IRCT20210206050260N1 IRCT 2021-04-17 Urology Research Center, Guilan University of Medical Sciences The efficacy of bupfentanyl in spinal anesthesia of patients with proximal ureteral stones Comparison of the efficacy of 0.5% bupivacaine with and without fentanyl in spinal anesthesia of patients with proximal ureteral stones under transureteral lithotripsy (TUL) 2021-04-05 anticipated 54 Complete https://irct.ir/trial/54293 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Diagnostic, Randomization description: Block randomization with blocks of size 4 with a ratio of 1 to 1 (as two groups A and B) via a online program named sealed envelop/randomisation, Blinding description: Neither the patient nor the evaluator is aware of the anesthesia drug combination assigned to the surgery. At the top of the checklist which be completed for each patient, the group type (A or B) will be recorded. 2-3 Spinal anesthesia. Intervention 1: Intervention group: Spinal injection of bupivacaine 10 mg with 0.5 ml fentanyl (25µg). Intervention 2: Control group: Spinal injection of bupivacaine 10 mg with 0.5 ml of normal saline. 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 Due to the possibility of prolonging the study and publication of the article, researchers will decide regarding the details of sharing the unidentifiable personal data of the participants after the end of the study and publication of the results in the form of an article.