Exacerbation of Chronic Pain following Spinal Cord Injury

Individuals With Prior Chronic Pain and Long-Term Opioid Treatment May Experience Persistence of That Pain Even After Subsequent Complete Cervical Spinal Cord Injury: Suggestions From a Prospective Case-Controlled Study

Objective

To determine whether chronic pain persists after complete spinal cord injury (SCI).

Design

Prospective observational study regarding the outcome of pre-existent chronic pain of inpatients admitted with new clinically diagnosed complete cervical SCI. For patients who acknowledged chronic pain of ≥3 years duration before the SCI, further questions explored whether they still experienced that pain, whether they were experiencing current posttraumatic pain, and whether they had any past exposure to opioids. The included patients were identified during the initial consultation in the trauma center for treatment of the SCI.

Setting

Level I trauma center.

Participants

From a total of 49 participants with acute cervical SCI with clinically diagnosed complete motor and sensory tetraplegia admitted between 2018 and 2020, 7 were selected on the basis of a history of chronic pain.

Intervention

Collected complete history and performed physical examination with serial follow-ups during the acute hospital stay until death or discharge.

Main Outcome Measures

The primary outcome was a finding of chronic pain experienced before new clinical diagnosis of complete SCI, compared with whether or not that pain continued after the SCI injury. The secondary outcome was the relation of persistent pain with opioid use; it was formulated after data collection.

Results

Among 49 patients with clinically diagnosed complete cervical SCIs, 7 had experienced prior chronic pain. Four participants experienced a continuation of the prior pain after their complete tetraplegia (4/7), whereas 3 participants did not (3/7). All the participants with continued pain had been previously treated with opioids, whereas those whose pain ceased had not received chronic opioid therapy.

Conclusions

There may be a unique form of chronic pain that is based in the brain, irrespective of peripheral pain or spinal mechanisms. Otherwise healthy people with longstanding antecedent chronic pain whose pain persists after acute clinically complete SCI with tetraplegia may provide a new model for evaluation of brain-based pain. Opioids may be requisite for this type of pain.

Neuropsychological Function in Traumatic Brain Injury and the Influence of Chronic Pain

Cognitive dysfunction, pain, and psychological morbidity all present unique challenges to those living with traumatic brain injury (TBI). In this study we examined (a) the impact of pain across domains of attention, memory, and executive function, and (b) the relationships between pain and depression, anxiety, and post-traumatic stress disorder (PTSD) in persons with chronic TBI. Our sample included 86 participants with a TBI and chronic pain (n = 26), patients with TBI and no chronic pain (n = 23), and a pain-free control group without TBI (n = 37). Participants visited the laboratory and completed a comprehensive battery of neuropsychological tests as part of a structured interview. Multivariate analysis of covariance using education as a covariate, failed to detect a significant group difference for neuropsychological composite scores of attention, memory, and executive function (p = .165). A follow-up analysis using multiple one-way analysis of variance (ANOVA) was conducted for individual measures of executive function. Post-hoc testing indicated that those in both TBI groups preformed significantly worse on measures of semantic fluency when compared to controls (p < 0.001, ηρ2 = .16). Additionally, multiple ANOVAs indicated that those with TBI and pain scored significantly worse across all psychological assessments (p < .001). We also found significant associations between measures of pain and most psychological symptoms. A follow-up stepwise linear regression among those in the TBI pain group indicated that post concussive complaints, pain severity, and neuropathic pain symptoms differentially contributed to symptoms of depression, anxiety, and PTSD. These findings suggest deficits in verbal fluency among those living with chronic TBI, with results also reinforcing the multidimensional nature of pain and its psychological significance in this population.

Neuropathic Pain and Spinal Cord Injury: Management, Phenotypes, and Biomarkers

Chronic neuropathic pain after a spinal cord injury (SCI) continues to be a complex condition that is difficult to manage due to multiple underlying pathophysiological mechanisms and the association with psychosocial factors. Determining the individual contribution of each of these factors is currently not a realistic goal; however, focusing on the primary mechanisms may be more feasible. One approach used to uncover underlying mechanisms includes phenotyping using pain symptoms and somatosensory function. However, this approach does not consider cognitive and psychosocial mechanisms that may also significantly contribute to the pain experience and impact treatment outcomes. Indeed, clinical experience supports that a combination of self-management, non-pharmacological, and pharmacological approaches is needed to optimally manage pain in this population. This article will provide a broad updated summary integrating the clinical aspects of SCI-related neuropathic pain, potential pain mechanisms, evidence-based treatment recommendations, neuropathic pain phenotypes and brain biomarkers, psychosocial factors, and progress regarding how defining neuropathic pain phenotypes and other surrogate measures in the neuropathic pain field may lead to targeted treatments for neuropathic pain after SCI.

Pilot clinical trial of a clinical meditation and imagery intervention for chronic pain after spinal cord injury

OBJECTIVE

To assess the feasibility and potential benefits of clinical meditation and imagery (CMI) for people with chronic spinal cord injury (SCI) and chronic pain.

DESIGN

Pilot randomized, controlled trial.

SETTING

Outpatients with SCI in the United States.

PARTICIPANTS

24 adults with chronic SCI (>1 year) and a >3 month history of pain rated ≥4/10 on average over the last week.

INTERVENTIONS

4-week program of once-weekly 2-hour group classes, offered in-person and online. CMI group participants were taught mindfulness, mantra meditation, and guided imagery practices. Control group participants received education on topics related to health and function after SCI.

OUTCOME MEASURES

Pain interference (primary outcome), pain cognitions, pain intensity/unpleasantness, depressive symptomology, perceived stress.

RESULTS

Pain interference decreased to a greater extent in the control group at both Day 42 and Day 70, with a large effect size (d > 1.0). Several secondary outcome measures showed changes consistent with more favorable outcomes in the CMI group at both Day 42 and Day 70, with a large effect size d > 0.80, including worst pain intensity over the last week, depressive symptomology, belief in pain as a sign of harm and perceived control over pain. Perceived stress improved to a greater extent in the control group (d = 1.16 at Day 42, d = .20 at Day 70).

CONCLUSION

CMI is feasible and acceptable to implement with people with SCI and chronic pain. Further study is warranted to assess potential benefits for pain-related outcomes.

Factors associated with neuropathic pain in Colombian patients with spinal cord injury of traumatic origin: case-control study

STUDY DESIGN

Case-control study.

OBJECTIVES

To identify factors associated with neuropathic pain (NP) in patients with spinal cord injury of traumatic origin (TSCI).

SETTING

University Hospital of Valle, Cali, Colombia.

METHODS

Study participants were individuals with diagnosis of TSCI who visited a trauma referral center from January 1st, 2016, to December 31st, 2016. Information was retrospectively extracted from the Hospital's Spinal Cord Injury registry and patients' medical records. Cases were defined as patients with NP and controls were those without NP. The exposure of interest was intentional injuries. Individuals were matched by age and stratified into 11 groups of ±3 years each.

RESULTS

We found 164 participants with an average age of 34 ± 13 years, of whom 95.1% were male, and 53.6% had NP. Neurogenic bladder and bowel occurred in 94.3% of NP patients. Cause of injury was not associated with NP. Older injuries were protective for NP (>10 years since injury OR = 0.10, 95% CI = 0.03-0.37, p < 0.0001) and neurogenic bladder and bowel were found as risk factors (OR = 5.89, 95% CI = 1.84-18.88; p = 0.003).

CONCLUSIONS

Our study uniquely shows time since injury as a protective factor for NP and neurogenic bladder and bowel as a risk factor, while violence was not found associated. This could help guide the scope of future research about NP secondary to SCI.

A Primary Care Provider's Guide to Pain After Spinal Cord Injury: Screening and Management

Individuals with spinal cord injury (SCI) often experience chronic pain as a secondary complication. It can significantly impair mental health, sleep, mood, and overall quality of life. It is important for providers within a primary care setting to recognize the different types of pain such as nociceptive and neuropathic. Various assessment tools are available to guide proper classification and subsequent management. Providers need to have a good knowledge base, structure, and patient focus when managing care. Nonpharmacological interventions are just as important and should be explored prior to or along with pharmacological interventions. Treatment modalities such as physical therapy, exercise, acupuncture, and cognitive behavioral therapy should be tailored to the individual to the greatest extent possible. Gabapentin, pregabalin, and amitriptyline have been studied extensively and are the first-line pharmacological agents for neuropathic pain. It is important to involve patients as equal stakeholders in any pain intervention with adequate lifelong follow-up. The aim of this article is to offer an overview of pain assessment, information, patient interaction, and treatment options available. Although chronic pain has remained difficult to treat successfully, primary care providers can play an integral role in delivering evidence-based and patient-centered care for managing chronic pain among individuals with 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.

Prevalence and associated factors of pain in the Swiss spinal cord injury population

STUDY DESIGN

Population-based, cross-sectional.

OBJECTIVES

To determine pain prevalence and identify factors associated with chronic pain in individuals with spinal cord injury (SCI) living in Switzerland.

SETTING

Swiss SCI Cohort Study (SwiSCI).

METHODS

Pain characteristics were assessed using an adapted version of the International SCI Pain Basic Data Set, adding one item of the SCI Secondary Conditions Scale to address chronic pain. Pain prevalence was calculated using stratification over demographic, SCI-related and socioeconomic characteristics; odds ratios (adjusted for non-response) for determinants of severity of chronic pain were calculated using stereotype logistic regressions.

RESULTS

Pain (in the past week) was reported by 68.9% and chronic pain by 73.5% (significant 36.9%) of all participants (N=1549; 28% female). Most frequently reported pain type was musculoskeletal (71.1%). Back/spine was the most frequently reported pain location (54.6%). Contrasting the 'significant' to the 'none/mild' category of chronic pain, adjusted odds ratios were 1.54 (95% CI: 1.18-2.01; P<0.01) for women (vs men); 6.64 (95% CI: 3.37-11.67; P<0.001) for the oldest age group 61+ (vs youngest (16-30)); 3.41 (95% CI: 2.07-5.62; P<0.001) in individuals reporting severe financial hardship (vs no financial hardship). Individuals reporting specific SCI-related health conditions were 1.41-2.92 (P<0.05) times more likely to report chronic pain as 'significant' rather than 'none/mild' compared with those without the respective condition.

CONCLUSIONS

Pain is highly prevalent in individuals with SCI living in Switzerland. Considered at risk for chronic pain are women, older individuals and individuals with financial hardship and specific secondary health conditions. Longitudinal studies are necessary to identify predictors for the development of pain and its chronification.

Management of Neuropathic Pain Associated with Spinal Cord Injury

Spinal cord injury (SCI) is an injury to the spinal cord that leads to varying degrees of motor and/or sensory deficits and paralysis. Chronic pain of both neuropathic and nociceptive type is common and contributes to reduced quality of life. The aim of the review is to provide current clinical understanding as well as discuss and evaluate efficacy of pharmacological interventions demonstrated in the clinical studies. The review was based on literature search in PubMed and Medline with words "neuropathic pain" and "spinal cord injury". The review included clinical studies and not experimental data nor case reports. A limited number of randomized and placebo-controlled studies concerning treatment options of neuropathic pain after SCI were identified. Amitriptyline, a tricyclic antidepressant and the antiepileptic drugs, gabapentin and pregabalin, are most studied with demonstrated efficacy, and considered to be the primary choice. Opioids have demonstrated conflicting results in the clinical studies. In addition, administration route used in the studies as well as reported side effects restrict everyday use of opioids as well as ketamine and lidocaine. Topical applications of capsaicin or lidocaine as well as intradermal injections of Botulinum toxin are new treatment modalities that are so far not studied on SCI population and need further studies. Non-pharmacological approaches may have additional effect on neuropathic pain. Management of pain should always be preceded by thorough clinical assessment of the type of pain. Patients need a follow-up to evaluate individual effect of applied measures. However, the applied management does not necessarily achieve satisfactory pain reduction. Further clinical studies are needed to evaluate the effect of both established and novel management options.

Effects of chronic pain on function, depression, and sleep among patients with traumatic spinal cord injury

BACKGROUND AND OBJECTIVES

The main objectives of this cross-sectional study were (1) to examine chronic pain using the Multidimensional Pain Inventory-Spinal Cord Injury (MPI-SCI) version and (2) to assess the relationship between chronic pain and functional status, depression, and sleep quality among patients with SCI.

DESIGN AND SETTINGS

This was a cross-sectional study of all eligible patients admitted to the Ministry of Health Ankara Diskapi Yildirim Beyazit Education and Research Hospital Physical Therapy and Rehabilitation Clinic between January 2007 and July 2010.

METHODS

Forty-four patients (33 male, 11 female) with traumatic SCI, aged >=18 years, who had pain continuing for >=6 months and were hospitalized in the physical therapy and rehabilitation clinic were included in this cross-sectional study. Chronic pain intensity, functional status, depression, and sleep quality were assessed according to the MPI-SCI, Functional Independence Measure (FIM), Hamilton Rating Scale for Depression (HAM-D), and Pittsburg Sleep Quality Index (PSQI), respectively.

RESULTS

A positive correlation was observed between "Pain Severity" (one of the subscales of the MPI-SCI) and HAM-D (r=0.487, P=.001) and PSQI (r=0.312, P=.039). "Pain Severity" was significantly higher in the "impaired sleep" group (P < .05) than in the "normal sleep" group and in the "depression" group (P < .05) than in the "no depression" group.

CONCLUSION

We identified a strong interrelationship between SCI-related "Pain Severity" and both depression and sleep quality. Hence, a comprehensive pain examination and management strategies including psychosocial interventions should be given particular consideration to address the critical issue of chronic pain in individuals with SCI.

Multidimensional clinical pain phenotypes after spinal cord injury

SUMMARY Persistent neuropathic pain after spinal cord injury (SCI) is a serious problem that significantly affects general health and wellbeing over and above what is caused by other medical consequences after SCI. The ideal approach to the management of the neuropathic pain conditions after SCI would be to identify the primary contributing mechanisms of pain in each person and tailor the treatment to these. However, despite significant basic and clinical research progress, this approach remains elusive. One strategy to further this effort is to define neuropathic pain phenotypes based on pain symptoms, sensory function/dysfunction and psychosocial factors, and determine the relationship between these and treatment outcomes and biomarkers including brain imaging. This approach will facilitate the interaction between basic and clinical science and translational research, further the understanding of the mechanisms that contribute to the development and maintenance of neuropathic pain after SCI, and thus the development of effective mechanisms-based pain treatment strategies.

Developing a model of associations between chronic pain, depressive mood, chronic fatigue, and self-efficacy in people with spinal cord injury

Chronic pain, chronic fatigue, and depressive mood are prevalent conditions in people with spinal cord injury (SCI). The objective of this research was to investigate the relationship between these conditions in adults with SCI. Multivariate analysis of variance, contingency analyses, and hierarchical regression were used to determine the nature of the relationship, as well as the contribution to this relationship of self-efficacy, a potential mediator variable. Seventy participants with SCI living in the community completed an assessment regimen of demographic and psychometric measures, including validated measures of pain, fatigue, depressive mood, and self-efficacy. Results indicated that participants with high levels of chronic pain had clinically elevated depressive mood, confusion, fatigue, anxiety and anger, low vigor, and poor self-efficacy. Participants with high chronic pain had 8 times the odds of having depressive mood and 9 times the odds of having chronic fatigue. Regression analyses revealed that chronic pain contributed significantly to elevated depressive mood and that self-efficacy mediated (cushioned) the impact of chronic pain on mood. Furthermore, both chronic pain and depressive mood were shown to contribute independently to chronic fatigue. Implications of these results for managing chronic pain in adults with SCI are discussed.

PERSPECTIVE

The relationship between pain, negative mood, fatigue, and self-efficacy in adults with SCI was explored. Results support a model that proposes that chronic pain lowers mood, which is mediated (lessened) by self-efficacy, whereas pain and mood independently increase chronic fatigue. Results provide direction for treating chronic pain in SCI.

Evaluation of an interdisciplinary program for chronic pain after spinal cord injury

OBJECTIVE

To assess efficacy of an interdisciplinary pain program adapted for persons with spinal cord injury (SCI) and chronic pain.

DESIGN

Prospective cohort.

SETTING

University-affiliated rehabilitation hospital.

PARTICIPANTS

Twenty-two persons with traumatic or nontraumatic SCI and chronic pain of at least 6 months' duration.

METHODS

Subjects participated in an interdisciplinary pain program consisting of biweekly group sessions for 10 consecutive weeks. Sessions incorporated patient education on chronic pain and associated pain mechanisms, cognitive behavioral therapy, self-management strategies (eg, energy conservation, ergonomics, goal setting, stress management, anger management, and coping skills), group discussions and activities, and either exercise or guided relaxation at the end of each session.

MAIN OUTCOME MEASURES

Multidimensional Pain Inventory SCI, Coping Inventory of Stressful Situations, Pain Stages of Change Questionnaire, and Life Satisfaction Questionnaire.

RESULTS

After participation in an interdisciplinary pain program, persons with SCI and chronic neuropathic pain demonstrated increased involvement in learning and maintenance of coping strategies for chronic pain. Participation also led to less pain interference in daily life and a greater sense of control over one's life.

CONCLUSIONS

Participation in an interdisciplinary pain program does not reduce pain severity, but it can help persons with SCI and chronic neuropathic pain cope with pain, lessen interference of pain, and improve their sense of control.

Dissociated predegenerated peripheral nerve transplants for spinal cord injury repair: a comprehensive assessment of their effects on regeneration and functional recovery compared to Schwann cell transplants

Several recent studies suggest that predegenerated nerves (PDNs) or dissociated PDNs (dPDNs) can improve behavioral and histological outcomes following transplantation into the injured rat spinal cord. In the current study we tested the efficacy of dPDN transplantation by grafting cells isolated from the sciatic nerve 7 days after crush. We did not replicate one study, but rather assessed what appeared, based on five published reports, to be a reported robust effect of dPDN grafts on corticospinal tract (CST) regeneration and locomotor recovery. Using a standardized rodent spinal cord injury model (200 kD IH contusion) and transplantation procedure (injection of GFP⁺ cells 7 days post-SCI), we demonstrate that dPDN grafts survive within the injured spinal cord and promote the ingrowth of axons to a similar extent as purified Schwann cell (SC) grafts. We also demonstrate for the first time that while both dPDN and SC grafts promote the ingrowth of CGRP axons, neither graft results in mechanical or thermal hyperalgesia. Unlike previous studies, dPDN grafts did not promote long-distance axonal growth of CST axons, brainstem spinal axons, or ascending dorsal column sensory axons. Moreover, using a battery of locomotor tests (Basso Beattie Bresnahan [BBB] score, BBB subscore, inked footprint, Catwalk, and ladderwalk), we failed to detect any beneficial effects of dPDN transplantation on the recovery of locomotor function after SCI. We conclude that dPDN transplants are not sufficient to promote CST regeneration or locomotor recovery after SCI.

Chronic pain following spinal cord injury

BACKGROUND

Chronic pain following spinal cord injury is common, and may result in a substantially reduced quality of life. The aim of the paper is to provide an overview of pain conditions resulting from spinal cord injuries and an update on therapy options.

METHOD

The article is based on literature searches in PubMed review articles for the period 2006-2011, using the search phrases «pain and spinal cord injury/injuries», «chronic pain and spinal cord injury/injuries» and «neuropathic pain and spinal cord injury/injuries». Some key articles on neuropathic pain are also included, irrespective of the year of publication.

RESULTS

Patients with spinal cord injury may develop nociceptive and/or neuropathic pain.The cause, nature and localisation of the pain must be established before therapy is initiated. Neuropathic pain should primarily be treated with amitriptyline, gabapentin or pregabalin. Duloxetine, lamotrigine and tramadol may also be effective. Local treatment with high-concentration capsaicin and lidocaine may relieve localised neuropathic pain. Selected patients with intractable chronic neuropathic pain can be treated with intrathecal medication using an implanted pain pump or by microsurgical DREZotomy (Dorsal Root Entry Zone). Physiotherapy, non-steroidal anti-inflammatory drugs and opioids are most widely used for treating nociceptive pain. Physical exercise and acupuncture may provide relief from shoulder pain.

INTERPRETATION

There may be several causes of chronic pain following spinal cord injury. Different measures have been tested for the management of chronic pain after spinal cord injury, but most studies have been performed on a limited number of patients. Further studies are needed to find more effective means of relieving pain following spinal cord injuries.

Sensory function after cavernous haemangioma: a case report of thermal hypersensitivity at and below an incomplete spinal cord injury

STUDY DESIGN

Case report of a 42-year-old woman with non-evoked pain diagnosed with a cavernous C7-Th6 spinal haemangioma.

OBJECTIVES

To assess the effect of intramedullary haemorrhage (IH) on nociception and neuropathic pain (NP) at and below an incomplete spinal cord injury (SCI).

SETTING

Sensorimotor Function Group, Hospital Nacional de Parapléjicos de Toledo (HNPT).

METHODS

T2*-susceptibility weighted image (SWI) magnetic resonance imaging (MRI) of spinal haemosiderin and a complete pain history were performed 8 months following initial dysaesthesia complaint. Thermal pain thresholds were assessed with short 1 s stimuli, while evidence for central sensitization was obtained with psychophysical electronic Visual Analogue Scale rating of tonic 10 s 3 °C and 48 °C stimuli, applied at and below the IH. Control data were obtained from 10 healthy volunteers recruited from the HNPT.

RESULTS

Non-evoked pain was present within the Th6 dermatome and lower legs. T2*-SWI MRI imaging detected extensive haemosiderin-rich IH (C7-Th5/6 spinal level). Cold allodynia was detected below the IH (left L5 dermatome) with short thermal stimuli. Tonic thermal stimuli applied to the Th6, Th10 and C7 dermatomes revealed widespread heat and cold allodynia.

CONCLUSION

NP was diagnosed following IH, corroborated by an increase in below-level cold pain threshold with at- and below-level cold and heat allodynia. Psychophysical evidence for at- and below-level SCI central sensitization was obtained with tonic thermal stimuli. Early detection of IH could lead to better management of specific NP symptoms, an appreciation of the role of haemorrhage as an aggravating SCI physical factor, and the identification of specific spinal pathophysiological pain mechanisms.

Coexisting mechanical hypersensitivity and anxiety in a rat model of spinal cord injury and the effect of pregabalin, morphine, and midazolam treatment

Background and purpose

Spinal cord injury (SCI) has detrimental consequences that include chronic neuropathic pain, which is seen in 40-50% of patients, and symptoms of anxiety and depression, which affect 13-45% of SCI patients. The coexistence of pain, anxiety, and depression is known from other neuropathic pain conditions, but the relationship between these symptoms is not clear and has not been investigated in a preclinical model of SCI so far.

The aim of this study was to investigate anxiety-like behavior and at-level mechanical hypersensitivity following experimental spinal cord contusion (SCC) in female Sprague-Dawley rats, and the effects of analgesic and anxiolytic drugs.

Methods

Mechanical sensitivity and elevated plus maze (EPM) behavior were measured pre- and postinjury in SCC and sham animals. Pregabalin 30 mg/kg, morphine 3 mg/kg, midazolam 0.5 mg/kg, and 0.9% NaCl were evaluated in a randomly allocated, blinded balanced design.

Results

SCC animals developed persistent at-level mechanical hypersensitivity and decreased open arm activity in the EPM, which indicates an anxiety-like state. Pregabalin, a dual-acting analgesic and anxiolytic drug reduced both hypersensitivity and anxiety-like behavior, while the analgesic drug morphine only reduced hypersensitivity. The anxiolytic drug midazolam in the dose used had no effect on either parameter.

Conclusions

SCC animals developed long lasting coexisting at-level mechanical hypersensitivity and anxiety-like behavior, but there was no evidence to support a causal relationship between pain and anxiety following SCI.

Implications

The findings that at-level mechanical hypersensitivity and anxiety-like behavior develops concomitantly in the spinal cord contusion models and that both symptoms is persistent provide basis for further investigation of the mechanisms and connection behind these two clinically relevant symptoms after injury to the central nervous system.

Pain symptom profiles in persons with spinal cord injury

OBJECTIVE

Persistent pain is a common consequence of spinal cord injury. A patient-specific assessment that combines both the identification of pain symptoms and psychosocial factors is needed for a tailored treatment approach. The aim of the study was to define pain symptom profiles and to determine their relationship with psychosocial factors in persons with spinal cord injury.

DESIGN

Face-to-face interview and examination.

SETTING

VA Medical Center and Miami Project to Cure Paralysis, Miami, Florida.

PATIENTS

Persons with spinal cord injury (135 men and 21 women) provided detailed descriptions of 330 neuropathic pains.

OUTCOME MEASURES

The American Spinal Injury Impairment Scale, pain history and measures of pain interference, life satisfaction, locus of control, social support and depression.

RESULTS

The exploratory factor analyses and regression analyses revealed three distinct symptom profiles: 1) aching, throbbing pain, aggravated by cold weather and constipation predicted by a combination of chance locus of control and lower levels of life satisfaction; 2) stabbing, penetrating, and constant pain of high intensity predicted by a combination of pain interference, localized pain, powerful others locus of control and depressed mood; and 3) burning, electric, and stinging pain aggravated by touch and muscle spasms predicted by pain interference.

CONCLUSIONS

Although these results need to be replicated in other spinal cord injury samples, our findings suggest that pain symptom profiles may be a useful way to further characterize pain in a comprehensive assessment strategy.

What are the risk factors of occurence and chronicity of neuropathic pain in spinal cord injury patients?

OBJECTIVE

Analyze the epidemiological data on neuropathic pain in spinal cord injury patients and determine the risk factors for its occurrence and chronicity.

METHOD

Review and analysis of the literature.

RESULTS

Epidemiological data report that 40% of spinal cord injury (SCI) patients suffer from neuropathic pain and 40% of these patients report an intense neuropathic pain. Some factors do not seem to be predictive for the onset of neuropathic pain: the level of injury, complete or incomplete injury, the existence of an initial surgery, sex. However, old age at the time of injury, bullet injury as the cause of trauma, early onset of pain in the weeks following the injury, their initial nature, intensity and continuous pain, as well as associated symptoms all appear to be negative prognostic factors.

CONCLUSION

Neuropathic pain in SCI patients is a major issue, its determining factors still need to be evaluated properly by refining the epidemiological data.

The effect of a series of repetitive transcranial magnetic stimulations of the motor cortex on central pain after spinal cord injury

OBJECTIVE

To study the analgesic effect of repetitive transcranial magnetic stimulation (rTMS) of the motor cortex on central pain in patients with chronic spinal cord injury (SCI).

DESIGN

Double-blind randomized controlled trial. Mean follow-up period was 4.5 weeks.

SETTING

General hospital.

PARTICIPANTS

Twelve paraplegic patients due to thoracic SCI suffering chronic central pain (11 completed the study) who were randomly selected from a list of eligible patients.

INTERVENTION

Real or sham 10 daily motor rTMS treatments (500 trains at 5 Hz for 10 s; total of 500 pulses at intensity of 115% of motor threshold) using figure-of-8 coil over the vertex.

MAIN OUTCOME MEASURES

Chronic pain intensity (visual analog scale [VAS], McGill Pain Questionnaire [MPQ]), pain threshold, and level of depression (Beck Depression Inventory).

RESULTS

Both real and sham TMS induced a similar, significant reduction in VAS scores (P<.001) immediately after each of the 10 treatment sessions and in VAS and MPQ scores after the end of the treatment series. However, only real rTMS conferred a significant increase in heat-pain threshold (4 degrees C, P<.05) by the end of the series. Most important, the reduction in MPQ scores in the real rTMS group continued during the follow-up period. Depression scores were equally reduced in both groups but similar to pain relief, depression continued to improve at follow-up in the real rTMS group.

CONCLUSIONS

Whereas the pain alleviation induced by a single rTMS treatment is probably due to placebo, patients with SCI may benefit from a series of rTMS treatments.

Effects of circuit resistance training on fitness attributes and upper-extremity pain in middle-aged men with paraplegia

OBJECTIVE

To examine the effects of circuit resistance exercise (CRT) training on muscle strength, endurance, anaerobic power, and shoulder pain in middle-aged men with paraplegia.

DESIGN

Repeated testing.

SETTING

Academic medical center.

PARTICIPANTS

Seven men (age range, 39-58y) with motor-complete paraplegia from T5 to T12 and confirmed shoulder pain occurring during daily activities.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Subjects underwent a 4-month CRT program using alternating resistance maneuvers and high-speed, low-resistance arm exercise. One-repetition maximal force was measured before training and monthly thereafter. Pretraining and posttraining peak oxygen uptake (Vo(2)peak) was measured by graded arm testing. Anaerobic power was measured before and after training using a 30-second Wingate Anaerobic Test. Shoulder pain was self-evaluated by an index validated for people with spinal cord injury (Wheelchair Users Shoulder Pain Index [WUSPI]).

RESULTS

Strength increases ranging from 38.6% to 59.7% were observed for all maneuvers (P range, .005-.008). Vo(2)peak increased after training by 10.4% (P=.01), and peak and average anaerobic power increased by 6% (P=.001) and 8.6% (P=.005), respectively. WUSPI scores +/- standard deviation were lowered from 31.9+/-24.8 to 5.7+/-5.9 (P=.008), with 3 of 7 subjects reporting complete resolution of shoulder pain.

CONCLUSIONS

CRT improves muscle strength, endurance, and anaerobic power of middle-aged men with paraplegia while significantly reducing their shoulder pain.

Pain after spinal cord injury: an evidence-based review for clinical practice and research. Report of the National Institute on Disability and Rehabilitation Research Spinal Cord Injury Measures meeting

BACKGROUND/OBJECTIVES

To examine the reliability, validity, sensitivity, and practicality of various outcome measures for pain after spinal cord injury (SCI), and to provide recommendations for specific measures for use in clinical trials.

DATA SOURCES

Relevant articles were obtained through a search of MEDLINE, EMBASE, CINAHL, and PubMed databases from inception through 2006.

STUDY SELECTION

The authors performed literature searches to find articles containing data relevant to the reliability and validity of each pain outcome measure in SCI and selected non-SCI populations.

DATA EXTRACTION

After reviewing the articles, an investigator extracted information utilizing a standard template. A second investigator reviewed the chosen articles and the extracted pertinent information to confirm the findings of the first investigator.

DATA SYNTHESIS

Taking into consideration both the quantity and quality of the studies analyzed, judgments on reliability and validity of the measures were made by the two investigators. Based upon these judgments, recommendations were formulated for use of specific measures in future clinical trials. In addition, for a subset of measures a voting process by a larger group of SCI experts allowed formulation of recommendations including determining which measures should be incorporated into a minimal dataset of measures for clinical trials and which ones need revision and further validity and reliability testing before use.

CONCLUSIONS

A 0-10 Point Numerical Rating Scale (NRS) is recommended as the outcome measure for pain intensity after SCI, while the 7-Point Guy/Farrar Patient Global Impression of Change (PGIC) scale is recommended as the outcome measure for global improvement in pain. The SF-36 single pain interference question and the Multidimensional Pain Inventory (MPI) or Brief Pain Inventory (BPI) pain interference items are recommended as the outcome measures for pain interference after SCI. Brush or cotton wool and at least one high-threshold von Frey filament are recommended to test mechanical allodynia/hyperalgesia while a Peltier-type thermotester is recommended to test thermal allodynia/hyperalgesia. The International Association for the Study of Pain (IASP) or Bryce-Ragnarsson pain taxonomies are recommended for classification of pain after SCI, while the Neuropathic Pain Scale (NPS) is recommended for measuring change in neuropathic pain and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) for quantitating neuropathic and nociceptive pain discrimination.

Internal Consistency, Stability, and Validity of the Spinal Cord Injury Version of the Multidimensional Pain Inventory

OBJECTIVE

To evaluate the internal consistency, stability, and construct validity of a spinal cord injury (SCI) version of the Multidimensional Pain Inventory (MPI-SCI).

DESIGN

Interview.

SETTING

Veterans Affairs medical center and university-based institute.

PARTICIPANTS

Community sample of persons with SCI and chronic pain (N=161).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

The MPI-SCI.

RESULTS

The internal consistency of the MPI-SCI subscales ranged from fair (.60) for affective distress to substantial (.94) for pain interference with activities. The subscales of the MPI-SCI (ie, life interference [r=.81], affective distress [r=.71], solicitous responses [r=.86], distracting responses [r=.85], general activity [r=.69], pain interference with activities [r=.78], pain severity [r=.69], negative responses [r=.69]) showed adequate stability. In contrast, the stability of the support (r=.59) and the life control subscales (r=.31) was unacceptably low. All MPI-SCI subscales with the exception of the perceived responses by significant others subscales showed good convergent, discriminant, and concurrent validity.

CONCLUSIONS

The MPI-SCI appears to be a reasonable measure for evaluating chronic pain impact after SCI. In clinical trials, however, supplementary instruments should be included to assess changes in affect, social support, and perceptions of life control.