To study the efficacy of ropivacaine (0.75%) with or without butorphanol as an adjuvant in single shot epidural anaesthesia in lower limb orthopedic surgeries. Int Jour of Biomed Res [Internet]. 2014 Dec. 30 [cited 2024 Oct. 19];5(12):725-30. Available from: https://ssjournals.co.in/index.php/ijbr/article/view/1458