Linden 1990.

Methods	Randomised controlled trial conducted in USA, number of centres unclear; patients initially divided into 4 groups based on surgical technique, and then further subdivided based on whether received antibiotics or not, to attain a total of 8 subgroups; study remained open until sufficient numbers were recruited and questionnaires returned Grading of quality: Randomisation = C Blinding = D Intention‐to‐treat analysis = C Follow‐up = C Overall quality grading = C
Participants	80 children (age range 13 months to 17 years (mean: 5 years)) undergoing tonsillectomy (indication not specified). Whether children undergoing adenotonsillectomy were included was not clear. Study and control group demographics and other characters not mentioned. Exclusion criteria: not specified
Interventions	No detail regarding the type of antibiotic or the method of administration given
Outcomes	Primary outcome: analgesic consumption (mean subjective rating on a scale of 1 to 3) Period of observation: 5 days
Notes	Anaesthetic technique not mentioned as controlled. Surgical technique was quasi‐controlled: 4 different surgical and haemostatic techniques in equal numbers (electrocautery + electrocautery, dissection + electrocautery, dissection + ligature, laser + laser) were used between the study and control groups. Follow‐up: follow‐up rate of the 40 patients recruited in each of the antibiotic and control groups unclear
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear