In breast surgery, regional anesthesia associated with general anesthesia during surgery has shown great results for the post-operative pain management, prevention of tumor recurrence and development of neuropathic pain. It has been shown that regional anesthesia attenuates the inflammatory response and systemic changes postoperatively during breast surgeries. Thus, it is important to include an additional analgesic intervention in breast surgery in order to decrease the local inflammatory response and the postoperative pain. Thus, the serratus anterior muscle plane (SAM) block associated with pectoral nerve block type I (PEC I) may be a safe and effective alternative for the intraoperative of breast surgery, since there is evidence of pain reduction. However, correlation between regional anesthesia, postoperative pain and inflammatory response in breast surgery has not been demonstrated. The aim of this study is to compare the standard intravenous analgesia versus systemic analgesia associated with the SAM block and PEC I during breath cancer surgery. The following parameters will be evaluated: consumption of opioid intra and post-operative; post-operative pain and release of plasma inflammatory cytokines. It is a clinical prospective, randomized and controlled study. Also, it will be evaluated the development of chronic neuropathic pain 12 months after mastectomy, the use of analgesic medication, quality of life, depressive symptoms, and the levels of interleukin (IL)-1 beta, IL-6, and IL-10 as predictors of pain and depression. 50 individuals will be randomly divided into two groups. A group of patients receive general anesthesia during surgery and intravenous analgesia after the surgery and another group will receive general anesthesia associated with SAM and PEC I block during intraoperative and postoperative systemic analgesia. The postoperative pain will be assessed using the Visual Analogue Scale pain in the recovery room and 24 hours after surgery. Blood sample will be collected for determination of serum cytokines before surgery and 24 hours after the surgery.
