IRCT20221208056751N1 IRCT 2022-12-17 Gorgan University of Medical Sciences Evaluation of ultrasound-guided LP success rate in children under 24 months Evaluation of ultrasound-guided LP success rate in children under 24 months ; Randomized clinical trial with control group 2023-01-10 anticipated 80 Complete https://irct.ir/trial/67436 interventional Randomization: Randomized, Blinding: Not blinded, Placebo: Not used, Assignment: Parallel, Purpose: Diagnostic, Randomization description: We use the block randomization method to randomize subjects into groups that result in equal sample sizes. At the beginning of the randomization process, we randomly choose one of the following blocks by randomly throwing the dice and divide the rest of the samples into 2 groups according to the order of the samples. A: intervention and B: control B A B A 2) B B A A 1) B A A B 4) A B B A 3) A A B B 6) A B A B 5). N/A Lumbar Puncture. Intervention 1: Intervention group: With the help of portable ultrasound, the suitable place for lumbar puncture is marked and then lumbar puncture will be done from that place. Intervention 2: Control group: With classical method, based on anatomical landmarks, lumbar puncture will be performed on control group patients. No - There is not a plan to make this available Justification or reason for not sharing IPD is "No more information"