Positioning for lumbar puncture in children evaluated by bedside ultrasound.

BACKGROUND

Lumbar punctures are commonly performed in the pediatric emergency department. There is no standard, recommended, optimal position for children who are undergoing the procedure.

OBJECTIVE

To determine a position for lumbar punctures where the interspinous space is maximized, as measured by bedside ultrasound.

METHODS

A prospective convenience sample of children under age 12 was performed. Using a portable ultrasound device, the L3-L4 or L4-L5 interspinous space was measured with the subject in 5 different positions. The primary outcome was the interspinous distance between 2 adjacent vertebrae. The interspinous space was measured with the subject sitting with and without hip flexion. In the lateral recumbent position, the interspinous space was measured with the hips in a neutral position as well as in flexion, both with and without neck flexion. Data were analyzed by comparing pairwise differences.

RESULTS

There were 28 subjects enrolled (13 girls and 15 boys) at a median age of 5 years. The sitting-flexed position provided a significantly increased interspinous space (P < .05). Flexion of the hips increased the interspinous space in both the sitting and lateral recumbent positions (P < .05). Flexion of the neck, did not significantly change the interspinous space (P = .998).

CONCLUSIONS

The interspinous space of the lumbar spine was maximally increased with children in the sitting position with flexed hips; therefore we recommend this position for lumbar punctures. In the lateral recumbent position, neck flexion does not increase the interspinous space and may increase morbidity; therefore, it is recommended to hold patients at the level of the shoulders as to avoid neck flexion.