-Case Reports-

Familial Congenital Ossicular Anomaly: A Case Report

Takeshi Matsunobu^*, Hirotaka Suzuki and Kimihiro Okubo

Department of Otolaryngology-Head and Neck Surgery, Nippon Medical School, Tokyo, Japan
^*Present address: Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, Saitama, Japan

Middle ear anomalies are uncommon in persons with intact auricles and external auditory canals. Most reported cases have been sporadic, and only a few were inherited. Every anomaly can be explained by embryonic ear development. Here, we report a case of bilateral congenital ossicular anomalies in a 7-year-old girl without anomalies of the external ear canal or tympanum. Her mother and two maternal aunts had the same congenital incudostapedial disconnection. A school examination revealed bilateral hearing loss (53.3 dB in the right ear and 51.7 dB in the left ear) indicative of bilateral conductive hearing loss. Her mother and two maternal aunts also had bilateral conductive hearing loss. Surgery on her left ear revealed the absence of the long limbs of the incus and incudostapedial disconnection. An interposition was performed between the crura of the stapes, the handle of the malleus, and the body of the incus. Postoperatively, hearing levels improved in both ears. Although the heredity pattern is unclear, we identified four individuals in the same family with the same bilateral anomalies, suggesting a hereditary origin.

J Nippon Med Sch 2025; 92: 457-462

Keywords
middle ear, conductive hearing loss, incus, bilateral hearing loss, heredity

Correspondence to
Takeshi Matsunobu, MD, PhD, Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
takeshim0471@gmail.com

Received, July 15, 2024
Accepted, September 30, 2024