IRCT20140427017455N5 IRCT 2019-03-25 Tehran University of Medical Sciences Effects of adding different doses of tramadol to bupivacaine solution for brachial plexus block on postoperative analgesia duration after arthroscopic shoulder surgery Comparison of the efficacy of different doses of adjuvant perineural tramadol to 0.25% bupivacaine in prolongation of postoperative analgesia in arthroscopic shoulder surgeries under interscalene block 2016-04-03 anticipated 60 Complete https://irct.ir/trial/16061 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: Randomization method: simple, Unit of randomization: individual, Tools of randomization: Software, Allocation concealment: by the same software, Blinding description: Patients are blind The researcher who injects the solution receives a prepared solution, therefore the researcher is blind. The care provider nurses in the operating room and the recovery room are blind. The research team member who evaluates the patient is also blind. 3 post shoulder arthroscopic surgery analgesia duration. Intervention 1: Intervention group 1: Perineural injection of 0.25% bupivacaine and 1/200000 epinephrine with 100 mg tramadol in 15 milliliters volume in interscalene block. Intervention 2: Intervention group 2: Perineural injection of 0.25% bupivacaine and 1/200000 epinephrine with 200 mg tramadol in 15 milliliters volume in interscalene block. Intervention 3: Control group: Perineural injection of 0.25% bupivacaine and 1/200000 epinephrine in 15 milliliters volume in interscalene block. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is Decision will be made later