The aim of the study is the identification, comparing continuous infusion of local anesthetics and steroids intralesionally with the current gold standard therapy (PCA), of the effective dose of local anesthetics and steroids within 7 days following abdominal surgery in order to halve the consumption of opioids and give the best pain control with a lower incidence of side effects and persistent chronic pain (at 1 and 3 months) We also plan to measure the peripheral inflammation and oxidative stress by analyzing the pro-inflammatory cytokines and anti-inflammatory properties.