Pain classification following spinal cord injury: the utility of verbal descriptors

Non-opioid pharmacologic treatment of chronic spinal cord injury-related pain

Purpose: Spinal cord injury-related pain is often a severe debilitating condition that adversely affects the patient's physical health, psychological wellbeing and quality of life. Opioid medications have historically been prescribed to this population with great frequency. As opioid abuse disorder becomes an ever-worsening public health issue, more attention must be placed upon non-opioid options. This paper reviews non-opioid medications to be considered when treating spinal cord injury-related pain. The pertinent literature is reviewed, and the advantages and pitfalls of various medication options are discussed in the complicated context of the individual with a spinal cord injury.Methods: Peer-reviewed journal articles and medication package insert data are reviewed.Results:. The non-opioid medications with the greatest evidence for efficacy in the treatment of chronic spinal cord injury-related pain are drawn from the antiepileptic drug and antidepressant categories though the specific selection must be nuanced to the particular individual patient. More research is required to understand the role of calcitonin, lithium, and marijuana in treating spinal cord injury-related pain.Conclusions: The complex clinical situation of each individual patient must be weighed against the risks and benefits of each medication, as reviewed in this paper, to determine the ideal treatment strategy for chronic spinal cord injury-related pain.

Brain White Matter Abnormality Induced by Chronic Spinal Cord Injury in the Pediatric Population: A Preliminary Tract-based Spatial Statistic Study

Objectives: Tract-based spatial statistics (TBSS) is a diffusion tensor imaging (DTI)-based processing technique that aims to improve the objectivity and interpretability of analysis of multisubject diffusion imaging studies. This study used TBSS to measure quantitative changes in brain white matter structures following spinal cord injury (SCI). Methods: Eighteen SCI subjects aged 8-20 years old (mean age, 16.5 years) were scanned using a conventional single-shot EPI DTI protocol using a 3.0T Siemens MR scanner. All participants underwent a complete International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) examination to determine the level and severity of injury. Five participants were classified as American Spinal Injury Association Impairment Scale (AIS) A, nine as AIS B, and four as AIS C/D. Imaging parameters used for data collection were as follows: 20 directions, b = 1000 s/mm², voxel size = 1.8 mm x 1.8 mm, slice thickness = 5 mm, TE = 95 ms, TR = 4300 ms, slices = 30, TA = 4:45 min. To generate TBSS, nonparametric permutation tests were used for voxel-wise statistical analysis of the fractional anisotropy (FA) skeletons between AIS groups. A two-tailed t test was applied to extract voxels with significant differences at p < .05. Results: Notable significant changes occurred throughout the corticospinal, spinothalamic, and dorsal column/medial lemniscus tracts. Altered regions in the temporal, occipital, and parietal lobes were also identified. Conclusion: These results suggest that white matter structures are altered differently between people with different AIS classifications. TBSS has the potential to serve as a screening tool to identify white matter changes in regions of interest.

Approach to Neuropathic Pain

Neuropathic pain is a common chief complaint encountered by neurologists and primary care providers. It is caused by disorders involving the somatosensory nervous system. The clinical evaluation of neuropathic pain is challenging and requires a multifaceted systematic approach with an emphasis on a thorough history and physical examination to identify characteristic signs and symptoms. Ancillary laboratory investigations, targeted imaging, and electrodiagnostic studies further help identify underlying etiologies to guide specific treatments. Management of neuropathic pain encompasses treating the underlying pathology as well as symptomatic control with nonpharmacological, pharmacological, and interventional therapies. Here, we present an approach to help evaluate patients with neuropathic pain.

Prevalence and Characteristics of Neuropathic Pain in Patients With Spinal Cord Injury Referred to a Rehabilitation Center

OBJECTIVE

To identify the prevalence and characteristics of neuropathic pain (NP) in patients with spinal cord injury (SCI) and to investigate associations between NP and demographic or disease-related variables.

METHODS

We retrospectively reviewed medical records of patients with SCI whose pain was classified according to the International Spinal Cord Injury Pain classifications at a single hospital. Multiple statistical analyses were employed. Patients aged <19 years, and patients with other neurological disorders and congenital conditions were excluded.

RESULTS

Of 366 patients, 253 patients (69.1%) with SCI had NP. Patients who were married or had traumatic injury or depressive mood had a higher prevalence rate. When other variables were controlled, marital status and depressive mood were found to be predictors of NP. There was no association between the prevalence of NP and other demographic or clinical variables. The mean Numeric Rating Scale (NRS) of NP was 4.52, and patients mainly described pain as tingling, squeezing, and painful cold. Females and those with below-level NP reported more intense pain. An NRS cut-off value of 4.5 was determined as the most appropriate value to discriminate between patients taking pain medication and those who did not.

CONCLUSION

In total, 69.1% of patients with SCI complained of NP, indicating that NP was a major complication. Treatment planning for patients with SCI and NP should consider that marital status, mood, sex, and pain subtype may affect NP, which should be actively managed in patients with an NRS ≥4.5.

Central pain syndromes

The management of pain in persons with neurological injuries is challenging and complex. A holistic view and clinical approach are necessary when addressing pain in patients with neurological impairment because interpreting signs and symptoms and deciphering sources of pain is never a straightforward process. This problem is further magnified with the management of central pain syndromes. The best approach is to have a good understanding of the clinical characteristics commonly found in this patient population, in particular for patients with stroke, multiple sclerosis (MS), or spinal cord injury (SCI), as central pain manifests differently between these groups. This paper will focus on the history, clinical presentation, pathophysiology, assessment, and treatment of central pain in patients with these types of neurological conditions. In addition to being at risk for a decline in quality of life, patients with pain syndromes are also prone to adverse responses to treatments (e.g., opioid addiction). It is therefore important to methodically analyze the similarities and differences between patients with different pain syndromes.

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.

Dopaminergic treatment of restless legs syndrome in spinal cord injury patients with neuropathic pain

Recent studies report high incidence of restless legs syndrome (RLS) in patients with spinal cord injury (SCI), who may also present pain and sensory disturbances. In the present manuscript, we examine and discuss diagnostic and treatment challenges of comorbid RLS and neuropathic pain (NP) in SCI. We evaluated seven men with a mean age of 55.6 (s.d.=14.0) years, with chronic complete or incomplete SCI at the thoracic or lumbar level, for complaints of sensory disturbances in the legs, which initially were attributed to drug-resistant NP. Because overlapped RLS was suspected, clinical evaluation of NP and RLS, serum ferritin and iron level assessment, and video polysomnographic (VPSG) studies were conducted. Pramipexole (0.18 mg q.d.^-1) was added to treat RLS, and a follow-up was performed at 2 months. We found that in six subjects the RLS was comorbid with NP and in one subject the symptoms of RLS were misdiagnosed as NP. VPSG revealed periodic limb movements (PLMs) in all patients, including PLMs of the legs, arms or both. Serum ferritin was <50 ng ml^-1 in two patients. RLS improved significantly after 2 months with pramipexole. On the basis of current findings, we recommend physicians to be aware of the comorbidity between RLS and NP secondary to SCI to include suitable diagnostic procedures and effective treatments.

Central Neuropathic Pain Syndromes

Chronic pain is common in patients with neurologic complications of a central nervous system insult such as stroke. The pain is most commonly musculoskeletal or related to obligatory overuse of neurologically unaffected limbs. However, neuropathic pain can result directly from the central nervous system injury. Impaired sensory discrimination can make it challenging to differentiate central neuropathic pain from other pain types or spasticity. Central neuropathic pain may also begin months to years after the injury, further obscuring recognition of its association with a past neurologic injury. This review focuses on unique clinical features that help distinguish central neuropathic pain. The most common clinical central pain syndromes-central poststroke pain, multiple sclerosis-related pain, and spinal cord injury-related pain-are reviewed in detail. Recent progress in understanding of the pathogenesis of central neuropathic pain is reviewed, and pharmacological, surgical, and neuromodulatory treatments of this notoriously difficult to treat pain syndrome are discussed.

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.

Evaluation of pain and its effect on quality of life and functioning in men with spinal cord injury

Background

Pain is one of the most important consequences of spinal cord injury (SCI). It may affect several aspects of life, especially the quality of life (QoL). Hence, this study was conducted to establish an understanding of pain and its correlates and effects on patients with SCI in our community.

Methods

In a cross-sectional study, 58 male veterans suffering from SCI were admitted to our center for a regular follow-up. Demographic and SCI-related descriptive information were gathered using a self-reported questionnaire. To evaluate the patients' pain quality and the effect of pain on daily life, a questionnaire in 3 parts of lumbar, cervical and shoulder pain was administered. EuroQoL questionnaire and General Health Questionnaire (GHQ) 12 were also used to assess the patients' QoL.

Results

The mean age of the participants was 45.91 ± 6.69 with mean injury time of 25.54 ± 5.91. forty-four patients (75.9%) reported pain, including lumbar pain (63%), cervical pain (39%) and shoulder pain (51%). The presence of pain was associated with lower QoL. Patients with lumbar pain reported a significant amount of pain affecting their daily life and this effect was higher in patients with lower GHQ score or anxiety/depressive disorder.

Conclusions

Musculoskeletal pain, is a common complaint in veterans with SCI and is inversely associated with functioning and general health status. Lumbar and shoulder pain affects patient's daily living more than cervical pain.

Moving towards multiple site outcomes in spinal cord injury pain clinical trials: An issue of clustered observations in trial design and analysis

INTRODUCTION

Pain remains a problem for many with spinal cord injury (SCI), and there is a need for sound, randomized clinical trials examining the efficacy of existing and novel therapeutics. SCI-related pain is complex, as more than one type of pain is often experienced. The purpose of this report is to (i) demonstrate how to design and power calculation of a clinical trial of SCI pain using multiple pain sites per individual; (ii) discuss consequences of failing to adjust for this; and (iii) provide intraclass correlation (ICC) estimates for common pain outcome measures that may be used to power future clinical trials in SCI pain.

METHOD

Using an existing dataset from a past SCI pain clinical trial, the ICC was calculated for common pain outcome measures to illustrate appropriate corrections for powering, analyzing and interpreting results from multiple pain sites per individual. The problem associated with not accounting for multiple pain sites per individual and the effect on the Type I error rate is also shown.

RESULTS AND DISCUSSION

Not accounting for the ICC can lead to (1) incorrect power estimates in the design of a trial, and (2) an inflated Type I error rate with a higher likelihood of misinterpretation of outcomes.

CONCLUSIONS

Powering for future SCI pain trials and statistical analysis of trial outcomes may be substantially compromised if methods do not account for the intra-individual associations between pain sites, ultimately affecting study interpretations and evidence-based practice. We present ICC estimates based on SCI pain data for purposes of estimating power for future trials.

Evaluation of the psychometric properties of the revised short-form McGill Pain Questionnaire

The recently revised version of the Short-Form McGill Pain Questionnaire (SF-MPQ-2) was created to assess both neuropathic and non-neuropathic pain. The current study extends prior research by testing the reliability and validity of the SF-MPQ-2 in a sample of U.S. veteran patients with a range of chronic pain diagnoses. Participants (N = 186) completed the SF-MPQ-2, a sociodemographic questionnaire, the Structured Clinical Interview for the DSM-IV, and self-report pain and psychiatric measures. Pain diagnoses were extracted from the electronic medical record. The SF-MPQ-2 total and scale scores demonstrated good-to-excellent internal consistency. Convergent and discriminant validity were supported, and SF-MPQ-2 total and scale scores increased with number of pain diagnoses and pain severity. Confirmatory factor analyses indicated that a 4-factor model fit the data better than a single-factor model. However, high intercorrelations among the 4 latent constructs were observed, and a second-order global pain construct also emerged. Overall, the SF-MPQ-2 demonstrated excellent reliability and validity in a sample of U.S. veteran patients with chronic neuropathic and non-neuropathic pain. Future psychometric studies of the SF-MPQ-2 should employ longitudinal data to evaluate the ability of scale scores to uniquely predict clinical and health service outcomes.

PERSPECTIVE

This article presents the psychometric properties of a revised version of the SF-MPQ-2. This measure may have great utility as a screening tool in clinical practice and as an outcome measure in clinical trials.

Central Neuropathic Pain in Spinal Cord Injury

Spinal cord injury (SCI) is a devastating medical condition affecting 1.2 million people in the United States. Central neuropathic pain is one of the most common medical complications of SCI. Current treatment options include opioids, antiepileptic agents such as gabapentin, antispastic agents such as baclofen or tizanidine, and tricyclic acid. Other options include complementary, nonpharmacological treatment such as exercise or acupuncture, interventional treatments, and psychological approaches. Although these treatment options exist, central neuropathic pain in patients with SCI is still extremely difficult to treat because of its complexity. To develop and provide more effective treatment options to these patients, proper assessment of and classification tools for central neuropathic pain, as well as a better understanding of the pathophysiology, are needed. A combination of approaches, from standard general pain assessments to medically specific questions unique to SCI pathophysiology, is essential for this population. A multidisciplinary approach to patient care, in addition with a better understanding of pathophysiology and diagnosis, will lead to improved management and treatment of patients with SCI displaying central neuropathic pain. Here we summarize the most recent classification tools, pathophysiology, and current treatment options for patients with SCI with central neuropathic pain.

Effects of noninvasive electroacupuncture at Hegu (LI4) and Sanyinjiao (SP6) acupoints on dysmenorrhea: a randomized controlled trial

BACKGROUND

This study aimed to evaluate the effects of noninvasive acupoint stimulation therapy with middle-frequency electrical waves on dysmenorrhea in young women.

METHODS

This randomized controlled trial enrolled 66 gynecology patients who had primary dysmenorrhea, which was defined as painful menstruation without pelvic pathology (secondary dysmenorrhea). Pathology was ruled out by gynecological ultrasound examination and serum concentration of CA-125. Subjects were randomly assigned to an experimental group (n=34) and control group (n=32). Main outcome measures included McGill Questionnaire Short-form and numerical rating scale for pain intensity. Acupuncture-like trancutaneous electrical nerve stimulation (AL-TENS) of middle-frequency (1000 Hz-10,000 Hz) was applied at Hegu (LI4) and Sanyinjiao (SP6) points in the experimental group twice weekly for 8 weeks; the control group received AL-TENS on nonacupoints. Pre- and postintervention results were recorded.

RESULTS

Prior to AL-TENS intervention, no significant differences were found in pain scale and pain intensity between experimental and control groups. After AL-TENS intervention, average total pain score in the experimental group was significantly lower than in the control group (experimental group 2.9±1.2, control group 5.4±2.2; p<0.001). Significant differences were observed between experimental and control groups in average change in pain scores between pre- and postintervention (experimental group 4.5±1.9, control group 1.39±2.0; p<0.001). Pain severity at postintervention was also significantly different between groups (p<0.001).

CONCLUSIONS

Noninvasive electro-acupuncture stimulation therapy with middle-frequency electric waves applied at both Hegu (LI4) and Sanyinjiao (SP6) acupoints mitigates pain in dysmenorrhea.

The clinical characteristics of neuropathic pain in patients with spinal cord injury

OBJECTIVES

The aim of the study was to evaluate the characteristics of neuropathic pain and observe intensity alterations in pain with regard to time during the day in spinal cord injury (SCI) patients.

METHODS

A total of 50 SCI patients (M/F, 40/10; mean age, 35±12 years) with at-level and below-level neuropathic pain were included in the study. All patients were examined and classified according to the ASIA/ISCoS 2002 International Neurologic Examination and Classification Standards. The history, duration, localization and characteristics of the pain were recorded. Neuropathic pain of patients was evaluated with the McGill-Melzack Pain Questionnaire and LANSS (Leeds Assessment of Neuropathic Symptoms and Signs) Pain Scale. Visual analog scale (VAS) was used to measure the severity of pain four times during the day. Quality of life was analyzed with Short Form 36.

RESULTS

Out of 50 patients, 10 were tetraplegic and 40 were paraplegic. In all, 28 patients had motor and sensory complete injuries (AIS A), whereas 22 patients had sensory incomplete (AIS B, C and D) injuries. The most frequently used words to describe neuropathic pain were throbbing, tiring, hot and tingling. Pain intensity was significantly higher in the night than in the evening, noon and morning (P<0.05) (VAS morning: 5.16±2.42, VAS noon: 5.24±2.52, VAS evening: 5.80±2.46 and VAS night: 6.38±2.19).

CONCLUSION

Neuropathic pain is a serious complaint in SCI patients and affects their quality of life. Neuropathic pain intensity was higher in the night hours than other times of day. This situation reinforces the need for a continued research and education on neuropathic pain in SCI.

Assessment of impairment in patients with acute traumatic spinal cord injury: a systematic review of the literature

The most common primary end-point of the trial on treatment of traumatic spinal cord injury (SCI) is the degree of impairment. The American Spinal Injury Association (ASIA) Standards have been widely used to assess motor function and pin-prick and light-touch sensory function. In addition, pain assessment is another clinically relevant aspect of the impairment in individuals with SCI. Given this, we sought to systematically review the studies that focused on the psychometric properties of ASIA Standards and all previously used outcome measures of pain in the SCI population in the acute care setting. For the primary literature search strategy, the MEDLINE, CINAHL, EMBASE, and Cochrane databases were sought out. Subsequently, a secondary search strategy was carried out using the articles listed in the references of meta-analysis, systematic, and non-systematic review articles. Two reviewers (JCF and VN) independently selected the articles that fulfill the inclusion and exclusion, assessed the level of evidence of each article, and appraised the psychometric properties of each instrument. Divergences during those steps were solved by consensus between both reviewers. Of 400 abstracts captured in our primary search strategy on the ASIA Standards, 16 full articles fulfilled the inclusion and exclusion criteria. An additional 40 references were obtained from two prior systematic reviews on ASIA Standards. While 45 of 56 of the studies on ASIA Standards provided level 4 evidence, there were 11 level 2b evidence studies. Convergent construct validity (n = 34), reliability (n = 12), and responsiveness (n = 10) were the most commonly studied psychometric properties of the ASIA Standards, but two prior studies examined their content validity. Of the 267 abstracts yielded in our primary search on pain assessment, 24 articles with level 4 evidence fulfilled the inclusion and exclusion criteria. There was no study that examined pain assessment in the acute care setting. While 18 of 24 articles studied an instrument for assessment of pain intensity, the remaining six studies were focused on classifications of pain in the SCI population. In conclusion, the ASIA Standards represent an appropriate instrument to categorize and evaluate spinal cord injured adults over time with respect to their motor and sensory function. Nevertheless, further investigation of the psychometric properties of the ASIA Standards is recommended due to a lack of studies focused on some key elements of responsiveness, including minimal clinically important difference. The visual analog scale (VAS) is the most commonly studied instrument of assessment of pain intensity in the SCI population. However, further investigation is required with regard to its reliability and responsiveness in the SCI population. Our results also suggest that there is no instrument with appropriate psychometric properties for this particular population.

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.

Pharmacological management of neuropathic pain following spinal cord injury

Spinal cord injury (SCI) has a number of severe and disabling consequences, including chronic pain, and around 40% of patients develop persistent neuropathic pain. Pain following SCI has a detrimental impact on the patient's quality of life and is a major specific healthcare problem in its own right. Thus far, there is no cure for the pain and oral pharmaceutical intervention is often inadequate, commonly resulting in a reduction of only 20-30% in pain intensity. Neuropathic pain sensations are characterized by spontaneous persistent pain and a range of abnormally evoked responses, e.g. allodynia (pain evoked by normally non-noxious stimuli) and hyperalgesia (an increased response to noxious stimuli). Neuropathic pain following SCI may be present at or below the level of injury. Oral pharmacological agents used in the treatment of neuropathic pain act either by depressing neuronal activity, by blocking sodium channels or inhibiting calcium channels, by increasing inhibition via GABA agonists, by serotonergic and noradrenergic reuptake inhibition, or by decreasing activation via glutamate receptor inhibition, especially by blocking the NMDA receptor. At present, only ten randomized, double-blind, controlled trials have been performed on oral drug treatment of pain after SCI, the results of most of which were negative. The studies included antidepressants (amitriptyline and trazodone), antiepileptics (gabapentin, pregabalin, lamotrigine and valproate) and mexiletine. Gabapentin, pregabalin and amitriptyline showed a significant reduction in neuropathic pain following SCI. Cannabinoids have been found to relieve other types of central pain, and serotonin noradrenaline reuptake inhibitors as well as opioids relieve peripheral neuropathic pain and may be used to treat patients with SCI pain.

Pain following spinal cord injury

Pain is one of the most common, severe, and treatment-resistant complications that follows SCI. Recent years have seen a surge of research on methods for assessing and treating spinal cord injury pain. In this article, pain after SCI is reviewed in terms of nature, scope, assessment techniques, and treatment strategies.

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.

Shoulder pain following tetraplegia: a follow-up study 2–4 years after injury

OBJECTIVES

To investigate (1) the characteristics of shoulder pain following discharge from rehabilitation for tetraplegia, (2) the relationship between pain and any associated risk factors and (3) the relationship between pain and functional activities, and pain and quality of life.

DESIGN

Longitudinal study.

SETTING

Spinal Injuries Unit, Australia.

METHODS

Participants (n=27) were surveyed between 2 and 4 years postinjury. Prospective data on shoulder pain during rehabilitation had been collected previously and allowed comparison with the follow-up data. Data collected included pain intensity and quality, the Wheelchair User's Shoulder Pain Index (WUSPI) and perceived effect of pain on quality of life.

RESULTS

Shoulder pain prevalence was 70%. Pain was associated with discharge motor level of C6-T1 (P=0.003). Pain was most commonly located in the shoulder joint. Pain was primarily aggravated by movement and cold weather and relieved by rest. The most painful activity was lifting an object from overhead. Quality of life was affected by pain in 68.4% of participants.

CONCLUSION

Shoulder pain is common following rehabilitation for tetraplegia and is associated with injury level. Pain is reported during daily tasks and adversely affects quality of life. Areas for further research are identified.

Cluster Analysis and Chronic Pain: An Empirical Classification of Pain Subgroups in a Spinal Cord Injury Sample

OBJECTIVE

To demonstrate the presence of homogeneous spinal cord injury (SCI) pain subgroups.

DESIGN

Prospective longitudinal design.

PARTICIPANTS

Persons with traumatic onset SCI (n = 1,334) with self-reported pain, pain interference, and depression.

OUTCOME MEASURES

Pain (Verbal Analogue Scale); Pain Interference (item from Short Form 12); Depression (Brief Patient Health Questionnaire).

RESULTS

Multivariate clustering indicated four SCI pain subgroups: (1) Low Pain (low pain intensity, pain interference, and depression); (2) Positive Adaptation to Pain (high pain intensity, low pain interference and depression); (3) Minimal Distress (high pain intensity, high pain interference, and low depression); and (4) Chronic Pain Syndrome (high pain intensity, pain interference, and depression).

CONCLUSIONS

Homogeneous SCI pain subgroups may be important for clinicians to consider in treatment planning and research.

Describing pain with physical disability: Narrative interviews and the McGill Pain Questionnaire

OBJECTIVES

To identify common pain descriptors used by people with physical disability-related pain and to suggest words that are likely to prompt responses in clinical interviews and assessments.

DESIGN

Open-ended interviews were coded and then contrasted with responses to a pain questionnaire, obtained through mail or interview surveys.

SETTING

Rehabilitation research program.

PARTICIPANTS

Twenty-eight people with physical disability-related pain in a series (n=54) of in-depth interviews and 1053 participants with disabilities who responded to mailed questionnaires or structured interviews about pain and its impact (459 with acquired lower-limb amputation, 471 with spinal cord injury, 123 with cerebral palsy).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Pain interview descriptions and McGill Pain Questionnaire (MPQ).

RESULTS

Different pain experiences were reflected in narrative descriptions and self-report questionnaire responses. We report the common terms, but across diagnoses use of terms does not appear to clearly differentiate distinct pain phenomenon. Narrative interviews support the use of several MPQ pain descriptors. However, discrete descriptors are recommended when assessing adults with physical disability.

CONCLUSIONS

We identified pain descriptors that appear to be most useful in assessing daily life and participation experiences with physical disability-related pain. These may be clinically useful, but caution is advised when doing diagnostic workups based solely on sensory and affective pain descriptions.

Exacerbation of Chronic Pain following Spinal Cord Injury

Because of the high prevalence and the refractory nature of pain following spinal cord injury (SCI), it is important to increase the understanding of what factors aggravate different types of pain. This information is related to pain generating mechanisms and may thus be useful in the diagnosis and management of these difficult pain conditions. The aims of the present study were to (1) identify variables (factors) that exacerbate chronic pain associated with SCI and (2) define the relationships among these patterns of pain exacerbation, specific pain characteristics, and psychological features. A sample out of 159 (75.5%) people with SCI and chronic pain, volunteered to participate in a mail survey. Over 50% of the sample indicated that prolonged sitting, infections, fatigue, muscle spasms, cold weather, and sudden movements exacerbated their pain. A principal components analysis detected five sets of factors that were reported to magnify pain: negative mood, prolonged afferent activity (bowel, bladder, somatic), weather, voluntary physical activity, and transient somatic afferent activity. Negative mood and prolonged afferent activity were frequently and significantly associated with both pain characteristics and psychosocial issues. A multiple regression analysis revealed that a combination of decreased activity levels due to pain (t = 3.54; p < 0.001), pain located in the frontal aspects of torso (including genitals) (t = 2.29; p < 0.05), "burning" (t = 2.26; p < 0.05), or "electric" (t = 2.09; p < 0.05) pain, and a limited perception of life control (t = -2.16; p < 0.05) was significantly associated with a high extent of pain aggravation (R2 = 0.39; p < 0.000).

Gender related differences in pain in spinal cord injured individuals

STUDY DESIGN

Out of a population of 456 patients with spinal cord injuries (SCI), 130 having pain were selected after matching, based on gender, age, American Spinal Injury Association (ASIA) impairment grade and level of lesion.

OBJECTIVE

To investigate whether gender differences with regard to pain perception and prevalence exist in a population of patients following spinal cord injury.

SETTING

Spinalis SCI Unit (out-patient clinic), Stockholm, Sweden.

METHOD

130 patients suffering from pain were assessed over a 12-month period in a yearly health control.

RESULTS

SCI women had a higher prevalence of nociceptive pain than men and their use of analgesics was greater. However, no differences between the sexes could be seen regarding pain and localization, onset, distribution, factors affecting pain, number of painful body regions, pain descriptors, ratings of pain intensities or in pain and life satisfaction.

CONCLUSION

This study showed that SCI men and women describe their pain very similarly. However, SCI women had a higher prevalence of nociceptive pain than men and their use of opiates and non-steroid anti-inflammatory drugs (NSAIDs) was greater.