P 83 Nerve ultrasound cross-sectional area reference values in children from 2 to 17 years and their correlation with demographic and anthropometric data

Abstract

Question: High-resolution ultrasound (HRUS) is of growing importance in the routine workup of disorders of the peripheral nervous system. However, reference values for children and adolescents are not available in most ultrasound laboratories. The correlation of cross-sectional area (CSA) values with demographic and anthropometric data has been analysed in adults, the exact influence of anthropometric data on nerve ultrasound reference values in children and adolescents is discussed in the literature (1,2). The present prospective observational study analyses the influence of height, weight, age, gender, and the volume of the hands on CSA values in nerve HRUS in healthy children and adolescents from 2 – 17 years. Methods: CSA were measured in 30 healthy children and adolescents from 2 – 17 years in the median, ulnar and radial nerves in the upper extremity and in the tibial, peroneal and sural nerve in the lower extremity at different nerve sites. Height, weight, age, handedness and gender were recorded, the volume of the hands was measured using the water displacement method. The intra-nerve CSA variability and the side-to-side difference ratio of the intra-nerve CSA variability (SSDIVA) for the median, ulnar and tibial nerves was calculated. Normal distribution of the data was tested using the Shapiro-Wilk test. Spearman’s rho and Pearson's correlation coefficient was calculated for CSA, intra-nerve CSA variability, SSDIVA and age, weight, gender, hand volume. Multiple linear regression analysis with backward exclusion was used to calculate the best model predicting CSA. Model selection was based on the Akaike information criterion (AIC). Results: Nerve CSA values were consistently lower than those reported for adults and increased in all measured nerve sites with increasing age, height and weight (see Figure 1 for the ulnar nerve and age groups). This increase had a tendency to levell off at an age of 14 – 17 years. The highest correlation coefficients and best-fitting model predicting CSA were found for the variable “weight”. Correlation coefficients were higher in a linear than in logarithmic model (Figure 2). Hand volume showed a positive correlation with age, weight and nerve CSA. Conclusions: Normal values for CSA in high-resolution nerve ultrasound should be adapted for children and adolescents. Demographic data such as height, weight and age can be considered to stratify and adjust normal values to the individual child's development. Corresponding with the findings of Druzhinin (1) and in contrast to the results of Schubert (2) our data suggest that weight, and not age, has the maximum influence on nerve CSA measurements.