Table 1 Summary of the included studies

Ramadan HH et al. 2010a [35]

Prospective interventional non-randomized

30 (55 sinuses)

6.6 (2–11)

48 Maxillary 2 Frontal 5 Sphenoid

Chronic sinusitis (> 3 months or 6 episodes per year) AND 2 failed courses of antibiotics AND positive CT scan

Adenoidectomy (n = 17)

52 weeks

Preop: 4.2, Postop: 3;

24 (80%) improved^a

NR

Second intervention by ESS (2);

AEs: NR

Ramadan HH et al. 2010b [36]

Prospective single arm cohort

24 (56 sinuses)

6.5 (2–11)

50 Maxillary 2 Frontal 4 Sphenoid

Refractory CRS which failed medical treatment AND evidence of CRS on CT scan

Adenoidectomy (n = 15); Ethmoidectomy (n = 6)

52 weeks

Preop: 4.9 (1.14), Postop: 2.95 (1.35);

21 improved^a

NR

AEs: None

Ramadan HH et al. 2012 [28]

Prospective single arm cohort

26 (33 sinuses)

7.7 (4–12)

33 Maxillary

Chronic sinusitis (> 3 months or 6 episodes per year) after failed adenoidectomy AND positive CT findings.

Ethmoidectomy (n = 4); Maxillary antrostomy (n = 3); Revision adenoidectomy (n = 2)

52 weeks

Preop: 4.6 (0.9), Postop: 3 (1.2);

21 (81%) improved^a

NR

AEs: None

Thottam PJ et al. 2012 [30]

Retrospective, two group cohort blinded

15 (40 sinuses)

9.3 (3–17)

30 Maxillary 10 Frontal

Refractory CRS (at least 90 days despite medical therapy) AND CT confirmed uncomplicated CRS with the presence of maxillary +/− frontal sinus disease.

Ethmoidectomy

> 4 months (average of 37 weeks)

SN-5: NR;

12 (80.0%) Improved^b

NR

Second intervention by ESS (1);

Off Antibiotic: 11 (73.3%);

AEs: None

Wang F et al. 2015 [29]

Prospective interventional non-randomized controlled

42

9.3 (7–12)

Maxillary and Frontal^c

Diagnosis of CRS according to EPOS 2012. Refractory CRS (defined as at least 2 years despite medical therapy)

Adenoidectomy

1 year

Preop: 4.3 (0.9), Postop: 2.9 (0.8);

39 (92.9%) improved^a

VAS

Preop: 5.2 (1.4),

Postop: 3.1 (1.6)

AEs: periorbital swelling (1)

Thottam PJ et al. 2016 [31]

Retrospective, two group cohort

13 (34 sinuses)

9.3 (3–18)

26 Maxillary 8 Frontal

Refractory sinus symptoms despite medical treatments AND CT scan confirmed uncomplicated CRS and the presence of maxillary sinus disease with a Lund-Mackay score greater than 5.

Ethmoidectomy

2 years

SN-5: NR;

10 (76.9%) Improved^b

NR

Second intervention by ESS (1);

AEs: NR

Soler ZM et al. 2017 [24]

Prospective single arm cohort

33

6.6 (2–12)

Maxillary, Frontal and Sphenoid^c

Diagnosis of CRS according to EPOS12, positive CT findings and disease resistant to medical treatments.

Adenoidectomy (n = 19); Inferior turbinate reduction (n = 6); Ethmoidectomy (n = 4); Tonsillectomy (n = 5); Others (n = 4)

6 months

Preop: 4.8 (1.2), Postop: 1.7 (0.8);

32 (97%) improved^a

NR

Second intervention (0);

AEs: None

Liu J et al. 2017 [25]

Prospective single arm cohort

30 (61 sinuses)

10.2 (6–15)

38 Maxillary 9 Frontal 14 Sphenoid

Confirmed by positive Nasal endoscopy and CT scan AND failed Medical management for at least 3 months

None

12 months

Preop: 23.04 (12.47), Postop: 1.07 (2.11)

Lund-Mackay score Preop: 12.29 (6.23), Postop: 1.39 (2.47);

VAS Preop: 17.86 (7.59),

Postop: 0.57 (1.60);

Endoscopic score of Lund-kennedy preop: 6.69 (3.07),

postop: 0.36 (1.89)

AEs: synechia (3)

Gerber ME et al. 2018 [32]

Randomized controlled blinded study

12

7

Maxillary^c

CRS with at least 12 weeks of two symptoms AND refractory to medical treatments AND recurrence (4 or more episodes per year) AND evidence of rhinosinusitis on CT scan.

Adenoidectomy with maxillary sinus irrigation (all patients)

12–18 months

Preop: 3.62 (1.24), Postop: 2.40 (1.11)

NR

NR

Zalzal HG et al. 2019 [33]

Retrospective single arm cohort

38

6.76

Maxillary^c

CRS with at least 90 days of 2 or more of symptoms, or endoscopic signs AND failure of medical treatment defined by EPOS 2012 AND previous adenoidectomy AND Lund-Mackay score of at least 5 AND maxillary sinus involvement.

None

5 years

SN-5: NR

NR

Second intervention by ESS: 5 (13.1%);

Off antibiotic: 26 (68.4%)