Blum 1989.

Methods	Randomized, controlled Method of randomisation: date of birth Kind of shunt: ventriculoperitoneal shunts, ventriculoatrial shunts and subduro‐peritoneal shunts Location: Germany Follow‐up: 8 weeks Duration: 2.5 years
Participants	Inclusion: children up to 14 years of age operated for hydrocephalus of various aetiologies Exclusion: hypersensitivity to selected drug, patients who received antibiotic therapy in the period from 7 days before the operation, prophylactic antibiotic in the same period, concurrent infections, immunosuppressive therapy, diabetes and other factors that impair wound healing, prophylaxis inadvertently continued or another antibiotic administered within 10 days of operation. Any of the following diseases: agammaglobulinaemia, agranulocytosis, leukaemia, severe anaemia, lymphoma, thymus aplasia, melanoma, cirrhosis of the liver, burns or uremia Treatment: 50; control: 50 (66 ventriculoperitoneal shunts, 30 ventriculoatrial shunts and 4 duro‐peritoneal shunts)
Interventions	Intravenous prophylactic cefazedone (50 mg/kg) versus placebo
Outcomes	Proportion of participants who had shunt infection 7 shunt infections occurred in the first 7 days and the other 3 were reported between the 2nd and 8th week
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	"All patients with an even date of birth were allocated to active treatment group"
Allocation concealment (selection bias)	High risk	Birth dates can be checked
Blinding of participants and personnel (performance bias) All outcomes	High risk	"Single blinded"
Blinding of outcome assessment (detection bias) All outcomes	High risk	"Single blinded"
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data
Selective reporting (reporting bias)	Low risk	Study protocol is not available but published reports include all expected outcomes including analysis
Other bias	Unclear risk	The difference in outcome between the treatment group and control group seems substantial but it is not statistically significant. Other biases than the above described could contribute to this effect