4 DISCUSSION
EC-LSC is a rarely encountered phenomenon in clinical practice. In this
study, we reviewed the data of 156 patients and found that seven
patients exhibited varying degrees of ossification (incidence, 4.5%).
The osseous tissue may hinder the further expansion of the cholesteatoma
from the attic to the aditus ad antrum. However, the osseous tissue
often fuses with key anatomical structures such as the semicircular
canals and ossicles that may obstruct the aditus ad antrum in severe
cases. This increases the difficulty of identifying the aforementioned
anatomical structures during surgery, which may elevate the probability
of intraoperative damage to the semicircular canals or to the ossicles
and the facial nerve in some cases.