Erector spinae plane block (ESPB) is a recently described block. Although there is still no consensus of its mechanism, the published case series seems to promise a new regional anesthesia technique for both chronic and acute pain. In this clinical trial, the postoperative analgesic effect of ESPB will be studied in patients underwent unilateral breast cancer surgery.

In this study 30 patients will be enrolled to study between March 2018-August 2018. All patient will be randomly selected who will be operated for breast cancer surgery between determined dates. Age, weight, ASA score, body mass index , additional dissease ststus will be recorded. The patients will be divided in two groups. One group will have ESPB at the end of the operation and the second group will be treated with multimodal analgesia techniques and both groups will receive patient controlled analgesia. Both groups will receive identical anaethesia protocols. Perioperative analgesia protocols will provide acetaminophen 1 gr and the same dose will be repeated in every 6 hours regardless of the pain scores. In postoperative period the pain scores of the patients will be recorded according to the numeric rating scale (NRS) in every three hours. If pain score raises over 4/10 on NRS the patient will receive tramadol 100mg as rescue analgesia. In case of persisting pain first, meperidine 50 mg will be apllied and other multimodal analgesic drugs will be added to protocol. At the end of the study 24 hours total opioid usage of patients, pain scores and side effects will statistically be analyzed.

Inclusion Criteria:

1. Being volunteer
2. Over 18 years old
3. Unilateral segmental mastectomy patients

Exclusion Criteria:

1. Emergency operations
2. Younger than 18 years old,
3. Non Volunteers
4. ASA 3 and 4 patients
5. Non-cooperative patients