A prospective study of pain and psychological functioning following traumatic spinal cord injury

Mental health impairment and recovery after a road traffic injury: where do we stand in Europe?

Individuals sustaining road traffic injuries (RTIs) have been shown to run an increased risk of impaired mental health over time and delayed recovery. It is often the case that mental health symptoms get less clinical attention among individuals sustaining RTIs and therefore psychological support tends to be delayed. Effective management of these aspects in a clinical setting is still challenging in Europe due to health systems' unpreparedness to predict the risk of poor mental health outcomes among survivors and appropriately intervene. Although a considerable amount of research is available in Australia, Canada and the US, the problem is still under-investigated in Europe. This paper reports on a review of the literature, which aims at identifying and presenting the latest research on the predisposing risk factors of poor mental health recovery among individuals sustaining an RTI in Europe. The review identified a huge mental health burden remaining long after the road traffic incident and a complex interplay of factors affecting mental health recovery after an RTI. Several challenges have been identified including the lack of a consistent definition for mental health recovery, the use of heterogeneous instruments and non-consistent epidemiological approaches and the lack of data collection mechanisms in Europe to capture the true impact of injuries. The paper concludes that existing efforts to fully understand the mental health outcomes of RTI patients remain inconsistent in Europe and offers evidence-based solutions to guide public health research and policy.

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

BACKGROUND

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.

METHOD

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.

RESULTS

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.

CONCLUSIONS

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.

SIGNIFICANCE STATEMENT

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.

Unraveling the physiological and psychosocial signatures of pain by machine learning

BACKGROUND

Pain is a complex subjective experience, strongly impacting health and quality of life. Despite many attempts to find effective solutions, present treatments are generic, often unsuccessful, and present significant side effects. Designing individualized therapies requires understanding of multidimensional pain experience, considering physical and emotional aspects. Current clinical pain assessments, relying on subjective one-dimensional numeric self-reports, fail to capture this complexity.

METHODS

To this aim, we exploited machine learning to disentangle physiological and psychosocial components shaping the pain experience. Clinical, psychosocial, and physiological data were collected from 118 chronic pain and healthy participants undergoing 40 pain trials (4,697 trials).

FINDINGS

To understand the objective response to nociception, we classified pain from the physiological signals (accuracy >0.87), extracting the most important biomarkers. Then, using multilevel mixed-effects models, we predicted the reported pain, quantifying the mismatch between subjective level and measured physiological response. From these models, we introduced two metrics: TIP (subjective index of pain) and Φ (physiological index). These represent possible added value in the clinical process, capturing psychosocial and physiological pain dimensions, respectively. Patients with high TIP are characterized by frequent sick leave from work and increased clinical depression and anxiety, factors associated with long-term disability and poor recovery, and are indicated for alternative treatments, such as psychological ones. By contrast, patients with high Φ show strong nociceptive pain components and could benefit more from pharmacotherapy.

CONCLUSIONS

TIP and Φ, explaining the multidimensionality of pain, might provide a new tool potentially leading to targeted treatments, thereby reducing the costs of inefficient generic therapies.

FUNDING

RESC-PainSense, SNSF-MOVE-IT197271.

The Relationship Between Physical Activity and Mental Health Among Individuals With Spinal Cord Injury: Protocol for a Scoping Review

BACKGROUND

Spinal cord injury (SCI) is a devastating condition that often leads to significant impairments in physical function, leading to disability and mental health disorders. Hence, understanding the prevalence of SCI and the relationship between physical activity and mental health in individuals with SCI is crucial for informing rehabilitation strategies and optimizing outcomes.

OBJECTIVE

This study aims to comprehensively analyze existing research on the link between physical activity and mental health and identify the level of physical activity and mental health status, the barriers to physical activity, and SCI's impacts on psychological well-being in individuals with SCI.

METHODS

An electronic search strategy will be used to identify prevalence studies published since 1993 in health-related databases such as PubMed, MEDLINE, COCHRANE Library, and Wiley Library using the following query: "Spinal Cord Injury" OR "Paraplegia" OR "Tetraplegia" AND "Physical Activity" OR "Exercise" AND "Mental Health" OR "Mental Illness" OR "Mental Disorder." Bibliographies of primary studies and review articles meeting the inclusion criteria will be searched manually to identify further eligible studies. The risk of bias in the included studies will be appraised using the Joanna Briggs Institute checklist for prevalence studies by 2 review authors. Any disagreement will be resolved by reaching a consensus.

RESULTS

Funding was received in October 2023, data collection will commence in July 2024, and the results are expected by 2025. We will summarize the selection of the eligible studies using a flowchart. The data from the studies will be extracted and tabulated. This scoping review will be published in a peer-reviewed journal in accordance with PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) guidelines.

CONCLUSIONS

This scoping review underscores the complex relationship between physical activity and mental health among individuals with SCI, highlighting the level of physical activity and mental health status, barriers to physical activity engagement, and psychological implications. Understanding these dynamics is crucial in devising tailored interventions aimed at enhancing mental well-being. This synthesis of evidence emphasizes the need for personalized strategies to promote physical activity, addressing unique challenges faced by this population to foster improved mental health outcomes and overall quality of life.

TRIAL REGISTRATION

Open Science Framework osf.io/ugx7d; https://osf.io/ugx7d/.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/56081.

Reciprocal association between pain and quality of life after newly acquired spinal cord injury

PURPOSE

Pain is highly prevalent in spinal cord injury (SCI) and a key determinant of quality of life (QoL). This is the first study to examine reciprocal associations between pain and QoL in patients undergoing their first inpatient rehabilitation after SCI.

METHODS

Longitudinal data, with three measurement time points (1 month and 3 months after SCI onset, and at discharge from inpatient rehabilitation) from the Inception Cohort of the Swiss Spinal Cord Injury Cohort Study. Participants were 381 individuals aged ≥ 16 years with a newly diagnosed traumatic or non-traumatic SCI. 75.1% were male and the average age was 53.2 years. Random intercept cross-lagged panel models were conducted to examine the reciprocal association between pain intensity and QoL, as measured with the International SCI QoL Basic Data Set three individual items (satisfaction with life, physical health, and psychological health) and total score (mean of the three individual items).

RESULTS

Both item and total QoL scores increased over time. 1 month: 5.3 (SD = 2.7), 3 months: 5.9 (SD = 2.3), discharge: 6.6 (SD = 2.0). Participants reported relatively low levels of pain intensity that remained stable over the course of inpatient rehabilitation. 1 month: 2.7 (SD = 2.3), 3 months: 2.6 (SD = 2.4), discharge: 2.7 (SD = 2.5). There were no significant cross-lagged associations between QoL and pain intensity across time.

CONCLUSION

Results indicate that pain intensity does not predict changes in QoL during first rehabilitation, and vice versa. Associations between pain intensity and QoL reported by previous studies may be attributable to individual characteristics and timely events that simultaneously influence pain and QoL.

Treatments perceived to be helpful for neuropathic pain after traumatic spinal cord injury: A multicenter cross-sectional survey study

DESIGN

Cross-sectional survey.

OBJECTIVE

To evaluate the perceived helpfulness of pharmacological and non-pharmacological interventions and their combinations for neuropathic pain (NeuP) and subcategories of NeuP after spinal cord injury (SCI).

SETTING

Six Spinal Cord Injury Model System Centers.

METHODS

Three hundred ninety one individuals at least one year post traumatic SCI were enrolled. A telephone survey was conducted to determine the pharmacologic and non-pharmacologic treatments used in the last 12 months for each participant's three worst pains, whether these treatments were "helpful", and if currently used, each treatments' effectiveness.

RESULTS

Two hundred twenty participants (56%) reported 354 distinct NeuPs. Pharmacological treatments rated helpful for NeuP were non-tramadol opioids (opioids were helpful for 86% of opioid treated NeuPs), cannabinoids (83%), and anti-epileptics (79%). Non-pharmacological treatments rated helpful for NeuP were massage (76%), body position adjustment (74%), and relaxation therapy (70%). Those who used both opioids and exercise reported greater NeuP treatment helpfulness compared to participants using opioids without exercise (P = 0.03).

CONCLUSIONS

Opioids, cannabinoids, and massage were reported more commonly as helpful than treatments recommended as first-line therapies by current clinical practice guidelines (CPGs) for NeuP after SCI (antiepileptics and antidepressants). Individuals with SCI likely value the modulating effects of pharmacological and non-pharmacological treatments on the affective components of pain in addition to the sensory components of pain when appraising treatment helpfulness.

Omega-conotoxin MVIIA reduces neuropathic pain after spinal cord injury by inhibiting N-type voltage-dependent calcium channels on spinal dorsal horn

Spinal cord injury (SCI) leads to the development of neuropathic pain. Although a multitude of pathological processes contribute to SCI-induced pain, excessive intracellular calcium accumulation and voltage-gated calcium-channel upregulation play critical roles in SCI-induced pain. However, the role of calcium-channel blockers in SCI-induced pain is unknown. Omega-conotoxin MVIIA (MVIIA) is a calcium-channel blocker that selectively inhibits N-type voltage-dependent calcium channels and demonstrates neuroprotective effects. Therefore, we investigated spinal analgesic actions and cellular mechanisms underlying the analgesic effects of MVIIA in SCI. We used SCI-induced pain model rats and conducted behavioral tests, immunohistochemical analyses, and electrophysiological experiments (in vitro whole-cell patch-clamp recording and in vivo extracellular recording). A behavior study suggested intrathecal MVIIA administration in the acute phase after SCI induced analgesia for mechanical allodynia. Immunohistochemical experiments and in vivo extracellular recordings suggested that MVIIA induces analgesia in SCI-induced pain by directly inhibiting neuronal activity in the superficial spinal dorsal horn. In vitro whole-cell patch-clamp recording showed that MVIIA inhibits presynaptic N-type voltage-dependent calcium channels expressed on primary afferent Aδ-and C-fiber terminals and suppresses the presynaptic glutamate release from substantia gelatinosa in the spinal dorsal horn. In conclusion, MVIIA administration in the acute phase after SCI may induce analgesia in SCI-induced pain by inhibiting N-type voltage-dependent calcium channels on Aδ-and C-fiber terminals in the spinal dorsal horn, resulting in decreased neuronal excitability enhanced by SCI-induced pain.

Exploring the Experience of Living with Pain after Spinal Cord Injury: A Qualitative Study

A spinal cord injury is a life-changing experience that results in functional limitations and an increased risk of secondary health conditions. People with spinal cord injury identify pain as the most devastating health problem following their injury that not only affects their social life but their mental well-being as well. This study is aimed at exploring the lived experience of living with pain by community-dwelling manual wheelchair users with spinal cord injuries. An explorative qualitative design was used to explore their experiences. In-depth interviews were recorded and transcribed, and the data were analysed using inductive thematic content analysis in the MAXQDA v2020. Fifteen manual wheelchair users with paraplegia participated in this study, and four themes were identified from their experience of living with pain: pain constantly lurks, pain is worse than the direct consequences of the SCI, pain is restrictive, and life continues despite the pain. Categories and subcategories included the participants being one with the pain; pain interfering with sleep; feelings of anger, isolation, and suicidal ideation; and uncertainties about what the future holds living with pain. Living with pain after SCI is a challenging feat, and effective management of pain is necessary to improve not only functioning and mobility but also mental health and life satisfaction.

Central neuropathic pain

Central neuropathic pain arises from a lesion or disease of the central somatosensory nervous system such as brain injury, spinal cord injury, stroke, multiple sclerosis or related neuroinflammatory conditions. The incidence of central neuropathic pain differs based on its underlying cause. Individuals with spinal cord injury are at the highest risk; however, central post-stroke pain is the most prevalent form of central neuropathic pain worldwide. The mechanisms that underlie central neuropathic pain are not fully understood, but the pathophysiology likely involves intricate interactions and maladaptive plasticity within spinal circuits and brain circuits associated with nociception and antinociception coupled with neuronal hyperexcitability. Modulation of neuronal activity, neuron-glia and neuro-immune interactions and targeting pain-related alterations in brain connectivity, represent potential therapeutic approaches. Current evidence-based pharmacological treatments include antidepressants and gabapentinoids as first-line options. Non-pharmacological pain management options include self-management strategies, exercise and neuromodulation. A comprehensive pain history and clinical examination form the foundation of central neuropathic pain classification, identification of potential risk factors and stratification of patients for clinical trials. Advanced neurophysiological and neuroimaging techniques hold promise to improve the understanding of mechanisms that underlie central neuropathic pain and as predictive biomarkers of treatment outcome.

A Case Study of Hypnosis Enhanced Cognitive Therapy for Pain in a Ventilator Dependent Patient during Inpatient Rehabilitation for Spinal Cord Injury

Early, acute pain following spinal cord injury (SCI) is common, can negatively impact SCI rehabilitation, and is frequently not responsive to biomedical treatment. Nonpharmacological interventions show promise in reducing pain for individuals with SCI. However, most psychological interventions rely heavily on verbal interaction between the individual being treated and the clinician, making them inaccessible for individuals with impaired verbal output due to mechanical ventilation. This case study aims to describe the adaptation and implementation of hypnotic cognitive therapy (HYP-CT) intervention for early SCI pain in the context of mechanical ventilation dependence and weaning. The participant was a 54-year-old male with C2 AIS A SCI requiring mechanical ventilation. Four sessions of HYP-CT were provided during inpatient rehabilitation with assessment prior to intervention, after the intervention sessions, and prior to discharge. The participant reported immediate reductions in pain intensity following each intervention session. Overall, he reported increases in self-efficacy and pain acceptance. He did not report any negative treatment effects and thought the intervention provided support during mechanical ventilation weaning. During treatment, he discontinued opioid pain medications and reported actively using intervention strategies. Our results support the potential for early, hypnotic cognitive therapy for individuals with SCI experiencing pain or distress while dependent on mechanical ventilation.

Differential target multiplexed spinal cord stimulation using a paddle-type lead placed at the appropriate site for neuropathic pain after spinal cord injury in patients with past spinal surgical histories: study protocol for an exploratory clinical trial

BACKGROUND

Neuropathic pain after spinal cord injury (SCI), both traumatic and non-traumatic, is refractory to various treatments. Spinal cord stimulation (SCS) is one of the neuromodulation therapies for neuropathic pain, although SCS has insufficient efficacy for neuropathic pain after SCI. The reasons are presumed to be inappropriate locations of SCS leads and conventional tonic stimulation itself does not have a sufficient analgesic effect for the pain. In patients with past spinal surgical histories, the cylinder-type leads are likely to be placed on the caudal side of the SCI because of surgical adhesions. Differential target multiplexed (DTM) stimulation is one of the latest new stimulation patterns that is superior to conventional stimulation.

METHODS

A single-center, open-label, randomized, two-way crossover trial is planned to investigate the efficacy of SCS using DTM stimulation placing a paddle lead at the appropriate site for neuropathic pain after SCI in patients with spinal surgical histories. The paddle-type lead delivers energy more efficiently than a cylinder-type lead. This study consists of two steps: SCS trial (first step) and SCS system implantation (second step). The primary outcome is rates of achieving pain improvement with more than 33% reduction 3 months after SCS system implantation. The secondary outcomes are to be evaluated as follows: (1) effectiveness of DTM and tonic stimulations during the SCS trial; (2) changes of assessment items from 1 to 24 months; (3) relationships between the result of the SCS trial and the effects 3 months after SCS system implantation; (4) preoperative factors associated with a long-term effect, defined as continuing for more than 12 months; and (5) whether gait function improves from 1 to 24 months.

DISCUSSION

A paddle-type lead placed on the rostral side of SCI and using DTM stimulation may provide significant pain relief for patients with intractable neuropathic pain after SCI in patients with past spinal surgical histories.

TRIAL REGISTRATION

Japan Registry of Clinical Trials (jRCT) jRCT 1042220093. Registered on 21 November 2022, and last modified on 6 January 2023. jRCT is approved as a member of the Primary Registry Network of WHO ICTRP.

Prevalence of secondary health conditions and mental status in persons with long-term spinal cord injury in South Africa: Comparison between public and private healthcare sectors

BACKGROUND

Spinal cord injuries typically result in a range of negative health outcomes and health states, which impacts overall functioning, health and well-being. It remains important to establish the prevalence (burden) of health outcomes to help with the development of optimal treatment strategies.

OBJECTIVES

To determine the prevalence and treatment rates of secondary health conditions (SHCs) and mental health states in persons with long-term spinal cord injury (SCI) receiving public compared with private healthcare services in South Africa.

METHODS

A cross-sectional survey included 200 community-dwelling persons with long-term SCI, 60% with paraplegia, 53% with complete injuries and 156 from the public and 44 from private healthcare sectors. The following modules of the International Spinal Cord Injury (InSCI) community survey were used: (i) demographic and injury characteristics; (ii) SHCs and treatment rates; and (iii) vitality and emotional well-being. All statistical analyses were stratified according to healthcare sector.

RESULTS

Pain (47% v. 57), sexual dysfunction (59% v. 41%) and muscle spasms (54% v. 43%) were the most common SHCs in both cohorts, and the period prevalence was significantly higher for sleeping problems (41% v. 25%), sexual dysfunction (59% v. 41%) and contractures (42% v. 20%) in the public compared with the private cohort. Persons with SCI in the private cohort received treatment more often for sleeping problems (100% v. 45%), autonomic dysreflexia (75% v. 27%) and pain (56% v. 33%) than their counterparts with public insurance. Negative mental health states were prevalent in both groups.

CONCLUSION

SHCs and negative mental health were common in persons with SCI in South Africa, while those with public insurance reporter a higher occurrence of sleep problems and contractures, as well as lower treatment rates. Overall, a need exists to better support persons with SCI in the long-term context to facilitate improved functioning and wellbeing.

Opioid Dependence and Associated Health Care Utilization and Cost in Traumatic Spinal Cord Injury Population: Analysis Using Marketscan Database

Background

Postinjury pain is a well-known debilitating complication of spinal cord injury (SCI), often resulting in long-term, high-dose opioid use with the potential for dependence. There is a gap in knowledge about the risk of opioid dependence and the associated health care utilization and cost in SCI.

Objectives

To evaluate the association of SCI with postinjury opioid use and dependence and evaluate the effect of this opioid dependence on postinjury health care utilization.

Methods

Using the MarketScan Database, health care utilization claims data were queried to extract 7187 adults with traumatic SCI from 2000 to 2019. Factors associated with post-SCI opioid use and dependence, postinjury health care utilization, and payments were analyzed with generalized linear regression models.

Results

After SCI, individuals were more likely to become opioid users or transition from nondependent to dependent users (negative change: 31%) than become nonusers or transition from dependent to nondependent users (positive change: 14%, p < .0001). Individuals who were opioid-dependent users pre-SCI had more than 30 times greater odds of becoming dependent after versus not (OR 34; 95% CI, 26-43). Dependent users after injury (regardless of prior use status) had 2 times higher utilization payments and 1.2 to 6 times more health care utilization than nonusers.

Conclusion

Opioid use and dependence were associated with high health care utilization and cost after SCI. Pre-SCI opioid users were more likely to remain users post-SCI and were heavier consumers of health care. Pre- and postopioid use history should be considered for treatment decision-making in all individuals with SCI.

Paving the way for a better management of pain in patients with spinal cord injury: An exploratory study on the use of Functional Electric Stimulation(FES)-cycling

CONTEXT/OBJECTIVE

Chronic pain is common in patients with spinal cord injury (SCI), for whom it negatively affects quality of life, and its treatment requires an integrated approach. To this end, lower limb functional electrical stimulation (FES) cycling holds promise.

OBJECTIVE

To investigate pain reduction in a sample of patients with SCI by means of lower limb rehabilitation using FES cycling.

DESIGN, SETTING AND PARTICIPANTS

Sixteen patients with incomplete and complete SCIs, attending the Neurorobotic Unit of our research institute and reporting pain at or below the level of their SCI were recruited to this exploratory study.

INTERVENTIONS

Patients undertook two daily sessions of FES cycling, six times weekly, for 6 weeks.

OUTCOME MEASURES

Pain outcomes were measured using the 0-10 numerical rating scale (NRS), the Multidimensional Pain Inventory for SCI (MPI-SCI), and the 36-Item Short Form Survey (SF-36). Finally, we assessed the features of dorsal laser-evoked potentials (LEPs) to objectively evaluate Aδ fiber pathways.

RESULTS

All participants tolerated the intervention well, and completed the training without side effects. Statistically significant changes were found in pain-NRS, MPI-SCI, and SF-36 scores, and LEP amplitudes. Following treatment, we found that three patients experienced high pain relief (an NRS decrease of at least 80%), six individuals achieved moderate pain relief (an NRS decrease of about 30-70%), and five participants had mild pain relief (an NRS decrease of less than 30%).

CONCLUSION

Our preliminary results suggest that FES cycling training is capable of reducing the pain reported by patients with SCI, regardless of American Spinal Injury Association scoring, pain level, or the neurological level of injury. The neurophysiological mechanisms underlying such effects are likely to be both spinal and supraspinal.

Ten-year safety of pluripotent stem cell transplantation in acute thoracic spinal cord injury

OBJECTIVE

The purpose of this study was to evaluate the safety of oligodendrocyte progenitor cells (LCTOPC1) derived from human pluripotent stem cells administered between 7 and 14 days postinjury to patients with T3 to T11 neurologically complete spinal cord injury (SCI). The rationale for this first-in-human trial was based on evidence that administration of LCTOPC1 supports survival and potential repair of key cellular components and architecture at the SCI site.

METHODS

This study was a multisite, open-label, single-arm interventional clinical trial. Participants (n = 5) received a single intraparenchymal injection of 2 × 106 LCTOPC1 caudal to the epicenter of injury using a syringe positioning device. Immunosuppression with tacrolimus was administered for a total of 60 days. Participants were followed with annual in-person examinations and MRI for 5 years at the time of this report and will be followed with annual telephone questionnaires for 6 to 15 years postinjection. The primary endpoint was safety, as measured by the frequency and severity of adverse events related to the LCTOPC1 injection, the injection procedure, and/or the concomitant immunosuppression administered. The secondary endpoint was neurological function as measured by sensory scores and lower-extremity motor scores as measured by the International Standards for Neurological Classification of Spinal Cord Injury examinations.

RESULTS

No unanticipated serious adverse events related to LCTOPC1 have been reported with 98% follow-up of participants (49 of 50 annual visits) through the first 10 years of the clinical trial. There was no evidence of neurological decline, enlarging masses, further spinal cord damage, or syrinx formation. MRI results during the long-term follow-up period in patients administered LCTOPC1 cells showed that 80% of patients demonstrated T2 signal changes consistent with the formation of a tissue matrix at the injury site.

CONCLUSIONS

This study provides crucial first-in-human safety data supporting the pursuit of future human embryonic stem cell-derived therapies. While we cannot exclude the possibility of future adverse events, the experience in this trial provides evidence that this cell type can be well tolerated by patients, with an event-free period of up to 10 years. Based on the safety profile of LCTOPC1 obtained in this study, a cervical dose escalation trial was initiated (NCT02302157).

Non-invasive Brain Stimulation for Central Neuropathic Pain

The research and clinical application of the noninvasive brain stimulation (NIBS) technique in the treatment of neuropathic pain (NP) are increasing. In this review article, we outline the effectiveness and limitations of the NIBS approach in treating common central neuropathic pain (CNP). This article summarizes the research progress of NIBS in the treatment of different CNPs and describes the effects and mechanisms of these methods on different CNPs. Repetitive transcranial magnetic stimulation (rTMS) analgesic research has been relatively mature and applied to a variety of CNP treatments. But the optimal stimulation targets, stimulation intensity, and stimulation time of transcranial direct current stimulation (tDCS) for each type of CNP are still difficult to identify. The analgesic mechanism of rTMS is similar to that of tDCS, both of which change cortical excitability and synaptic plasticity, regulate the release of related neurotransmitters and affect the structural and functional connections of brain regions associated with pain processing and regulation. Some deficiencies are found in current NIBS relevant studies, such as small sample size, difficulty to avoid placebo effect, and insufficient research on analgesia mechanism. Future research should gradually carry out large-scale, multicenter studies to test the stability and reliability of the analgesic effects of NIBS.

The demographics of pain after spinal cord injury: a survey of our model system

STUDY DESIGN

Survey OBJECTIVES: Better understand the demographics of pain after spinal cord injury (SCI).

SETTING

Academic Level 1 trauma center and SCI Model System.

METHODS

A survey including general demographic questions, questions of specific interest to the authors, the standardized SCI Pain Instrument (SCIPI), International SCI Pain Data Set, Basic form (ISCIPDS:B), Patient Reported Outcomes Measurement Information System (PROMIS) neuropathic 5a (PROMIS-Neur), and PROMIS nociceptive 5a (PROMIS-No).

RESULTS

81% of individuals with SCI experience chronic pain and 86% of individuals with pain have neuropathic pain. 55% of individuals had shoulder pain. Females and those who recall >5/10 pain during initial hospital stay had significantly higher PROMIS-Neur scores. Completeness of injury correlates inversely with the degree of neuropathic pain. Those who recall >5 pain during the initial hospital stay and those who reported the worst or second worst pain as being shoulder pain had significantly higher PROMIS-No scores. Lumbosacral injuries trended towards higher PROMIS-No scores and had the highest PROMIS-Neur scores. Those with tetraplegia were more likely to develop shoulder pain and those with shoulder pain had higher PROMIS-No scores.

CONCLUSIONS

Chronic pain is almost universal in patients with SCI. Pain is more commonly reported as neuropathic in nature and females reported more neuropathic pain than males. Physicians should monitor for nociceptive shoulder pain, particularly in those with tetraplegia. Patients with incomplete injuries or lumbosacral injuries are more likely to report higher levels of neuropathic pain and pain levels should be monitored closely. Those with more neuropathic and nociceptive pain recall worse pain at initial hospitalization. Better understanding pain demographics in this population help screen, prevent and manage chronic pain in these patients.

Sleep apnea and unilateral upper and lower extremity allodynia as a result of a large thoracic disc herniation: a case report

Background

Clinically significant disc herniations in the thoracic spine are rare accounting for approximately 1% of all disc herniations. In patients with significant spinal cord compression, presenting symptoms typically include ambulatory dysfunction, lower extremity weakness, lower extremity sensory changes, as well as bowl, bladder, or sexual dysfunction. Thoracic disc herniations can also present with thoracic radiculopathy including midback pain and radiating pain wrapping around the chest or abdomen. The association between thoracic disc herniation with cord compression and sleep apnea is not well described.

Case presentation

The following is a case of a young male patient with high grade spinal cord compression at T7-8, as a result of a large thoracic disc herniation. The patient presented with complaints of upper and lower extremity unilateral allodynia and sleep apnea. Diagnosis was only made once the patient manifested more common symptoms of thoracic stenosis including left lower extremity weakness and sexual dysfunction. Following decompression and fusion the patient’s allodynia and sleep apnea quickly resolved.

Conclusions

Thoracic disc herniations can present atypically with sleep apnea. We recommend taking into consideration that sleep symptoms may resolve when planning treatment for thoracic disc herniation.

Maladaptive reorganization following SCI: The role of body representation and multisensory integration

In this review we focus on maladaptive brain reorganization after spinal cord injury (SCI), including the development of neuropathic pain, and its relationship with impairments in body representation and multisensory integration. We will discuss the implications of altered sensorimotor interactions after SCI with and without neuropathic pain and possible deficits in multisensory integration and body representation. Within this framework we will examine published research findings focused on the use of bodily illusions to manipulate multisensory body representation to induce analgesic effects in heterogeneous chronic pain populations and in SCI-related neuropathic pain. We propose that the development and intensification of neuropathic pain after SCI is partly dependent on brain reorganization associated with dysfunctional multisensory integration processes and distorted body representation. We conclude this review by suggesting future research avenues that may lead to a better understanding of the complex mechanisms underlying the sense of the body after SCI, with a focus on cortical changes.

How Do Fluctuations in Pain, Fatigue, Anxiety, Depressed Mood, and Perceived Cognitive Function Relate to Same-Day Social Participation in Individuals With Spinal Cord Injury?

OBJECTIVE

This study aimed to examine same-day associations of pain, fatigue, depressed mood, anxiety, and perceived cognitive function with social participation in the daily lives of adults with spinal cord injury (SCI).

DESIGN

Observational study used a combination of baseline surveys and 7 end-of-day (EOD) diaries.

SETTING

General community.

PARTICIPANTS

Individuals with SCI (N=168; mean age, 49.8y; 63% male, 37% female).

MAIN OUTCOME MEASURES

Patient-Reported Outcomes Measurement Information System short form measures (Ability to Participate in Social Roles and Activities, Pain Intensity, Depression, Anxiety, Cognitive Function Abilities) were adapted for daily administrations as EOD diaries.

RESULT

Results of multivariable model showed that daily increases in fatigue (B=-0.10; P=.004) and depressive symptoms (B=-0.25; P=<.001) and decreases in perceived cognitive function (B=0.11; P=<.001) were significantly related to worse same-day social participation. Daily fluctuations in anxiety and pain were unrelated to same-day social participation.

CONCLUSIONS

This is the first study that shows within-person associations of common SCI symptoms with social participation in the daily lives of adults with SCI. Results from the current study may help to develop more effective individualized treatments of symptoms and symptom effect aimed at improving social participation.

Variability in clinical and neurophysiological evaluation of pain development following acute spinal cord injury: a case report

INTRODUCTION

Chronic neuropathic pain (NeP) often develops following traumatic spinal cord injury (SCI). This case report explores variability in clinical and neurophysiological aspects of pain evaluation in early post-trauma stages.

CASE PRESENTATION

A 34-year old female presenting with acute incomplete sensorimotor tetraplegia C4 AIS D was examined by neurological examination and pain assessment at three time points after acute trauma T1 (8 weeks), T2 (11 weeks), and T3 (24 weeks). Quantitative sensory testing (QST) and laser-evoked potentials (LEPs) were measured above (control area), at (area of NeP), and below (foot) the neurological level of injury (NLI). Musculo-skeletal and neuropathic pain were clinically present already during T1 but showed variations in localization and occurrence over time. Neuropathic pain classification varied between time points due to shifting of NLI. Above-level QST revealed minor, less pronounced abnormalities similar to at-level site. At-level QST (site of NeP) showed loss for thermal and mechanical detection thresholds but also gain of function for mechanical pain thresholds with a tendency of amelioration over time. QST below-level did not reveal remarkable changes over time. LEPs above- and below-level were within normal limits. At-level LEPs abolished after T1.

DISCUSSION

In early stages post injury (up to 6 month) variations in pain presentation for both, musculo-skeletal and neuropathic pain as well as QST and LEP could be demonstrated. These findings suggest ongoing adaption mechanisms in sensory pathways, which require further exploration and may be relevant for prognostic and preventive strategies against the development of chronic neuropathic and nociceptive pain.

1-kHz high-frequency spinal cord stimulation alleviates chronic refractory pain after spinal cord injury: a case report

Background

Patients with spinal cord injury (SCI) frequently complain of intractable pain that is resistant to conservative treatments. Here, we report the successful application of 1-kHz high-frequency spinal cord stimulation (SCS) in a patient with refractory neuropathic pain secondary to SCI.

Case presentation

A 69-year-old male diagnosed with SCI (C4 American Spinal Injury Association Impairment Scale A) presented with severe at-level bilateral upper extremity neuropathic pain. Temporary improvement in his symptoms with a nerve block implied peripheral component involvement. The patient received SCS, and though the tip of the leads could not reach the cervical vertebrae, a 1-kHz frequency stimulus relieved the intractable pain.

Conclusions

SCI-related symptoms may include peripheral components; SCS may have a considerable effect on intractable pain. Even when the SCS electrode lead cannot be positioned in the target area, 1-kHz high-frequency SCS may still produce positive effects.

During capsaicin-induced central sensitization, brush allodynia is associated with baseline warmth sensitivity, whereas mechanical hyperalgesia is associated with painful mechanical sensibility, anxiety and somatization

BACKGROUND

Mechanical hyperalgesia and allodynia incidence varies considerably amongst neuropathic pain patients. This study explored whether sensory or psychological factors associate with mechanical hyperalgesia and brush allodynia in a human experimental model.

METHODS

Sixty-six healthy volunteers (29 male) completed psychological questionnaires and participated in two quantitative sensory testing (QST) sessions. Warmth detection threshold (WDT), heat pain threshold (HPT) and suprathreshold mechanical pain (STMP) ratings were measured before exposure to a capsaicin-heat pain model (C-HP). After C-HP exposure, brush allodynia and STMP were measured in one session, whilst mechanical hyperalgesia was measured in another session.

RESULTS

WDT and HPT measured in sessions separated by 1 month demonstrated significant but moderate levels of reliability (WDT: ICC = 0.5, 95%CI [0.28, 0.77]; HPT: ICC = 0.62, 95%CI [0.40, 0.77]). Brush allodynia associated with lower WDT (z = -3.06, p = 0.002; ϕ = 0.27). Those with allodynia showed greater hyperalgesia intensity (F = 7.044, p = 0.010, η_p ²  = 0.107) and area (F = 9.319, p = 0.004, η_p ²  = 0.163) than those without allodynia. No psychological self-report measures were significantly different between allodynic and nonallodynic groups. Intensity of hyperalgesia in response to lighter mechanical stimuli was associated with lower HPT, higher STMP ratings and higher Pain Sensitivity Questionnaire scores at baseline. Hyperalgesia to heavier probe stimuli associated with state anxiety and to a lesser extent somatic awareness. Hyperalgesic area associated with lower baseline HPT and higher STMP ratings. Hyperalgesic area was not correlated with allodynic area across individuals.

CONCLUSIONS

These findings support research in neuropathic pain patients and human experimental models that peripheral sensory input and individual sensibility are related to development of mechanical allodynia and hyperalgesia during central sensitization, whilst psychological factors play a lesser role.

SIGNIFICANCE

We evaluated differential relationships of psychological and perceptual sensitivity to the development of capsaicin-induced mechanical allodynia and hyperalgesia. Fifty percent of healthy volunteers failed to develop mechanical allodynia. Baseline pain sensitivity was greater in those developing allodynia and was related to the magnitude and area of hyperalgesia. State psychological factors, whilst unrelated to allodynia, were related to mechanical hyperalgesia. This supports that the intensity of peripheral sensory input and individual sensibility are related to development of mechanical allodynia and hyperalgesia during central sensitization, whilst psychological factors play a lesser role.

Health outcomes among detoxification patients: The role of chronic pain

Understanding associations between chronic pain and health outcomes among detoxification patients may help improve treatment outcomes and abstinence rates. Exercise is a modifiable lifestyle factor that may reduce the effect of pain on outcomes in this population. The current study examined whether baseline pain, exercise, and their interaction were associated with psychiatric and medical severity, and abstinence self-efficacy, over six months following detoxification. Participants were veteran patients in alcohol or opioid detoxification treatment (N = 298) who were followed for six months (91.1%). Psychiatric severity and abstinence self-efficacy improved over the six months after detoxification; medical severity was stable. More intense pain at baseline was associated with poorer psychiatric and medical outcomes during the post-detoxification period. Regular exercise at baseline was associated with less psychiatric severity and more abstinence self-efficacy during the post-detoxification period. A significant pain by exercise interaction at baseline indicated that regular exercise was associated with more abstinence self-efficacy during the post-detoxification period only among participants with less intense pain. Pain by exercise interactions was not significant for the outcomes of psychiatric and medical severity. Among detoxification patients, exercise may be beneficial in improving outcomes among those with less intense pain.

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.

Biomarkers for predicting central neuropathic pain occurrence and severity after spinal cord injury: results of a long-term longitudinal study

Central neuropathic pain (CNP) after spinal cord injury (SCI) is debilitating and immensely impacts the individual. Central neuropathic pain is relatively resistant to treatment administered after it develops, perhaps owing to irreversible pathological processes. Although preemptive treatment may overcome this shortcoming, its administration necessitates screening patients with clinically relevant biomarkers that could predict CNP early post-SCI. The aim was to search for such biomarkers by measuring pronociceptive and for the first time, antinociceptive indices early post-SCI. Participants were 47 patients with acute SCI and 20 healthy controls. Pain adaptation, conditioned pain modulation (CPM), pain temporal summation, wind-up pain, and allodynia were measured above, at, and below the injury level, at 1.5 months after SCI. Healthy control were tested at corresponding regions. Spinal cord injury patients were monitored for CNP emergence and characteristics at 3 to 4, 6 to 7, and 24 months post-SCI. Central neuropathic pain prevalence was 57.4%. Central neuropathic pain severity, quality, and aggravating factors but not location somewhat changed over 24 months. Spinal cord injury patients who eventually developed CNP exhibited early, reduced at-level pain adaptation and CPM magnitudes than those who did not. The best predictor for CNP emergence at 3 to 4 and 7 to 8 months was at-level pain adaptation with odds ratios of 3.17 and 2.83, respectively (∼77% probability) and a cutoff value with 90% sensitivity. Allodynia and at-level CPM predicted CNP severity at 3 to 4 and 24 months, respectively. Reduced pain inhibition capacity precedes, and may lead to CNP. At-level pain adaptation is an early CNP biomarker with which individuals at risk can be identified to initiate preemptive treatment.

Caring for patients with a traumatic spinal cord injury

ABSTRACT

The physical, emotional, and financial impact of a traumatic spinal cord injury (TSCI) can be devastating. This article discusses the pathophysiology of TSCI, medical and surgical management during the acute and subacute phases of injury, and nursing care for patients with TSCI.

Prevalence of chronic pain after spinal cord injury: a systematic review and meta-analysis

BACKGROUND

The reported prevalence of chronic pain after spinal cord injury (SCI) varies widely due, in part, to differences in the taxonomy of chronic pain. A widely used classification system is available to describe subcategories of chronic pain in SCI, but the prevalence of chronic pain in SCI based on this system is unknown.

OBJECTIVE

The primary objective of this systematic review and meta-analysis is to determine the prevalence of chronic pain after SCI based on the International Spinal Cord Injury Pain (ISCIP) classification system.

EVIDENCE REVIEW

A comprehensive search of databases from January 1980 to August 2019 was conducted. The risk of bias was assessed using a modified tool developed for uncontrolled studies. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to assess certainty in prevalence estimates.

FINDINGS

A total of 1305 records were screened, and 37 studies met inclusion criteria. The pooled prevalence of overall chronic pain was 68% (95% CI 63% to 73%). The pooled prevalence of neuropathic pain in 13 studies was 58% (95% CI 49% to 68%); the pooled prevalence of musculoskeletal pain in 11 studies was 56% (95% CI 41% to 70%); the pooled prevalence of visceral pain in 8 studies was 20% (95% CI 11% to 29%) and the pooled prevalence of nociceptive pain in 2 studies was 45% (95% CI 13% to 78%). Meta-regression of risk of bias (p=0.20), traumatic versus non-traumatic etiology of injury (p=0.59), and studies where pain was a primary outcome (p=0.32) demonstrated that these factors were not significant moderators of heterogeneity. Certainty in prevalence estimates was judged to be low due to unexplained heterogeneity.

CONCLUSION

This systematic review and meta-analysis extends the findings of previous studies by reporting the prevalence of chronic pain after SCI based on the ISCIP classification system, thereby reducing clinical heterogeneity in the reporting of pain prevalence related to SCI.

High individual pain variability in people living with HIV: A graphical analysis

BACKGROUND

People living with HIV (PLWH) frequently experience pain. Following calls to analyse individual-level data in addition to group-level data in pain studies, we compared individual and group-level changes in pain prevalence, intensity and number of pain sites over 48 weeks in a large cohort of PLWH. This is the largest ever cohort study of pain in PLWH, and is the first to report pain at the level of the individual.

METHODS

Participants included all participants with complete pain records from a randomized clinical trial (RCT) for the treatment of HIV (n = 787/1053). At weeks 0, 12, 24, 36 and 48 we assessed participants' pain in the last week; presence of pain, and if present, the intensity and locations of the pain. We used standard averaging methods to describe data at the group level, and unique graphical reporting methods to analyse data at the level of the individual.

RESULTS

Group-level data demonstrated a trend for pain prevalence to decline over time (19% week 0, 12% week 48). Worst pain intensity remained stable (median between 4/10 and 5/10), as did the number (median = 1) and common sites of pain across the 48 weeks. In contrast, individual-level data demonstrated high intra-individual variability with regards to the presence of pain, and the intensity and location of the pain.

CONCLUSIONS

While our group-level data were similar to previous longitudinal studies, an apparent reduction in pain over 48 weeks, the individual-level data showed large variability within individuals in that same time frame.

SIGNIFICANCE

This graphical analysis highlights the high variability in pain (pain prevalence, intensity and body sites) across time in people living with HIV, and how presenting averaged data hides this important variability. Our data support the reporting of individual-level data in human experimental and observational studies.

Fatty acid suppression of glial activation prevents central neuropathic pain after spinal cord injury

About half of patients with spinal cord injury (SCI) develop debilitating central neuropathic pain (CNP), with no effective treatments. Thus, effective, safe, and novel therapies are needed urgently. Previously, docosahexaenoic acid (DHA) was reported to confer neuroprotection in preclinical SCI models. However, its therapeutic potential on SCI-CNP remains to be elucidated. Here, we demonstrated for the first time that intravenous DHA administrations with 3-day intervals (250 nmol/kg; starting 30 minutes after injury and maintained for 6 weeks) effectively prevented SCI-CNP development in a clinically relevant rat contusion model. SCI-CNP was assessed by a novel sensory profiling approach combining evoked pain measures and pain-related ethologically relevant rodent behaviours (burrowing, thigmotaxis, and place/escape avoidance) to mimic those for measuring human (sensory, affective, cognitive, and spontaneous) pain. Strikingly, already established SCI-CNP could be abolished partially by similar DHA administrations, starting from the beginning of week 4 after injury and maintained for 4 weeks. At spinal (epicenter and L5 dorsal horns) and supraspinal (anterior cingulate cortex) levels, both treatment regimens potently suppressed microglial and astrocyte activation, which underpins SCI-CNP pathogenesis. Spinal microgliosis, a known hallmark associated with neuropathic pain behaviours, was reduced by DHA treatments. Finally, we revealed novel potential roles of peroxisome proliferator-activated and retinoid X receptors and docosahexaenoyl ethanolamide (DHA's metabolite) in mediating DHA's effects on microglial activation. Our findings, coupled with the excellent long-term clinical safety of DHA even in surgical and critically ill patients, suggest that systemic DHA treatment is a translatable, effective, safe, and novel approach for preventing and managing SCI-CNP.

Neuropathic Pain: From Mechanisms to Treatment

Neuropathic pain caused by a lesion or disease of the somatosensory nervous system is a common chronic pain condition with major impact on quality of life. Examples include trigeminal neuralgia, painful polyneuropathy, postherpetic neuralgia, and central poststroke pain. Most patients complain of an ongoing or intermittent spontaneous pain of, for example, burning, pricking, squeezing quality, which may be accompanied by evoked pain, particular to light touch and cold. Ectopic activity in, for example, nerve-end neuroma, compressed nerves or nerve roots, dorsal root ganglia, and the thalamus may in different conditions underlie the spontaneous pain. Evoked pain may spread to neighboring areas, and the underlying pathophysiology involves peripheral and central sensitization. Maladaptive structural changes and a number of cell-cell interactions and molecular signaling underlie the sensitization of nociceptive pathways. These include alteration in ion channels, activation of immune cells, glial-derived mediators, and epigenetic regulation. The major classes of therapeutics include drugs acting on α₂δ subunits of calcium channels, sodium channels, and descending modulatory inhibitory pathways.

Characterization of pain syndromes in patients with neuromyelitis optica

BACKGROUND

Pain is common and refractory in spinal cord injury (SCI). Currently, most studies evaluated pain in male-predominant traumatic-SCI. Also, concomitant secondary pain syndromes and its temporal evolution were seldom reported.

METHODS

We aimed to prospectively describe the main and secondary pain and its associated factors in inflammatory-SCI evaluating neuromyelitis optica (NMO) patients. In-remission NMO patients underwent neurological, imaging and autoantibody evaluations. Questionnaires detailing main and secondary pains, functional state, mood, catastrophizing, quality of life (QoL) and "non-motor symptoms" were used at two time points.

RESULTS

Pain was present in 53 (73.6%) of the 72 patients included. At-level neuropathic pain was the most common main pain syndrome, affecting 32 subjects (60.4% of those with pain). Over 70% (n = 38) of this cohort reported two pain syndromes. Those without pain were significantly younger (26.1 ± 12.7 y.o. in those without pain and 40.1 ± 12.5, 37.2 ± 11.4 y.o. in those whose main pain was neuropathic and non-neuropathic, respectively, p = .001), and no differences in the inflammatory status were observed between groups. On follow-up, one-fifth (n = 11) had a different main pain syndrome from the first visit. Pain impacted QoL as much as disability and motor strength.

CONCLUSION

Pain is a prevalent and disabling non-motor symptom in NMO-SCI. Most patients experience more than one pain syndrome which can change in time even in the absence of clinical relapse. Age of the inflammatory-SCI was a major determinant of pain. Acknowledging temporal changes and multiplicity of pain syndromes in NMO-SCI may give insights into more precise designs of clinical trials and general management of pain in SCI.

SIGNIFICANCE

In this longitudinal study with NMO-related SCI, pain affected almost three-quarters of patients with NMO. Over 70% have more than one pain syndrome and at-level neuropathic pain is the most common type of pain syndrome. Patients without pain were significantly younger but had the same burden of inflammatory lesions than those with pain. During follow-up, up to one fifth of patients presented with changes in the main pain syndromes, which can occur even in the absence of clinical activity of the inflammatory disease. In this cohort, Pain affected quality of life as much as disability or motor strength.

Current Evidence Lacking to Guide Clinical Practice for Spinal Cord Stimulation in the Treatment of Neuropathic Pain in Spinal Cord Injury: A Review of the Literature and a Proposal for Future Study

BACKGROUND/OBJECTIVE

Chronic pain is commonly reported in individuals with spinal cord injuries (SCIs), with recent prevalence reported as high as 80%. Uncontrolled pain is known to decrease quality of life, attenuate mood, and impact sleep. Spinal cord stimulation (SCS) for the treatment of refractory pain was first used in the SCI population in 1972. To date there have been no randomized controlled trials examining the effect of SCS on neuropathic pain post-SCI. A literature review in 2009 identified 27 studies, the majority prior to 2000, that included at least 1 patient with SCI. Given the significant advancements in the field of SCS, this review examines the updated evidence of SCS for the treatment of neuropathic pain in individuals with SCI and provides guidance on future investigations.

METHODS

MEDLINE and EMBASE databases were searched. All published reports, case series, and clinical trials reviewing SCS for neuropathic pain that included at least 1 individual with SCI were included.

RESULTS

The initial search identified 376 reports, of which 22 met inclusion criteria, for a total of 69 patients. All reports were of very low quality. A majority of the reported patients were male, underwent tonic stimulation, and reportedly experienced improvement in pain and spasticity, with decreased use of pain medication.

CONCLUSIONS

The synthesized findings from primarily case studies support the safety of SCS in SCI with the suggestion of potential pain relief benefit; however, data from low-quality studies are insufficient for informing clinical practice. A well-designed, prospective clinical trial is proposed to further investigate this indication.

Regional Hyperexcitability and Chronic Neuropathic Pain Following Spinal Cord Injury

Spinal cord injury (SCI) causes maladaptive changes to nociceptive synaptic circuits within the injured spinal cord. Changes also occur at remote regions including the brain stem, limbic system, cortex, and dorsal root ganglia. These maladaptive nociceptive synaptic circuits frequently cause neuronal hyperexcitability in the entire nervous system and enhance nociceptive transmission, resulting in chronic central neuropathic pain following SCI. The underlying mechanism of chronic neuropathic pain depends on the neuroanatomical structures and electrochemical communication between pre- and postsynaptic neuronal membranes, and propagation of synaptic transmission in the ascending pain pathways. In the nervous system, neurons are the only cell type that transmits nociceptive signals from peripheral receptors to supraspinal systems due to their neuroanatomical and electrophysiological properties. However, the entire range of nociceptive signaling is not mediated by any single neuron. Current literature describes regional studies of electrophysiological or neurochemical mechanisms for enhanced nociceptive transmission post-SCI, but few studies report the electrophysiological, neurochemical, and neuroanatomical changes across the entire nervous system following a regional SCI. We, along with others, have continuously described the enhanced nociceptive transmission in the spinal dorsal horn, brain stem, thalamus, and cortex in SCI-induced chronic central neuropathic pain condition, respectively. Thus, this review summarizes the current understanding of SCI-induced neuronal hyperexcitability and maladaptive nociceptive transmission in the entire nervous system that contributes to chronic central neuropathic pain.

A cohort study of the association between psychosocial factors and pain in patients with Spinal Cord Injury and Stroke

PURPOSE

To explore associations between psychosocial factors and pain intensity and pain interference in a population with a new neurological injury on admission to rehabilitation, and after six months.

MATERIALS AND METHODS

A longitudinal, prospective cohort study with participants with stroke or Spinal Cord Injury (SCI) completing questionnaires for pain intensity and interference, mental health, pain coping strategies and pain attitudes and beliefs within two weeks of admission to inpatient rehabilitation. After six months, participants completed measures of pain intensity and pain interference only.

RESULTS

In all 32 participants completed the questionnaires at baseline and 19 after six months. Several associations between a person's mental health and certain beliefs were associated with pain outcomes. Additionally, poorer baseline mental health was associated with greater pain intensity and pain interference after six months, and a stronger belief in a medical cure for pain at baseline was associated with less pain intensity and pain interference after six months.

CONCLUSIONS

Psychosocial factors are associated with pain early after stroke and SCI. Psychosocial factors are also associated with pain outcomes several months after stroke and SCI. This highlights the importance of psychosocial factors in both of these populations and their relationship with pain outcomes.

Treatment of at-level spinal cord injury pain with botulinum toxin A

Study design

Randomized, double-blinded, placebo-controlled, cross-over study.

Objective

To explore whether botulinum toxin A (BoNTA) could be effective for treating at-level spinal cord injury (SCI) pain.

Setting

Outpatient SCI clinic, New York, USA.

Methods

Participants were randomized to receive subcutaneous injections of either placebo or BoNTA with follow-up (office visit, telephone, or e-mail) at 2, 4, 8, and 12 weeks to assess the magnitude of pain relief post injection. Crossover of participants was then performed. Those who received placebo received BoNTA, and vice versa, with follow-up at 2, 4, 8, and 12 weeks.

Results

Eight participants completed at least one of the two crossover study arms. Four completed both arms. The median age of the eight participants was 45 years (range 32-61 years) and 75% were male. All had traumatic, T1-L3 level, complete SCI. Although our data did not meet statistical significance, we noted a higher proportion of participants reporting a marked change in average pain intensity from baseline to 8 and 12 weeks post-BoNTA vs. post-placebo (33% vs. 0%). At 2 and 4 weeks post-BoNTA, almost all participants reported some degree of reduced pain, while the same was not seen post-placebo (83% vs. 0%).

Conclusion

The subcutaneous injection of BoNTA may be a feasible approach for the control of at-level SCI pain and is worthy of further study.

Sponsorship

The onabotulinumtoxinA (BOTOX) used in this study was provided by Allergan (Irvine, CA).

Implementing volunteer peer mentoring as a supplement to professional efforts in primary rehabilitation of persons with spinal cord injury

Study design

A feasibility study, supplemented by a noncontrolled pretest/posttest.

Objectives

To examine if a nationwide volunteer peer-mentoring program for in-patients with acute/subacute spinal cord injury is feasible and achievable.

Setting

The Spinal Cord Injury Center of Western Denmark and Clinic for Spinal Cord Injuries, Rigshospitalet, Denmark.

Methods

Volunteer mentor groups were formed similarly in two highly specialized SCI centers covering Denmark. Hospital staff was responsible for referral to the mentoring project and for the interdisciplinary evaluation of patient eligibility. At each of the two centers, a person living with the consequences of SCI coordinated the intervention in collaboration with healthcare personnel. Designated project personnel introduced eligible participants to the project. Staff at the SCI centers arranged to fit in the supplementary mentoring with ongoing treatment. A self-report questionnaire was completed prior to and after peer intervention. Outcome: patient reports regarding mentoring sessions, change in quality of life (QoL), depression items from the Short Form Health Survey (SF-36), pain frequency and intensity (11-point Numerical Rating Scale).

Results

A nationwide mentor corps was established. Fifty-two eligible in-patients completed the study. Significant improvement in QoL was found after mentoring. Frequency and intensity of pain did not change, although five out of nine depression items improved significantly. A majority (94%) of the participants recommended others to meet with a peer mentor.

Conclusions

Establishing a nationwide volunteer mentor system at a highly specialized neuro-rehabilitation units for SCI in-patients is both feasible and acceptable.

Pulse article: opioid prescription for pain after spinal cord damage (SCD), differences from recommended guidelines, and a proposed algorithm for the use of opioids for pain after SCD

Study design

Online questionnaire of spinal cord injury (SCI) physicians.

Objectives

The objective of this study is to characterize the approach to opioid prescription for persons with spinal cord damage (SCD).

Setting

An international online questionnaire.

Methods

A survey was posted online and circulated among international societies within the field of SCI medicine from August to November 2018.

Results

One hundred and twenty-three physicians responded to the survey. Of these, 107 (92%) managed pain for persons with SCD. Most (82%) felt that opioid prescription was appropriate for uncontrolled acute pain, but fewer (67%) felt it was appropriate for chronic pain. Of those who felt opioids had a role in the treatment of neuropathic pain, 46% did not think there should be a specific upper limit of opioid dose. The majority (85%) would continue prescribing high doses (250 morphine milligram equivalent (MME) doses/day) if that dose were effective. Tramadol was the most common opioid prescribed first line.

Conclusion

Most physicians who responded to this survey prescribe opioids for intractable pain after SCD. A significant proportion of respondents believed that there should not be a specific upper limit of opioid dose prescribed if the drug is tolerated; this does not align with current recommendations. Most physicians do not feel influenced in their prescribing habits by regulatory bodies. If physicians decide to taper an opioid that is being tolerated well, it is most commonly related to a fear of the patient developing an opioid-use disorder. The authors propose an algorithm that may help align practice patterns with current recommended practice guidelines.

Evaluation of a Clinical Protocol to Assess and Diagnose Neuropathic Pain During Acute Hospital Admission: Results From Traumatic Spinal Cord Injury

OBJECTIVES

A clinical protocol was developed for clinicians to routinely assess and initiate treatment for patients with neuropathic pain (NP) in an acute care setting. The objectives of this study were to: (1) determine the incidence and onset of NP in patients with traumatic spinal cord injury during acute care and (2) describe how the implementation of a clinical protocol impacts the assessment and diagnosis of NP.

MATERIALS AND METHODS

The study was a cohort analysis with a pre-post-test utilizing a historical control. Data were retrospectively collected from a patient registry and charts. Participants were randomly selected in cohort 1 (control) and cohort 2 (NP clinical protocol).

RESULTS

The incidence of NP was 56% without significant difference between the cohorts (P=0.3). Onset of NP was 8 days (SD=14) across the study and >85% of the participants with NP were diagnosed within 2 weeks. Participants with incomplete injuries had a significant earlier onset than participants with complete injuries (6.2±12.8, 10.9±15.8 d; P=0.003). The mean number of days from hospital admission to initial assessment decreased with use of the NP clinical protocol (3.7±5.7 d; P=0.02).

DISCUSSION

This study demonstrates a high incidence and early onset of NP in traumatic spinal cord injury during acute hospital care, with an earlier emergence in participants with incomplete injury. The NP clinical protocol ensured continuous assessment and documentation of NP while decreasing the time to an initial screen, but did not impact diagnosis.

Progression of Neuropathic Pain after Acute Spinal Cord Injury: A Meta-Analysis and Framework for Clinical Trials

The translation of therapeutic interventions to humans with spinal cord injury with the goal of promoting growth and repair in the central nervous system could, inadvertently, drive mechanisms associated with the development of neuropathic pain. A framework is needed to evaluate the probability that a therapeutic intervention for acute spinal cord injury modifies the progression of neuropathic pain. We analyzed a large, longitudinal dataset from the European Multi-Center Study about Spinal Cord Injury (EMSCI) and compared these observations with a previously published Swedish/Danish cohort. A meta-analysis was performed to produce aggregate estimates for the transition period between 1-6 months and the transition period between 1-12 months after injury. A secondary analysis used logistic regression to explore associations between the progression of neuropathic pain and demographics, pain characteristics, and injury characteristics. For overall neuropathic pain, 72% presenting with pain symptoms at one month reported persisting symptoms at six months, and 23% who did not have neuropathic pain at one month later had it develop. From 1-12 months, there was a similar likelihood of pain persisting (69%) and slightly higher rate of pain developing (36%). Characteristics that were significantly associated with the progression of pain included age and sensory and motor preservation. We provide historical benchmarks for estimating the progression of neuropathic pain during the first year after acute SCI. This information will be useful for comparison and evaluating safety during early phase acute spinal cord injury trials.

Spinal Cord Stimulation for Pain Treatment After Spinal Cord Injury

In addition to restoration of bladder, bowel, and motor functions, alleviating the accompanying debilitating pain is equally important for improving the quality of life of patients with spinal cord injury (SCI). Currently, however, the treatment of chronic pain after SCI remains a largely unmet need. Electrical spinal cord stimulation (SCS) has been used to manage a variety of chronic pain conditions that are refractory to pharmacotherapy. Yet, its efficacy, benefit profiles, and mechanisms of action in SCI pain remain elusive, due to limited research, methodological weaknesses in previous clinical studies, and a lack of mechanistic exploration of SCS for SCI pain control. We aim to review recent studies and outline the therapeutic potential of different SCS paradigms for traumatic SCI pain. We begin with an overview of its manifestations, classification, potential underlying etiology, and current challenges for its treatment. The clinical evidence for using SCS in SCI pain is then reviewed. Finally, future perspectives of pre-clinical research and clinical study of SCS for SCI pain treatment are discussed.

An examination of diurnal variations in neuropathic pain and affect, on exercise and non-exercise days, in adults with spinal cord injury

STUDY DESIGN

Case series.

OBJECTIVES

The temporal relationships between exercise, neuropathic pain and affect are not well understood. The purpose of this study was to utilize ecological momentary assessment to measure intra-individual diurnal variations in neuropathic pain and affect on exercise and non-exercise days. This study aimed to provide a deeper understanding of how neuropathic pain and affect change from pre- to post-exercise, and over time.

SETTING

Community.

METHODS

Six physically active men with SCI participated in a 6-day protocol (M age = 39.33 ± 8.24; 83.3% tetraplegics; years post injury = 6-17 years). Using their Smartphones, participants completed the Feeling Scale, Felt Arousal Scale, and Neuropathic Pain Scale in response to six daily prompts, and before and after exercise. Paired samples t-tests were conducted on changes in neuropathic pain and affect from pre to post-exercise. Bivariate Pearson's correlational analyses were computed between time of day, neuropathic pain and affect.

RESULTS

Participants experienced a significant decrease in neuropathic pain (t(5) = 3.93; p = 0.01) following completion of at least one bout of exercise. A large, but non-significant increase (Hgav = 0.76) in Feeling Scale scores occurred following one bout of exercise. Time of day, neuropathic pain and affect were significantly correlated for two participants.

CONCLUSIONS

Overall, results suggest exercise can reduce neuropathic pain, and may also increase feelings of pleasure. Given the inconsistent pattern of results across participants, further research is needed to look at both individual characteristics, and characteristics of exercise that may moderate changes in neuropathic pain and affect for adults with SCI.

Opioids should not be prescribed for chronic pain after spinal cord injury

Most people with spinal cord injury (SCI) have chronic pain and effective treatments have not been identified. Within the first two decades of the 21st century, opioids have been commonly prescribed in an attempt to manage pain after SCI, however, the risks and absence of benefit of opioids have become more apparent as opioid crises have developed around the world. This perspective is an argument for why opioids should no longer be prescribed to treat chronic pain after SCI.

Neuropathic Pain After Spinal Cord Injury: Challenges and Research Perspectives

Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that remains difficult to treat because underlying mechanisms are not yet fully understood. In part, this is due to limitations of evaluating neuropathic pain in animal models in general, and SCI rodents in particular. Though pain in patients is primarily spontaneous, with relatively few patients experiencing evoked pains, animal models of SCI pain have primarily relied upon evoked withdrawals. Greater use of operant tasks for evaluation of the affective dimension of pain in rodents is needed, but these tests have their own limitations such that additional studies of the relationship between evoked withdrawals and operant outcomes are recommended. In preclinical SCI models, enhanced reflex withdrawal or pain responses can arise from pathological changes that occur at any point along the sensory neuraxis. Use of quantitative sensory testing for identification of optimal treatment approach may yield improved identification of treatment options and clinical trial design. Additionally, a better understanding of the differences between mechanisms contributing to at- versus below-level neuropathic pain and neuropathic pain versus spasticity may shed insights into novel treatment options. Finally, the role of patient characteristics such as age and sex in pathogenesis of neuropathic SCI pain remains to be addressed.

Sensorimotor Activity Partially Ameliorates Pain and Reduces Nociceptive Fiber Density in the Chronically Injured Spinal Cord

A large proportion of patients suffering from spinal cord injury (SCI) develop chronic central neuropathic pain. Previously, we and others have shown that sensorimotor training early after SCI can prevent the development of mechanical allodynia. To determine whether training initiated in the subchronic/chronic phase remains effective, correlates of below-level neuropathic pain were analyzed in the hindpaws 5-10 weeks after a moderate T11 contusion SCI (50 kDyn) in adult female C57BL/6 mice. In a comparison of SCI and sham mice 5 weeks post-injury, about 80% of injured animals developed mechanical hypersensitivity to light mechanical stimuli, whereas testing of noxious stimuli revealed hypo-responsiveness. Thermal sensitivity testing showed a decreased response latency after injury. Without intervention, mechanical and thermal hyper-responsiveness were evident until the end of the experiment (10 weeks). In contrast, treadmill training (2 × 15 min/day; 5 × /week) initiated 6 weeks post-injury resulted in partial amelioration of pain behavior and this effect remained stable. Analysis of calcitonin gene-related peptide (CGRP)-labeled fibers in lamina III-IV of the lumbar dorsal horn revealed an increase in labeling density after SCI. This was not due to changes in the number or size distribution of CGRP-labeled lumbar dorsal root ganglion neurons. Treadmill training reduced the CGRP-labeling density in the spinal cord of injured mice, whereas the density of non-peptidergic isolectin-B4 (IB4)⁺ fibers showed no changes in lamina IIi and a slight reduction of sparse IB4 labeling in laminae III-IV. Thus, sensorimotor activity initiated in the subchronic/chronic phase of SCI remains effective in ameliorating pain behavior and influencing structural changes of the nociceptive system.

Quality of life after spinal cord injury: The impact of pain

BACKGROUND

Pain is a common complication after spinal cord injury (SCI). A mixture of nociceptive and neuropathic pain (NP) can present. Limited studies have investigated the impact of different pain phenotypes on quality of life (QoL) post-SCI.

METHODS

Members registered to a national support group for those with SCIs were surveyed (n = 1574). The survey comprised questions relating to demographics and SCI characteristics, The Douleur Neuropathique 4 (DN4) (interview), the International SCI Pain Basic Data Set recording the worst pain and the World Health Organisation Quality of Life BREF (WHOQOL-BREF). An ANCOVA model with post hoc analysis explored between group factors of pain type and intensity of pain categories on QoL, controlling for additional confounding variables. Significance was set p < 0.05. A linear regression explored whether pain intensity, type or interference best predicted QoL.

RESULTS

The response rate was 41% (n = 643), 70% (n = 447) were male. The mean age of respondents was 52 years (SD 14.2) and mean time from SCI was 17 years (SD 12.4). In the previous week, 71% (n = 458) experienced pain, 37% (n = 236) of which had NP as defined in the study. Respondents experiencing NP demonstrated significantly poorer QoL than those without pain (p < 0.001) or nociceptive pain (p < 0.05). Those reporting high pain intensity had significantly lower QoL than those with moderate or no pain (p < 0.001). Pain interference consistently and best-predicted domains of QoL (p < 0.001).

CONCLUSION

High-intensity pain and NP negatively impacts QoL post-SCI. However pain interference more than intensity or type best explains the variance in QoL reported.

SIGNIFICANCE

Neuropathic pain type and severe pain intensities negatively impact QoL after SCI. Pain interference items better predict reported QoL than either pain type or intensity, suggesting better pain management strategies are warranted.

Pain After Spinal Cord Injury Is Associated With Abnormal Presynaptic Inhibition in the Posterior Nucleus of the Thalamus

Pain after spinal cord injury (SCI-Pain) is one of the most debilitating sequelae of spinal cord injury, characterized as relentless, excruciating pain that is largely refractory to treatments. Although it is generally agreed that SCI-Pain results from maladaptive plasticity in the pain processing pathway that includes the spinothalamic tract and somatosensory thalamus, the specific mechanisms underlying the development and maintenance of such pain are yet unclear. However, accumulating evidence suggests that SCI-Pain may be causally related to abnormal thalamic disinhibition, leading to hyperactivity in the posterior thalamic nucleus (PO), a higher-order nucleus involved in somatosensory and pain processing. We previously described several presynaptic mechanisms by which activity in PO is regulated, including the regulation of GABAergic as well as glutamatergic release by presynaptic metabotropic gamma-aminobutyric acid (GABA_B) receptors. Using acute slices from a mouse model of SCI-Pain, we tested whether such mechanisms are affected by SCI-Pain. We reveal 2 abnormal changes in presynaptic signaling in the SCI-Pain condition. The substantial tonic activation of presynaptic GABA_B receptors on GABAergic projections to PO-characteristic of normal animals-was absent in mice with SCI-Pain. Also absent in mice with SCI-Pain was the normal presynaptic regulation of glutamatergic projections to the PO by GABA_B receptors. The loss of these regulatory presynaptic mechanisms in SCI-Pain may be an element of maladaptive plasticity leading to PO hyperexcitability and behavioral pain, and may suggest targets for development of novel treatments.

PERSPECTIVE

This report presents synaptic mechanisms that may underlie the development and maintenance of SCI-Pain. Because of the difficulty in treating SCI-Pain, a better understanding of the underlying neurobiological mechanisms is critical, and may allow development of better treatment modalities.

Prevalence and factors associated with a higher risk of neck and back pain among permanent wheelchair users: a cross-sectional study

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To determine the prevalence of, and factors associated with, spinal pain among wheelchair users.

SETTING

Four Spanish hospitals specialized in providing care for wheelchair users.

METHODS

Persons who had used a wheelchair for a median (IRQ) of 10 (5;19) years, 27% of them due to reasons other than spinal cord injury, were recruited consecutively (n = 750). Data on 43 demographic, psychosocial, ergonomic, and clinical variables were collected, and analyzed. Main outcome measures were: point prevalence of neck (NP), thoracic (TP), low back pain (LBP), and pain at any spinal level (PASL); and factors associated with them.

RESULTS

Point prevalence was 56% for NP, 54% for TP, 45% for LBP, and 76% for PSAL. PASL was associated with a lower quality of life (OR (95% CI) 0.91 (0.86; 0.97)). Multivariable regression models showed that the main factors associated with significant pain (≥1.5 VAS points) were: (a) For NP: cervical spinal injury and wheelchair seat cushion thickness, (b) For TP: thoracic spinal injury and sagittal index, (c) For LBP: thoracic or lumbar spinal injury, with some sensitivity remaining, (d) For PASL: being female, living alone, and using a non-power wheelchair. Discrimination (AUC) of these models ranged between 0.638 and 0.818. p-values in the Hosmer-Lemeshow test ranged between 0.420 and 0.701.

CONCLUSIONS

Prevalence of spinal pain among wheelchair users is high. It is associated with a lower quality of life. Future studies should assess whether using a power wheelchair affects PASL, and if the thickness of seat cushion affects NP.

SPONSORSHIP

Spanish Back Pain Research Network.

Increased psychological distress among individuals with spinal cord injury is associated with central neuropathic pain rather than the injury characteristics

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

Central neuropathic pain (CNP) is common after spinal cord injury (SCI). The psychological impact of CNP is not clear. Previous studies reported depression and pain catastrophizing among patients with SCI and CNP; however, the lack of control groups prevented discerning whether these were attributed to CNP or to the SCI itself. The aim was to examine the psychological distress among individuals with SCI with and without CNP and controls to evaluate its impact and possible source.

SETTING

Outpatient clinic of a large rehabilitation center.

METHODS

Individuals with SCI and CNP (n = 27) and without CNP (n = 23), and able-bodied controls (n = 20) participated. Data collection included sociodemographics, SCI characteristics, and level of post-traumatic stress disorder (PTSD), anxiety, stress, depression, and pain catastrophizing. The sensory, affective, and cognitive dimensions of CNP were analyzed.

RESULTS

Individuals with SCI and CNP exhibited elevated levels of PTSD, anxiety, stress, depression, and pain catastrophizing compared to the two control groups, which presented similar levels. The psychological variables among the CNP group correlated positively only with the affective dimension of CNP. Neither CNP nor the psychological variables correlated with SCI characteristics.

CONCLUSIONS

Irrespective of CNP intensity, the affective dimension (suffering) is associated with increased psychological distress. Perhaps individual differences in the response to SCI and/or individual traits rather than the mere exposure to SCI may have a role in the emergence of CNP and psychological distress/mood dysfunction. Rehabilitation programs should prioritize stress management and prevention among individuals with SCI and CNP.