The broad aim of this study is to compare the effectiveness of paravertebral and pectoral blocks on pain and physical well-being of patients undergoing immediate implant-based breast reconstruction.

Inclusion Criteria:

• Adult patient 18 years or older
• Scheduled for unilateral or bilateral immediate implant-based breast reconstruction
• Therapeutic or prophylactic indication
• Patient understands the study procedures and objectives and is willing to participate
• Patient willing to and capable of providing informed consent

Exclusion Criteria:

• Delayed breast reconstruction
• Allergy or contraindication to local anesthetics (PVB or PECS blocks)
• History of radiation therapy
• Planned sedation or general anesthesia protocol variation
• Morbid obesity as defined as a BMI greater than 40 kg/m2
• Renal insufficiency
• Chronic pain syndrome or central sensitization disorders (e.g., fibromyalgia, CRPS)
• Use of implanted pain devices or neuromodulators
• Pre-existing neurological deficits in the surgical field
• Current chronic opioid use (daily use within the 2 weeks before surgery and duration of use greater than 4 weeks)
• Use of any nerve medications in the past 6 months, including antiepileptic medications (gabapentin, carbamazepine)
• History of drug or alcohol abuse or habitual alcohol intake greater than two standard drinks per day (e.g., two beers, two glasses of wine, or two mixed drinks)
• Any comorbidity that results in moderate or severe functional limitation, inability to communicate with the investigators or hospital staff
• History of a psychiatric disorder which would interfere with the study procedure
• Incarceration
• Any issue that at the discretion of the investigator would contraindicate the subject's participation
• Inability to understand the procedures and objectives of the study
• Inability to or unwilling to provide informed consent