Rhomboid Intercostal Block With Sub-Serratus Plane Block Versus Erector Spinae Block

This study compares two types of nerve block techniques used to control pain after a modified radical mastectomy (breast removal surgery for cancer): the Rhomboid Intercostal with Sub-Serratus Plane Block versus the Erector Spinae Block. Both use local anesthetic injections in the back area to reduce post-surgical pain. The study wants to find which technique works better. **You may be eligible if...** - You are a female breast cancer patient scheduled for a modified radical mastectomy - You are between 18 and 65 years old - Your BMI is between 20 and 35 - You are in generally good pre-surgical health (ASA status II or III) **You may NOT be eligible if...** - You are under 18 or over 65 years old - Your BMI is below 20 or above 35 - You have a known allergy to local anesthetics or opioids - You have a history of chronic pain or psychological disorders - You have conditions that prevent regional anesthesia (such as bleeding disorders or skin infections at the injection site) - You decline to participate Talk to your doctor to see if this trial is right for you.