Retrospective study comparing success rates of lumbar puncture positions in infants

A lumbar puncture (LP) is performed in the emergency room for diagnostic purposes; unsuccessful or traumatic LPs can complicate decision making. The sitting position has a larger interspinous process compared to lateral recumbent and is safer in sick neonates at risk for cardiac and respiratory instability.Our study aims to determine which position (lateral recumbent or sitting) is associated with a greater likelihood of successful lumbar puncture in infants <3 months when performed in the emergency room.This is a retrospective chart review in infants aged <3 months who had a LP performed in a pediatric emergency room. The primary outcome was the rate of successful LPs, defined as obtaining adequate CSF to send for all studies. The secondary outcome was the proportion of atraumatic LPs by position, defined as <500 RBCs or < 10,000 RBCs.A total of 557 charts were reviewed with 116 in the sitting position and 441 in the lateral recumbent position. The primary outcome of adequate CSF fluid collection was not significantly different between groups (63% sitting position versus 58% lateral recumbent position; p = 0.22). In addition, the proportion of atraumatic LPs showed no significant difference regardless of RBC cutoff (<500 RBCs p = 0.83, <10,000 RBCs p = 0.60).This study found no evidence that there is a difference in rate of LP success nor the proportion of traumatic LP in infants less than 3 months of age when positioned in the sitting position compared to the lateral recumbent position.