The purpose of this study was to determine neck strength characteristics of children indirectly using scaling relationships through a caprine animal model. Cadaver caprine cervical spines of different ages were tested mechanically in non-destructive bending and destructive tensile modes. Injuries induced in destructive testing such as endplate failure and ligament tears were consistent with clinical observations. Specimens demonstrated statistically significant increased strength characteristics with age. Scaling relationships were developed with respect to the adult specimens. For the tensile failure load the scaling percentages were 78%, 38%, 20%, and 12% for the twelve-, six-, three-, and one-year old, respectively. The tensile stiffness parameter yielded slightly higher scale factors of 85%, 54%, 23%, and 17%, whereas the bending stiffness parameter resulted in 62%, 57%, 15%, and 11% values for twelve-, six-, three-, and one-year-old age groups respectively. The caprine model therefore, suggests that tolerance values for the one- and three-year-old may be lower than the values obtained using current scaling techniques.
Abstract