Effect of Pectoral Nerve Block on Post-op Pain in Patients Undergoing Mastectomy and Immediate Reconstruction

Inclusion Criteria: 1. Patients age 18-90 years old 2. Subjects able to read and understand the informed consent 3. American Society of Anesthesiologists (ASA) physical status I and II 4. Subjects scheduled to undergo unilateral or bilateral mastectomy with immediate breast reconstruction with submuscular placement of tissue expander or permanent implant under general anesthesia, including: * subjects diagnosed with breast cancer * subjects diagnosed with atypia or other high risk proliferative breast disease * subjects with a family history who are considered at high risk for breast cancer (including those with hereditary or genetic predisposition) Exclusion Criteria: 1. Subjects unable to read or understand the informed consent 2. ASA physical status III or IV 3. Subjects with an allergy to local anesthetic 4. Subjects with a medical contraindication to regional anesthetic, such as coagulopathy or local infection 5. Subjects with a pre-existing submuscular implant 6. Subjects scheduled to undergo mastectomy with myocutaneous flap reconstruction 7. Subjects scheduled to undergo mastectomy without immediate reconstruction 8. Subjects with a history of chronic pain or chronic opioid use