Modified 45-degree head-up tilt increases success rate of lumbar puncture in patients undergoing spinal anesthesia

Lumbar puncture (LP) is one of the most common procedures performed in medicine. The aim of this prospective study is to determine the success rate of LP in lateral decubitus with 45-degree head-up tilt position, and compare it with traditional positions like sitting and lateral decubitus.

Three hundred and thirty patients between 25 and 85 years of age who had undergone abdominal, urologic, and lower limb extremities surgeries were enrolled and 300 patients were divided into three different groups. The LP was performed with a 25-G atraumatic needle, either in the standard sitting position (group S, n = 100), lateral decubitus, knee-chest position (group L, n = 100) or lateral decubitus, knee-chest position with a 45-degree head-up tilt (group M, n = 100). The free flow of clear cerebrospinal fluid (CSF) upon first attempt was considered to be evidence of a successful LP.

Total LP success rate was significantly higher in group M (85 %) than in groups S and L (70 and 65 %, respectively) (p = 0.004). When the significance between the groups was evaluated according to age, the increase in the LP success rate was not significant for ≤65 and >65 age groups. There were no differences among the three groups in terms of bloody CSF (p = 0.229) and the number of attempts before dural puncture (p = 0.052).

The lateral decubitus in knee-chest position with a 45-degree head-up tilt may be the preferred position for spinal anesthesia in young and elderly patients, due to the high success rate.