“disproportion theory” of the cervical spine and spinal cord in patients with juvenile cervical flexion myelopathy: A study comparing cervical magnetic resonance images with those of normal controls

Abstract

BACKGROUND Cervical flexion myelopathy is quite a rare condition affecting mainly adolescent males who present with muscular atrophy of the upper extremities. Its etiology is still unknown, as is the cause of its marked male preponderance. Disproportion of the cervical spine and spinal cord is suspected to be one of the etiological causes, however, this has yet to be confirmed. METHODS We performed a comparative study of the cervical magnetic resonance (MR) images of six male patients with juvenile cervical flexion myelopathy and of 34 young, normal controls. RESULTS In normal controls, the cervical spines and spinal cords were significantly straighter in tall than in short males and in females than in males. In these patients, the cervical spine and spinal cord shapes were straighter, and the cervical spine length/height and cervical spinal cord length/height ratios were significantly higher than those of the height-matched male group. In the female group, the cervical spine and cervical spinal cord shapes were similar to the patient group; however, the cervical spine length/height and spinal cord length/height ratios as well as the heights were significantly smaller than those of the patients. CONCLUSIONS The cervical spinal cords of the patients were considered to be stretched even with the neck in neutral position, reflecting disproportion of the cervical spine and spinal cord. The shorter length of the cervical spine and spinal cord in females was suspected to be one of the reasons for the marked male preponderance.