Table 1 PICO criteria for including studies
| Population | Patients of at least 18 years undergoing breast surgery. |
| Intervetion | Postoperative analgesia with locoregional anesthesia techniques. |
| Comparator | Standard pain treatment. |
| Outcomes | Pain Intensity, Opioid Consumption, Adverse Events, Patient Satisfaction. |
| Study TYPE | Randomized Controlled Trial. |
| Time | From 2010 to present. |