Study on the Postoperative Pain Calls for More Methods to Control Potential Bias

There are no conflicts of interest. trial of immediate postoperative pain following single‑incision versus traditional laparoscopic cholecystectomy. Chin Med Westert GP, Drenth JP, et al. Prospective multicentre cohort study of patient‑reported outcomes after cholecystectomy for uncomplicated symptomatic cholecystolithiasis. of pain perception and tramadol consumption using intravenous patient‑controlled analgesia. single‑dose preoperative dexamethasone minimize stress response and improve recovery after laparoscopic cholecystectomy? Surg Pain relief from combined wound and intraperitoneal local anesthesia for patients who undergo laparoscopic cholecystectomy. under spinal anaesthesia vs. general anaesthesia: A meta‑analysis of randomized controlled trials. We thank Dr. Liu et al. very much for their attention on our recent article. In that paper, we reported a prospective randomized clinical trial comparing outcomes between traditional laparoscopic cholecystectomy and single‑incision laparoscopic cholecystectomy (SILC). It revealed that the SILC‑treated patients had a significantly lower pain score only at postoperative 6 hours, but at 24 hours and longer after surgery pain scores were not different between the two groups. In the earlier reports of clinical trials of SILC from 2007 to 2011, the safety and feasibility of the SILC have been confirmed by many studies. However, besides the obvious better cosmesis, whether the SILC had more benefits, such as less postoperative pain, shorter hospital stays, faster return to work, and routine activity, was unknown. Therefore, we set the postoperative pain as the primary outcome in this randomized controlled trial. The visual analog scale (VAS) is a psychometric response scale which lacks objectivity, but at present, it is regarded as the most common measurement instrument to evaluate the postoperative pain. Hence, it was used in the clear majority of the clinical trial of single‑incision laparoscopic surgery. We totally agree with Dr. Liu et al. that the preoperative psychological disorders would affect postoperative pain score. However, unfortunately, we did not find a well‑designed trial as a satisfactory reference before the date of recruitment, November 1, 2011. Moreover, we were afraid that paying too much attention to the psychological factors would bring more bias to the study when lacking a better measurement instrument than VAS. All the patients underwent general anesthesia without any special medication such as dexamethasone. Actually, we had noticed that single‑dose preoperative dexamethasone would decrease VAS. [6] Hence, all the anesthetists were told not to use dexamethasone when the patient was recruited. Furthermore, to exclude all potential affecting factors and control the potential confounding bias, we did not use any local …