Establishment of an adaptable acute pain model for induction of nociceptive stimuli of defined intensity and duration using thermal stimulation

Abstract

In previous years numerous acute pain models to investigate the pathophysiological mechanisms of pain and to validate treatment procedures have been described. Due to the specific questions addressed by different trials standardized protocols are often missing. Therefore, the research results obtained are only comparable or reproducible to alimited extent. The transferability of acquired knowledge to clinical pain is limited by the mostly short test duration of already established models. The aim of this study was to establish a standardized protocol for an acute pain model that induces nociceptive thermal stimuli of defined intensity and variable duration using adevice for quantitative sensory testing (QST). The greatest possible exclusion of factors influencing pain perception was achieved. In order to reduce the risk of thermal tissue damage acapsaicin cream was applied to the test area, which led to asignificant increase in the perceived pain intensity of heat stimuli. From previously performed experiments on thermal pain thresholds and temporal aspects of pain adaptation, the parameters for stimulus lengths and thermode temperatures for acold and heat pain model could be derived. The acute pain model established here was able to induce significant heat and cold pain stimuli over variable periods of time. An average pain intensity of NRS ≥ 6 was reported by the test participants. Among the 30subjects no tests were terminated due to intolerance. The established acute pain model in this study is characterized by the induction of thermal pain stimuli of defined intensity and variable duration. There is no danger of significant thermal tissue damage and the pain was tolerated by all study participants. The pain model can easily be established using adevice for quantitative sensory testing.