Cochlear trajectory in pediatric patients.

OBJECTIVES/HYPOTHESIS: As cochlear implantation increases, surgeons are noting possible anatomical differences in pediatric population. Outcome objectives were to study pediatric temporal bone anatomy using high-resolution temporal bone imaging, and analyze the anatomical differences in group 1 (<12 months) versus group 2 (1-4 years) versus group 3 (5-10 years) versus group 4 (10-18 years). STUDY DESIGN: Retrospective chart and radiologic review. METHODS: A retrospective chart and radiologic review of pediatric patients undergoing high-resolution computer tomography of the temporal bones from April 2001 to February 2013 was conducted. Scans were reviewed to record the transmastoid angle and transcanal angle. RESULTS: Seven hundred fifty patients were identified. A total of 1,426 ears were reviewed. The age range was 8 days to 21 years. Of the patients, 57.0% (n = 407) were male. The patients were divided into four groups: group 1 (<12 months), group 2 (1-4 years), group 3 (5-10 years), and group 4 (10-18 years). The transmastoid angle was observed to have variability. Significant differences were observed between groups 2 and 3 (P = .0028) and groups 2 and 4 (P = .0432). Analysis on the transcanal angle was performed. Significant differences existed between age groups 1 and 3 (P = .0150), groups 1 and 4 (P = .0038), and groups 2 and 4 (P = .0358). CONCLUSIONS: Considerable variation exists in pediatric temporal bones. The largest difference in the transmastoid angle was seen in children aged 1 to 4 years. The largest variability in the transcanal angle is between the infant (<12 months) and children >4 years of age. These differences are surgically relevant for round window identification and facial nerve safety during cochlear implant surgery in infants.

The relationship of age and radiographic incidence of superior semicircular canal dehiscence in pediatric patients.

OBJECTIVE: To determine if age affects radiographic incidence of superior semicircular canal dehiscence (SSCD) in pediatric patients. STUDY DESIGN: Retrospective case review. SETTING: Tertiary children's hospital. PATIENTS: Patients (0-18 yr) with high-resolution computed tomography (CT) temporal bone scans from April 2001 to February 2013. INTERVENTIONS: Diagnostic high-resolution CT temporal bone scans. MAIN OUTCOME MEASURES: Findings of dehiscent, thin, or normal SSC on CT scans (including reconstructed Poschl views). Interobserver radiographic interpretation rate between neuroradiologist and otologist. RESULTS: Seven-hundred CT scans (1,400 ears) were reviewed, and 1,188 ears were acceptable for analysis. Twenty-three ears (1.9%) had dehiscent SSC, 185 ears (15.6%) had thin SSC, and 980 ears (82.5%) had normal SSC. Median ages of dehiscent, thin, and normal canals were 5, 7, and 9 years, respectively ( p < 0.05). As age increased, the incidence of dehiscent and thin SCC cases decreased; for example, dehiscent or thin canal existed in 51.4% of children less than 12 months, 17.5% of children between 1 and 2 years, 18.5% of children between 3 and 10 years, and 10.9% of children between 11 and 18 years. The κ value of agreement between neuroradiologist and otologist was 0.814, demonstrating a high value of agreement (p < 0.05). CONCLUSION: Radiographic SSCD, although uncommon, appears to be more prevalent in younger children, especially infants younger than 12 months. This suggests that the SSC may develop more bony covering with age.