Growth Patterns of the Neurocentral Synchondrosis (NCS) in Immature Cadaveric Vertebra

Abstract

Study design: Gross anatomic study of osteological specimens.

Objectives: To evaluate the age of closure for the neurocentral synchondrosis (NCS) in all 3 regions of the spine in children aged 1 to 18 years old.

Summary of background data: The ossification of the human vertebra begins from a vertebral body ossification center and a pair of neural ossification centers located within the centrum called the NCS. These bipolar cartilaginous centers of growth contribute to the growth of the vertebral body, spinal canal, and posterior elements of the spine. The closure of the synchondroses is dependent upon location of the vertebra and previous studies range from 2 to 16 years of age. Although animal and cadaveric studies have been performed regarding NCS growth and early instrumentation's effect on its development, the effects of NCS growth disturbances are still not completely understood.

Methods: The vertebrae of 32 children (1 to 18 y old) from the Hamann-Todd Osteological collection were analyzed (no 2 or 9 y old specimens available). Vertebrae studied ranged from C1 to L5. A total of 768 vertebral specimens were photographed on a background grid to allow for measurement calibration. Measurements of the right and left NCS, pedicle width at the NCS, and spinal canal area were taken using Scandium image-analysis software (Olympus Soft Imaging Solutions, Germany). The percentage of the growth plate still open was found by dividing the NCS by the pedicle width and multiplying by 100. Data were analyzed with JMP 11 software (SAS Institute Inc., Cary, NC).

Results: The NCS was 100% open in all 3 regions of the spine in the 1- to 3-year age group. The cervical NCS closed first with completion around 5 years of age. The lumbar NCS was nearly fully closed by age 11. Only the thoracic region remained open through age 17 years. The left and right NCS closed simultaneously as there was no statistical difference between them. In all regions of the spine, the NCS appeared to close sooner in males than in females. Spinal canal area increased with age up to 12 years old in the cervical and thoracic spine but did not significantly change after age 3 in the lumbar spine.

Conclusions: In conclusion, closure of the NCS differed among the cervical, thoracic, and lumbar spine regions. The NCS reached closure in males before females even though females mature faster and reach skeletal maturity sooner than males. However, it is not determined whether the continued open NCS in females to a later age may be a factor in their increased rate of scoliosis.