Within the H2020 QSPainRelief project (http://qspainrelief.eu), we will conduct a clinical study in patients suffering from disabling post-operative to assess the different effects of combinatorial treatments on the central nervous system using EEG and other non-invasive electrophysiological techniques and relate these effects to real-life clinical efficacy and safety. The data generated by this clinical study will be used to calibrate a model to predict response to combinatorial treatments for pain.