Comparing analgesic efficacy of the regional block with different‐volume ropivacaine after a modified radical mastectomy

Abstract

In a prospectively randomized double-blind controlled clinical study with 40 breast cancer patients who underwent modified radical mastectomy, Lin et al. 1 compared the postoperative analgesic efficacy and stress alleviative effects of a modified type-2 pectoral nerve block using two volumes of 0.3% ropivacaine. They demonstrated that 40-ml ropivacaine compared to 30-ml ropivacaine did not significantly improve postoperative pain control and stress attenuation. However, there were several issues in this study that we wished to discuss with the authors and improve interpretation of their findings.First, when a randomized controlled trial was designed to determinate the effects of a treatment on primary outcome, all of other known factors affecting primary outcome assessment must be standardized to avoid the potential bias. In the demographic data of this study, however, the extent of breast cancer, severity of preoperative pain and the use of analgesics were not taken into account. The authors provided two types of surgery including mastectomy combined with lymph node biopsy and mastectomy combined with lymph node dissection, but not details of surgical procedures. It has been