Pectoral Nerve Blocks for Breast Augmentation Surgery: Comment

By a randomized, double-blind, dual-centered controlled trial in 73 adult female patients undergoing aesthetic breast augmentation surgery under general anesthesia, Aarab et al.¹  showed that compared to multimodal analgesic regimen alone, pectoral nerve blocks combined with multimodal analgesia significantly improved postoperative pain control and decreased total opioid consumption over the first 5 postoperative days. In addition to the limitations described by the authors in the discussion, however, we note several issues in the results of this study that deserve further clarification.

First, a numerical rating scale score of 3 or less is generally considered as satisfied pain control.²  In this study, other than 0.5 h after extubation, the mean numerical rating scale scores at other time points in the early postoperative period were 3 or less, indicating that most of patients have a satisfied pain control. Patient satisfaction was very good in both groups. In this case, it is difficult for readers to determine whether early postoperative pain control improved by adding pectoral nerve blocks to multimodal analgesia should be considered clinically important.

Second, between-group differences in opioid consumption were of questionable clinical significance. Differences in milligram oral morphine equivalents were 3 mg in the first 6 h after extubation and 10.5 mg from 6 to 24 h postoperatively (total, 13.5 mg 0 to 24 h postoperatively, equivalent to about 4.5 mg of intravenous morphine).³  Although the recommendation of 10 mg of intravenous morphine equivalents per 24 h as the minimal clinically important difference was published⁴  well after the study by Aarab et al.¹  was designed and performed, the 4.5-mg difference is nonetheless much less. In addition, the total between-group difference from postoperative days 1 through 5 was 21-mg oral morphine equivalents. Given that duration of pectoral nerve block is limited and the total between-group difference in oral morphine consumption was very small, we question the clinical value of this opioid sparing.

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The authors declare no competing interests.