Are otolaryngologists underdiagnosing EVA?
Background: Enlarged vestibular aqueduct (EVA) is the most commonly identified CT scan anomaly found in children with sensorineural hearing loss (SNHL). Current radiographic criteria for EVA (defined by Valvassori and Clemis in 1978, using hypocycloidal polytomography), is a vestibular aqueduct larger than 1.5 mm at the midpoint. A new criteria, the Cincinnati criteria (proposed by Boston and colleagues), based on CT scan and statistical analysis, defined EVA as ≥1.0 mm at the midpoint or ≥2.0 mm at the operculum.
Explore this issue:March 2010
Study Design: Cohort study, retrospective review. This study represents the largest CT-based assessment of vestibular aqueducts ever published.
Setting: One hundred thirty cochlear implant recipients at St. Louis Children’s Hospital
Synopsis: Of 163 patients who underwent cochlear implantation at St. Louis Children’s Hospital between January 2003 and August 2007, 242 ears (130 patients) were included for review. Measurements of the vestibular aqueduct were performed at the midpoint and at the operculum at an angle of 90 degrees from the posterior wall of the petrous bone. EVA was identified using both the Valvassori criteria and the Cincinnati criteria. The Cincinnati criteria diagnosed 44 percent of patients with EVA, compared to 16 percent with the Valvassori criteria. The Cincinnati criteria were more likely than the Valvassori criteria to diagnose bilateral EVA (45 percent vs. 36 percent). Among the 70 ears defined as EVA by the Cincinnati criteria but judged normal by the Valvassori criteria, 59 had no other reason for their hearing loss.
Bottom Line: This study supports the Cincinnati criteria for the identification of EVA in children with SNHL. The Valvassori and Clemis criteria, based on older technology, likely underdiagnose EVA.
Citation: Dewan K, Wippold FJ II, Lieu JE. Enlarged vestibular aqueduct in pediatric sensorineural hearing loss. Otolaryngol Head Neck Surg. 2009;140(4):552-558.