BACKGROUND AND OBJECTIVES: General anesthesia for breast surgery may be supplemented by using a regional anesthetic technique. We evaluated the efficacy of the first pectoral nerve block (Pecs I) in treating postoperative pain after breast cancer surgery.
METHODS: A randomized, double-blind, dual-centered, placebo-controlled trial was performed. One hundred twenty-eight patients scheduled for unilateral breast cancer surgery were recruited. A multimodal analgesic regimen and surgeon-administered local anesthetic infiltration were used for all patients. Ultrasound-guided Pecs I was performed using bupivacaine or saline. The primary outcome was the patient pain score (numerical rating scale [NRS]) in the recovery unit 30 minutes after admission or just before the morphine administration (NRS =4/10). The secondary outcomes were postoperative opioid consumption (ie, in the recovery unit and after 24 hours).
RESULTS: During recovery, no significant difference in NRS was observed between the bupivacaine (n = 62, 3.0 [1.0-4.0]) and placebo (n = 65, 3.0 [1.0-5.0]) groups (P = 0.55). However, the NRS was statistically significantly different, although not clinically significant, for patients undergoing major surgeries (mastectomies or tumorectomies with axillary clearance) (n = 29, 3.0 [0.0-4.0] vs 4.0 [2.0-5.0], P = 0.04). Morphine consumption during recovery did not differ (1.5 mg [0.0-6.0 mg] vs 3.0 mg [0.0-6.0 mg], P = 0.20), except in the major surgery subgroup (1.5 mg [0.0-6.0 mg] vs 6.0 mg [0.0-12.0 mg], P = 0.016). Intraoperative sufentanil and cumulative morphine consumption up to 24 hours did not differ between the 2 groups. Three patients experienced complications related to the Pecs I.
CONCLUSIONS: Pecs I is not better than a saline placebo in the presence of multimodal analgesia for breast cancer surgery. However, its role in extended (major) breast surgery may warrant further investigation.
CLINICAL TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov, identifier NCT01670448.
This is an excellent prospective clinical trial with relevant results. This study shows that a purely motor block can not provide effective analgesia by lack of extension to the axillary fossa, the intercostobrachial nerve and the lateral branches of the intercostal nerves. 3 remarks: 1) This study compared PEC1 +wound infiltration vs placebo + wound infiltration, and not strictly speaking PEC1 alone. 2) An identical proportion received preoperative oral premedication but authors did not detailed the drug used. 3) Effectiveness was observed in the primary outcome and morphine request during major surgery probably because the fascial pectoralis is very adherent to the muscle and its ablation is frequent even in the case of a conservative surgery. Pain is also driven by this muscular contraction despite pain was not affected after.
This is an interesting and worthwhile study, but there are several significant flaws. Firstly, about 15% of patients had a superomedial incision which you would not expect a PECS 1 block to cover. This significantly reduces the power of this study to show a difference between groups. Additionally, if 3mg bolus's of morphine were given in recovery, a difference of 1.5mg might not be a statistically significant difference. However, if this was presented as percentage of patients who didn't have morphine at all, it may well be a statistically significant difference. Thirdly having a statistically significant difference in the major surgery is a convincing result given that the study was grossly underpowered for this. Also, the pre-medication was not described. It may be with a decent pre-med. Its no surprise that there is not a difference in pain scores afterwards with a minor procedure like wide local excision.
I don't personally perform pectoral block for breast cancer surgery, however for those who do, this article shows that only patients having extensive breast surgery may benefit from this intervention. Every intervention is not without risk of complications and it is worth considering findings of this study when planing a PEC block for breast surgery.