frirage in reducing knee pain in traumatic injuries. These findings support the recommendation to use effriction as the primary method in knee pain therapy, while frirage may be considered for more specific contexts. Keywords: Effriction; frirage; massage therapy; knee injuries; therapy duration

ID: 332552 Mapping Hybrid Structural-Functional Connectome in Individuals with Chronic Spinal Cord Injury and Neuropathic Pain

ID: 332552 Mapping Hybrid Structural-Functional Connectome in Individuals with Chronic Spinal Cord Injury and Neuropathic Pain

Discovery of a novel KV7.2/7.3 channels agonist for the treatment of neuropathic pain

Here, we designed, synthesized and evaluated a series of compounds as KV7.2/7.3 channels (or KCNQ2/3) agonists. The new compounds were assayed in vitro for KCNQ2/3 and other receptors binding affinity. The desired compound 16 showed high activity for KCNQ2/3 (EC50 = 1.03 ± 0.07 μM) without acute liver injury compared to flupirtine. It demonstrated powerful dose-dependent effects in multiple analgesic models, such as chronic constriction injury (CCI, ED50 = 12.02 mg/kg) and streptozotocin-induced diabetic peripheral neuropathic pain (DPNP, ED50 = 9.63 mg/kg) models. Additionally, compound 16 showed low affinity for human ether-a-go-go-related gene (hERG), high thresholds for acute toxicity, good motor performance in the rotarod test and acceptable pharmacokinetic properties. These results suggest the potentiality of compound 16 for the treatment of neuropathic pain.

Genicular artery embolisation versus sham embolisation for symptomatic osteoarthritis of the knee: a randomised controlled trial

ObjectiveTo determine the efficacy of genicular artery embolisation (GAE) compared with sham GAE for pain reduction in patients with symptomatic mild-to-moderate knee osteoarthritis (KOA).DesignDouble-blind randomised sham-controlled clinical trial conducted from...

Effects of Cannabidiol (CBD) on Doxorubicin-Induced Anxiety and Depression-like Behaviors and mRNA Expression of Inflammatory Markers in Rats.

Background: Post-treatment side effects of chemotherapy can include cognitive deficits commonly known as Chemo-brain. The treatment of patients with Doxorubicin (DOX), one of the most widely used chemotherapeutic drugs in the treatment of cancer, can induce depression, anxiety, and impaired cognitive function. Cannabidiol (CBD) is a non-psychoactive component of Cannabis sativa that has been identified as a possible therapeutic agent against many neurodegenerative disorders, including traumatic brain injury, spinal cord injury, Tau-protein-induced neurodegeneration, and neuropathic pain. Therefore, this study aimed to assess whether oral CBD administration could reduce DOX-induced anxiety and depression-like behaviors and alter the expression of mRNA associated with neuroinflammation. Methods: Female Long Evans Hooded rats received intraperitoneal injections of DOX (6 mg/kg) or the vehicle (0.9% saline) once a week for four weeks, followed by oral administration of CBD (10 mg/kg) three times a week for the same period. Results: CBD was significantly protective against DOX-induced anxiety and depression-like behaviors, as measured by several behavioral tests. Furthermore, CBD improved DOX-induced alterations in the gene expression of biomarkers of neuroinflammation in the hippocampus and prefrontal cortex. Conclusions: This provides insights into future studies on possible mechanisms by which DOX-induced cognitive dysfunction could be alleviated by CBD.

Establishment of a Magnetically Controlled Scalable Nerve Injury Model.

Animal models of peripheral nerve injury (PNI) serve as the fundamental basis for the investigations of nerve injury, regeneration, and neuropathic pain. The injury properties of such models, including the intensity and duration, significantly influence the subsequent pathological changes, pain development, and therapeutic efficacy. However, precise control over the intensity and duration of nerve injury remains challenging within existing animal models, thereby impeding accurate and comparative assessments of relevant cases. Here, a new model that provides quantitative and off-body controllable injury properties via a magnetically controlled clamp, is presented. The clamp can be implanted onto the rat sciatic nerve and exert varying degrees of compression under the control of an external magnetic field. It is demonstrated that this model can accurately simulate various degrees of pathology of human patients by adjusting the magnetic control and reveal specific pathological changes resulting from intensity heterogeneity that are challenging to detect previously. The controllability and quantifiability of this model may significantly reduce the uncertainty of central response and inter-experimenter variability, facilitating precise investigations into nerve injury, regeneration, and pain mechanisms.

Effect of Different Insertion Methods on LMA Protector-Related Complications: A Prospective Randomized Double-Blind Clinical Trail.

The authors compared the effect of 2 insertion methods, namely the conventional laryngeal mask airway (LMA) insertion and the index finger-assisted LMA insertion, on the incidence of complications associated with LMA Protector insertion. The authors enrolled 300 patients, who underwent painless bronchoscopy. The patients ranged in age between 18 and 75 and were classified as American Society of Anesthesiologists grade I to III. They were randomly divided into 2 groups: a control group of 150 patients and an assisted group comprising 150 patients. LMA was inserted using the conventional and index finger-assisted insertion methods in both groups, respectively. The primary outcome was postoperative complications, such as oral mucosal injury and pharyngeal pain. Secondary outcomes included the success rate of first-time insertion, the incidence rate of inverse folding of LMA tips, oropharyngeal leak pressure (OLP), and other postoperative complications. Compared with the conventional LMA insertion method, index finger-assisted LMA insertion can significantly reduce the incidence rate of oral mucosal injury and pharyngeal pain, with fewer insertion failures. There was a statistically significant difference between the 2 groups in the visual field grading before adjustment for LMA alignment (P<0.0001). The conventional insertion method increased the likelihood of inverse folding of LMA tips. When the conventional insertion method was utilized, there was a significant difference in airway pressure and tidal volume before and after alignment under a fiberoptic bronchoscope (P<0.0001), but no significant difference in visual field grading and respiratory mechanics-related indicators. Index finger-assisted insertion can significantly reduce the incidence rate of LMA Protector-related complications and inverse folding of LMA tips.

High failure rate but promising clinical performance after implantation of a flexible medial meniscus prosthesis at 1-year follow-up.

After unsatisfactory results in a first-in-human clinical investigation with an anatomically shaped medial meniscus prosthesis, the prosthesis and its fixation technique were altered. This interim analysis of a prospective single-arm clinical investigation aims to evaluate safety and clinical performance in a first-in-human study with the redesigned meniscus prosthesis system. Ten patients suffering from medial postmeniscectomy pain syndrome were treated with the meniscus prosthesis. Patient-reported outcome measures were obtained at baseline and at 6-week, 3-, 6-, and 12-month follow-up. Radiographs and magnetic resonance imaging scans were obtained to evaluate joint degeneration and prosthesis location. The device alterations resolved the issues occurring with the previous design, but four prostheses were explanted after fixation failure or subluxation of the prosthesis. Five out of six patients who reached 1-year follow-up reported a clinically significant improvement of the knee injury and osteoarthritis outcome score pain subscale. Imaging revealed no adverse effects on joint degeneration. The failure mechanisms that occurred with the previous design have been resolved, but the new fixation technique introduced new safety issues. Improvement of positioning and fixation techniques are considered essential future adaptations to reduce the risk of failure. The good clinical outcomes reported by the patients reaching 1-year follow-up indicate that the medial meniscus prosthesis is a potential solution for patients suffering from postmeniscectomy pain syndrome. Level II.

Which adults aged 65 and older are at low-risk for cervical spine injuries after low-level falls?

The population is aging and falls are a common reason for emergency department visits. Appropriate imaging in this population is important. The objectives of this study were to estimate the prevalence of cervical spine injury and identify factors associated with cervical spine injuries in adults ≥ 65years after low-level falls. This was a pre-specified sub-study of a prospective observational cohort study of intracranial bleeding in emergency patients ≥ 65years presenting after low-level falls. The primary outcome was cervical spine injury. The risk factors of interest were Glasgow coma scale (GCS) < 15, head injury, neck pain, age, and frailty defined as Clinical Frailty Scale ≥ 5. Multivariable logistic regression was used to measure the strength of association between risk factors and cervical spine injury. A descriptive analysis of absence of significant risk factors was performed to determine patients who may not require imaging. There were 4308 adults ≥ 65 who sustained low-level falls with mean age of 82.0 (standard deviation ± 8.8) years and 1538 (35.7%) were male; 23 [0.5% (95% confidence interval (CI) 0.3-0.8%)] were diagnosed with cervical spine injuries. The adjusted odds ratios and 95% CIs were 1.3 (0.5-3.2) for GCS < 15, 5.3 (1.7-26.7) for head injury, 13.0 (5.7-31.2) for new neck pain, 1.4 (1.0-1.8) for 5-year increase in age, and 1.1 (0.4-2.9) for frailty. Head injury or neck pain identified all 23 cervical spine injuries. Management was a rigid collar in 19/23 (82.6%) patients and none had surgery. In emergency patients ≥ 65years presenting after a low-level fall, head injury, neck pain, and older age were associated with the diagnosis of cervical spine injury. There were no cervical spine injuries in those without head injury or neck pain. Patients with no head injury or neck pain may not require cervical spine imaging.

Exoskeleton Training for Spinal Cord Injury Neuropathic Pain (ExSCIP): Protocol for a Phase 2 Feasibility Randomised Trial

Background Following Spinal Cord Injury (SCI), 53% of people develop neuropathic pain (NP). NP can be more debilitating than other consequences of SCI, and a persistent health issue. Pharmacotherapies are commonly recommended for NP management in SCI, although severe pain often remains refractory to these treatments in many sufferers. Furthermore, poor medication adherence exists, stemming from unacceptable side-effects and fear of dependency. Sensorimotor stimulation using active walking with robotic assistance has not been well studied in NP after SCI, despite convincing locomotor-based pre-clinical studies, identifying prevention and reversal of NP. Our primary aim is to assess the impact of exoskeleton-based walking on NP intensity and interference after SCI and examine feasibility outcomes for progression to a definitive trial. Methods This is a phase 2 single-blinded, randomised feasibility study. It will test the feasibility and acceptability of exoskeleton-based walking 3 times per week for 12 weeks (intervention), as a mechanistic-based intervention for NP after SCI. The comparator will be an equally dosed, blended relaxation programme devoid of motor imagery prompts. 40 participants with moderate-to-severe NP post SCI will be recruited and randomised to intervention and comparator groups. The primary outcomes are feasibility outcomes for progression to definitive trial which include recruitment and retention rates, adverse events and acceptability of the intervention. Secondary outcomes explore changes in NP intensity and interference as measured by the International Spinal Cord Injury Pain Basic Data Set 3.0 (ISCIPBDS) at baseline, post-intervention (week 13) and at 6-month follow-up. Conclusions There is a need to explore non-pharmacological management of NP after SCI. The findings of this feasibility trial will inform the development of a future multicentre, international RCT, Trial Registration NCT06463418, 08/07/2024, https://clinicaltrials.gov/study/NCT06463418.

Effect of aerobic exercise program on neuropathic pain and quality of life in person with paraplegia: study protocol for a randomized controlled trial

BackgroundIndividuals with spinal cord injury (SCI) often suffer from neuropathic pain which is often disabling and negatively affects function, participation, and quality of life (QoL). Pharmacological treatments lack efficacy in neuropathic pain reduction hence studying alternatives to drug treatment is necessary. Preclinical evidence of various aerobic exercises has shown positive effects on neuropathic pain but scientific studies investigating its effect in the SCI human population are limited.MethodologyThis study is a double-blind, parallel, two-group, randomized controlled trial with an interventional study design that aims to evaluate the effectiveness of aerobic exercise program on neuropathic pain and quality of life (QoL) in individuals with chronic paraplegia. Thirty individuals with chronic paraplegia with the neurological level of injury from T2 to L2 will be recruited from the rehabilitation department at a super specialty hospital based on the inclusion criteria. Using a 1:1 allocation ratio, the participants will be randomly assigned to one of the two groups. The intervention group will perform high-intensity interval training (HIIT) aerobic exercise using an arm ergometer based on their peak heart rate, and the control group will perform free-hand arm aerobic exercise. In both groups, the intervention will be delivered as 30-min sessions, four times a week for 6 weeks.Outcome measuresInternational Spinal Cord Injury Pain Basic Data Set Version 3.0 will be used for diagnosing and assessing neuropathic pain and its interference with day-to-day activities, mood, and sleep. The International Spinal Cord Society (ISCoS) QoL basic data set will be used to assess QoL, and 6-min push test distance will be used to assess peak heart rate and aerobic capacity.DiscussionThe effectiveness of the aerobic exercise program will be assessed based on the changes in neuropathic pain score and its interference with day-to-day activities, mood, sleep, QoL, and aerobic capacity after 3 weeks mid-intervention and after 6 weeks post-intervention. The trial will provide new knowledge about the effectiveness of the aerobic exercise program in improving neuropathic pain and QoL in individuals with chronic paraplegia.Trial registrationClinical Trials Registry-India CTRI/2023/08/056257. Registered on 8 August 2023.

Explorative sensory profile evaluation in central neuropathic pain following spinal cord injury.

Sensory profiling in neuropathic pain using quantitative sensory testing (QST) has not been extended to central neuropathic pain due to spinal cord injury (SCI). This study aims to fill this gap by evaluating sensory profiles in patients with neuropathic SCI pain. We retrospectively analysed consecutive QST data from 62 patients with neuropathic spinal cord injury pain (SCIP), following the German Research Network on Neuropathic Pain protocol. The study included at-level and below-level SCIP due to a spinal cord lesion, and at-level SCIP following a cauda equina lesion. QST parameters were compared between diagnostic groups. QST profiles of below-level SCIP (central neuropathic pain) were manually assigned to sensory phenotypes based on literature and expert opinion. No statistical difference in QST parameters between pain diagnoses was found. For central neuropathic pain (below-level SCIP), three phenotypes were descriptively observed: loss of function (59%), thermal and mechanical hyperalgesia combination (16%), and mechanical hyperalgesia (19%). The remaining 5% of patients did not fit a common pattern. There was no statistical difference in clinical and psychological variables between phenotypes. In a subgroup analysis, the loss of function phenotype weakly correlated with older age, longer time since injury, and longer pain duration. Here, we capture sensory phenotypes of central neuropathic pain following SCI. The limited sample size, high rate of missing values, and the retrospective nature of the study mean that results should be seen as strictly exploratory. Further research should replicate these findings and explore the significance of phenotypes. The evaluation of sensory phenotypes by quantitative sensory testing in central neuropathic pain due to SCI adds a new perspective on sensory phenotypes in comparison to peripheral neuropathic pain. The described thermal and mechanical hyperalgesia combination might represent involvement of the spinothalamic tract. In addition, there was a trend towards older age and longer time since injury in patients with loss of function.

Epigenetic Regulation and Molecular Mechanisms of Burn Injury-Induced Nociception in the Spinal Cord of Mice.

Epigenetic mechanisms, including histone post-translational modifications (PTMs), play a critical role in regulating pain perception and the pathophysiology of burn injury. However, the epigenetic regulation and molecular mechanisms underlying burn injury-induced pain remain insufficiently explored. Spinal dynorphinergic (Pdyn) neurons contribute to heat hyperalgesia induced by severe scalding-type burn injury through p-S10H3-dependent signaling. Beyond p-S10H3, burn injury may impact various other histone H3 PTMs. Double immunofluorescent staining and histone H3 protein analyses demonstrated significant hypermethylation at H3K4me1 and H3K4me3 sites and hyperphosphorylation at S10H3 within the spinal cord. By analyzing Pdyn neurons in the spinal dorsal horn, we found evidence of chromatin activation with a significant elevation in p-S10H3 immunoreactivity. We used RNA-seq analysis to compare the effects of burn injury and formalin-induced inflammatory pain on spinal cord transcriptomic profiles. We identified 98 DEGs for burn injury and 86 DEGs for formalin-induced inflammatory pain. A limited number of shared differentially expressed genes (DEGs) suggest distinct central pain processing mechanisms between burn injury and formalin models. KEGG pathway analysis supported this divergence, with burn injury activating Wnt signaling. This study enhances our understanding of burn injury mechanisms and uncovers converging and diverging pathways in pain models with different origins.

“I don’t know the correct way to describe it”: neuropathic pain experiences among athletes with spinal cord injury

BackgroundChronic pain among athletes is often misinterpreted as tissue damage resulting from sport. While researchers have started to examine neuropathic pain among athletes with spinal cord injury (SCI), there is...