Influence of psychological factors on the benefit from interpectoral and pectoserratus plane block for recovery after partial mastectomy: a randomized controlled trial.

Background: The interpectoral and pectoserratus plane (PECs) blocks have been reported to provide favorable postoperative analgesia after mastectomy. However, studies have reported controversial data regarding its effect on the quality of recovery (QoR). We aimed to evaluate the effect of the PECs block in light of baseline psychological factors and pain sensitivity.

Methods: Patients undergoing partial mastectomy were randomly assigned to receive either a PECs block (PECs group, n = 69) or no block (control group, n = 70). We assessed the preoperative psychosocial factors and pain recognition using the Hospital Anxiety Depression Scale (HADS), Pain Catastrophizing Scale (PCS), Breast Cancer Pain Questionnaire (BCPQ), temporal pain summation (TPS), and pressure pain threshold and tolerance; we then conducted the interaction test to evaluate the moderating role of these factors on the efficacy of the PECs block.

Results: The global QoR-15 score 1 d after surgery did not differ between the groups (136.50 [124.00, 144.00] vs. 141.00 [127.00, 148.00], P = 0.061); however, the score was enhanced in patients who were depressed, did not ruminate pain aberrantly, and did not have pre-existing pain. The pain Verbal Numeric Rating Scale (VNRS) 1 d after surgery was not different between the groups; however, the TPS score showed an interaction, indicating that the PECs block could reduce pain intensity in patients with high pain sensitivity.

Conclusions: The PECs block did not enhance the QoR-15 score or pain intensity after mastectomy, but its efficacy was pronounced in patients with several specific emotional traits and pain perception.