Discussion
Two cases we described are migratory fish bones in the pharynx. They
were hidden in the flexible fiberoptic laryngoscopy.
We adopted
specific
treatment
for each patient. Fortunately, every patient had a favorable outcome.
Patients suspected of fish bone impaction usually undergo physical and
laryngoscopic examination. A fish bone in the base of tongue or
hypopharynx usually requires flexible fiberoptic laryngoscopy for
observation. However, it is difficult to determine the precise
localisation of fish bone in cases with an endoscopically invisible fish
bone. Sharp fish bone is prone to damage to the mucosa, and muscle
contractions after entering into the pharynx may contribute to the
migration4. Migratory fish bone is associated with an
increased incidence of complications. Therefore, it is important to make
a diagnosis correctly. CT scan is considered as the most sensitive
modality for detecting ingested fish bones due to it has a sensitivity
of 100% in the soft tissues5. Therefore, CT is
recommended in cases of suspected migration of ingested foreign bodies
into surrounding tissues, as demonstrated in the present cases.
The
retropharyngeal space consists of the loose soft tissue between the
buccopharyngeal fascia and the prevertebral fascia. Due to the structure
of the retropharyngeal space, we surmised that fish bone can migrate
freely in the retropharyngeal space. Indeed, we found that fish bone
entered the
retropharyngeal
space can swam away in the first case. During the operation, it is
difficult to identify the location of fish bone in the retropharyngeal
space. We suggest that locating the approximate position of the fish
bone by CT, in addition, surgeons should prolong the longitudinal
incision to find it in the surrounding tissues.
The incidence of foreign bodies in the
hypopharynx
is not uncommon. However, complete visualization of the foreign body in
the hypopharynx is usually difficult because most of the hypopharynx is
anatomically
closed in the resting state. Modified Killian’s method can be applied to
remove of an endoscopically invisible fish bone5.
Unfortunately, the second case had severe sore throat symptoms when he
bowed and turned head. We removed the fish bone through gastroscopy.
During the course of gastroscopy, the hypopharynx was fully exposed.
This suggests gastroscopy may be a good alternative method for
visualization and removal of fish
bones in such cases.