Chronic Neuropathic Pain in SCI

Analysis of the influencing factors related to neuropathic pain in patients with spinal cord injuries: a retrospective study

BACKGROUND

The aim of this study was to investigate the related influencing factors of neuropathic pain (NP) in patients with spinal cord injury (SCI).

METHODS

Patients diagnosed with SCI between January 2016 and December 2019 in the Department of Rehabilitation Medicine, Affiliated Hospital of Guizhou Medical University, were screened for NP by using the Douleur Neuropathique 4 (DN4) questionnaire. A total of 133 patients diagnosed with SCI with NP were finally included in the study. We collected the patients' basic information, including gender, age, body mass index (BMI), disease course, injury segment, American Spinal Injury Association (ASIA) grade, occupation, educational level, whether painkillers were used, stability of economic support, and pain level. Univariate and multiple ordered logistic regression analyses were used to examine the influencing factors of NP in the patients with SCI.

RESULTS

The chi-square test revealed that disease course, injury level, severity of SCI (ASIA classification), stable economic support during hospitalization, and the use of painkillers had statistical significance (p < .01). A multivariate logistic regression analysis was performed to analyze the influencing factors of NP. ASIA grade, stable economic support, and use of painkillers were independent influencing factors of NP in patients with SCI, among which injury severity was the independent risk factor (odds ratio [OR] > 1). Stable economic support and painkiller use were protective factors (OR < 1).

CONCLUSIONS

In this study, we found no significant correlation between NP after SCI and sex, age, BMI, disease course, injury level, and occupation. However, the injury severity was an independent risk factor, and stable economic support and painkiller use were protective factors.

Precision spinal gene delivery-induced functional switch in nociceptive neurons reverses neuropathic pain

Second-order spinal cord excitatory neurons play a key role in spinal processing and transmission of pain signals to the brain. Exogenously-induced change in developmentally-imprinted excitatory neurotransmitter phenotype of these neurons to inhibitory has not yet been achieved. Here we use a subpial dorsal horn-targeted delivery of AAV (adeno-associated virus) vector(s) encoding GABA (gamma-Aminobutyric acid,) synthesizing-releasing inhibitory machinery in mice with neuropathic pain. Treated animals showed a progressive and complete reversal of neuropathic pain (tactile and brush-evoked pain behavior) which persisted for minimum 2.5 months post-treatment. The mechanism of this treatment effect results from the switch of excitatory to preferential inhibitory neurotransmitter phenotype in dorsal horn nociceptive neurons and a resulting increase in inhibitory activity in regional spinal circuitry after peripheral nociceptive stimulation. No detectable side effects (such as sedation, motor weakness or loss of normal sensation) were seen between 2-13 months post-treatment in naive adult mice, pigs and non-human primates. The use of this treatment approach may represent a potent and safe treatment modality in patients suffering from spinal cord- or peripheral nerve-injury induced neuropathic pain.

Morphine Resistance in Spinal Cord Injury-Related Neuropathic Pain in Rats is Associated With Alterations in Dopamine and Dopamine-Related Metabolomics

Opioids are not universally effective for treating neuropathic pain following spinal cord injury (SCI), a finding that we previously demonstrated in a rat model of SCI. The aim of this study was to determine analgesic response of morphine-responsive and nonresponsive SCI rats to adjunct treatment with dopamine modulators and to establish if the animal groups expressed distinct metabolomic profiles. Thermal thresholds were tested in female Long Evans rats (N = 45) prior to contusion SCI, after SCI and following injection of morphine, morphine combined with dopamine modulators, or dopamine modulators alone. Spinal cord and striatum samples were processed for metabolomics and targeted mass spectrometry. Morphine provided analgesia in 1 of 3 of SCI animals. All animals showed improved analgesia with morphine + pramipexole (D3 receptor agonist). Only morphine nonresponsive animals showed improved analgesia with the addition of SCH 39166 (D1 receptor antagonist). Metabolomic analysis identified 3 distinct clusters related to the tyrosine pathway that corresponded to uninjured, SCI morphine-responsive and SCI morphine-nonresponsive groups. Mass spectrometry showed matching differences in dopamine levels in striatum and spinal cord between these groups. The data suggest an overall benefit of the D3 receptor system in improving analgesia, and an association between morphine responsiveness and metabolomic changes in the tyrosine/dopamine pathways in striatum and spinal cord. PERSPECTIVE: Spinal cord injury (SCI) leads to opioid-resistant neuropathic pain that is associated with changes in dopamine metabolomics in the spinal cord and striatum of rats. We present evidence that adjuvant targeting of the dopamine system may be a novel pain treatment approach to overcome opioid desensitization and tolerance after SCI.

Effectiveness of Hydrotherapy on Neuropathic Pain and Pain Catastrophization in Patients With Spinal Cord Injury: Protocol for a Pilot Trial Study

Background

Neuropathic pain (NP) is one of the most frequent spinal cord injury (SCI) complications. Pain, quality of life, and functionality are associated and can lead to pain catastrophization. Pharmacological management of patients with NP secondary to SCI is widely known and there is increasing evidence in the area. Nevertheless, nonpharmacological management is not fully elucidated since its efficacy is inconclusive.

Objective

We hypothesize that (1) hydrotherapy is effective in reducing NP secondary to SCI. Additionally, our secondary hypotheses are that (2) hydrotherapy decreases the catastrophization of NP, and that (3) hydrotherapy improves life quality and minimizes the degree of disability, when compared to physical therapy.

Methods

A sample of approximately 20 participants will be randomly assigned to either the intervention (hydrotherapy) or control group (standard physical therapy). Both interventions will be administered twice a week over a 9-week period (18 sessions in total). Primary outcomes are changes in neuropathic pain perception and pain catastrophization. Secondary outcomes are changes in disability and quality of life scores. They will be assessed at baseline and follow-up at 4 weeks after discharge. Validated Spanish language scales that will be used are the following: Numerical Pain Rating Scale, Pain Catastrophization, Health-related Quality of life, and the World Health Organization’s Disability Assessment Schedule 2.0. Generalized mixed linear models will be used for comparing baseline and postintervention means of each group and their differences, together with 95% CIs and P values. A P value of less than .05 will be considered significant.

Results

Recruitment began in April 2019, and we recruited the last participants by December 2019, with 10 individuals assigned to hydrotherapy and 8 to physical therapy (control). Results from this study will be disseminated via scientific publication, in ClinicalTrials.gov, and in national and international conferences in the latter half of 2022.

Conclusions

This trial will explore the effects of hydrotherapy on neuropathic pain, together with functionality and quality of life, in patients with SCI. Furthermore, this study aims to evaluate these therapeutic modalities, including perception variables, and mental processes, which may affect the clinical condition and rehabilitation outcomes in these patients. Hydrotherapy is likely to be a safe, efficient, and cost-effective alternative to the current standard of care for NP secondary to SCI, with comparable results between the two.

Trial Registration

ClinicalTrials.gov NCT04164810; https://clinicaltrials.gov/ct2/show/NCT04164810

International Registered Report Identifier (IRRID)

DERR1-10.2196/37255

Pregabalin and Gabapentin in Patients with Spinal Cord Injury-Related Neuropathic Pain: A Network Meta-Analysis

INTRODUCTION

This study was performed to explore the efficacy and safety of pregabalin and gabapentin in patients with spinal cord injury (SCI)-induced neuropathic pain to determine which treatment is most suitable for such patients.

METHODS

We searched the PubMed, MEDLINE, Embase, and Cochrane Library databases from database inception to August 31, 2020. The quality of the included studies was assessed. We selected the average pain intensity after treatment and the proportion of patients who discontinued treatment because of adverse effects as the outcome indicators for efficacy and safety, respectively. Statistical analyses were performed using Stata, v16.0, and RevMan, v5.3, software.

RESULTS

We included eight randomized controlled trials that examined four interventions (pregabalin, gabapentin, carbamazepine, and amitriptyline). Based on the average pain intensity after treatment, the efficacy order from highest to lowest was pregabalin, gabapentin, amitriptyline, carbamazepine, and placebo. Based on the proportion of patients who discontinued treatment because of adverse effects, the order from highest to lowest was pregabalin, amitriptyline, carbamazepine, gabapentin, and placebo. In addition, five studies reported the overall incidence of treatment-related adverse effects for two interventions (pregabalin and gabapentin). According to the pooled analysis of these studies, the order for the overall incidence of treatment-related adverse effects from highest to lowest was pregabalin, gabapentin, and placebo.

CONCLUSIONS

This study revealed that for patients with SCI-related neuropathic pain, pregabalin was the most effective for relieving pain, whereas gabapentin performed better in aspects associated with drug therapy-related safety.

Prevalence and impact of neuropathic and non-neuropathic pain in chronic spinal cord injury

OBJECTIVE

Compare prevalence, intensity ratings, and interference ratings of neuropathic pain (NeuP) and nociceptive pain in people with chronic spinal cord injury (SCI) DESIGN: Cross-sectional survey SETTING: Six SCI Model System centers in the US PARTICIPANTS: Convenience sample of 391 individuals with traumatic SCI, aged 18 years or older, 81% male, 57% white INTERVENTIONS: Not applicable MAIN OUTCOME MEASURES: Survey based on the International Spinal Cord Injury Pain Basic Data Set (ISCIPBDS) and the Spinal Cord Injury Pain Instrument (SCIPI), including 0-10 numerical ratings of pain intensity and pain interference with daily activities, mood, and sleep RESULTS: 80% of those surveyed reported having at least one pain problem; 58% reported two or more pain problems; 56% had probable NeuP; and 49% had non-NeuP. When comparing ratings for all pains (n=354 for NeuP, n=290 for non-NeuP) across subjects, probable NeuPs were significantly more intense (6.9 vs. 5.7) and interfered more with activities (5.2 vs. 3.7), mood (4.9 vs. 3.2), and sleep (5.4 vs. 3.6) than non-NeuPs (all p<0.001). However, when comparing ratings for probable NeuPs and non-NeuPs within subjects, for the subgroup of 94 participants with both pain types, only ratings for sleep interference were found to be significantly different between the pain types . Additionally, we found significantly greater prevalence of NeuP and non-NeuP for women compared to men, and of NeuP for those with paraplegia compared to those with tetraplegia.

CONCLUSIONS

Independent assessment of the pain conditions experienced by an individual with SCI is useful in understanding the differential impact that pain type has on quality of life. This is particularly important with regard to sleep interference and should be kept in mind when determining treatment strategies for meeting patient-centered outcome goals.

Interrelationship of Neurogenic Obesity and Chronic Neuropathic Pain in Persons With Spinal Cord Injury

The prevalence of obesity and of neuropathic pain are both estimated at above 50% in the population of people with chronic spinal cord injury (SCI). These secondary consequences of SCI have significant negative impact on physical functioning, activities of daily living, and quality of life. Investigations of relationships between weight or body composition and chronic neuropathic pain in people with SCI are lacking, but investigations in non-SCI cohorts suggest an association between obesity and the presence and severity of neuropathic pain conditions. In the present article, we present a review of the literature linking obesity and neuropathic pain and summarize findings suggesting that metabolic syndrome and chronic, systemic inflammation due to excess adiposity increase the risk for neuropathic pain after an SCI.

Changes to Biceps and Supraspinatus Tendons in Response to a Progressive Maximal Treadmill-Based Propulsion Aerobic Fitness Test in Manual Wheelchair Users: A Quantitative Musculoskeletal Ultrasound Study

Objective

To investigate if the completion of a recently developed treadmill-based wheelchair propulsion maximal progressive workload incremental test alters the integrity of the long head of the biceps and supraspinatus tendons using musculoskeletal ultrasound imaging biomarkers.

Method

Fifteen manual wheelchair users completed the incremental test. Ultrasound images of the long head of the biceps and supraspinatus tendons were recorded before, immediately after, and 48 hours after the completion of the test using a standardized protocol. Geometric, composition, and texture-related ultrasound biomarkers characterized tendon integrity.

Results

Participants propelled during 10.2 ± 2.9 minutes with the majority (N = 13/15) having reached at least the eighth stage of the test (speed = 0.8 m/s; slope = 3.6°). All ultrasound biomarkers characterizing tendon integrity, measured in the longitudinal and transversal planes for both tendons, were similar (p = 0.063 to 1.000) across measurement times.

Conclusion

The performance of the motorized treadmill wheelchair propulsion test to assess aerobic fitness produced no changes to ultrasound biomarkers of the biceps or supraspinatus tendons. Hence, there was no ultrasound imaging evidence of a maladaptive response due to overstimulation in these tendons immediately after and 48 hours after the performance of the test.

Treatments that are perceived to be helpful for non-neuropathic pain after traumatic spinal cord injury: a multicenter cross-sectional survey

STUDY DESIGN

Cross-sectional survey.

OBJECTIVES

The objective of the study was to identify the treatments that people with traumatic spinal cord injury (SCI) used for their non-neuropathic pains (nonNeuPs) and how they subjectively rated the helpfulness of those treatments.

SETTING

Six centers from the Spinal Cord Injury Model Systems.

METHODS

Three hundred ninety one individuals who were at least 1-year post-traumatic SCI were enrolled. A telephone survey was conducted for pharmacologic and non-pharmacologic treatments utilized in the last 12 months for each participant's three worst pains and the perceived helpfulness of each treatment for each pain.

RESULTS

One hundred ninety (49%) participants reported at least one nonNeuP (Spinal Cord Injury Pain Instrument score < 2) in the previous 7 days. NSAIDs/aspirin, acetaminophen, opioids, and cannabinoids were the most commonly used and helpful pharmacologic treatments for overall nonNeuP locations (helpful in 77-89% of treated pains). Body position adjustment, passive exercise, massage, resistive exercise, and heat therapy were reported as the most commonly used non-pharmacological treatments for nonNeuPs. Heat therapy, aerobic exercise, massage, and body position adjustment were the most helpful non-pharmacological treatments for overall nonNeuP locations (helpful in 71-80% of treated pains). Perceived helpfulness of treatments varied by pain locations, which may be due to different mechanisms underlying pains in different locations.

CONCLUSIONS

Results of the study may help guide clinicians in selecting pain-specific treatments for nonNeuPs. The self-reported helpfulness of heat therapy, exercise, and massage suggests a possible direction for clinical trials investigating these treatments of nonNeuP while limiting the side effects accompanying pharmacologic treatments.

Mental Imagery as a Rehabilitative Therapy for Neuropathic Pain in People With Spinal Cord Injury: A Randomized Controlled Trial

BACKGROUND

Pain of neuropathic origin in spinal cord injury (SCI) is unbearable and challenging to treat. Research studies conducted in the past have shown that mental imagery (MI) techniques have a significant impact on the reduction of symptoms of central neuropathic pain in people with SCI.

OBJECTIVES

The objective of this study was to evaluate the effect of MI training on pain intensity, neuropathic pain symptoms, and interference of pain with function in SCI.

METHODS

A total of 42 SCI participants with central neuropathic pain (duration 6-12 months) were recruited and randomly allocated to MI or control groups. A MI training protocol was administered to MI group and for 30 min/d for 5 days. Outcome measures were assessed at baseline and at the end of 4 weeks.

RESULTS

There was significant reduction in differences of mean [95% CI] scores of numeric rating scale (-2.1 [CI -2.78 to -1.41]; P < .001) between groups. Mean [95% CI] total scores of Neuropathic Pain Symptom Inventory declined in MI group as compared with control group (-4.52 [CI -5.86 to -3.18]; P < .001). Similarly, Brief Pain Inventory interference scale total dropped significantly (P < .001) in MI group. Majority of participants in the MI group (55%) reported improvement in scores of Patients' Global Impression of Change scale as compared with control group where most of the participants (52%) reported no change.

CONCLUSIONS

This study shows the effectiveness of the MI protocol developed as a rehabilitative approach in improving central neuropathic pain in SCI. Trial Registration. Clinical Trials Registry-India under Indian Council of Medical Research; CTRI/2018/07/014884. Registered July 16, 2018.

Intercellular communication and ion channels in neuropathic pain chronicization

BACKGROUND

Neuropathic pain is caused by primary lesion or dysfunction of either peripheral or central nervous system. Due to its complex pathogenesis, often related to a number of comorbidities, such as cancer, neurodegenerative and neurovascular diseases, neuropathic pain still represents an unmet clinical need, lacking long-term effective treatment and complex case-by-case approach.

AIM AND METHODS

We analyzed the recent literature on the role of selective voltage-sensitive sodium, calcium and potassium permeable channels and non-selective gap junctions (GJs) and hemichannels (HCs) in establishing and maintaining chronic neuropathic conditions. We finally focussed our review on the role of extracellular microenvironment modifications induced by resident glial cells and on the recent advances in cell-to-cell and cell-to-extracellular environment communication in chronic neuropathies.

CONCLUSION

In this review, we provide an update on the current knowledge of neuropathy chronicization processes with a focus on both neuronal and glial ion channels, as well as on channel-mediated intercellular communication.

What determines low satisfaction with life in individuals with spinal cord injury?

OBJECTIVE

To examine variables associated with satisfaction with life (SWL) in individuals with a spinal cord injury (SCI).

DESIGN

Cross-sectional, national survey to assess SWL, demographic and injury characteristics, health care utilization, chronic conditions (obesity, diabetes, heart problems, lung problems, hypertension, high cholesterol), symptoms (poor sleep, pain, depression), social support, grief/loss, and independence.

SETTING/PARTICIPANTS

Community-dwelling Veterans with SCI. Outcome Measures/Analyses: Bivariate analyses were conducted to assess differences in demographics, injury characteristics, chronic conditions, symptoms, social support, grief/loss, and independence in individuals who reported low SWL (≤20) vs. average/high SWL (21-35). Multivariate logistic regression assessed factors independently associated with low SWL.

RESULTS

896 Veterans with SCI (62%) responded. Average age was 62 years, the majority were male (94%), Caucasian (77%), and had paraplegia (61%). Odds of low SWL were 2.4 times greater for individuals experiencing pain (OR = 2.43, CI95: 1.47-4.02, P = 0.0005). Odds of low SWL were increased for individuals reporting greater grief/loss due to their SCI (OR = 1.14, CI95: 1.10-1.18, P < 0.0001). Lesser odds of low SWL were seen for individuals reporting greater emotional social support (OR = 0.97, CI95: 0.96-0.99, P < 0.0001) and independence (OR = 0.94, CI95: 0.90-0.97, P < 0.0001).

CONCLUSIONS

Pain and feelings of grief/loss due to injury were associated with low SWL. Self-perceived independence and good social support were associated with better SWL. Along with addressing pain and facilitating independence and social support, these findings suggest that interventions to improve SWL should focus on helping individuals deal with grief/loss due to injury.

Autonomic Dysreflexia as a Potential Adverse Effect of Duloxetine and Amitriptyline Combination Therapy: A Case Report

Pharmacologic triggers of autonomic dysreflexia (AD) have rarely been described. This report describes the case of a 31-year-old woman with T3 American Spinal Injury Association Impairment Scale A spinal cord injury who developed recurrent AD while receiving duloxetine and amitriptyline combination therapy for neuropathic pain. After excluding other AD generators, duloxetine was discontinued and the AD episodes resolved. Although secondary hypertension is a known side effect of amitriptyline and duloxetine, neither drug has been previously associated with AD. One potential mechanism for inhibition of duloxetine metabolism is discussed. Unexplained AD in at-risk patients receiving duloxetine and amitriptyline should prompt consideration of an adverse reaction to combination therapy. LEVEL OF EVIDENCE: V.

Promoting Long-Term Health among People with Spinal Cord Injury: What's New?

A key ingredient to successful health promotion is a primary care provider who can offer an informed first response to lifestyle issues, emerging problems and chronic challenges. This article aims to assist family physicians to play their role in promoting the health of people with SCI, by summarizing the latest evidence in the management of spinal cord injury in primary care. This study used a scoping review methodology to survey peer-reviewed journal articles and clinical guidelines published between January 2012 to June 2016. This search strategy identified 153 articles across 20 topics. A prevention framework is used to identify five primary, nine secondary, four tertiary, and two quaternary prevention issues about which family physicians require current information. Major changes in the management of SCI in primary care were noted for 8 of the 20 topics, specifically in the areas of pharmacological management of neuropathic pain and urinary tract infection; screening for bowel and bladder cancer; improvements in wound care; and clarification of dietary fibre recommendations. All of these changes are represented in the 3rd edition of Actionable Nuggets-an innovative tool to assist family physicians to be aware of the best practices in primary care for spinal cord injury.

Effectiveness of amitriptyline and lamotrigine in traumatic spinal cord injury-induced neuropathic pain: a randomized longitudinal comparative study

STUDY DESIGN

Randomized longitudinal comparative study.

OBJECTIVES

To compare the efficacy of lamotrigine and amitriptyline in the management of traumatic spinal cord injury (SCI)-induced neuropathic pain (NP).

SETTING

Sawai Man Singh Medical College and Hospital, Jaipur, India.

METHODS

A total of 147 individuals with NP were randomized for a 3-week trial of either amitriptyline or lamotrigine. Amitriptyline was administered orally at doses of 25, 50 and 100 mg once daily at night time, and lamotrigine was administered orally at doses of 25, 50 and 100 mg twice daily, both for 1 week by means of optional titration. Assessment of NP was done at baseline and thereafter at 1, 2 and 3 weeks using Short-form MC Gill Pain Questionnaire-2 (SFMPQ2) scores.

RESULTS

There was a significant difference between the mean values of the SFMPQ2 score at baseline and those at each follow-up for amitriptyline. Similar results were seen in the lamotrigine group. When the differences in mean SFMPQ2 scores at different time frames from baseline were compared with those of the other group, values were found to be nonsignificant as seen on the Mann-Whitney U-test.

CONCLUSIONS

These findings support the use of both amitriptyline and lamotrigine in the management of NP after traumatic SCI.

Changes in Pain Processing in the Spinal Cord and Brainstem after Spinal Cord Injury Characterized by Functional Magnetic Resonance Imaging

Traumatic spinal cord injury (SCI) has a number of devastating consequences, including high prevalence of chronic pain and altered pain sensitivity. The causes of altered pain states vary depending on the injury and are difficult to diagnose and treat. A better understanding of pain mechanisms after SCI is expected to lead to better diagnostic capabilities and improved treatments. We therefore applied functional magnetic resonance imaging (fMRI) of the brainstem and spinal cord in a group of participants with previous traumatic SCI to characterize changes in pain processing as a result of their injuries. The same thermal stimulus was applied to the medial palm (C8 dermatome) as a series of repeated brief noxious thermal pulses in a group of 16 participants with a cervical (n = 14) and upper thoracic (n = 2) injuries. Functional MRI of the brainstem and spinal cord was used to determine the neuronal activity evoked by the noxious stimulation, and connectivity between regions was characterized with structural equation modeling (SEM). The results show that pain ratings, the location and magnitude of blood oxygenation-level dependent fMRI results, and connectivity assessed with SEM varied widely across participants. However, the results varied in relation to the perceived pain and the level/severity of injuries, particularly in terms of hypothalamus connectivity with other regions, and descending modulation via the periaqueductal gray matter-rostral ventromedial medulla-cord pathway. The results, therefore, appear to provide sensitive indicators of each individual's pain response, and information about the mechanisms of altered pain sensitivity. The ability to characterize changes in pain processing in individuals with SCI represents a significant technological advance.