Impact of Pectoralis Nerve Block (PECS) on postoperative pain in patients submitted to mastectomy with lymphadenectomy

OBJECTIVE: Breast cancer is the most common malignant neoplasm in women worldwide. Surgery has been traditional treatment and, generally, it´s mastectomy with lymphadenectomy, that can causes postoperative pain. Therefore, we seek to study regional anesthesic techniques that can minimize this effect, such as the interpectoral block (PECS). METHODS: randomized controlled study with 82 patients with breast cancer who underwent mastectomy with lymphadenectomy from January 2020 to October 2021 in oncology hospital. INTERVENTIONS: two randomized groups (control - exclusive general anesthesia and PECS group - received PECS block with levobupivacaine/ropivacaine and general anesthesia). We applied a questionnaire with Numeric Rating Scale for pain 24h after surgery. We used Shapiro-Wilk, Mann-Whitney and Chi-square tests, and analyzed the data in R version 4.0.0 (ReBEC). RESULTS: in the PECS group, 50% were pain-free 24h after surgery and in the control group it was 42.86%. The majority who presented pain classified it as mild pain (VAS from 1 to 3) - (42.50%) PECS group and (40.48%) control group (p=0.28). Only 17.50% consumed opioids in the PECS group, similar to the control group with 21.43%. (p=0.65). There was a low rate of complications such as PONV in both groups. In the subgroup analysis, there was no statistical difference between the groups that used levobupivacaine or ropivacaine regarding postoperative pain and opioid consumption. DISCUSSION: the studied group had a low rate of pain in the postoperative period and it influenced the statistical analysis. There wasn´t difference in postoperative pain in groups. CONCLUSION: was not possible to demonstrate better results with the association of the PECS block with total intravenous analgesia. Need further studies to assess the efficacy of the nerve block.