Simultaneous, unilateral plugging of superior and posterior semicircular canal dehiscences to treat debilitating hyperacusis.
OBJECTIVE
To describe a case of bilateral superior and posterior semicircular canal dehiscences, and the use of a unilateral transmastoid approach to address both right-sided defects simultaneously.


METHODS
In a patient with right-sided hyperacusis, bilateral dehiscence of both the superior and the posterior semicircular canals was identified, located adjacent to the common crus, together with a right-sided, anterosuperiorly positioned sigmoid sinus and a high-riding jugular bulb. Results for audiography and cervical vestibular evoked myogenic potential testing were consistent with right-sided semicircular canal dehiscence. At surgery, a right-sided transmastoid approach provided access to plug both defects simultaneously, following posterior mobilisation of the sigmoid sinus. The patient's hyperacusis was completely resolved, with a 10-30 dB improvement in his right ear air conduction hearing, without decrement in bone conduction.


CONCLUSIONS
In properly selected patients, a transmastoid approach can be used to effectively manage superior semicircular canal dehiscence and posterior semicircular canal dehiscence simultaneously. Pre-operative computed tomography is recommended to evaluate the dehiscence sites and to identify complicating vascular anatomy.
School of Medicine and Public Health, University of Wisconsin - Madison, USA.
P T
PT
Dang
Department of Radiology, Section of Neuroradiology, University of Wisconsin - Madison, USA.
T A
TA
Kennedy
Department of Surgery, Division of Otolaryngology and Waisman Center, University of Wisconsin - Madison, USA.
S P
SP
Gubbels
D001299:Audiometry; D006319:Hearing Loss, Sensorineural / Q000209:etiology; D006801:Humans; D012001:Hyperacusis / Q000150:complications / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012665:Semicircular Canals / Q000473:pathology / Q000601:surgery*