Comparison between levobupivacaine alone and levobupivacaine with fentanyl in extending the duration and postoperative analgesia of supraclavicular brachial plexus block for elective upper limb orthopedic surgeries

Youssef, Mahmoud Gamal El-Din; Abdelgaber, Ghada; Hala Rashad Ahmed Mahmoud; Abbas, Fawzy;