I t is with great interest that I read the article by Wallace et al., "The Effect of Pectoral Nerve Blocks on Opioid Use and Postoperative Pain in Masculinizing Mastectomy: A Randomized Controlled Trial," 1 and the Discussion by Berli and Togioka 2 in the March of 2024 issue of the Journal. I believe the results and conclusions would have been entirely different if a more appropriate regional anesthetic block, such as the serratus anterior plane (SAP) block, had been chosen for the study. [3][4][5] According to known anatomy and physiology of pectoral nerve (Pecs) blocks, the hypothesis of this study should have been that patients receiving an ultrasound-guided Pecs block would report no differences in pain scores compared with control subjects, which turned out to be true. The Pecs 1 block, which was performed in this study, has no dermatomal distribution, which is an important detail, as the sensory innervation of the mammary gland and overlying skin comes from T3 to T6. 6 The Pecs 1 block only anesthetizes the medial and lateral pectoral nerves, which block nociceptive pain due to stretch, tear, or injury to the pectoralis major muscle, none of which occurs during gender-affirming mastectomy. Pecs 1 blocks are better suited for procedures that involve manipulation of the pectoralis major muscle, such as submuscular breast implant placement, and in these circumstances, the Pecs 1 block has been found to be very effective in reducing postoperative pain. 7,8 The Pecs 2 block, which was also performed in this study as part of the same single injection (ie, combined Pecs, Pecs 1+2), targets the axillary area by anesthetizing the intercostobrachial nerve (T2) and possibly T3, depending on the degree of propagation of the anesthetic agent down the lateral chest wall. 9 Pecs 2 blocks are better suited for procedures that involve manipulation of the axillary area, such as axillary dissection or sentinel lymph node biopsy, neither of which is done during gender-affirming mastectomy.The SAP regional anesthetic block reliably covers dermatomes T2 through T8, which would be a more logical choice in the setting of surgery of the mammary gland. 10 The lateral branches of the intercostal nerves are blocked up and down the lateral chest wall, giving anesthesia to the lateral two-thirds of the hemithorax. The SAP block, however, does not cover the anterior branches of the intercostal nerves, which emerge in the parasternal intercostal spaces, which innervate the medial one-third of the hemithorax. Local parasternal subcutaneous infiltration is required there to achieve complete anesthesia of the hemithorax.I am an advocate for regional nerve blocks, 11 and I use them liberally in my practice to improve patient experience and dramatically decrease opioid usage among my patients. The Pecs 1 and SAP blocks have been particularly effective in the setting of cosmetic submuscular breast augmentation, 12 and transversus abdominis plane blocks in the setting of abdominoplasty. 13 I have found that mastopexy and reduction mammaplasty ar...
