Erector Spinae Plane versus Pectoralis Nerve Block for Mastectomy in Cancer Patients: A Retrospective, Multicenter Cohort Study.

Background: Mastectomy patients require effective acute postoperative pain management. Regional anesthesia techniques such as fascial plane blocks are important pain treatment modalities to address pain control. This study compared the effects of the erector spinae plane (ESP) block versus the pectoralis nerve (PECS) block in providing postoperative analgesia for mastectomy patients.

Methods: This retrospective study included 517 breast cancer patients undergoing mastectomy from 2017 to 2020, with 428 receiving a PECS block and 89 an ESP block. The primary outcome examined was total opioid use during hospital stay measured in morphine milligram equivalents (MME). Secondary outcomes included length of hospital stay, post-anesthesia care unit (PACU) pain scores, PACU postoperative nausea and vomiting (PONV), 30-day readmission rates, and development of postmastectomy pain within six months of surgery.

Results: No significant difference in median total opioid use between the ESP (53 MME (IQR: 38-80 MME)) and PECS (60 MME (IQR: 30-82.5 MME)) groups. Multivariable analysis confirmed no difference in total opioid consumption. There was no significant difference between the two groups in PACU average and maximum pain scores, PACU PONV, hospital length of stay, 30-day hospital readmission, and development of postmastectomy pain within six months of surgery.

Conclusion: Compared to the PECS block, the ESP block demonstrated no significant difference in acute pain outcomes and recovery in patients undergoing mastectomy for breast cancer, with similar hospital discharge times and long-term outcomes.