Prediction of Outcome of Interventional Pain Management

Interventional pain management for back and neck pain is widely used, but the indications and relative merits of these techniques rest subject to discussion. This study aims to identify prognostic criteria for patients who might specifically benefit from interventional pain management. Specifically, the nociceptive reflex threshold will be investigated, which is a measure of central sensibilisation and thus a potentially important prognostic factor.

Interventional pain management is resource-intensive and carries non-negligible risks. Not all patients profit equally from such procedures. For those who do not benefit, the risk of potential complications is futile, and the resources are wasted. Therefore, a possibility to distinguish responding patients from non-responders would be important. Central pain sensitization has been related to poor outcome, and electrical pain and reflex thresholds are a good measure of pain hypersensitivity at least in chronic low back pain. Especially the nociceptive flexion reflex (NFR) threshold has been identified to correlate well with central pain hypersensibility. Successful interventional pain treatment has been shown to reverse central hypersensibility as measured by the NFR threshold. NFR threshold, in contrast to pain threshold, seems to be a measure independent of psychological factors. Thus the NFR threshold could give information independent of psychological factors in order to predict poor outcome of interventional pain management procedures. The study will be a prospective observational trial of diagnostic accuracy.