Opioids have been used for analgesia since many years, but despite potent analgesia they are
also associated to side effects, including opioid induced Hyperalgesia (OIH).
OIH in the surgical setting is debated, and may predispose patients to higher analgesic
consumption in the preoperative period, and peripheral and central sensitization. The aim of
the study is to compare remifentanil-based vs non opioid analgesia (clonidine, lidocaine,
ketamine) for intraoperative management of patients undergoing laparoscopic left
hemicolectomy, with the hypothesis that non- opiod treated patients will have lower morphine
consumption in the first 24 hours after surgery. Peripheral and central hyperalgesia will be
tested with Von Frey hairs and pin-prick to evaluate acute CNS (Central Nervous System)
sensitization after surgery. Acute and persistent (1 and 3 months) pain will be registered,
together with any side effect and parameters of surgical rehabilitation.