Anatomiste de talent, Bartolomeo
Eustachi a fait progresser cette science dans la
seconde moitié du XVIe siècle. Outre la
fameuse trompe d'Eustache, il a
révélé l'existence de la valvule qui
porte son nom, des surrénales, du canal
thoracique.
Le grand oeuvre de Bartolomeo Eustachi devait
être un traité d'anatomie « De
dissensionibus ac controvesiis anatomicis ». Il
devait comporter 47 planches anatomiques,
dessinées avec l'aide de Pier Matteo Pini,
richement détaillées et
légendées. Seulement 8 planches furent
publiées de son vivant. Les 39 autres, perdues,
ont été longtemps recherchées. Elles
ont été retrouvées 162 ans plus tard
chez un descendant de Pier Matteo Pini. Publiées
en 1714 sous le titre « Tabulae anatomicae
Bartolomaei Eustachi quas a tenebris tandem vindicatas
» (illustrations anatomiques de Bartolomeo Eustachi
sauvées de l'obscurité), elles font de leur
auteur, avecVésale, l'un des pères de
l'anatomie moderne.
Radiopaque
contrast dye in nasopharynx reaches the middle
ear during swallowing and/or
yawning
B Winther, JM Gwaltney, CD Phillips,
J Hendley
Departments of
Otolaryngology, Head and Neck Surgery,
University of Virginia Health System,
Charlottesville, Virginia,
USA
Introduction
The middle ear is believed to be sterile
under normal conditions. However, it is possible
that nasopharyngeal fluid containing bacteria
and bacterial DNA may transiently reflux through
the Eustachian tube (ET) to reach the middle ear
during normal activities. This possibility has
been examined using a roentgenographic technique
as described by Wittenborg and Neuhauser. Using
this method Bluestone and coworkers studied 120
children with active or previous middle ear
effusions who either had tympanostomy tubes in
place at the time of the study or had had them
in the past. Reflux of contrast material through
the ET into the middle ear occurred in 15/219
ears (7%) following multiple swallows. In 7
control children without a history of ear
disease (14 ears), reflux into the middle ear
was not observed after multiple swallowing
episodes. Based on these findings it has been
suggested that, during swallowing, fluid from
the nasopharynx is prevented from refluxing into
a normal middle ear with an intact tympanic
membrane by the narrow midportion (isthmus) of
the ET and by the cushion of air or gas present
in the intact middle ear and mastoid air cell
system. However, a clinical diagnosis of
presumed acute bacterial otitis media has been
made in up to a quarter of normal children with
colds. Bacteria have been detected in 60 - 70%
of middle ear secretion samples obtained by
tympanocentesis from suspected cases. This
suggests that displacement of bacteria in
nasopharyngeal secretion to the middle ear of
children may be a more frequent occurrence than
anticipated from the work reported by Bluestone
and colleagues, or that negative middle ear
pressure during colds may facilitate aspiration
of nasopharyngeal secretion into the middle
ear.
In this descriptive study, CT scans of the
temporal bone were utilized to examine whether
radiopaque contrast medium in the nasopharynx
was displaced into the middle ear cavity during
swallowing and/or yawning in healthy
adults.
Discussion
In these healthy adults, swallowing and
yawning with radiopaque contrast dye at
the ET orifice allowed it to enter the middle
ear, as evidenced by the presence of residual
contrast dye visualized by CT. Under natural
conditions, nasopharyngeal secretions/fluid may
overlie the orifice of the ET when an individual
is either supine or lying on his/her side during
sleep. In this study the lateral decubitus
technique, in which there was ambient air
pressure at the orifice during swallowing and
yawning, resulted in deposition of
contrast dye in the middle ear. This suggests
that secretion overlying the ET orifice may
reach the middle ear on opening of the ET during
sleep in healthy adults. The effect of viral
respiratory infection, which has been shown to
produce ET dysfunction, on this phenomenon is
not known.
The majority of adults carry bacterial
species in the nasopharynx which are the cause
of otitis media; the bacteria are usually
present in titers of > 10*3 colony-forming
units per milliliter of secretion. In view of
the findings in our study, it seems likely that
bacteria in nasopharyngeal fluid/secretion
frequently reach the middle ear by way of the
normal ET. Also, bacterial DNA from the
nasopharynx may do likewise, making it difficult
to interpret the significance of bacterial DNA
detection in middle ear fluid.
Ciliary epithelial and mucus-secreting cells
line a portion of the wall of the middle ear and
the entire ET. Mucociliary transport helps
maintain the sterility of the middle ear by
clearing foreign particles entrapped in the
mucus blanket. The direction of flow of the
mucus blanket is from the middle ear via the ET
to nasopharynx. Thus, the normal sterility of
the middle ear cavity, like that of the sinuses,
is likely due to the effectiveness of the
mucociliary epithelium in clearing bacteria from
the nasopharynx which reach the cavity during
activities of daily life.
Generalization of the findings of this study
is limited by the small number of subjects
examined. However, contrast medium was detected
in the ears of two out of three subjects in each
positional group, suggesting that reflux during
swallowing and yawning is a common event.
Exposure of additional subjects to radiation,
although minimal, was not felt to be justified.
Also, the study was performed in adults rather
than children. In young children, nasopharyngeal
secretion would be expected to reach the middle
ear with even greater ease because the ET is
shorter and straighter than in adults.
