Injuries in Adolescent Spine Exposed to Compressive Loads

In a cadaveric experiment, 16 functional spinal units (FSUs) obtained from 7 subjects with a mean age of 16.3 years were tested in compression to failure. The deformation rate was 5 mm/min. The bone mineral content (BMC) in the vertebrae was determined by using dual-photon absorptiometry (DPA). In 15 of the FSUs, traumatic changes were registered. Three different types of changes were seen. In nine vertebrae, there was a rupture in the cartilaginous end plate, in 12, a separation of the end plate from the vertebral body, and in three vertebrae, a compression fracture was registered. A close relation was found between BMC and the ultimate force (r2 = 0.63), the ultimate displacement (r2 = 0.73), and the energy absorption (r2 = 0.74). The weakest part of a spinal segment in this experimental situation is the growth plate.