Fluoro-guided lumbar punctures fail more for infants, elderly

Mar 22, 2009

When an infant less than 1 year of age needs a lumbar puncture, radiologists should consider using an ultrasound-guided procedure instead of fluoroscopy, researchers at Wake Forest University School of Medicine in Winston-Salem, NC, recommend.

In a retrospective study, they discovered that the failure rate for traumatic lumbar puncture during 2005 and 2006 was 58.8% for infants, compared with a 3.2% failure rate in children ages 12 months and older. Caution must also be taken with geriatric patients, as patients older than 80 have a higher risk of bleeding.

These findings were revealed in a study led by Dr. Annette Johnson, an associate professor of radiologic sciences, to determine the factors associated with increased risk of traumatic fluoroscopy-guided lumbar puncture. The study was published in the March issue of the American Journal of Neuroradiology (2009, Vol. 30:3, pp. 512-515).

Fluoroscopy-guided lumbar punctures are often performed after a difficult or failed bedside lumbar puncture attempt. The rate of fluoroscopy-guided lumbar puncture is estimated to range from zero to 24%, compared with 10.5% to 20% for conventional procedures.

Wake Forest researchers evaluated the records of 742 patients, ranging in age from infancy to 90 years, and found an average rate of traumatic lumbar puncture of 13.3%. The rate of traumatic lumbar puncture was significantly higher at the L4-L5 level, at 19%, compared with 9% at the L2-L3 level, 10% at the L3-L4 level, and 13% at the L5-S1 level.

Patients between the ages of 11 and 80 years averaged a 12.4% failure, compared with older patients who had a 25.9% failure rate. The researchers suggested that this may have been a factor of poor patient cooperation by elderly patients with altered mental status, or medications that could predispose them to bleeding.

The high rate of failure in infants may have been caused by overinsertion of the lumbar spine needle, leading to injury of the venous epidural plexus. The researchers also speculated that the high rate may be linked to traumatic epidural or subdural collections as a result of prior failed bedside lumbar puncture.