In Summary, for those who received an intracranial ventricular shunt:

Benefits in NNT

  • 95% with systemic antibiotics saw no benefit
  • 5% with systemic antibiotics were helped by preventing an infection
  • 91% with an antibiotic-impregnated device saw no benefit
  • 9% with an antibiotic-impregnated device were helped by preventing an infection
  • 1 in 20 with systemic antibiotics were helped (infection prevented)
  • 1 in 11 with an antibiotic-impregnated device were helped (infection prevented)

Harms in NNT

  • An unknown number in both groups were harmed by medication side effects
  • An unknown number were harmed (medication side effects)

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Source: Ratilala BO, Costa J, Sampaio C. Antibiotic prophylaxis for surgical introduction of intracranial ventricular shunts. Cochrane Database of Systematic Reviews 2009, Issue 1. Art No.: CD005365.

Efficacy Endpoints: All-cause mortality, infection of the device

Harm Endpoints: Adverse events of antibiotics

Narrative: Often patients develop a very dangerous condition, where brain swelling compresses brain matter within the skull. This can cause a patient to experience anything from mild symptoms of headache to rapid death. Devices are often surgically placed into the ventricles of the brain to ‘decompress’ the swelling. In certain situations when the pressure is dangerously high, the devices may be life saving. Ventricular shunts work by draining cerebrospinal fluid (CSF) to another part of the body or to the outside environment. As with any surgical procedure, placement of a ventricular shunt poses risks including the introduction of infections, which are typically devastating and often fatal. As a result researchers have studied the use of systemic antibiotics and also antibiotic-impregnated devise to reduce the infection risk. This Cochrane review examines the best evidence for using systemic antibiotics and catheter impregnated antibiotics to prevent infections when placing intraventricular devices.
The Cochrane review included seventeen randomized control trials with 2134 patients. For the outcome of all-cause mortality, there were insufficient data. In terms of infection of the device the review found that both systemic antibiotics and antibiotic-impregnated catheters decreased infections with an NNT of 20 and 11, respectively. Additionally, a preplanned subgroup analysis by the Cochrane reviewers found that additional antibiotics (more than just around the time of the procedure) did not confer additional benefit.

Caveats: All the included trials were randomized, however details of the study protocol and methods (randomization, concealment, etc.) for some trials were unknown. Additionally, all studies were analyzed per-protocol and not intention-to-treat, which presents a serious bias in the individual results. As a result, this calls into question the validity of the results found by the Cochrane Reviewers. Furthermore, the trials mostly included patients receiving internal shunts and analyzed data for both adults and children in aggregate. Only one study looked at a very small subset of patients that received an external shunt and found no difference in infection rates with the use of antibiotics, however it was a small sample and no conclusions can be drawn.

Unfortunately, the review reported that only two of the included trials had data on adverse events from the antibiotics. However, the two studies used different drugs and different patient populations. One was stopped early for harm from the antibiotics, which may indicate an under-reported major problem, and the second article did not report their harm data in the published paper.

Overall, while there are serious methodologic limitations, and we would like to see a large, high quality randomized trial on the subject, it appears that a current best guess suggests that antibiotics (either systemically or impregnated into the device) will reduce shunt infections.

Author: Jarone Lee, MD, MPH

Published/Updated: February 11, 2013

  1. The Title Bar

    The title bar is color-coded with our overall recommendation.

    • Green: Benefits outweigh risks.
    • Yellow: Unclear risk/benefit profile.
    • Red: Benefits do not outweigh risks.
    • Black: Obvious harms, no clear benefits.
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