Pectoralis I and Serratus Anterior Plane Block Analgesia for Bilateral Mastectomy: A Case Series

Poorly controlled acute breast surgery postoperative pain is associated with delayed recovery, increased morbidity, impaired quality of life, and prolonged opioid use during and after hospitalization. Recently, ultrasound-guided pectoralis nerve (PECS) I block and serratus anterior plane (SAP) block, together or individually, have emerged as a potential method to relieve pain, decrease opioid requirements, and improve patient outcomes.

The aim of this study was to assess if the addition of a PECS I/SAP block in patients undergoing bilateral mastectomies provides more effective perioperative analgesia compared to standard analgesia.

Retrospective case series.

Tertiary academic medical center.

For patients undergoing breast cancer surgery, different approaches to analgesia by anesthesiologists at our institution provided an opportunity to compare patients who received a PECS I/SAP block to patients who received standard peri- and postoperative pain control from May 1, 2019 through November 30, 2020. Adult women who had bilateral mastectomy and reconstruction with tissue expanders for breast cancer were included. Bilateral PECS I/SAP blocks were performed with 60 mL 0.25% bupivacaine and 266 mg liposomal bupivacaine. The standard analgesia group had a balanced general anesthetic with volatile anesthetic, opioids (fentanyl or hydromorphone), and muscle relaxant. The postoperative analgesic regimen was similar in both groups. Pain scores (Numeric rating Scale) and opioid consumption (converted to oral morphine milligram equivalent [MME]) intraoperatively, and on postop day (POD) 0 up to POD 3 were collected. Length of stay data were collected as a secondary outcome.

Forty patients were included (n = 17 PECS I/SAP block; n = 23 standard analgesia). Baseline characteristics were similar between groups; most patients in the PECS I/SAP block (93%) and standard analgesia (96%) groups were discharged on POD 1 or 2. Intra-operative opioid requirements were lower in the PECS I/SAP block vs the standard analgesia group (median 56 MME, interquartile range [IQR] 44-62 vs median 65 MME, IQR 63-83, respectively, P = 0.002). Opioid requirements were similar in the block group compared to the standard analgesia group from POD 0 to POD 2. Pain scores from POD 0 to POD2, postanesthesia care unit length of stay, and hospital length of stay were also similar between the PECS I/SAP block and standard analgesia group.

The retrospective nature of this study and its reliance on medical records are limitations.

The PECS I/SAP block may potentially reduce pain in patients having breast surgery for cancer by providing analgesia to the lateral and anterior chest wall. While this analysis showed a reduction in intraoperative opioid consumption, no significant postoperative benefit in either pain scores, opioid consumption, or length of stay was observed. This may be in part due to the PECS I/SAP block not providing adequate analgesia to the medial portion of the breast.