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. 2020 Mar;24(17):1–114. doi: 10.3310/hta24170

Silver-impregnated, antibiotic-impregnated or non-impregnated ventriculoperitoneal shunts to prevent shunt infection: the BASICS three-arm RCT.

Conor L Mallucci, Michael D Jenkinson, Elizabeth J Conroy, John C Hartley, Michaela Brown, Tracy Moitt, Joanne Dalton, Tom Kearns, Michael J Griffiths, Giovanna Culeddu, Tom Solomon, Dyfrig Hughes, Carrol Gamble; BASICS study collaborators
PMCID: PMC7184313  PMID: 32238262

Abstract

BACKGROUND

Insertion of a ventriculoperitoneal shunt to treat hydrocephalus is one of the most common neurosurgical procedures worldwide. Shunt infection affects up to 15% of patients, resulting in long hospital stays, multiple surgeries and reduced cognition and quality of life.

OBJECTIVES

The aim of this trial was to determine whether or not antibiotic-impregnated ventriculoperitoneal shunts (hereafter referred to as antibiotic shunts) (e.g. impregnated with rifampicin and clindamycin) or silver-impregnated ventriculoperitoneal shunts (hereafter referred to as silver shunts) reduce infection compared with standard ventriculoperitoneal shunts (hereafter referred to as standard shunts).

DESIGN

This was a three-arm, superiority, multicentre, parallel-group randomised controlled trial. Patients and a central primary outcome review panel, but not surgeons or operating staff, were blinded to the type of ventriculoperitoneal shunt inserted.

SETTING

The trial was set in 21 neurosurgical wards across the UK and the Republic of Ireland.

PARTICIPANTS

Participants were patients with hydrocephalus of any aetiology who were undergoing insertion of their first ventriculoperitoneal shunt.

INTERVENTIONS

Participants were allocated 1 : 1 : 1 by pressure-sealed envelope to receive a standard non-impregnated, silver-impregnated or antibiotic-impregnated ventriculoperitoneal shunt at the time of insertion. Ventriculoperitoneal shunts are medical devices, and were used in accordance with the manufacturer's instructions for their intended purpose.

MAIN OUTCOME MEASURES

The primary outcome was time to ventriculoperitoneal shunt failure due to infection. Secondary outcomes were time to failure for any cause, reason for failure (infection, mechanical), types of ventriculoperitoneal shunt infection, rate of infection after first clean (non-infected) revision and health economics. Outcomes were analysed by intention to treat.

RESULTS

Between 26 June 2013 and 9 October 2017, 1605 patients from neonate to 91 years of age were randomised to the trial: n = 36 to the standard shunt, n = 538 to the antibiotic shunt and n = 531 to the silver shunt. Patients who did not receive a ventriculoperitoneal shunt (n = 4) or who had an infection at the time of insertion (n = 7) were not assessed for the primary outcome. Infection occurred in 6.0% (n = 32/533) of those who received the standard shunt, in 2.2% (n = 12/535) of those who received the antibiotic shunt and in 5.9% (n = 31/526) of those who received the silver shunt. Compared with the standard shunt, antibiotic shunts were associated with a lower rate of infection (cause-specific hazard ratio 0.38, 97.5% confidence interval 0.18 to 0.80) and a decreased probability of infection (subdistribution hazard ratio 0.38, 97.5% confidence interval 0.18 to 0.80). Silver shunts were not associated with a lower rate of infection than standard shunts (cause-specific hazard ratio 0.99, 97.5% confidence interval 0.56 to 1.74). The ventriculoperitoneal shunt failure rate attributable to any cause was 25.0% overall and did not differ between arms. Antibiotic shunts save £135,753 per infection avoided. There were no serious adverse events.

LIMITATIONS

It was not possible to blind treating neurosurgeons to the ventriculoperitoneal shunt type. The return rate for patient-reported outcomes was low. Limitations to the economic evaluation included failure to obtain Hospital Episode Statistics data from NHS Digital, as per protocol. Reliance on patient-level information and costing systems data mitigated these limitations.

CONCLUSIONS

Antibiotic shunts have a reduced infection rate compared with standard shunts, whereas silver shunts do not. Antibiotic shunts are cost-saving.

FUTURE WORK

A sample collection has been established that will enable the study of surrogate markers of ventriculoperitoneal shunt infection in cerebrospinal fluid or blood using molecular techniques. A post hoc analysis to study factors related to shunt failure will be performed as part of a future study. An impact analysis to assess change in practice is planned.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN49474281.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 17. See the NIHR Journals Library website for further project information.

Plain language summary

Hydrocephalus (commonly known as ‘water on the brain’) is a condition that can affect all age groups, from babies to the elderly. In hydrocephalus, there is an accumulation of the normal brain fluid in the fluid cavities (ventricles) of the brain. Untreated, hydrocephalus can be life-threatening. The most common treatment involves an operation to insert a tube into the swollen ventricles to drain off the excess fluid. This is called a ventriculoperitoneal shunt. In the UK, 3000–3500 shunt operations are performed each year. The main risks of a shunt operation are infection (surgical meningitis) and blockage without infection. Infection results in the need for at least two further surgeries, antibiotic treatment and a prolonged hospital stay (minimum of 2 weeks). Shunt infections can affect mental abilities and can be life-threatening. People who have blockages without infection, on the other hand, usually need only a single operation to replace the blocked part and only a few days in hospital. Two new types of shunt catheter have been introduced to try to reduce shunt infection: antibiotic-impregnated shunts and silver-impregnated shunts. This study was designed to assess whether or not either of these new shunts reduce infection compared with standard shunts. This study also included an analysis of the cost and health benefits of the different shunts used. A total of 1605 children and adults, who were treated in neurosurgical units across the UK and the Republic of Ireland, participated in this study. Consent was provided by all participants in the trial. Each participant had an equal chance of receiving one of the three shunt types. Shunt infection occurred in 6% of participants receiving standard shunts, 5.9% of participants receiving silver-impregnated shunts and 2.2% of participants receiving antibiotic-impregnated shunts. This study has demonstrated a major reduction in shunt infections in new shunts when using antibiotic-impregnated shunts compared with standard or silver-impregnated shunts. A health economic analysis has indicated that antibiotic-impregnated shunts are cost-saving.

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