Discussion
Here, we describe two cases of migratory fish bones in the pharynx that
were not observable via flexible fiberoptic laryngoscopy. We used a
specific treatment for each patient. Fortunately, all patients had
favorable outcomes.
Patients suspected of having fish bone impaction usually undergo
physical and laryngoscopic examinations. A fishbone at the base of the
tongue or hypopharynx usually requires flexible fiberoptic laryngoscopy
for observation. However, it is difficult to determine the precise
localization of fish bones in cases with an endoscopically undetectable
fishbone. Sharp fish bones are more prone to cause mucosal damage.
Moreover, muscle contractions after entering the pharynx may contribute
to migration4. Migratory fish bones are associated
with an increased incidence of complications. Therefore, it is important
to establish this diagnosis early and accurately. CT is considered the
most sensitive (sensitivity = 100%) modality for detecting ingested
fish bones in soft tissues5. Therefore, CT is
recommended when suspecting the migration of ingested foreign bodies, as
demonstrated in the present cases.
The retropharyngeal space consists of loose soft tissue between the
buccopharyngeal fascia and the prevertebral fascia. Owing to this
structure, fish bones can migrate freely into the retropharyngeal space.
This was consistent with our observations on the first case. During the
operation, it is difficult to identify the location of the fishbone in
the retropharyngeal space. We suggest the use of CT to approximate the
position of the fishbone, followed by an extended longitudinal incision
to identify its exact location in the surrounding tissues.
The incidence of foreign bodies in the hypopharynx is common. However,
complete visualization of the foreign body is usually limited by the
anatomically closed hypopharynx in its resting state. Modified Killian’s
method can be applied to remove an endoscopically invisible fish
bone5. Unfortunately, the second patient had severe
sore throat symptoms upon head flexion and rotation. In this case, we
removed the fishbone through gastroscopy, which fully exposed the
hypopharynx. This suggests that gastroscopy may be a good alternative
for the visualization and removal of fish bones in such cases.