Eustachian tube formation and angulation in dogs affected by primary secretory otitis media

Primary secretory otitis media (PSOM) is common especially in brachycephalic
dogs. Various aetiologies have been discussed, including infectious,
inflammatory and morphological causes. However, there remains a lack of
data supporting any of the current hypothesis. The aim of the current study
was to elucidate the role of the Eustachian tube in PSOM. Computer
tomography images of 72 dogs with or without PSOM were evaluated in
the study. Morphological measurements (Eustachian tube length and width)
and angulation of the Eustachian tube of 97 control ears were compared
to 47 PSOM affected ears. Data are reported as Median with 25-75 percentiles.
Groups were compared with a Mann Whitney U-test and a Pvalue
of less than 0.05 was deemed significant. Eustachian width was significant
smaller in width in affected cases (1.02 (0.86-1.46)) compared to
controls (1.29 (0.71- 1.52)), as was angulation wider in affected (42.22
(33.91-44.43)) versus non-affected (35.64 (31.91-40.12)) respectively. This
study demonstrates that Eustachian tube width and angulation might contribute
to development of PSOM, which is similar to what has been shown
in children. Future studies are needed to explore if the morphological
changes have functional consequences and therefore lead to PSOM.