Table 1 The basic characteristics of eligible studies

Name year: Khalid A. Al-Mazrou 2009

Methods: RCT (double-blind)

Participants: 40 children (age ranged from 3 to 17 years, from 2002 to 2003) with symptoms and signs suggestive of snoring and/or obstructive sleep apnea and adenoid hypertrophy, any patient with recurrent adenoid enlargement, bleeding tendency, or with sever bilateral deviated nasal septum were excluded

Interventions: endoscopic powered adenoidectomy versus curettage adenoidectomy

Outcomes: the mean blood loss, operative time, operative or postoperative complications (postoperative follow up of all patients was from 3 to 24 months, median of 6 months)

Name year: Murat Songu, MD 2010

Methods: RCT (double blind)

Participants: 38 patients who underwent adenoidectomy alone or in combination (age ranged from 8 to 12 years old) study was performed from April 2008 to September 2009

Interventions: endoscopic assisted adenoidectomy versus curettage adenoidectomy

Outcomes: adenoidectomy/nasopharyngeal ratios, operative time, blood loss, symptom improvement

Name year: Özmen Öztürk · Şenol Polat 2012

Methods: RCT (no blind)

Participants: 53 patients (younger than 16 years, with the presence of nasal airway obstruction with sleep disordered breathing, otitis media with effusion or recurrent otitis media, and chronic or recurrent rhinosinusitis). Completed the study (the 6 months follow-up) between, the study performed from January 2004 to December 2010

Interventions: powered-assisted endoscopic adenoidectomy versus curettage adenoidectomy

Outcomes: VAS score, score improvement, the average ratio of choanal opening obstructed, the reduction of adenoid size

Name year: Paul Stanislaw 2000

Methods: RCT (unclear)

Participants: 90 patients (age from 1 to 13 years old) underwent power assisted adenoidectomy and 87 patients (age from 1 to 12 years old) underwent conventional curettage adenoidectomy

Interventions: power assisted adenoidectomy versus conventional curettage adenoidectomy

Outcomes: operative time, blood loss, completeness and depth of resection, injuries to surrounding structures, short and long term complication, surgeon satisfaction with the procedure and patients’ postoperative recovery period

Name year: Nicole Murray 2002

Methods: RCT (unclear)

Participants: 100 children underwent powered partial adenoidectomy and 40 children underwent conventional partial adenoidectomy, the study period from October 1997 to July 1998. All patients younger than 20 years old

Interventions: powered partial adenoidectomy versus conventional partial adenoidectomy

Outcomes: operative time (specific quantification of the time removal and hemostasis), blood loss, complications, adenoid size, plate length, submucus cleft stigmata

Name year: Zhang G. Y. 2013

Methods: RCT (single blind)

Participants: 50 patients (age from 1 to 18 years old) underwent endoscopic assisted adenoidectomy and 50 patients (age from 1 to 18 years old) underwent conventional curettage adenoidectomy (period from January 2008 to December 2011), adenoidectomy effectiveness was followed up 6th and 12th month

Interventions: conventional curettage adenoidectomy versus endoscopic assisted adenoidectomy

Outcomes: operative time, blood loss, hospital stay, effective rate, complications

Name year: Feng Y. H. 2006

Methods: RCT (double blind)

Participants: 18 patients underwent endoscopic adenoidectomy and 16 underwent conventional curettage adenoidectomy, patients follow up from 6 to 12 months. All patients younger than 18 years old

Interventions: conventional curettage adenoidectomy versus endoscopic assisted adenoidectomy

Outcomes: operative time, blood loss, complications