The Influence of Growth Blocking of the Neurocentral Cartilages on the Development of the Spinal Canal. An Experimental Study in Pigs.

BACKGROUND

The neurocentral cartilage (NCC) is crucial for vertebral development and spinal canal shape, with its peak activity occurring around ages 5-6. The objective of this experimental animal study was to investigate whether bilateral epiphysiodesis of the NCC using pedicle screws can induce spinal canal narrowing in the thoracolumbar spine.

METHODS

Twenty-four domestic pigs were divided into four groups based on the level of NCC blockage: low thoracic, thoracolumbar transitional hinge, upper lumbar spine, and caudal lumbar levels below L5. The animals were monitored for 8-9 months, during which morphological, morphometric, and radiological parameters were analyzed and compared to those of 14 control pigs.

RESULTS

No asymmetrical growth or coronal deformities were observed (p > 0.05). NCC caused a significant reduction in sagittal pedicle length (-2.94 mm, 32.6%) in lower lumbar segments (L3-L6) and a 3.11 mm (29.6%) decrease in the anteroposterior canal diameter, leading to segmental stenosis most pronounced caudally. The transverse diameter of the canal remained largely unchanged. Morphologically, slight lumbar hyper lordosis and compensatory thoracic kyphosis were observed.

CONCLUSIONS

Symmetrical NCC growth arrest using pedicle screws induces spinal canal narrowing through decreased sagittal diameter, linked to insufficient development of vertebral pedicles. These findings suggest caution in employing thoracolumbar pedicle screws in skeletally immature patients with an open NCC.