title: Congenital anomalies of the incudostapedial joint.
abstract: OBJECTIVE
  To describe congenital anomalies of the incudostapedial joint (ISJ) and to discuss the possible unique embryogenesis of the ISJ based on the two anomalies that were encountered.
  
  
  METHODS
  Tertiary care medical center.
  
  
  METHODS
  Retrospective review of the medical records of all patients with ISJ anomalies.
  
  
  RESULTS
  Four patients presented with congenital hearing loss. Upon further workup, we observed a preserved incudostapedial joint (ISJ) with deficiencies of the incus and stapes in three cases. Our fourth case demonstrated the inverse pattern of the congenital anomalies in which the ISJ was missing with an intact proximal incus and stapes crura. Three patients opted for surgical intervention with improvement in hearing. One case preferred hearing amplification over surgery.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Neurotology and Skull Base Surgery, Department of Otolaryngology - Head and Neck Surgery, University of California, Irvine, USA.
authors.forename: Marlon M
authors.initials: MM
authors.lastname: Maducdoc
authors.affiliation: Division of Neurotology and Skull Base Surgery, Department of Otolaryngology - Head and Neck Surgery, University of California, Irvine, USA.
authors.forename: Yaser
authors.initials: Y
authors.lastname: Ghavami
authors.affiliation: Division of Neurotology and Skull Base Surgery, Department of Otolaryngology - Head and Neck Surgery, University of California, Irvine, USA.
authors.forename: David
authors.initials: D
authors.lastname: Shamouelian
authors.affiliation: Division of Neurotology and Skull Base Surgery, Department of Otolaryngology - Head and Neck Surgery, University of California, Irvine, USA.
authors.forename: Hossein
authors.initials: H
authors.lastname: Mahboubi
authors.affiliation: Division of Neurotology and Skull Base Surgery, Department of Otolaryngology - Head and Neck Surgery, University of California, Irvine, USA; Department of Biomedical Engineering, University of California, Irvine, USA. Electronic address: hdjalili@uci.edu.
authors.forename: Hamid R
authors.initials: HR
authors.lastname: Djalilian
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006314:Hearing Loss, Conductive / Q000151:congenital; D006801:Humans; D007188:Incus / Q000002:abnormalities* / Q000000981:diagnostic imaging; D008297:Male; D011859:Radiography; D012189:Retrospective Studies; D013199:Stapes / Q000002:abnormalities* / Q000000981:diagnostic imaging
keywords: Congenital; Embryology; Incudostapedial joint; Incus; Ossicles; Stapes