A Randomized Trial to Compare the Effect of Addition of Fentanyl or Butorphanol to Hyperbaric Ropivacaine for Spinal Anesthesia in Elective Infraumbilical Surgery

Abstract Background: Prefilled hyperbaric ropivacaine eliminates risks of contamination and inconsistency associated with manual glucose addition. While opioid adjuvants are widely used to enhance spinal anesthesia, comparative data on fentanyl and butorphanol in combination with prefilled hyperbaric ropivacaine are limited. This trial evaluated the effect of fentanyl or butorphanol adjuvant on prefilled hyperbaric ropivacaine for spinal anesthesia in elective infraumbilical surgery. Materials and Methods: In this prospective, triple-blind, randomized controlled trial, 90 American Society of Anesthesiologists I–II patients aged 18–60 years undergoing elective infraumbilical surgery were randomized (1:1:1) to receive 15 mg prefilled hyperbaric ropivacaine alone (RC), with 25 μg fentanyl (RF), or with 25 μg butorphanol (RB). The primary outcomes were sensory and motor block characteristics and duration of postoperative analgesia. Secondary outcomes were hemodynamic stability, quality of intraoperative analgesia, and adverse events. Results: All randomized patients completed the trial. Both adjuvants significantly prolonged sensory block compared with control (RB: 158.4 ± 32.7 min; RF: 151.2 ± 26.0 min; RC: 132.2 ± 29.1 min; P < 0.001). Motor block duration was longer in RB (168.6 ± 38.7 min) than in RF (153.2 ± 18.4 min) or RC (149.6 ± 28.1 min; P = 0.03). Postoperative analgesia lasted longest in RF (296.0 ± 50.5 min), exceeding both RB (227.5 ± 73.9 min) and RC (216.9 ± 47.1 min; P < 0.001). Hemodynamic stability was maintained across groups, and adverse events were few and manageable. Conclusion: Both fentanyl and butorphanol enhanced the efficacy of prefilled hyperbaric ropivacaine for spinal anesthesia, with fentanyl providing superior postoperative analgesia and butorphanol serving as a suitable alternative where fentanyl access is restricted.