The Relationship Between the Third Window Abnormalities and Inner Ear Malformations in Children with Hearing Loss

OBJECTIVE: To evaluate the relationship between the third window abnormalities and congenital inner ear malformations in pediatric patients
with different types of hearing loss. If such a relationship should exist, it would be important to take it into account, in order to diagnose and treat
pediatric hearing loss cases more accurately.
METHODS: Two hundred twenty-one children with hearing loss who had temporal bone computed tomography (CT) examination and were
identified from 2013 to 2018 were retrospectively evaluated. The types of hearing loss were grouped as sensorineural hearing loss (SNHL), conductive
hearing loss (CHL), and mixed hearing loss (MHL). Third window abnormalities included superior semicircular canal (SC) dehiscence,
posterior SC dehiscence, enlarged vestibular aqueduct (EVA), X-linked stapes gusher, perilymph fistula, and bone dyscrasias. Congenital inner ear
malformations included cochleovestibular, SC, and internal acoustic canal malformations. The relationships were analyzed with chi-square and
Fisher’s exact tests.
RESULTS: In the study, 40 patients had unilateral hearing loss and 181 had bilateral hearing loss. In 402 ears, the rates of SNHL, CHL, and MHL were
88.5%, 6.9%, and 4.4%, respectively. EVA was the most common third window abnormality (41/402; 9.7%), and SC malformations were the most
common inner ear malformations (53/402; 13.2%). In the SNHL group, superior and posterior SC dehiscence were associated with cochleovestibular
malformations (P = .035 and.020, respectively). In the CHL group, there was a relationship between EVA and SC malformations (P = .041).
No relationships were found in the MHL group.
CONCLUSION: Third window abnormalities and congenital inner ear malformations may be encountered simultaneously in children with SNHL
and CHL.