Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Resolution of otitis media with effusion (OME)
Systematic review	297 children with bilateral OME 3 RCTs in this analysis	Resolution of OME based on tympanometry 6 months 56/144 (39%) with adenoidectomy with unilateral tympanostomy tube 26/153 (17%) with unilateral tympanostomy tube	Risk difference 0.22 95% CI 0.12 to 0.32	Effect size not calculated	Adenoidectomy plus unilateral tympanostomy tube
Systematic review	298 children with bilateral OME 3 RCTs in this analysis	Resolution of OME based on tympanometry 12 months 68/143 (48%) with adenoidectomy with unilateral tympanostomy tube 31/155 (20%) with unilateral tympanostomy tube	Risk difference 0.29 95% CI 0.19 to 0.39	Effect size not calculated	Adenoidectomy plus unilateral tympanostomy tube
Systematic review	153 children with bilateral OME 2 RCTs in this analysis	Resolution of OME based on otoscopy 6 months 35/72 (49%) with adenoidectomy with unilateral tympanostomy tube 17/81 (21%) with unilateral tympanostomy tube	Risk difference 0.27 95% CI 0.13 to 0.42	Effect size not calculated	Adenoidectomy plus unilateral tympanostomy tube
RCT 3-armed trial	169 children aged 2 to 14 years with persistent OME In review	Resolution of OME 12 months 82% of ears with adenoidectomy with bilateral tympanostomy tubes 77% of ears with bilateral tympanostomy tubes Absolute numbers not reported	Risk difference –5% 95% CI –8% to + 17%		Not significant
RCT 3-armed trial	169 children aged 2 to 14 years with persistent OME In review	Resolution of OME 24 months 85% of ears with adenoidectomy with bilateral tympanostomy tubes 82% of ears with bilateral tympanostomy tubes Absolute numbers not reported	Risk difference –3% 95% CI –10% to +15%		Not significant
Hearing
Systematic review	74 ears 3 RCTs in this analysis	Hearing 6 months with with ventilation tube plus adenoidectomy with with ventilation tube alone Absolute results not reported	Mean difference 2.1 dB Reported as not significant 95% CI presented graphically		Not significant
Systematic review	74 ears 3 RCTs in this analysis	Hearing 12 months with with ventilation tube plus adenoidectomy with ventilation tube alone Absolute results not reported	Mean difference 2.4 dB Reported as not significant 95% CI presented graphically		Not significant
Systematic review	79 ears 3 RCTs in this analysis	Hearing 6 months with ventilation tube plus adenoidectomy with ventilation tube alone Absolute results not reported	Mean difference 1.1 dB Reported as not significant 95% CI presented graphically		Not significant
Systematic review	79 ears	Hearing 12 months with ventilation tube plus adenoidectomy with ventilation tube alone Absolute results reported graphically	Mean difference 1.1 dB Reported as not significant 95% CI presented graphically		Not significant
Systematic review	72 ears	Hearing 6 months with ventilation tube plus adenoidectomy with ventilation tube alone Absolute results not reported	Mean difference 2.6 dB Reported as not significant 95% CI presented graphically		Not significant
Systematic review	72 ears	Hearing 12 months with ventilation tube plus adenoidectomy with ventilation tube alone Absolute results not reported	Mean difference 1.7 dB Reported as not significant 95% CI presented graphically		Not significant