Pediatric Calvarial Bone Thickness in Patients With and Without Aural Atresia.

OBJECTIVE: To compare temporal bone thickness along a three-dimensional arc of potential osseointegrated implant sites for bone-anchored hearing aids in children with and without aural atresia using computed tomographic imaging (CT).

STUDY DESIGN: Retrospective case review.

SETTING: Tertiary children's hospital.

PATIENTS: Children with or without aural atresia aged less than 11 years who had a temporal bone CT.

INTERVENTION (S): Calvarial bone volume on CT was rendered in three-dimensional and thickness was reconstructed and measured at up to 12 defined sites along an arc of recommended implant sites.

MAIN OUTCOME MEASURE (S): Determining whether a majority of observed potential implant sites have 2, 3, or 4 mm of bone thickness while controlling for age differences and atresia status.

RESULTS: A total of 40 atretic (from 34 patients) and 34 control (from 34 patients) temporal bones were compared using CT. Likelihood ratio tests indicated that diagnosis did not have a statistically significant effect on whether patients reached thresholds of 2, 3, or 4 mm at most observed sites (p = 0.781, 0.773, and 0.529, respectively) when adjusting for age. For all children measured, 93% had >50% of measured points greater than or equal to 2 mm thick.

CONCLUSION: Most children had greater than 2 mm of temporal bone thickness at >50% of the sites measured regardless of age or atresia diagnosis. The likelihood of reaching 4 mm of thickness at most sites improves with age. In unilateral patients, there was not a significant difference in thickness between affected and unaffected sides. There was also no significant difference in thickness when comparing patients with atresia to those without.