Do antibiotic-impregnated shunts reduce infection in hydrocephalus?

Every year, nearly 400,000 children worldwide develop hydrocephalus, in which excess fluid accumulates in the brain. Many of these children have shunts placed to allow this fluid to drain. Antibiotic-impregnated shunts are widely championed as the best choice, but a recent study calls their necessity into question.

The study, published in the Journal of Neurosurgery Pediatrics, is one of the first randomized prospective trials to directly compare antibiotic and non-antibiotic shunts in children. The researchers, led by Benjamin C. Warf, MD, a neurosurgeon at Boston Children’s Hospital, followed 248 children in Uganda. They found no statistically significant difference between the two groups in infection rates, deaths, reoperations or shunt malfunctions.

Antibiotic shunts: the benefits and drawbacks

Antibiotic-impregnated shunts feature tubing with antibiotics specially selected to target bacteria that thrive on the skin, since these strains are the most common causes of shunt infection. In lab studies, they have been shown to fend off bacterial colonization for up to eight weeks.

This sounds great in theory, and has made antibiotic shunts the standard of care in the U.S. But in actual practice, says Warf, they have never been demonstrated to reduce the incidence of infection.

Antibiotic shunts are nearly ten times as expensive as the non-antibiotic alternative, a concern since more than half of children with hydrocephalus live in middle- and low-income countries. Another concern is that the regular, potentially unnecessary use of antibiotic-impregnated shunts may contribute to antibiotic resistance.

What the numbers say

The team randomly assigned hydrocephalus patients at CURE Children’s Hospital of Uganda to receive either an antibiotic Bactiseal Universal Shunt or a non-antibiotic Chhabra Shunt. They then evaluated the patients after one month, three months, six months and then annually.

A smaller, retrospective cohort study of 160 patients at the same hospital, published in 2014, found that 5 percent of the antibiotic shunt group developed infections compared to 13.8 percent in the non-antibiotic group. This difference was not statistically significant, but did show a potential trend researchers wanted to investigate further.

In the new study, that trend was diminished. The antibiotic group had an infection rate of 6.5 percent, versus 7.4 percent in the non-antibiotic group, a result far from statistical significance. Secondary indicators — death rate and reoperation — also showed no statistical difference between the two groups.

Rethinking recommendations

The team calculated that a sample of more than 5,000 patients would be needed to tease out whether the differences in infection rate represent random chance or a true difference in efficacy. In the meantime, decisive evidence in favor of antibiotic-impregnated shunts for pediatric patients has yet to be found.

The use of these more expensive shunt products lacks adequate scientific support.

“The study fails to support the marketing of these much more expensive shunts to low-income countries where resources are scarce, although it is possible that efficacy could vary regionally with differences in the bacteria causing shunt infections,” says Warf. “Clearly, though, for this population of infants in East Africa, the added cost cannot be justified. Furthermore, the use of these more expensive shunt products here in the U.S. lacks adequate scientific support, and the Ugandan study casts further doubt on the practice.”

Edith Mbabazi-Kabachelor, MD, of CURE Children’s Hospital, Mbale, Uganda, was first author on the paper. The Harvard Medical School Program in Global Surgery and Social Change also participated in the study. The work was funded by the John D. and Katherine T. MacArthur Foundation, the Doris Duke Charitable Foundation, the Harvard Program in Global Surgery and Social Change and Harvard Catalyst.