[Variation of the position of the conus medullaris in adolescent idiopathic scoliosis patients with a Cobb angle greater than 40 degrees: Analysis of MRI].

OBJECTIVE

To investigate the position of the conus medullaris in adolescent idioppathic scoliosis (AIS) with a greater curve and the relationship of that with age, sex, curve severity and curve pattern.

METHODS

In this study, 202 AIS patients with a Cobb angle greater than 40 degrees on coronal plane were included. And 52 age-matched healthy adolescents were recruited to serve as controls. Both of them displayed neurologically normal upon physical examinations. The T1-weighted, sagittal, spino-echo magnetic resonance imaging (MRI) of lumbar spine was performed on both of AIS patients and healthy controls. According to a standard method described previously, the position of the conus medullaris relative to lumbar vertebrae and intervertebral disc space was measured.

RESULTS

There was no significant difference in the distributions of the positions of the conus medullaris in AIS patients and healthy controls. In both groups, the mean position of the conus medullaris located at the same level, the lower 1/3 of L(1) (range: the middle 1/3 of T(12) to L(2 - 3) disc space). No significant correlations were found between the position of the conus medullaris and age or sex in AIS and control subjects. It was shown that the positions of the conus medullaris were not significantly different among AIS patients with different curve severity and curve patterns.

CONCLUSIONS

The distribution of the conus location in AIS patients is shown to be ranged from the middle 1/3 of T(12) to L(2 - 3) disc space, with no significant difference when compared to controls. No significant associations are found between the conus position with curve severity and curve patterns, indicating the conus location might be of no significant relevance of research on AIS pathogenesis and curve progression.