The aim of this study is to compare the efficiency of serratus anterior plane block and erector spina plane block on analgesic consumption, postoperative pain and patient's satisfaction and recovery quality in patients undergoing mastectomy.

Mastectomy may cause severe postoperative pain. There are several analgesic methods for postoperative pain management. Serratus anterior plane (SAP) block is an interfascial plane block which is performed into the fascial plane of serratus anterior muscle. It provides effective analgesia in anterior, posterior and lateral dermatomes of thorax. There are several studies about its analgesic efficacy for mastectomy pain. The erector spina plane (ESP) block is another novel plan block which provides analgesia at multi-dermatomal area of the anterior, posterior, and lateral thoracic and abdominal walls. There are some studies about its effectiveness for postoperative mastectomy pain management. However, according to our best knowledge, there is no literature comparing the efficacy of ESP block and SAP block patients undergoing mastectomy.

Inclusion Criteria:

• American society of score anesthesiologist I-II-III
• Elective modified radical mastectomy
• 18-65 years old

Exclusion Criteria:

• neurological disease
• coagulopathy disease or using anticoagulants
• non-cooperative
• allergic to one of the drugs used in the study
• recurrent breast cancer
• body mass index is above 35