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.

Life satisfaction in individuals with a spinal cord injury and pain.

OBJECTIVE: To assess and describe life satisfaction in individuals with spinal cord injury (SCI) with regard to pain. DESIGN: A cross-sectional descriptive study of self-reported life satisfaction in individuals with SCI, with and without pain. SETTING: Spinal outpatient clinic. SUBJECTS: Two hundred and thirty patients with SCI were mailed a questionnaire. INTERVENTIONS: Mailed survey. MAIN MEASURES: Ratings of pain intensity, pain unpleasantness, mood, and life satisfaction (LiSat-9). RESULTS: In total 191 (83%) of the questionnaires were returned and analysed. Patients with pain experienced lower life satisfaction compared with individuals who were pain free. Continuous pain interfered to a greater extent than did intermittent pain. In logistic regression analysis the univariate relationship between pain and low life satisfaction was removed. Predictive for lower scores of life satisfaction were higher ratings of mood disorders. CONCLUSION: Life satisfaction is negatively affected in patients with SCI and pain compared to patients with SCI but without pain. Higher levels of anxiety and depression seem to be predictive for this decreased life satisfaction.

Lack of interchangeability between visual analogue and verbal rating pain scales: a cross sectional description of pain etiology groups.

BACKGROUND: Rating scales like the visual analogue scale, VAS, and the verbal rating scale, VRS, are often used for pain assessments both in clinical work and in research, despite the lack of a gold standard. Interchangeability of recorded pain intensity captured in the two scales has been discussed earlier, but not in conjunction with taking the influence of pain etiology into consideration. METHODS: In this cross-sectional study, patients with their pain classified according to its etiology (chronic/idiopathic, nociceptive and neuropathic pain) were consecutively recruited for self-assessment of their actual pain intensity using a continuous VAS, 0-100, and a discrete five-category VRS. The data were analyzed with a non-parametric statistical method, suitable for comparison of scales with different numbers of response alternatives. RESULTS: An overlapping of the VAS records relative the VRS categories was seen in all pain groups. Cut-off positions for the VAS records related to the VRS categories were found lower in patients with nociceptive pain relative patients suffering from chronic/idiopathic and neuropathic pain. When comparing the VAS records transformed into an equidistant five-category scale with the VRS records, systematic disagreements between the scales was shown in all groups. Furthermore, in the test-retest a low percentage of the patients agreed to the same pain level on the VAS while the opposite hold for the VRS. CONCLUSION: The pain intensity assessments on VAS and VRS are in this study, not interchangeable due to overlap of pain records between the two scales, systematic disagreements when comparing the two scales and a low percentage intra-scale agreement. Furthermore, the lower VAS cut-off positions relative the VRS labels indicate different meaning of the rated pain intensity depending on pain etiology. It is also indicated that the scales have non-linear properties and that the two scales probably have different interpretation. Our findings are in favor of using the VRS in pain intensity assessments but if still the VAS is preferred, the VAS data should be analyzed as continuous using statistical methods suitable for ordinal data. Furthermore, our findings indicate a risk to over or under estimate the patient's perceived pain when interpreting condensed VAS data.

Evaluation of variations in sensory and pain threshold assessments by electrocutaneous stimulation.

Assessed sensory and pain thresholds can change consequently to disturbances associated with ongoing pain. Such assessments could be an additional method in the daily clinical evaluation of perceived pain. To study the test-retest variability within-day and between-day of such procedures a newly developed instrument producing electrocutaneous stimulation, PainMatcher (PM), was used to assess the electrical sensory thresholds (EST) and pain thresholds (EPT) in healthy volunteers and in patients with pain. The produced data were considered ordinal and analyzed with rank-invariant statistics with properties of analyzing systematic disagreement, bias, and individual variations. The percentage agreements within +/- 1PM value for EST were in the two groups of healthy volunteers and patients in pain 94% and 92%, and for EPT assessments 49% and 78%, respectively. The variability in the EST assessments is possibly explained by a slight bias while the individual variations were negligible between the two occasions. The assessed EPT were unbiased in both groups while individual variations were significant among the healthy volunteers but negligible among the patients in pain. The EST was found to be increased in pain patients compared to healthy volunteers, p < 0.03, and the EPT decreased in pain patients compared to healthy volunteers, p < 0.001. The results in this study indicate stable and reliable assessments of EST and EPT except for a possible bias. The threshold assessment procedure followed in this study may be a valuable tool in the clinical evaluation of sensory and pain assessments in pain patients.