Jin F, et al. - A hypothesis was tested that performing rectus sheath block (RSB) after surgery would result in a longer duration of the analgesic effects and have a subtle influence on sleep time after surgery but that it would not decrease the perioperative cytokine levels of patients undergoing gynecological surgery. Among female patients undergoing elective midline incision transabdominal gynecological surgery, preoperative RSB vs postoperative RSB might preserve postoperative sleep via inhibiting the increase of interleukin-6 [IL-6] without shortening the analgesia time.