The Level of Conus Medullaris in 629 Healthy Japanese Individuals.

Hiroaki Nakashima,Shiro Imagama,Masaaki Machino,Hiroyuki Tomita,Mikito Tsushima,Sadayuki Ito,Kazuyoshi Kobayashi,Keigo Ito,Naoki Segi,Kei Ando,Yoshito Katayama,Hiroyuki Koshimizu

doi:10.3390/jcm10143182

Hiroaki Nakashima, Shiro Imagama + Show 10 more

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https://doi.org/10.3390/jcm10143182

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Abstract

The conus medullaris typically terminates at the L1 level; however, variations in its level and the factors associated with the conus medullaris level are unclear. We investigated the level of conus medullaris on magnetic resonance imaging in healthy volunteers. In total, 629 healthy adult volunteers (≥50 individuals of each sex and in each decade of age from 20 to 70) were enrolled. The level of the conus medullaris was assessed based on the T2-weighted sagittal magnetic resonance images, and factors affecting its level were investigated employing multivariate regression analysis including the participants’ background and radiographical parameters. L1 was the most common conus medullaris level. Participant height was significantly shorter in the caudally placed conus medullaris (p = 0.013). With respect to the radiographical parameters, pelvic incidence (p = 0.003), and pelvic tilt (p = 0.03) were significantly smaller in participants with a caudally placed conus medullaris. Multiple regression analysis showed that the pelvic incidence (p < 0.0001) and height (p < 0.0001) were significant factors affecting the conus medullaris level. These results indicated that the length of the spinal cord varies little among individuals and that skeletal differences affect the level of the conus medullaris.

Highlights

The conus medullaris is located at the terminal end of the spinal cord
There were no significant differences related to gender (p = 0.48), body weight (p = 0.14) or body mass index (BMI) (p = 0.96) (Table 1)
The LL was smaller in the caudal levels of conus medullaris (56.7◦, 52.1◦, 50.5◦, 49.1◦, 46.9◦, and 46.0◦ in the Th11-12, T12, T12-L1, L1, L1-2, and L2 conus medullaris level, respectively; p = 0.10), the difference did not reach statistical significance

Summary

Introduction

The conus medullaris is located at the terminal end of the spinal cord. The lowermost tapering extremity of the spinal cord is called the conus medullaris [1,2,3,4,5,6]. The thoracolumbar junction includes the conus medullaris and cauda equina. Injury to these neurological structures is associated with functional consequences. The conus medullaris and cauda equina are a transition point from the central to the peripheral nervous system, and injury to this point can result in a series of upper and lower motor neuron symptoms, depending on the location of the injury. The conus medullaris is placed caudally to L2 vertebrae in children younger than 1 year of age; it is found in the lower third of

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