Background and Aims Rebound pain is an acute increase in pain severity after a peripheral nerve block (PNB) has worn off, generally manifesting within 24 h after the block performance. This observational study aims to observe the incidence and factors of rebound pain after PNB.

Methods Before subject enrollment, the ethics committee approved the study (137/01), and it was registered at ClinicalTrials.gov (NCT03048214). Ortopedia surgery patients who received PNB for anesthesia or analgesia for 10 months were included. Postoperatively, all subjects received multimodal analgesia. Patients were visited at 0, 12, and 24 hours postoperatively and were analyzed for the incidence of rebound pain, numeric rating scale (NRS) pain score, motor and sensory block times. Rebound pain was mainly described as burning, dull aching pain and severe pain (NRS score >7).

Results In the preliminary report was enrolled 119 subjects, and the rebound pain rate was 24.3%. Rebound pain is more common in upper extremity blocks (p<0.01). Rebound pain was seen more in PNB applied for anesthesia than in PNB used for analgesia. (p=0.018). Opioid analgesic consumption rates were high during the rebound pain.

Conclusions Despite multimodal analgesia, we think rebound pain can be seen more, especially in upper extremity blocks and when applied for anesthesia.