Background: To evaluate the analgesic efficacy and spread of variable volumes of local anesthetics (LA) in Erector spinae plane block (ESPB).
Methods: Sixty patients aged between 18 and 50 years with an ASA I-II and scheduled for breast cancer surgery were randomized to receive either ESPB with 20 ml 0.25% bupivacaine (Standard volume ESPB), or with 40 ml 0.