Electrical Evoked Potentials After Perioperative Pain Neuroscience Education or Back School Education: A Subgroup Analysis of a Randomized Controlled Trial

Background/Objectives: Biopsychosocial pain neuroscience education (PNE) has recently gained attention in preparing patients for surgery. PNE is expected to influence pain coping strategies and descending nociceptive inhibition. The goal of this study was to compare cortical evoked responses during experimental pain processing using a conditioned pain modulation (CPM) paradigm between patients receiving perioperative PNE (PPNE) or perioperative biomedical back school education (PBSE). Methods: This predefined EEG subgroup analysis included only participants with complete EEG recordings at baseline and 6 weeks. Of these, twenty-three patients with low back-related leg pain, scheduled for lumbar spine surgery, were randomized to either two sessions of PPNE or two sessions of PBSE. All patients were stimulated electrically at the median nerve of the symptomatic side and the sural nerve of the symptomatic and non-symptomatic side before and 6 weeks after the educational sessions, while evoked potentials were recorded by electroencephalography (EEG). Subsequently, this protocol was repeated during the application of the CPM paradigm by immersing the hand contralateral to the symptomatic side into cold water. Results: A significant decrease in the amplitude of the waveforms during CPM was found compared to the waveforms before CPM at the non-symptomatic sural nerve. No significant differences were found at the other test locations. For the waveforms of the CPM effect (subtracted waveforms), no significant treatment effects were revealed between the PPNE and PBSE groups. Conclusions: These exploratory findings suggest that PPNE was not associated with differential modulation of EEG evoked potentials during CPM compared with PBSE at 6 weeks post-surgery.