Line graph with mean (SD) of numerical rating scale for pain at rest on the y axis over time (h) on the x axis. The means (SDs) of the pectoral nerve block and control groups are represented. The mixed model shows that, regardless of the group, the numerical rating scale changes significantly over time (P < 0.001). Likewise, considering all times overall, the two groups have significantly different numerical rating scale values (P = 0.044), with the graph showing lower values for pectoral nerve block patients. On the other hand, the evolution of the numerical rating scale over time is not different between the two groups (the interaction term is not significant, P = 0.817).