question: Background The purpose of this study was to determine whether electrical twitch-obtaining intramuscular stimulation (ETOIMS) can be an alternative to intravenous patient-controlled analgesia (IV-PCA) for postoperative pain management in pneumothorax patients undergoing single-port video-assisted thoracoscopic surgery (VATS). Methods This preliminary prospective randomized study was conducted between March 2017 and July 2017. A total of 26 patients undergoing single-port VATS were randomly assigned to two groups: the ETOIMS group (n=12), which received intramuscular stimulation prior to chest tube insertion toward the end of procedure, and the IV-PCA group (n=14), which received continuous infusion of fentanyl with a basal rate of 10 µg/mL/h. To measure postoperative pain, visual analogue scale (VAS; range, 0-10) was used as the primary endpoint. Results Baseline characteristics were not different between the two groups. According to the linear mixed model, there was statistical difference in the serial VAS score between the two groups (P=0.007). The ETOIMS group showed a significantly lower VAS score compared with the IV-PCA group, especially at postoperatively hour 8, day 1, and day 2. Conclusions We showed that ETOIMS may be a safe, effective, and simple alternative for pain management after single-port VATS.