Prediction of Outcome of Interventional Pain Management

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Observational Study of the Nociceptive Flexion Reflex Threshold to Predict Outcome After Interventional Pain Management Procedures in Patients With Chronic Back and Neck Pain. A Study of Diagnostic Accuracy

Conditions
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Neck Pain, Low Back Pain, Chronic Pain

Intervention / Treatment
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* Device: nociceptive flexion reflex (NFR) threshold (Paintracker, Dolosys GmbH, Berlin, Germany)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients with chronic low back or neck pain (duration >3 months) scheduled for the following interventions: epidural injection, facet block, medial branch block, facet radiofrequency denervation, spinal cord stimulator implantation Exclusion Criteria: inability to understand the patient information or the study questionnaires patients <18 years old patients with implanted pacemakers or defibrillators

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| observational cohort<br>patients undergoing interventional pain management procedures | Device: nociceptive flexion reflex (NFR) threshold (Paintracker, Dolosys GmbH, Berlin, Germany)<br>* measurement of the NFR threshold using the Paintracker device<br>* Other names: R3 reflex;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ROC-AUC for incidence of pain reduction>30% at 1 week | Primary study outcome is the diagnostic accuracy of the NFR threshold, measured as area under the receiver operating characteristic ROC curve, for the following main pain management outcome: pain reduction of 30% one week after the interventional procedure | 1 week | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ROC-AUC for incidence of pain reduction>30% at 1 month | Area Under the curve (AUC) of the receiver-operating characteristic (ROC) of the relation between NFR reflex threshold and the incidence of pain reduction>30% at 1 month | 1 month | 
| ROC-AUC for incidence of pain reduction>30% at 3 months | Area Under the curve (AUC) of the receiver-operating characteristic (ROC) of the relation between NFR reflex threshold and the incidence of pain reduction>30% at 3 months | 3 months | 
| ROC-AUC for incidence of pain reduction>30% at 6 months | Area Under the curve (AUC) of the receiver-operating characteristic (ROC) of the relation between NFR reflex threshold and the incidence of pain reduction>30% at 6 months | 6 months | 
| ROC-AUC for physical functioning at 1 week |  | 1 week | 
| ROC-AUC for emotional functioning at 1 week |  | 1 week | 
| ROC-AUC for patient rating of improvement and satisfaction at 1 week |  | 1 week | 
| adverse events of interventional pain management |  | 1 week | 
| patient disposition at 1 week, 1,3, and 6 months | The presence or unexcused absence of the patient at each consultation visit is noted | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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nociceptive flexion reflex, interventional pain management