In this prospective single-blind study, patients will be divided into 2 groups with the closed envelope method. Patients will be taken to the block application room before the operation. Standard monitoring (pulse oximetry, noninvasive blood pressure, ECG) will be applied to the patients. Premedication will be provided with 1mg IV midazolam after peripheral vascular access. Blocks will be performed by an experienced anesthesiologist under the guidance of USG and evaluated by another anesthesiologist who is blind to the block technique. After the antisepsis of the area, a 22G 100 mm stimulator needle will be used in the infraclavicular approach and a 22G 50 mm in the supraclavicular block. Intermittent negative aspiration will be performed during all procedures to detect possible vascular puncture. 30 ml of 1:1 0.5% bupivacaine and 2% prilocaine plus 5 mcg adrenaline per ml will be used as local anesthetic mixture. The infraclavicular block will be applied by the lateral sagittal method under USG guidance. Supraclavicular block will be applied in the coronal oblique plane while the probe is placed on the clavicle. Following the blocks, the 5th, 10th, 15th, 20th, 25th, and 30th-minute sensory block levels, 10th, 20th, and 30th-minute motor block levels will be recorded. Sensory block level; Axillary, median, radial, ulnar, musculocutaneous, cutaneous brachia, and cutaneous antebrachii medialis nerve level will be evaluated with the pinprick test and its level will be recorded. (0 = painful, no block; 1 = partial block-analgesia, only tactile sensation; 2 = complete block, no pain). The motor block will be evaluated with a modified bromage scale: 0: No blocks, he can lift his arm; 1: Arm is weak but active; 2: Arm is motionless but fingers are active; 3: Complete block, no movement in hand or arm.

Block success; At the 30th minute of LA application, the pinprick test will define the presence of insensibility or only a sense of touch in the musculocutaneous, radial, ulnar, median, cutaneous antebrachii nerves. If any of these nerves are not blocked, it will be considered a failed block.

Postoperative analgesia time; It will be considered as when the NRS(Numeric Rating Scale) is≥1.

Pain Score Follow-up; patients' pain scores will be recorded by checking their NRS scores at the 2nd, 6th, 12th, 24th hours.

Sensory (the time from local anesthetic injection until the patient fully perceives the upper limb) and motor (the time from local anesthetic injection until the patient's upper extremity regains full muscle strength) block time will be recorded as the block return time. Pain score during block application will be evaluated with the NRS. Block application time will be defined as the time from the moment the needle passes the skin until the local anesthetic is given and withdrawn. Block formation time will be defined as the time required to initiate anesthesia and analgesia in all 5 distal nerves. Patient and surgeon satisfaction will be evaluated as 1 = complete dissatisfaction, 2 = moderate satisfaction, 3 = full satisfaction, after the procedure. Patients will be followed up for 24 hours in terms of undesirable side effects, vascular puncture, hematoma, signs of LA toxicity, respiratory distress, pneumothorax, and horner syndrome. As rescue anesthesia, sedoanalgesia will be tried with remifentanil infusion, if it is not successful, general anesthesia will be started with a laryngeal mask. As postoperative analgesic regimen, patients will receive 3 x 1000 mg IV acetaminophen. As rescue analgesia, Tramadol 1 mg/kg IV will be ordered to be administered when the patient's NRS is 3 or more. The first time when the patient receives rescue analgesia and the total dose of rescue analgesia for the first 24 hours will be recorded.