ABSTRACT:ObjectiveTo explore the reliability of the new index, which is the ratio of nasopharynx free airway to trachea airway size (NS/TS) as the preoperative assessment for adenoidectomy in snoring children.Methods150 cases of snoring children were selected according to the criteria and underwent the electronic nasopharyngeal endoscopy and X|ray digital photography of nasopharynx lateral view respectively.The digital images obtained by nasopharyngeal endoscopy were evaluated by the treatment software for airway to choana (A/C).The adenoid to nasopharynx ratio(A/N) and NS/TS were measured through nasopharynx lateral images, and both compared with A/C.ResultsThe correlation between A/C [mean value: (0.14±0.01)(0.12~0.16)] and A/N [mean value: (0.78±0.09)(0.76~0.79)] (r=0.110, P>0.05) was unfounded, but there was a high correlation between NS/TS [mean value: (0.16±0.01) (1.14~0.18)] and A/C (r=0.430, P<0.001).ConclusionsThe new parameter, The NS/TS can replace the A/N as a more effective indication parameter in preoperative assessment of snoring children for adenoidectomy.Meanwhile, for children who can not tolerate nasopharyngeal endoscopy, NS/TS may replace nasopharyngeal endoscopy as a supplement to the gold standard.