Lifetime morphological characteristics of the L_IV-L_V intervertebral disc in young and middle-aged adults

Morphoscopic and morphometric characteristics of the L_IV–L_V intervertebral disc were assessed according to magnetic resonance images of the lumbar spine of 90 patients (66 men, 24 women). The morphometric parameters of the L_IV–L_V intervertebral disc and nucleus pulposus were compared between young (18–44 years old) and middle-aged (45–60 years old) adults and in groups determined by sex and body type. In addition, morphoscopic characteristics, namely, the shape of the intervertebral disc and nucleus pulposus in the axial plane, were evaluated. Results. In normal intervertebral disc, L_IV–L_V on the axial section most often presents in a kidney-shaped (51%), elliptical (45%), and round (4%) form. The L_IV–L_V nucleus pulposus normally has an oval (50%), kidney (45%), and less often a lemniscate (5%) shape. The shape and individual morphometric parameters of the intervertebral disc and nucleus pulposus of the L_IV–L_V segment have significant sex differences. Thus, the most lateral height of the intervertebral disc on the right and left, anteroposterior size and area of the intervertebral disc, and anteroposterior size, width, and area of the nucleus pulposus are significantly larger in men than in women. When assessing the influence of body type on intervertebral disc structural features, no significant differences in its shape were found between asthenics, normo- and hypersthenics, while individual dimensions (intervertebral disc height in the center and its dorsal height) were significantly larger in hypersthenics. The kidney-shaped form of the nucleus pulposus was significantly more common in asthenics and the oval form in hypersthenics, whereas the morphometric parameters of the nucleus pulposus did not significantly differ between extreme body types. Statistically significant differences in the shape of the nucleus pulposus were found between age groups. The results of the analysis of morphometric characteristics revealed the intervertebral disc height tended to decrease in middle-aged people compared with young people. The results can be used in planning spine surgery and designing artificial intervertebral discs.