Bernard 1991.

Study characteristics
Methods	Single‐centre, parallel‐group RCT with 18 months of follow‐up Randomised by child
Participants	Location: Canada, single centre Setting of recruitment and treatment: otolaryngology clinic at the Children’s Hospital of Eastern Ontario Study dates: not reported Sample size: Number randomised: 139 (68 to surgical treatment; 71 to medical treatment) Number completed: 125 (60 in surgical treatment group; 65 in medical treatment group) Participant (baseline) characteristics: Age, years: Surgical treatment = mean 4.7 years Medical treatment = mean 5.0 years Gender Surgical treatment: 34 (56.7%) male, 26 (43.3%) female Medical treatment: 34 (52.3%) male, 31 (47.7%) female Hearing loss at baseline Surgical treatment = mean 30.7 dB HL Medical treatment = mean 29.6 dB HL Inclusion criteria: Age 2.5 to 7 years Long‐standing (greater than 3 months) middle ear effusion as indicated by type B tympanogram (in at least 1 ear) and otoscopic evidence (fluid/air fluid levels) of middle ear effusion for at least 3 months preceding entry into the trial At least 2 physician‐documented trials of antibacterials for AOM or OME, of at least 10 days’ duration in the 3 months preceding entry into the trial History of hearing loss (based on parental reports) of > 3 months’ duration at the time of entry into the trial Hearing loss of at least 25 dB HL (hearing level based on the ANSI 53.6 1969 standard) air conduction at 2 or more frequencies, 0.5 kHz, 1 kHz, 2 kHz and 4 kHz (pure‐tone audiometry), in at least 1 ear Bone conduction thresholds within normal limits (0 to 10 dB HL) bilaterally Air‐bone gap of > 15 dB at frequencies with elevated air conduction thresholds Exclusion criteria: Cervicofacial abnormality (cleft palate, Down syndrome) Documented immune insufficiency Documented allergy to sulfonamide Previous insertion of VT Documented speech delay
Interventions	Intervention Bilateral myringotomy and insertion of VTs at the anterior‐inferior quadrant of the tympanic membrane by the same otolaryngologist 10 participants had Reuter bobbin ventilation tubes; the remaining 58 had Richard T ventilation tubes N = 68 Comparison Sulfisoxazole 75 mg/kg divided into 2 daily doses for 6 months N = 71
Outcomes	Proportion with normal/impaired hearing (not extracted because of insufficient data) Mean final hearing threshold Assessed with pure tone audiometry at 0.5 kHz, 1 kHz, 2 kHz and 4kHz Adverse events: Persistent perforation Myringosclerosis Tube otorrhoea Antibiotic group: medication‐related side effects, rash, nausea, vomiting AOM episodes
Funding sources	"This work was funded by the National Health and Welfare Research and Development Program, Ottawa, Canada (grant 6606‐2944‐42). The sulfisoxazole was kindly provided by Hoffmann Laroche Canada Ltd."
Declarations of interest	No declaration was made.
Notes	Research integrity checklist: No retraction notices identified Prospective registration not applicable (published before 2010) Baseline characteristics are not excessively similar Plausible loss to follow‐up reported No implausible results The number randomised to each group was not identical
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The method used for sequence generation was not reported.
Allocation concealment (selection bias)	Unclear risk	No attempt to conceal allocation was reported.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of participants and personnel is not reported. There is a strong possibility that participants and personnel could identify which treatment a participant received and hence change their behaviour as a result.
Blinding of outcome assessment (detection bias) All outcomes	High risk	The only outcome reported to have been conducted blind to treatment allocation was tympanometry, “tympanometry was conducted only at 18 months to keep the audiologist “blind” to treatment group”. However, the other outcomes of episodes of AOM and some adverse events, such as rash and nausea, are more likely to be influenced by lack of blinding. Thus, some outcomes are at low risk of detection bias and others are at high risk, giving an overall rating of high.
Incomplete outcome data (attrition bias) All outcomes	Low risk	8 of 68 (12%) participants in the VT group and 6 of 71 (8%) in the control group were lost to follow‐up. Reasons for loss to follow‐up were reported as participants moving out of town and parental refusal to attend follow‐up appointments.
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration was found. All outcomes specified in the published paper were reported.
Other bias	High risk	The first 10 surgical participants received a different VT to subsequent participants. A different VT was used for later participants as it was reported that these VT were "more effective in managing hearing loss". The authors do not consider the effect of the use of different VT on outcomes. 31 of 65 (48%) medically treated participants were retreated with VT and 6 of 60 (10%) were retreated with sulfonamide. Analysis was according to the ITT principle.