New patterns of the growing L3 vertebra and its 3 ossification centers in human fetuses – a CT, digital, and statistical study

Abstract

BackgroundThis study describes reference data for L3 vertebra and its 3 ossification centers at varying gestational ages.Material/MethodsUsing CT, digital-image analysis and statistics, the growth of L3 vertebra and its 3 ossification centers in 55 spontaneously aborted human fetuses aged 17–30 weeks was examined.ResultsNeither sex nor right-left significant differences were found. The height and transverse and sagittal diameters of the L3 vertebral body increased logarithmically. Its cross-sectional area followed linearly, whereas its volume increased parabolically. The transverse and sagittal diameters of the ossification center of the L3 vertebral body varied logarithmically, but its cross-sectional area and volume grew linearly. The ossification center-to-vertebral body volume ratio gradually declined with age. The neural ossification centers increased logarithmically in length and width, and proportionately in cross-sectional area and volume.ConclusionsWith no sex differences, the growth dynamics of the L3 vertebral body follow logarithmically in height, sagittal and transverse diameters, linearly (in cross-sectional area), and parabolically (in volume). The growth dynamics of the 3 ossification centers of the L3 vertebra follow logarithmically in transverse and sagittal diameters, and linearly (in cross-sectional area and volume). The age-specific reference intervals of the L3 vertebra and its 3 ossification centers present the normative values of clinical importance in the diagnosis of congenital spinal defects.

Digital image analysis of ossification centers in the axial dens and body in the human fetus

“…Vignolo et al [26] reported that ossification started earlier in female fetuses, thus male fetuses were more difficult to assess in this respect. The present paper and our previous findings [4, 5, 22–24] have not confirmed any sex differences in ossification of the spine. Therefore, in the present study both numerical data and statistical analysis are presented aggregately without taking sex into account.…”

“…As reported in the medical literature, the vertebral body ossification centers revealed a natural logarithmic increase in both transverse and sagittal diameters. This was substantiated by Baumgart et al [5] in relation to vertebra C4 ( y  = −8.836 + 3.708 × ln(age) and y  = −7.748 + 3.240 × ln(age), respectively) and by Szpinda et al [23, 24] in relation to both vertebrae T6 ( y  = −14.784 + 6.115 × ln(age) and y  = −12.065 + 5.019 × ln(age), respectively) and L3 ( y  = −27.610 + 10.341 × ln(age) and y  = −13.858 + 5.636 × ln(age), respectively).…”

“…Its volume gradually increased from the C1 to L3 vertebra, and sharply decreased from the L4 to S5 vertebra. Of note, on the same fetal material Szpinda and his collaborators carried out a comprehensive morphometric analysis including growth curves for typical vertebrae C4 [5], T6 [23] and L3 [24]. However, Castellana and Kosa [7] were the only authors to measure the axial ossification centers in a large sample, consisting of 106 human fetuses aged 16–40 weeks.…”

“…However, Castellana and Kosa [7] were the only authors to measure the axial ossification centers in a large sample, consisting of 106 human fetuses aged 16–40 weeks. Therefore, the numerical findings obtained by Szpinda’s team [4, 23, 24] and Castellana and Kosa [7] are indispensable to complete this discussion. In the material under examination, both transverse and sagittal diameters of the odontoid and body ossification centers of the axis grew in accordance with a natural logarithmic regression.…”

“…Because of flexion–extension at the atlantooccipital joint and rotation at the atlantoaxial joint, 3-dimensional sonographic evaluation of the atlas and axis in utero fetuses may frequently misjudge their malalignment or offset phenomena [12]. To date, the quantitative analysis of some linear, planar and spatial dimensions of ossification centers of the spine has been established in detail using computed tomography and digital image analysis only for the C4 [5], T6 [23] and L3 [24] vertebrae. Therefore, this study involved advanced morphometric analysis of the non-typical axial vertebra, the dens of which from a developmental point of view is actually the atlantal body.…”