Group 1: COM with isolated tympanic membrane perforation, Group 2: COM
with cholesteatoma/retraction pocket, mm3: cubic millimeter.
(COM:Chronic otitis media)
Data are presented as Median (Interquartile Range).
Six and four cases were excluded while comparing the volumes of frontal
sinuses because of frontal sinus agenesis for group 1 and group 2,
respectively.