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.