Mastectomy is a technique often used in breast cancer surgery. Patients experience moderate to severe pain postoperatively after this procedure. Various plane blocks, NSAIDs, and opioid analgesics can be administered to these patients as components of multimodal analgesia. In the the study, the investigators aimed to evaluate the analgesic effects of the serratus plane block, the parasternal block added to the serratus plane block, and the dermatomal differences.

Inclusion Criteria:

1. American Society of Anesthesiologist's physiologic state I-III patients
2. To undergo Mastectomy Surgery
3. Being between the ages of 18-65 years

Exclusion Criteria:

• Having a known heart, kidney, liver or hematological disease
• Having a history of peptic ulcer, gastrointestinal bleeding, allergy, chronic pain
• Routine analgesic use and history of analgesic use in the last 24 hours
• Not willing to participate in the study
• Uncooperative patients who have coagulopathy or use anticoagulant drugs
• To be allergic to one of the drugs to be used