The Effect of Pectoral Nerve Blocks on Opioid use and Postoperative Pain in Masculinizing Mastectomy
Adam Wallace, MD1, Peter, Yeh, MD1, Esther Kim, MD1 1University of California, San Francisco, San Francisco, CA
Background: Gender affirmation surgery is on the rise, with the masculinizing bilateral mastectomy being the most common procedure performed. Currently, there is lack of data regarding intraoperative and postoperative pain control for this at risk population. Pectoralis nerve (Pecs) blocks have shown to be effective in oncologic breast reduction procedures, but their role is unclear in gender affirmation breast surgery. It is our aim to study the effects of the Pecs I and II regional nerve blocks in patients undergoing masculinizing mastectomy.
Methods: A randomized, double-blind, placebo-controlled trial is underway. Patients undergoing bilateral gender affirmation mastectomy by a single surgeon are randomized to receive a bilateral ultrasound guided Pecs block with Ropivacaine or to receive a placebo injection (saline). Intra operative and postoperative opioid requirements are compared, as well as subjective pain scores at set postoperative time points. The patient, surgeon, and anesthesia team in the case are blinded to the randomization. The primary outcome is the patient's pain score (Numerical Rating Scale). The secondary outcome is opioid consumption, which is reflected as Morphine Milligram Equivalents (MME) for ease of comparison. Pain scores were collected at set time points: 1 hour, 2 hours, 4 hours, 6 hours, and 12 hours post op, as well as a daily average on postoperative days 1 through 7.
Results: 16 patients have been enrolled between July, 2020 and December, 2020. Nine have been randomized to the intervention group, and seven to the control group. There has been no difference in intraoperative MME between the Pecs block group and control (10.0 vs. 9.2, p=0.55). Additionally, there is no difference in postoperative MME between the Pecs block group and control (34.2 vs. 30.2, p=0.37). The reported pain score at 6 hours post procedure is lower in the Pecs block group when compared to the control group (2.1 vs. 3.9, p=0.018). Similarly, the averaged pain score at postoperative day 1 is lower in the Pecs block group (3.0 vs. 4.3, p=0.03). None of the other time points have statistically significant differences in pain scores.
Conclusion: To date, in patients undergoing bilateral gender affirmation mastectomy, there has been no reduction in intraoperative opioid consumption in patients receiving a Pecs block when compared to placebo. While there are lower reported pain scores in the Pecs block group at 2 postoperative time points (6 hours and POD 1), this is not consistent with reported scores at prior or subsequent time points. A major limitation thus far is sample size. This is an ongoing trial and as more results becomes available, additional conclusions may be drawn.
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