Superior Semicircular Canal Dehiscence: Diagnostic and Therapeutic Aspects

Introduction: Superior canal dehiscence syndrome (SCDS) is a rare medical condition of the inner ear, first described in 1998 by Dr. Lloyd B. Minor of Johns Hopkins, USA, leading to hearing and balance symptoms in those affected. The SCDS must be part of the differential diagnosis of vertigo and even of the isolated hearing losses.

Objective: Describe the symptomatology, diagnosis, and treatment of SCDS.

Method: Based on literature review and clinical observational experience in a tertiary referral hospital for neurotological disorders in the United States—Massachusetts Eye and Ear Infirmary, Boston, MA, the authors describe two case reports of patients with SCDS. Case 1: Male, 48 years old, with a history of fracture in the left temporal bone, presents ipsilateral mixed hearing loss and dizziness, which was worsened with physical activities. CT scan showed a defect in the floor of middle fossa and SCD and meningoencephalocele. Case 2: Female, 29 years old, with vertigo induced by weight lifting and noise exposure and also hearing loss and autophonia after gestation. On physical examination, vertical nystagmus. VEMP positive left. CT scan also showed a defect in the floor of middle fossa and SCD. Both patients were submitted to a middle fossa craniotomy for observation and subsequent correction of the defect, with improvement in symptoms.

Conclusion: Although it is a rare condition, the SCDS should be included in the differential diagnosis of vertigo. It should also be considered in cases of conductive hearing loss, especially those with preserved acoustic reflexes.