Paramedian versus midline approach of spinal anesthesia: a systematic review and meta-analysis with trial sequential analysis

Midline approach of spinal anesthesia has been widely used for patients undergoing surgical procedures. However, it might not be effective for obstetric patients and elderly with degenerative spine changes. Primary objective was to examine the success rate at the first attempt between the paramedian and midline spinal anesthesia in adults undergoing surgery. Databases of MEDLINE, EMBASE, and CENTRAL were searched from their starting date until February 2023. Randomized clinical trials (RCTs) comparing the paramedian versus midline approach of spinal anesthesia were included. The primary outcome was the success rate at the first attempt of spinal anesthesia. Our review included 36 RCTs (n = 5379). Compared to the midline approach, paramedian approach may increase success rate at the first attempt but the evidence is very uncertain (OR: 0.47, 95