| Black 199052 | Age 4–9 years; operation indication for glue ear (secretory OM) based on the clinical judgement of the otolaryngologist | Previous operations on tonsils, adenoids or ears; cleft palate or any sensorineural deafness; conditions other than glue ear, such as gross nasal obstruction |
| Casselbrant 200911 | Age 2–3.9 years; history of bilateral middle ear effusion (MEE) for at least 3 months, unilateral for ≥ 6 months or unilateral for 3 months after extrusion of one grommet with the other still in place and patent, and who had completed a 10-day course of a broad-spectrum antimicrobial agent within the past month | Previous tonsillectomy and/or adenoidectomy; previous ear surgery other than tympanocentesis or myringotomy with or without tube insertion; history of seizure disorder, diabetes mellitus, asthma requiring daily medication or any health condition that would make entry potentially disadvantageous to the child; medical conditions with a predisposition for MEE, such as cleft palate, Down syndrome, congenital malformations of the ear; cholesteatoma or chronic mastoiditis; severe retraction pockets; acute or chronic diffuse external OM; perforation of the tympanic membrane; intracranial or intratemporal complications of MEE; upper respiratory tract obstruction attributable to tonsil or adenoid enlargement or both with cor pulmonale, sleep apnoea or severe dysphagia; conductive hearing loss attributable to destructive changes in the middle ear; sensorineural hearing loss; distance from hospital that would make follow-up difficult |
| Dempster 199312 | Age 3–12 years; otoscopic evidence of bilateral OME with a pure-tone air conduction threshold average over 0.5, 1 and 2 kHz of > 25 dBHL, and with an air-bone gap over 0.5, 1 and 2 kHz of > 25 dB, and a type B tympanogram | Previous adenoidectomy or aural surgery or additional symptoms requiring surgical intervention, e.g. recurrent sore throat; cleft palate |
| Hammarén-Malmi 200515,51 | Age 1–4 years; recurrent AOM (more than three episodes of AOM during the preceding 6 months or more than five episodes of AOM during the preceding 12 months) or a suspicion of chronic OME as judged by examination with a pneumatic otoscope | Previous adenotonsillar surgery or placement of tympanostomy tubes; children with asthma, cleft palate or diabetes or children who were judged to require prompt removal of adenoids because of obstructive symptoms resulting in continuous mouth breathing or sleep apnoea, were excluded |
| Koivunen 200416 | Age 10 months to 2 years; three or more episodes of AOM in the last 6 months | Previously performed adenoidectomy or tympanostomy tube placement; cranial anomalies; documented immunological disorders and ongoing antimicrobial chemoprophylaxis |
| Kujala 201217 | Age 10 months to 2 years; at least three AOM episodes during the past 6 months and residence within 25 miles of the hospital | Chronic OME; a prior adenoidectomy or tympanostomy tubes; cranial anomalies; documented immunological disorders or ongoing anti-microbial prophylaxis for a disease other than AOM |
| Mattila 200318 | Age 1–2 years; three to five events of AOM during the last 6 months or four to six events of AOM during the last year | Nothing known about exclusion criteria |
| Maw 1986,19 199310 | Age 2–9 years; persistent subjective hearing difficulty; pneumatic otoscopic confirmation of bilateral effusions; symmetrical audiometric hearing loss > 25 dB at one or more frequencies; impedance measurements not showing a peak A-type curve | Resolution of effusions in one or both ears during 3 months’ preoperative follow-up; upper airway obstruction from gross adenoidal hyperplasia; parents’ refusal of randomisation; reappraisal of audiometric data, either because the loss was asymmetrical or because of superadded sensorineural loss; loss to preoperative follow-up; the child was found to be ineligible for inclusion because at the moment of operation he or she did not have bilateral effusion |
| MRC Multicentre Otitis Media Study Group 201220 | Age 3.5–7 years; on two qualifying visits, 3 months apart, a bilateral B + B or B + C2 tympanogram combination (modified Jerger) and better-ear hearing loss ≥ 20 dBHL averaged across 0.5, 1, 2 and 4 kHz and an air-bone gap > 10 dB; non-independence of these markers entails that the conjunction is not greatly more stringent than the 20-dBHL component alone | Previous ear surgery; craniofacial structural abnormalities; severe systemic disease (e.g. diabetes) and non-OME ear disease (e.g. perforation). Optional exclusion: hearing loss ≤ 40 dBHL in the better-hearing ear55 |
| Nguyen 200421 | Age 18 months to 18 years; following indications for grommet insertion as the first surgical treatment of OM: (1) recurrent OM with more than three episodes during the preceding 6 months or more than four during the preceding 12 months, (2) OME persisting for > 3 months or producing a conducting hearing loss > 30 dB with a type B tympanogram or (3) both | Previous grommet insertion; Down syndrome; craniofacial anomalies such as cleft palate; immune deficiency; bleeding disorders; ciliary dyskinesia; follow-up period of < 6 months |
