Corey Amlong, Moltu Guy, Kristopher M Schroeder, Melanie J Donnelly Department of Anesthesiology, University of Wisconsin Hospital and Clinics, Madison, WI, USA Purpose: Paravertebral blocks (PVBs) are a method of limiting postoperative pain for patients undergoing video-assisted thoracoscopic surgery (VATS). We began providing ultrasound-guided PVBs for patients undergoing VATS in the spring of 2011, using an out-of-plane approach. The aim of this study was to evaluate this practice change. Methods: Following institutional review board approval, we reviewed the charts of 114 patients undergoing VATS by one surgeon at our institution between January 2011 and July 2012. Of the 78 eligible patients, 49 patients received a PVB prior to surgery. We evaluated opioids administered in the perioperative period, pain scores, and side effects from pain medications. Results: Patients who received a preoperative PVB required fewer narcotics intraoperatively and during their hospital stay (P=0.001 and 0.011, respectively). Pain scores on initial assessment and in recovery were lower in patients who received a PVB (P=0.005), as were dynamic and resting pain scores at 24 hours after surgery (P=0.003 and P<0.001, respectively). Patients receiving a PVB had fewer episodes of treated nausea both in the postanesthesia care unit (P=0.004) and for the first 24 hours after surgery (P=0.001). These patients also spent less time in recovery (P=0.025) than the patients who did not receive a block. Conclusion: The current study suggests improved outcomes in patients who underwent VATS with a preoperative PVB. All variables showed a trend toward improved results in patients who obtained a preoperative PVB. Keywords: nerve blocks, video-assisted thoracoscopic surgery, anesthesia, pain