Classification of chronic pain associated with spinal cord injuries

Objectives: To determine interrater reliability of a classification system for chronic pain in persons with spinal cord injury (SCI) and to determine the frequency and characteristics of various pain types as categorized by this system. Design: Independent categorization (based on questionnaires; for 15 persons, questionnaires plus personal interviews) by 2 investigators. Setting: Community. Participants: A total of 163 individuals aged : 18 years with SCI and pain. Interventions: Not applicable. Main Outcome Measures: Pain categories, Short-Form McGill Pain Questionnaire, and Chronic Pain Grade questionnaire. Results. Among 41 (25%) questionnaires categorized independently by 2 investigators, strength of agreement in categorizing 68 pain problems was substantial (kappa=.68). For 15 persons whose pain was categorized in person by 2 investigators, strength of agreement was also substantial (kappa=.66). Among 163 survey respondents with pain, the most common worst pain was SCI pain (31.9%). Mean characteristic pain intensity +/- standard deviation for worst pain, regardless of type, was 61.02 +/- 19.5 on a scale from 0 to 100. On average, for worst pain, respondents reported moderate pain-related disability (43.70 +/- 29.4; scale range., 0-100). Although certain pain descriptors were more often associated with a specific type of pain, none was pathognomonic. Conclusions: Substantial interrater reliability was achieved in determining pain categories by use of responses to a questionnaire with a classification system based on presumed pathology. Adding interviews with patients increased our ability to classify pain but did not improve overall interrater reliability. (C) 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.