A rare case of a spindle handle and malleus bar without deformities of the external ear: a case report and literature review

Mitsuhiro Aoki; Chiaki Yamaguchi; Natsuko Obara; Kenji Suzuki; Yasuhiro Isono; Hideki Mori

doi:10.18203/issn.2454-5929.ijohns20263394

Authors

Mitsuhiro Aoki Department of Otolaryngology, Ogaki Tokushukai Hospital, Ogaki, Japan
Chiaki Yamaguchi Department of Otolaryngology, Ogaki Tokushukai Hospital, Ogaki, Japan
Natsuko Obara Department of Otolaryngology, Gifu University School of Medicine, Gifu, Japan
Kenji Suzuki ENT Ogaki Nishi Clinic, Ogaki, Japan
Yasuhiro Isono Isono ENT Clinic, Tarui, Japan
Hideki Mori Department of Diagnostic Pathology, Ogaki Tokushukai Hospital, Ogaki, Japan

DOI:

https://doi.org/10.18203/issn.2454-5929.ijohns20263394

Keywords:

Middle ear malformation, Conductive hearing loss, Malleus bar, Spindle handle

Abstract

Congenital fixation of the malleus and incus is an uncommon cause of conductive hearing loss. The malleus bar, characterized by a bony bridge from the malleus neck to the posterior annulus, presents diagnostic challenges preoperatively due to its subtle radiological features. A 9-year-old boy visited our hospital with hearing loss as his main complaint with autism spectrum disorder. The left tympanic membrane lacked identifiable structures such as the short process or umbilicus, and the malleus appeared rod-shaped, oriented anteriorly. Intraoperative findings confirmed a bony cord extending from the posterior wall of the tympanic cavity to the malleus, with the chorda tympani nerve running parallel. The malleus exhibited restricted mobility due to the malleus bar, which was easily severed, leading to enhanced ossicular mobility and hearing improvement. Histopathological analysis confirmed the bony composition of the excised tissue. Postoperative audiometry indicated a reduction in hearing loss, although a residual air-bone gap persisted. This report presents a rare case involving a spindle-shaped malleus handle and malleus bar in the middle ear, occurring without external ear deformities, emphasizing the importance of detailed anatomical assessment.

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