Pressure Transmission to the Inner Ear by Mastoid Palpation after Transmastoid Surgery for Superior Canal Dehiscence

Objective: To discuss an effect of transmastoid repair of superior semicircular canal dehiscence and its resolution using a mastoid titanium mesh plate. Patients: A 53-year-old woman with a history of superior canal dehiscence syndrome (SCDS) and subsequent transmastoid repair experienced dizziness and a loud, drum-like sound in her repaired ear when touching the ear. Palpating the skin over the mastoid defect reproduced the symptoms and could be observed on binocular microscopy as tympanic membrane deformation synchronous with mastoid palpation. Intervention (s): Surgery to place a titanium mesh cranioplasty plate over the mastoid cavity. Main Outcome Measure (s): Reduction in dizziness and auditory symptoms when palpating the mastoid. Results: In follow-up 2 months after surgery, palpation of the left mastoid no longer results in vertigo or hearing a loud sound. Hearing and vestibular function remained unchanged. Conclusions: Despite resolution of SCDS symptoms after transmastoid plugging and resurfacing of the superior semicircular canal involving mastoidectomy, patients can be bothered by dizziness and vertigo when pressing on the mastoid soft tissue envelope. This acts like a balloon that, when compressed, changes middle ear pressure and moves the tympanic membrane and can even cause alternobaric vertigo. This can be avoided or resolved by rigidly reconstructing the defect in the mastoid bone.