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NIHR Signal Fewer infections with antibiotic-impregnated shunts for hydrocephalus

Published on 22 January 2020

doi: 10.3310/signal-000863

Antibiotic-impregnated shunt catheters led to fewer infections than standard catheters in this study, although the overall rate of shunt revision remained about the same.

In hydrocephalus, a shunt is a device consisting in part of a long catheter (a tube) that relieves the raised pressure of fluid in the ventricles of the brain. It is inserted internally and works by simply draining the fluid, most commonly, to the abdomen. These shunts may need revision because of infection or mechanical failure (for example, blockage), so shunt catheters are impregnated with silver or an antibiotic to try and reduce the risk of infection.

This large NIHR-funded trial found that 2% of patients with antibiotic shunt catheters needed revisions because of infection, compared with 6% for standard or silver shunt catheters. The overall revision rate was about 25% for all types.

By using antibiotic-impregnated shunt catheters, about 4% of people avoided infection they may otherwise have developed. This trial supports the use of these shunt catheters in UK practice.

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Why was this study needed?

Hydrocephalus affects around 88 in 100,000 children, 11 in 100,000 adults and 175 in 100,000 adults over 65. A peritoneal shunt is one of the most common treatments for the condition, but 7% to 15% of shunts fail because of infection, and more fail from other causes.

Infection with a shunt in place requires reoperation for revision, and a potentially lengthy hospital stay for antibiotic treatment. Infection affects survival, as well as the quality of life and cognitive function.

Previous systematic reviews concluded there was insufficient evidence that either silver or antibiotic-impregnated shunt catheters reduced the rate of infection. This study was set up to answer the question as to which type of shunt catheter was more clinically and cost-effective.

What did this study do?

The trial was undertaken in 21 regional neurosurgery centres in the UK and Ireland and randomised 1,605 adults and children to standard, silver or antibiotic shunt systems (catheters impregnated with rifampicin and clindamycin), and followed them for an average 22 months.

The patients had hydrocephalus from any cause and were due to receive their first ventriculoperitoneal shunt. Patients were excluded if they had active infection at the time of insertion.

The randomised controlled trial (BASICS) allocated participants to receive standard, silver or antibiotic-impregnated shunt catheters, with treatment allocation revealed only in the operating theatre and withheld from the outcome assessors and most of the surgeons managing the suspected infection. Researchers followed patients for up to 24 months (mean follow-up 22 months). Where the surgeon thought a revision was due to infection, a review panel (blinded to shunt allocation) checked the data on clinical presentation and treatment given. The primary outcome was time to infection, and revision rates and cost-effectiveness were also assessed.

What did it find?

  • Shunt catheters were removed for an infection in 6% of participants with standard catheters, 2% with antibiotic catheters and 6% with silver catheters.
  • Shunt catheter removal or revision for any cause occurred in 24% of participants with standard catheters, 25% with antibiotic catheters and 26% with silver catheters.
  • The antibiotic shunt catheters delayed any infection compared with the standard catheter (hazard ratio (HR) 0.38, 97.5% confidence interval (CI) 0.18 to 0.80). The silver catheter was no better than a standard catheter (HR 0.99, 95% CI 0.56 to 1.74).
  • Children were more likely to need shunt revision due to infection than adults. Some 8% of 592 children, 5% of 499 adults under 65 and 1% of 503 adults aged 65 and over required revision due to infection.
  • Average costs for the duration of the study period (24 months) were £18,707 for standard catheter shunts, £14,192 for antibiotic catheters and £17,385 for silver catheters.

What does current guidance say on this issue?

A 2014 guideline from the American Association of Neurological Surgeons said: “Antibiotic-impregnated shunt (AIS) tubing may be associated with a lower risk of shunt infection compared with conventional silicone hardware and thus is an option for children who require placement of a shunt.”

At the time, the authors of this guideline said the evidence was Level III, meaning an unclear degree of clinical certainty.

What are the implications?

The results of the BASICS study suggest that antibiotic-impregnated shunt catheters should be the first choice for people having a first ventriculoperitoneal shunt inserted for treatment of hydrocephalus, regardless of age or cause of illness.

Although antibiotic-impregnated shunt catheters may not reduce the numbers of revisions required for any cause, infections in the cerebrospinal fluid cause significant morbidity and require longer and more expensive treatment as well as revision compared with just revision for mechanical failure.

The increased price of these shunt catheters could be expected to be recovered by the reduction in treatment for shunt infection.

Citation and Funding

Mallucci CL, Jenkinson MD, Conroy EJ et al. Antibiotic or silver versus standard ventriculoperitoneal shunts (BASICS): a multicentre, single-blinded, randomised trial and economic evaluation. Lancet 2019;394:1530-9.

The study was funded by the NIHR Health Technology Assessment Programme (project number 10/104/30).

Why was this study needed?

Hydrocephalus affects around 88 in 100,000 children, 11 in 100,000 adults and 175 in 100,000 adults over 65. A peritoneal shunt is one of the most common treatments for the condition, but 7% to 15% of shunts fail because of infection, and more fail from other causes.

Infection with a shunt in place requires reoperation for revision, and a potentially lengthy hospital stay for antibiotic treatment. Infection affects survival, as well as the quality of life and cognitive function.

Previous systematic reviews concluded there was insufficient evidence that either silver or antibiotic-impregnated shunt catheters reduced the rate of infection. This study was set up to answer the question as to which type of shunt catheter was more clinically and cost-effective.

What did this study do?

The trial was undertaken in 21 regional neurosurgery centres in the UK and Ireland and randomised 1,605 adults and children to standard, silver or antibiotic shunt systems (catheters impregnated with rifampicin and clindamycin), and followed them for an average 22 months.

The patients had hydrocephalus from any cause and were due to receive their first ventriculoperitoneal shunt. Patients were excluded if they had active infection at the time of insertion.

The randomised controlled trial (BASICS) allocated participants to receive standard, silver or antibiotic-impregnated shunt catheters, with treatment allocation revealed only in the operating theatre and withheld from the outcome assessors and most of the surgeons managing the suspected infection. Researchers followed patients for up to 24 months (mean follow-up 22 months). Where the surgeon thought a revision was due to infection, a review panel (blinded to shunt allocation) checked the data on clinical presentation and treatment given. The primary outcome was time to infection, and revision rates and cost-effectiveness were also assessed.

What did it find?

  • Shunt catheters were removed for an infection in 6% of participants with standard catheters, 2% with antibiotic catheters and 6% with silver catheters.
  • Shunt catheter removal or revision for any cause occurred in 24% of participants with standard catheters, 25% with antibiotic catheters and 26% with silver catheters.
  • The antibiotic shunt catheters delayed any infection compared with the standard catheter (hazard ratio (HR) 0.38, 97.5% confidence interval (CI) 0.18 to 0.80). The silver catheter was no better than a standard catheter (HR 0.99, 95% CI 0.56 to 1.74).
  • Children were more likely to need shunt revision due to infection than adults. Some 8% of 592 children, 5% of 499 adults under 65 and 1% of 503 adults aged 65 and over required revision due to infection.
  • Average costs for the duration of the study period (24 months) were £18,707 for standard catheter shunts, £14,192 for antibiotic catheters and £17,385 for silver catheters.

What does current guidance say on this issue?

A 2014 guideline from the American Association of Neurological Surgeons said: “Antibiotic-impregnated shunt (AIS) tubing may be associated with a lower risk of shunt infection compared with conventional silicone hardware and thus is an option for children who require placement of a shunt.”

At the time, the authors of this guideline said the evidence was Level III, meaning an unclear degree of clinical certainty.

What are the implications?

The results of the BASICS study suggest that antibiotic-impregnated shunt catheters should be the first choice for people having a first ventriculoperitoneal shunt inserted for treatment of hydrocephalus, regardless of age or cause of illness.

Although antibiotic-impregnated shunt catheters may not reduce the numbers of revisions required for any cause, infections in the cerebrospinal fluid cause significant morbidity and require longer and more expensive treatment as well as revision compared with just revision for mechanical failure.

The increased price of these shunt catheters could be expected to be recovered by the reduction in treatment for shunt infection.

Citation and Funding

Mallucci CL, Jenkinson MD, Conroy EJ et al. Antibiotic or silver versus standard ventriculoperitoneal shunts (BASICS): a multicentre, single-blinded, randomised trial and economic evaluation. Lancet 2019;394:1530-9.

The study was funded by the NIHR Health Technology Assessment Programme (project number 10/104/30).

Antibiotic or silver versus standard ventriculoperitoneal shunts (BASICS): a multicentre, single-blinded, randomised trial and economic evaluation

Published on 17 September 2019

Mallucci, C. L.,Jenkinson, M. D.,Conroy, E. J.,Hartley, J. C.,Brown, M.,Dalton, J.,Kearns, T.,Moitt, T.,Griffiths, M. J.,Culeddu, G.,Solomon, T.,Hughes, D.,Gamble, C.

Lancet , 2019

BACKGROUND: Insertion of a ventriculoperitoneal shunt for hydrocephalus is one of the commonest neurosurgical procedures worldwide. Infection of the implanted shunt affects up to 15% of these patients, resulting in prolonged hospital treatment, multiple surgeries, and reduced cognition and quality of life. Our aim was to determine the clinical and cost-effectiveness of antibiotic (rifampicin and clindamycin) or silver shunts compared with standard shunts at reducing infection. METHODS: In this parallel, multicentre, single-blind, randomised controlled trial, we included patients with hydrocephalus of any aetiology undergoing insertion of their first ventriculoperitoneal shunt irrespective of age at 21 regional adult and paediatric neurosurgery centres in the UK and Ireland. Patients were randomly assigned (1:1:1 in random permuted blocks of three or six) to receive standard shunts (standard shunt group), antibiotic-impregnated (0.15% clindamycin and 0.054% rifampicin; antibiotic shunt group), or silver-impregnated shunts (silver shunt group) through a randomisation sequence generated by an independent statistician. All patients and investigators who recorded and analysed the data were masked for group assignment, which was only disclosed to the neurosurgical staff at the time of operation. Participants receiving a shunt without evidence of infection at the time of insertion were followed up for at least 6 months and a maximum of 2 years. The primary outcome was time to shunt failure due the infection and was analysed with Fine and Gray survival regression models for competing risk by intention to treat. This trial is registered with ISRCTN 49474281. FINDINGS: Between June 26, 2013, and Oct 9, 2017, we assessed 3505 patients, of whom 1605 aged up to 91 years were randomly assigned to receive either a standard shunt (n=536), an antibiotic-impregnated shunt (n=538), or a silver shunt (n=531). 1594 had a shunt inserted without evidence of infection at the time of insertion (533 in the standard shunt group, 535 in the antibiotic shunt group, and 526 in the silver shunt group) and were followed up for a median of 22 months (IQR 10-24; 53 withdrew from follow-up). 32 (6%) of 533 evaluable patients in the standard shunt group had a shunt revision for infection, compared with 12 (2%) of 535 evaluable patients in the antibiotic shunt group (cause-specific hazard ratio [csHR] 0.38, 97.5% CI 0.18-0.80, p=0.0038) and 31 (6%) of 526 patients in the silver shunt group (0.99, 0.56-1.74, p=0.96). 135 (25%) patients in the standard shunt group, 127 (23%) in the antibiotic shunt group, and 134 (36%) in the silver shunt group had adverse events, which were not life-threatening and were mostly related to valve or catheter function. INTERPRETATION: The BASICS trial provides evidence to support the adoption of antibiotic shunts in UK patients who are having their first ventriculoperitoneal shunt insertion. This practice will benefit patients of all ages by reducing the risk and harm of shunt infection. FUNDING: UK National Institute for Health Research Health Technology Assessment programme.

Expert commentary

This is a complex and detailed trial that has fulfilled the declared objectives. The researchers have successfully determined that shunt infection rates can be reduced by the choice of shunt catheters, proving that antibiotic-impregnated catheters result in a statistically significant reduction in shunt infection.

As a neurosurgeon, this study is of great clinical interest and it is a very significant step in hydrocephalus treatment.

Overall, this study has provided a valuable and definitive answer to a long-running debate about the optimal shunt catheters to use for the treatment of hydrocephalus. It is excellent.

John Goodden, Consultant Paediatric Neurosurgeon, Leeds Teaching Hospitals NHS Trust; Honorary Senior Lecturer, University of Leeds

The commentator was the site principal investigator for Leeds and recruited patients for the BASICS trial

Expert commentary

Silver-impregnated shunt catheters need no longer be considered. The antibiotic-impregnated catheter promises to reduce brain infections and repeat operations as well as saving costs for the NHS. By reducing infections, antibiotic use and therefore resistance are also reduced. Some infections (2%) remained, many of these due to gram-negative bacteria against which the impregnated catheter has no activity.

The speculation that some malfunctions not coded as infections might be due to antibiotics released from the catheter is unlikely in view of published evidence to the contrary.

Acceptance of the impregnated shunt catheters as standard is now expected.

Roger Bayston, Professor of Surgical Infection, Faculty of Medicine and Health Sciences, University of Nottingham

The commentator is the named inventor of one of the catheters trialled

Expert commentary

The most common treatment for hydrocephalus is the diversion of cerebrospinal fluid flow with a shunt operation. Post-operative infection risks serious harm to the patient, and the entire shunt system needs to be removed, a temporary system put in place and then a new system implanted at considerable expense.

The BASICS trial randomised patients of all ages to either antibiotic-impregnated, silver, or standard shunt catheters in patients having their first shunt operation. The infection rate was equivalent in both the standard and silver-impregnated groups – 6% – but in the antibiotic-impregnated group was only 2%. The rate of other complications was equivalent across all three groups. The estimated cost saving was £135,753 per infection avoided.

The results support the use of antibiotic-impregnated shunt catheters to reduce the risk of postoperative infection in patients having their first shunt operation.

Lewis Thorne, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust