Symphysis pubis width in the pediatric population: A computerized tomography study

BACKGROUND: Defining pathologic widening of the pubic symphysis in the pediatric population continues to be a clinical challenge. The purpose of this study is to define a normal range of pubic symphyseal widths in various age and gender groups using axial computerized tomography (CT) scans. METHODS: Axial CT images of 140 patients aged between 2 years and 15 years were obtained from our database of preexisting scans. Using a commercially available software package, the single image with the narrowest pubic symphyseal width was identified and measured. Patients were further stratified based on gender and by age into three groups: group A (age 2-5 years), group B (age 6-11 years), and group C (age 12-15 years). RESULTS: The mean width ± 95% confidence interval for all cases was 4.59 mm ± 0.18 mm. The mean width for male and female patients was 4.86 mm ± 0.26 mm and 4.33 mm ± 0.24 mm, respectively. Based on the two-way analysis of variance, both age group and gender had a statistically significant effect. Post hoc testing demonstrated a statistically significant difference in mean symphyseal width between groups A and C (p < 0.0001) and groups B and C (p = 0.0025) but not between groups A and B (p = 0.055). When grouped by age, the mean male pubic symphyseal width was found to be 5.10 mm, 4.93 mm, and 4.45 mm, while the mean female width was found to be 4.94 mm, 4.33 mm, and 3.54 mm at 2 to 6 years, 7 to 11 years, and 12 to 15 years of age, respectively. CONCLUSION: In the pediatric population, males seem to have a wider pubic symphysis than females of the same age group. In both males and females, pubic symphyseal width decreases during the transition from infancy toward skeletal maturity. LEVEL OF EVIDENCE: Epidemiologic study, level III.