An Aggregate Sternal Force-Deflection Model.

Understanding the force-deflection behavior of the sternum is an important element in designing devices for implants for chest wall deformity repair. Human growth and variability makes a single measure of the stiffness difficult to determine. This work takes empirical data from the literature to develop aggregate sternal force-deflection models. Statistical methods were used to determine possible groupings based on patient age and the effect of gender. It was found that three age groups could be used, representing childhood (4-10 years), adolescence (11-19 years), and adulthood (26-53 years). Gender was found to have a statistical p-value of 0.068, 0.0611, and 0.012, respectively, in the proposed age groups. Jittering of the data was used to account for human variability and assumptions made in data comparisons. The jittered results followed that of the initial data set. Childhood force-deflection behavior follows a relatively constant stiffness, adolescence experiences a growth period of increasing stiffness, and adulthood stiffnesses again begin to stabilize around a relatively constant value.