Superior semicircular canal dehiscence syndrome: Successful treatment with repair of the middle fossa floor: technical case report.
OBJECTIVE
Superior semicircular canal dehiscence syndrome has recently been reported as a cause of pressure- or sound-induced oscillopsia (Tullio phenomenon). We report the presentation and successful treatment of 3 patients with superior semicircular dehiscence syndrome by a joint neurosurgical/neuro-otology team.


METHODS
Patient 1 is a 37-year-old man who presented with complaints of disequilibrium, fullness in the left ear, hearing loss, and oscillopsia when pressure was applied to the left external auditory canal. Patient 2 is a 46-year-old man who presented with complaints of disequilibrium, fullness in the left ear, and blurred vision associated with heavy lifting or straining. On examination, pneumatic otoscopy produced a sense of motion. Patient 3 is a 29-year-old woman who presented with chronic disequilibrium that resulted in frequent falls. She had a positive fistula test on the left, and vertical nystagmus was elicited when pressure was applied to the left ear. In each patient, high-resolution computed tomographic scanning through the temporal bone revealed dehiscence of the superior semicircular canal on the symptomatic side.


METHODS
In all 3 cases, a subtemporal, extradural approach was performed with repair of the middle fossa floor using calcium phosphate BoneSource (Howmedica Leibinger, Inc., Dallas, TX). All patients recovered well, with resolution of their symptoms.


CONCLUSIONS
Superior semicircular canal dehiscence syndrome is a cause of disequilibrium associated with sound or pressure stimuli. The workup includes a detailed history, electronystagmography including Valsalva maneuvers, and a high-resolution computed tomographic scan though the temporal bone. An extradural repair of the middle fossa floor with BoneSource can successfully treat this condition.
Peterson
Eric C
EC
Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington 98195, USA. ericpete@u.washington.edu
Lazar
Daniel A
DA
Nemecek
Andrew N
AN
Duckert
Larry
L
Rostomily
Robert
R
D000328:Adult; D035301:Cranial Fossa, Middle / Q000601:surgery*; D006801:Humans; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods*; D012665:Semicircular Canals / Q000601:surgery*; D013577:Syndrome; D016896:Treatment Outcome; D014717:Vertigo / Q000175:diagnosis / Q000517:prevention & control*; D014786:Vision Disorders / Q000175:diagnosis / Q000517:prevention & control*