Congenital anomalies of the incudostapedial joint

Isolated ISJ malformations are uncommon potential causes of congenital conductive hearing loss. Although numerous patterns of ossicular anomalies have been reported in the literature, our case series is the first to demonstrate both the absence of the ISJ in one patient and the presence of the ISJ in the presence of missing stapes crura and incus body in other patients. Though limited by the small number of cases, the inverse relationship of the single case compared to the three other cases, suggests a possible independent embryological development pathway for the ISJ. Therefore, an embryological explanation of the defects should be considered. Additionally, surgical intervention can improve hearing outcomes for patients with isolated ISJ anomalies.