Comparison of Acute Postoperative Pain Between Preemptive Ultrasound-Guided Pectoral Nerve Block and Intraoperative Pectoral Nerve Block in Patients Undergoing Mastectomy

Pectoral nerve block is an effective postoperative pain control strategy for patients undergoing mastectomy. Preemptive analgesia is also recognized as a key component of multimodal pain management strategies. The purpose of this study was to compare the efficacy of preemptive ultrasound-guided pectoral nerve block (PECs block) with intraoperative PECs block. In this study, a randomized controlled trial with 44 patients undergoing mastectomy with general anesthesia was conducted, and the patients were allocated into two groups. The preemptive group received preemptive ultrasound-guided PECs block with 10 ml of 0.25% bupivacaine mixed with 1% lidocaine with epinephrine 1:200,000 for PEC I and 20 ml for PEC II, while the intraoperative group received intraoperative pectoral nerve block with 10 ml of same mixture for PEC I and 20 ml for PEC II. The primary outcome was pain intensity using a visual analogue scale (VAS). The secondary outcomes were cumulative morphine consumption over 72 hr postoperatively, total anesthetic time and complications. The study showed that at 20 hr postoperatively, the mean VAS score in the intraoperative group was 1.41 ± 1.22, which was statistically significantly lower than the 2.22 ± 1.34 observed in the preemptive group (p = 0.040). There were no complications reported in either group, and cumulative morphine consumption did not differ significantly between groups at any time point. The total anesthetic time was significantly shorter in the intraoperative group (111 ± 3.54 min) compared with the preemptive group (140 ± 2.84 min, p < 0.001). Therefore, the intraoperative PECs block resulted in significantly lower VAS scores at 20 hr postoperatively, although the clinical relevance may be limited. Additionally, the intraoperative approach may offer practical advantages in clinical settings, such as reduced anesthesia time.