Can a short spinal cord produce scoliosis?

Abstract

Some patients with scoliosis have a relatively short vertebral canal. This poses the question of whether a short spinal cord may sometimes cause scoliosis. The present paper presents two observations that may support this concept. It presents a scoliosis model demonstrating what effect a short, unforgiving spinal cord might have on the spinal column. The model uses two flexible parallel tubes with the facility to tighten one. It demonstrates that a short, unforgiving spinal cord could produce the abnormal rotatory anatomy observed at the apex in scoliosis, with first lordosis, then lateral deviation and finally a rotation of the vertebral column, with the rotation occurring between the canal and the vertebral body, around the axis of the cord. The anatomy of the apical vertebra is described from two museum specimens, a computed tomography (CT) myelogram and seven magnetic resonance imaging (MRI) studies. The study confirms that the vertebral canal and the intervertebral foraminae retain their original orientation. The spinal cord is eccentric in the canal towards the concavity of the curve; the major component of rotation occurs anterior to the vertebral canal and the axis of this rotation seems to be at the site of the spinal cord. These observations do not establish that a short spinal cord will result in scoliosis, but the results are compatible with this hypothesis, and that impairment of spinal cord growth factors may sometimes be responsible for scoliosis.

Idiopathic scoliosis: Etiological concepts and hypotheses

“…These results further support and develop the Roth-Porter concept of uncoupled neuro-osseous growth in the pathogenesis of AIS [48][49][50]52]. This so-called asynchronous neuro-osseous growth may promote stretching-tethering forces between the cranial and caudal extremities of the vertebral column, leading to the initiation and progression of thoracic AIS.…”

Variation in Anisotropy and Diffusivity along the Medulla Oblongata and the Whole Spinal Cord in Adolescent Idiopathic Scoliosis: A Pilot Study Using Diffusion Tensor Imaging

“…In previous studies, only part of the cord was examined because this was the intrinsic limitation of DTI by its relatively small FOV. 33,34 In this study, we have used an effective validated in-house method, 22 which enabled analysis of the entire spinal cord by stitching DTI acquired at different levels. As the diffusion tensor images of the entire spinal cord were stitched and connected together, ROIs could then be correctly positioned with reference to the vertebral and intervertebral levels.…”

“…Of note, it was even more challenging for patients with AIS compared with healthy controls. The stretching of the cord in AIS made it lie closer to the thecal sac and spinal canal over the curved segments, 8,33 leading to gradient inhomogeneities in these areas. Furthermore, the ROIs were defined in an oblique manner in the coronal view at the curved segments.…”

Recent advances in the aetiology of adolescent idiopathic scoliosis

“…The sagittal plane of AIS is known to be associated with hypokyphosis, and a relative imbalance of growth of anterior and posterior structures has been postulated as a cause [41,43]. The spinous processes and the spinal cord in the vertebral canal tend to remain towards the mid-line whilst the vertebral bodies rotate towards the convexity of the curve.…”