This British study is a multi-center single-blind randomized control trial of three types of ventriculoperitoneal shunt (standard, antibiotic impregnated, and silver impregnated). The primary outcome was presence of infection. Secondary economic analysis was also performed. The study was considered single-blind because the surgeon placing the shunt knew the assigned shunt type, but all personnel received training in non-disclosure. Outcome (shunt infection) was determined by the study PI and chief microbiologist using standardized shunt infection definitions.
Subjects were randomized 1:1:1, with a total target sample size of 1606. All patients were undergoing first shunt placement without concurrent CSF infection. Patients of all ages were eligible. Finally, economic analysis was performed using British National Health Service (NHS) cost data and calculating cost from the NHS perspective. Because 3 groups were being compared, statistical significance was set to p<0.025 (97.5% confidence interval).
Antibiotic impregnated shunts were found to have lower infection rate than standard shunts (cause-specific hazard ratio 0.38, p=0.0038). Silver impregnated shunts did not show a difference compared to standard shunts (csHR 0.99, p=0.96). Survival analysis showed no difference between groups, and there was no difference between groups for shunt failure or other adverse event. Economic analysis showed that antibiotic shunts had the lowest mean total costs.
This study provides evidence in favor of routine use of antibiotic impregnated shunts for preventing shunt infection and shows favorable economic effects for antibiotic impregnated shunts.