PMC6363674_01
(A) Preoperative audiogram displays right-sided low frequency conductive hearing loss. (B) Postoperative audiogram displays slight hearing improvement at low frequency compared with the preoperative hearing level. Conductive hearing loss remained due to fixation of the footplate.
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F1
An 8-year-old boy was referred to our hospital for further evaluation of right-sided conductive hearing loss identified at a health check-up at school (Figure 1A). In the postoperative audiogram, conductive hearing loss improved by 15-20 dB at a low frequency but was still present due to fixation of the footplate (Figure 1B).
(A,B) Axial section of the CT scan of the right temporal bone. The cyst (white arrow head) and small bone dehiscence in the vestibule (black arrow head) are shown. (C,D) Coronal section of the CT scan shows the cyst (marked with a white arrow head) and small bone dehiscence in the vestibule (black arrow head). (E) Intraoperative picture during exploratory tympanotomy. A cyst can be seen anteroinferior to the oval window. CTN, Chorda tympani nerve. (F) Schematic illustration of the middle ear in the surgery. A small bone dehiscence (marked with an arrow) was found anterior to the stapes footplate after removal of the cyst. RW, round window.
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F2
Serial computed tomography (CT) imaging showed a small soft-tissue density lesion close to the oval window (Figures 2A,C,D). A small bone dehiscence within the otic capsule was also indicated in the CT images (Figures 2A,B,D). A small cyst (anterior to the oval window) and fixation of the stapes footplate were found during an exploratory tympanotomy (Figure 2E). A small bone dehiscence, considered to be a FAF, was found anterior to the stapes footplate after removal of the cyst (Figure 2F).