Fetal spine ossification: the gender and individual differences illustrated by ultrasonography

Lions & sea lions & bears, oh my: utilizing museum specimens to study the ossification sequence of carnivoran taxa

BACKGROUND

Mammalian skeletons are largely formed before birth. Heterochronic changes in skeletal formation can be investigated by comparing the order of ossification for different elements of the skeleton. Due to the challenge of collecting prenatal specimens in viviparous taxa, opportunistically collected museum specimens provide the best material for studying prenatal skeletal development across many mammalian species. Previous studies have investigated ossification sequence in a range of mammalian species, but little is known about the pattern of bone formation in Carnivora. Carnivorans have diverse ecologies, diets, and biomechanical specializations and are well-suited for investigating questions in evolutionary biology. Currently, developmental data on carnivorans is largely limited to domesticated species. To expand available data on carnivoran skeletal development, we used micro-computed tomography (micro-CT) to non-invasively evaluate the degree of ossification in all prenatal carnivoran specimens housed in the Harvard Museum of Comparative Zoology. By coding the presence or absence of bones in each specimen, we constructed ossification sequences for each species. Parsimov-based genetic inference (PGi) was then used to identify heterochronic shifts between carnivoran lineages and reconstruct the ancestral ossification sequence of Carnivora.

RESULTS

We used micro-CT to study prenatal ossification sequence in six carnivora species: Eumetopias jubatus (Steller sea lion, n = 6), Herpestes javanicus (small Indian mongoose, n = 1), Panthera leo (lion, n = 1), Urocyon cinereoargenteus (gray fox, n = 1), Ursus arctos arctos (Eurasian brown bear, n = 1), and Viverricula indica (small Indian civet, n = 5). Due to the relatively later stage of collection for the available specimens, few heterochronic shifts were identified. Ossification sequences of feliform species showed complete agreement with the domestic cat. In caniforms, the bear and fox ossification sequences largely matched the dog, but numerous heterochronic shifts were identified in the sea lion.

CONCLUSIONS

We use museum specimens to generate cranial and postcranial micro-CT data on six species split between the two major carnivoran clades: Caniformia and Feliformia. Our data suggest that the ossification sequence of domestic dogs and cats are likely good models for terrestrial caniforms and feliforms, respectively, but not pinnipeds.

An Easy and Effective Method for Evaluating the Position of Conus Medullaris: Counting the Number of Vertebral Ossification Center Below the End of Conus Medullaris

OBJECTIVE

This study aimed to ascertain the conus medullaris position by counting the number of ossification centers in the vertebral bodies below the conus medullaris endpoint (N) and assess its utility in screening for closed spinal dysraphism and tethered cord syndrome.

METHODS

A total of 900 normal fetuses and 146 fetuses with closed spinal dysraphism or tethered cord syndrome were included in this study. The N values were tallied and compared along the spinal longitudinal plane. The receiver operating characteristic curve was utilized, and the cut-off value of N was analyzed.

RESULTS

The counting of N was successfully performed in 856 normal and 146 abnormal fetuses. In the normal group, an increase in N with gestational age was observed. Specifically, in the subgroup of 17-20 wk fetuses, N was ≥6 in 117 out of 131 cases. This figure increased to 211 out of 213 in 21-24 wk and 512 out of 512 in 25-41 wk, respectively. Cases with N ≥7 accounted for 715 out of 856 fetuses in the 17-41 wk range. In the abnormal group, N was less than 7 in 152 out of 163 fetuses, showing statistical differences between the two groups. With a cut-off value of 6.5, specificity and sensitivity reached 93.3% and 83.5%.

CONCLUSIONS

The counting of N was found to be a straightforward and efficient method for evaluating the position of the conus medullaris.

Comparing a common clavicle maturation-based age estimation method to ordinary regression analyses with quadratic and sex-specific interaction terms in adolescents

Established methods of age estimation are based on correlating defined maturation stages of bony structures with tables representing the observed range of biological ages in the majority of cases. In this retrospective monocentric study in southwestern Germany, common age estimation methodology was assessed in n = 198 subjects at the age of 25 or younger by analyzing the influence of age, quadratic age, biological sex and age-sex interaction on the ossification stages of the medial epiphysis fugue. Three readers (ICC ≥ 0.81 for left/right side) evaluated routine care computed tomography images of the clavicle with a slice thickness of 1 mm. By using least square regression analyses, to determine the real biological age a quadratic function was determined corrected for the age estimated by established methods and sex (R2 = 0.6 each side), reducing the mean absolute error and root mean squared error in the age estimation of women (2.57 and 3.19) and men (2.57 and 3.47) to 1.54 and 1.82 for women, and 1.54 and 2.25 for men. In women, the medial clavicle epiphysis seem to fuse faster, which was particularly observable from approximately 18 years of age. Before that age, the estimation method was relatively close to the ideal correlation between assessed and real age. To conclude, the presented new method enables more precise age estimation in individuals and facilitates the determination and quantification of additional variables, quantifying their influence on the maturation of the medial clavicle epiphysis based on the established ossification stages.

Sex differences in pediatric caudal epidural anesthesia under sedation without primary airway instrumentation

STUDY OBJECTIVE

To identify sex differences associated with caudal epidurals, the most commonly used technique of pediatric regional anesthesia, based on individually validated data of ultrasound-guided blocks performed between 04/2014 and 12/2020.

METHODS

Prospectively collected and individually validated data of a cohort of children aged between 0-15 years was analyzed in a retrospective observational study. We included pediatric surgeries involving a primary plan of caudal epidural anesthesia under sedation (without airway instrumentation) and a contingency plan of general anesthesia. Sex-specific rates were analyzed for overall failure of the primary anesthesia plan, for residual pain, for block-related technical complications and for critical respiratory events. We used Fisher´s exact tests and multivariable logistic regressions were used to evaluate sex-specific associations.

RESULTS

Data from 487 girls and 2060 boys ≤15 years old (ASA status 1 to 4) were analyzed. The primary-anesthesia-plan failure rate was 5.5% (95%CI 3.8%-7.8%) (N = 27/487) among girls and 4.7% (95%CI 3.9%-5.7%) (N = 97/2060) among boys (p = 0.41). Residual pain was the main cause of failure, with rates of 4.5% (95%CI 2.9-6.6%) (N = 22/487) among girls and 3.0% (95%CI 2.3-3.8%) (N = 61/2060) among boys (p = 0.089). Block-related technical complications were seen at rates of 0.8% (95%CI 0.3%-1.9%) (N = 4/487) among girls vs 2.5% (95%CI 0.5-2.7%) (N = 51/2060) among boys and, hence, significantly more often among male patients (p = 0.023). Male sex was significantly associated with higher odds (adjusted OR: 3.18; 95% CI: 1.12-9; p = 0.029) for such technical complications regardless of age, ASA status, gestational week at birth or puncture attempts. Critical respiratory events occurred at a 1.7% (95%CI 1.2%-2.3%) rate (N = 35/2060) twice as high among boys as 0.8% (95%CI 0.3%-1.9%) (N = 4/487) among girls (p = 0.21).

CONCLUSIONS

While the the primary-anesthesia-plan failure rate was equal for girls and boys, technical complications and respiratory events are more likely to occur in boys.

Accessory articulation of the transverse processes in the cervical spine

Accessory articulation between the transverse processes of the C6 and C7 vertebrae is an extremely rare anatomic variant that has only been previously described in two instances. In this report, we present the case of a 25-year-old male who sustained numerous injuries associated with a physical assault. A CT study of the cervical spine revealed a linear lucency mimicking a fracture but found on closer inspection to represent an accessory articulation between the anterior tubercles of the right transverse processes of the C6 and C7 vertebrae. In this report, we summarize this patient's clinical course, and provide an up-to-date review of the current literature, imaging characteristics, and potential mechanisms of the development of this anatomic variant. Our case also includes an incomplete version of the anomaly contralaterally as well as features of secondary osseous stress hypertrophy; these features have not been previously described and may aid in diagnosis. Finally, we provide the first-ever augmented reality model of this variant to fully convey its geometry and facilitate its unequivocal identification.

Normal fetal development of the cervical, thoracic, and lumbar spine: A postmortem study based on magnetic resonance imaging

OBJECTIVE

Before evaluating spinal pathology, it is essential to have knowledge of the normal spinal development at different gestational ages. This study aims to characterize normal spinal growth in human fetuses during the second and third trimesters.

METHODS

Postmortem 3.0 T magnetic resonance imaging (MRI) was performed on 55 fetuses at 17-42 gestational weeks by using three-dimensional T2-weighted sequences. Morphological changes and quantitative measurements of the fetal spine were assessed. The correlation between centrum ossification center volume (COCV) and gestational age was investigated.

RESULTS

The cervical, thoracic, and lumbar COCVs showed a positive relationship with gestational age (p < 0.05). No gender differences were found in the volumetric development of the cervical, thoracic, and lumbar centrum ossification centers (COCs). The average volumetric growth rate per COC was larger in the lumbar spine than in the cervical and thoracic spine. The L1-L5 COCVs also showed a linear positive relationship with gestational age.

CONSULTS

Postmortem 3.0 T MRI clearly demonstrated spinal changes in external contour and internal structure with gestational age. These findings expand our understanding of the early growth pattern of the human spine and could be further used to assess the developmental conditions of the fetal spine.

Normal development of sacrococcygeal centrum ossification centers in the fetal spine: a postmortem magnetic resonance imaging study

PURPOSE

To describe the temporal pattern of the appearance of the S1-Co1 centrum ossification centers (COCs) and provide reference data for the S1-S5 COCs and sacral length at various gestational ages (GAs).

METHODS

Postmortem magnetic resonance imaging (MRI) was performed on 71 fetuses (GA, 17-42 weeks) using the 3D dual-echo steady-state with water excitation T2 sequence in the sagittal plane. To confirm the reliability of this sequence, the MRI data were compared with the CT and histologic data obtained from two fetuses (GAs, 21 and 30 weeks). The presence or absence of each sacrococcygeal COC was recorded. Sacral length and S1-S5 COC height, sagittal diameter, transverse diameter, cross-sectional area, and volume were measured.

RESULTS

All fetuses showed S1-S3 COCs by 17 weeks, S4 COCs by 19 weeks, and S5 COCs by 28 weeks. The S4, S5, and Co-1 COCs were visualized in 70 (98.59%), 51 (71.83%), and 21 (29.58%) fetuses, respectively. Sacral length, height, sagittal, and transverse diameters increased linearly, while cross-sectional area and volume increased exponentially with advancing GA. Mean growth rates of the sagittal and transverse diameters, cross-sectional area, and volume, but not of height, significantly differed among the S1-S5 vertebrae.

CONCLUSION

We have presented the timing of appearance of individual sacrococcygeal COCs and the age-specific, normative MRI reference values for sacral length and the morphometric parameters of the sacral COCs, which are of clinical importance in the diagnosis of congenital sacral abnormalities and skeletal dysplasia.

Morphometric study of the neural ossification centers of the atlas and axis in the human fetus

Purposes

The knowledge of the developing cervical spine and its individual vertebrae, including their neural processes may be useful in the diagnostics of congenital vertebral malformations. This study was performed to quantitatively examine the neural ossification centers of the atlas and axis with respect to their linear, planar and volumetric parameters.

Methods

Using the methods of CT, digital-image analysis and statistics, the size of neural ossification centers in the atlas and axis in 55 spontaneously aborted human fetuses aged 17–30 weeks was studied.

Results

Without any male–female and right–left significant differences, the best fit growth dynamics for the neural ossification centers of the atlas and axis were, respectively, modelled by the following functions: for length: y = −13.461 + 6.140 × ln(age) ± 0.570 and y = −15.683 + 6.882 × ln(age) ± 0.503, for width: y = −4.006 + 1.930 × ln(age) ± 0.178 and y = −3.054 + 1.648 × ln(age) ± 0.178, for cross-sectional area: y = −7.362 + 0.780 × age ± 1.700 and y = −9.930 + 0.869 × age ± 1.911, and for volume: y = −6.417 + 0.836 × age ± 1.924 and y = −11.592 + 1.087 × age ± 2.509.

Conclusions

The size of neural ossification centers of the atlas and axis shows neither sexual nor bilateral differences. The neural ossification centers of the atlas and axis grow logarithmically in both length and width and linearly in both cross-sectional area and volume. The numerical data relating to the size of neural ossification centers of the atlas and axis derived from the CT and digital-image analysis are considered specific-age reference values of potential relevance in both the ultrasound monitoring and the early detection of spinal abnormalities relating to the neural processes of the first two cervical vertebrae in the fetus.

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

Purposes

The detailed understanding of the anatomy and timing of ossification centers is indispensable in both determining the fetal stage and maturity and for detecting congenital disorders. This study was performed to quantitatively examine the odontoid and body ossification centers in the axis with respect to their linear, planar and volumetric parameters.

Methods

Using the methods of CT, digital image analysis and statistics, the size of the odontoid and body ossification centers in the axis in 55 spontaneously aborted human fetuses aged 17–30 weeks was studied.

Results

With no sex difference, the best fit growth dynamics for odontoid and body ossification centers of the axis were, respectively, as follows: for transverse diameter y = −10.752 + 4.276 × ln(age) ± 0.335 and y = −10.578 + 4.265 × ln(age) ± 0.338, for sagittal diameter y = −4.329 + 2.010 × ln(age) ± 0.182 and y = −3.934 + 1.930 × ln(age) ± 0.182, for cross-sectional area y = −7.102 + 0.520 × age ± 0.724 and y = −7.002 + 0.521 × age ± 0.726, and for volume y = −37.021 + 14.014 × ln(age) ± 1.091 and y = −37.425 + 14.197 × ln(age) ± 1.109.

Conclusions

With no sex differences, the odontoid and body ossification centers of the axis grow logarithmically in transverse and sagittal diameters, and in volume, while proportionately in cross-sectional area. Our specific-age reference data for the odontoid and body ossification centers of the axis may be relevant for determining the fetal stage and maturity and for in utero three-dimensional sonographic detecting segmentation anomalies of the axis.

Morphometric study of the two fused primary ossification centers of the clavicle in the human fetus

Purposes

A satisfactory understanding of the clavicle development may be contributing to both the diagnosis of its congenital defects and prevention of perinatal damage to the shoulder girdle. This study was carried out to examine the transverse and sagittal diameters, cross-sectional area and volume of the two fused primary ossification centers of the clavicle.

Methods

Using the methods of CT, digital-image analysis and statistics, the size for two fused primary ossification centers of the clavicle in 42 spontaneously aborted human fetuses at ages of 18–30 weeks was studied.

Results

Without any male–female and right-left significant differences, the best fit growth models for two fused primary ossification centers of the clavicle were as follows: y = −31.373 + 15.243 × ln(age) ± 1.424 (R² = 0.74) for transverse diameter, y = −7.945 + 3.225 × ln(age) ± 0.262 (R² = 0.78), y = −4.503 + 2.007 × ln(age) ± 0.218 (R² = 0.68), and y = −4.860 + 2.117 × ln(age) ± 0.200 (R² = 0.73) for sagittal diameters of the lateral, middle and medial ends respectively, y = −31.390 + 2.432 × age ± 4.599 (R² = 0.78) for cross-sectional area, and y = 28.161 + 0.00017 × (age)⁴ ± 15.357 (R² = 0.83) for volume.

Conclusions

With no sex and laterality differences, the fused primary ossification centers of the clavicle grow logarithmically in both transverse and sagittal diameters, linearly in cross-sectional area, and fourth-degree polynomially in volume. Our normative quantitative findings may be conducive in monitoring normal fetal growth and screening for inherited faults and anomalies of the clavicle in European human fetuses.

Cross-sectional study of C1-S5 vertebral bodies in human fetuses

INTRODUCTION

Knowledge on the normative spinal growth is relevant in the prenatal detection of its abnormalities. The present study determines the height, transverse and sagittal diameters, cross sectional area, and volume of individual C1-S5 vertebral bodies.

MATERIAL AND METHODS

Using the methods of computed tomography (CT), digital image analysis, and statistics, the size of C1-S5 vertebral bodies in 55 spontaneously aborted human fetuses aged 17-30 weeks was examined.

RESULTS

All the 5 examined parameters changed significantly with gestational age (p < 0.01). The mean height of vertebral bodies revealed an increase from the atlas (2.39 ±0.54 mm) to L2 (4.62 ±0.97 mm), stabilized through L3-L4 (4.58 ±0.92 mm, 4.61 ±0.84 mm), and then was decreasing to S5 (0.43 ±1.06 mm). The mean transverse diameter of vertebral bodies was increasing from the atlas (1.20 ±1.96 mm) to L1 (6.24 ±1.46 mm), so as to stabilize through L2-L3 (6.12 ±1.65, 6.12 ±1.61 mm), and finally was decreasing to S5 (0.26 ±0.96 mm). There was an increase in sagittal diameter of vertebral bodies from the atlas (0.82 ±1.34 mm) to T7 (4.76 ±0.85 mm), its stabilization for T8-L4 (4.73 ±0.86 mm, 4.71 ±1.02 mm), and then a decrease in values to S5 (0.21 ±0.75 mm) was observed. The values for cross-sectional area of vertebral bodies were increasing from the atlas (2.95 ±5.25 mm(2)) to L3 (24.92 ±11.07 mm(2)), and then started decreasing to S5 (0.48 ±2.09 mm(2)). The volumetric growth of vertebral bodies was increasing from the atlas (8.60 ±16.40 mm(3)) to L3 (122.16 ±74.73 mm(3)), and then was decreasing to S5 (1.60 ±7.00 mm(3)).

CONCLUSIONS

There is a sharp increase in size of fetal vertebral bodies between the atlas and the axis, and a sharp decrease in size within the sacral spine. In human fetuses the vertebral body growth is characterized by maximum values in sagittal diameter for T7, in transverse diameter for L1, in height for L2, and in both cross-sectional area and volume for L3.

Skeletal development on fetal magnetic resonance imaging

Prenatal magnetic resonance imaging (MRI) is being increasingly used, in addition to standard ultrasound, for the diagnosis of congenital diseases beyond the central nervous system. Previous studies have demonstrated that MRI may be useful for the in utero visualization of spinal dysraphism and for differentiating between isolated and complex skeletal disorders with associated abnormalities. More recently, attention has focused on the visualization of the human fetal skeleton for the delineation of normal and pathological development of skeletal structures. On 1.5 T, in particular, echoplanar imaging enables the delineation of various epimetaphyseal structures and morphometric measurements of the fetal long bones from 18 gestational weeks until term. This information gathered from prenatal MRI might be helpful in the diagnosis of focal bone abnormalities and generalized skeletal disorders, such as bone dysplasias. Further clinical research, along with the refinement of the newest techniques, will enable expansion of the preliminary findings and help in determining the impact of fetal magnetic resonance bone imaging in the routine clinical setting. This review summarizes the current data in the literature and the authors' clinical experience with the magnetic resonance visualization of the developing fetal skeleton and also comments on the potential future applications of this technique.

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

Background

This study describes reference data for L3 vertebra and its 3 ossification centers at varying gestational ages.

Material/Methods

Using 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.

Results

Neither 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.

Conclusions

With 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.

Extensive cervical spine and foregut anomaly in 'serpentine syndrome'

INTRODUCTION

We report an extremely rare and challenging combination of congenital anomalies. Only five similar cases have been described in the English language medical literature to date.

PRESENTATION OF CASE

A male infant was born at 30(+5) weeks gestation by emergency caesarian section. Cervical spine rachischisis, shortened oesophagus, intrathoracic stomach, atretic duodenum and absent spleen were noted, in addition to respiratory insufficiency. Gastrointestinal re-anastomosis, particularly oesophageal lengthening, was not feasible at the initial thoracotomy. Surgical stabilization of the cervical spine was unlikely to be successful until two years of age. Asplenia predisposed the infant to sepsis from encapsulated organisms, and recurrent respiratory infections occurred.

DISCUSSION

A close relationship exists between the upper gastrointestinal tract and cervical spine during embryonic development. An embryonic aberration at this level could account for all the deformities present in this infant. Tethering of the embryonic cervical oesophagus to the somites in the first trimester, preventing foregut elongation, and producing ischaemia at the coeliac axis, is suggested as the aetiology.

CONCLUSION

This case presented a challenge to the multi-disciplinary team involved in his management and prompted extensive consultation with international experts. After considerable counseling of the parents, care was directed towards palliation.

Morphometric study of the T6 vertebra and its three ossification centers in the human fetus

Purpose

Knowledge on the normative growth of the spine is critical in the prenatal detection of its abnormalities. We aimed to study the size of T6 vertebra in human fetuses with the crown-rump length of 115–265 mm.

Materials and methods

Using the methods of computed tomography (Biograph mCT), digital image analysis (Osirix 3.9) and statistics, the normative growth of the T6 vertebral body and the three ossification centers of T6 vertebra in 55 spontaneously aborted human fetuses (27 males, 28 females) aged 17–30 weeks were studied.

Results

Neither male–female nor right–left significant differences were found. The height, transverse, and sagittal diameters of the T6 vertebral body followed natural logarithmic functions as y = −4.972 + 2.732 × ln(age) ± 0.253 (R² = 0.72), y = −14.862 + 6.426 × ln(age) ± 0.456 (R² = 0.82), and y = −10.990 + 4.982 × ln(age) ± 0.278 (R² = 0.89), respectively. Its cross-sectional area (CSA) rose proportionately as y = −19.909 + 1.664 × age ± 2.033 (R² = 0.89), whereas its volumetric growth followed the four-degree polynomial function y = 19.158 + 0.0002 × age⁴ ± 7.942 (R² = 0.93). The T6 body ossification center grew logarithmically in both transverse and sagittal diameters as y = −14.784 + 6.115 × ln(age) ± 0.458 (R² = 0.81) and y = −12.065 + 5.019 × ln(age) ± 0.315 (R² = 0.87), and proportionately in both CSA and volume like y = −15.591 + 1.200 × age ± 1.470 (R² = 0.90) and y = −22.120 + 1.663 × age ± 1.869 (R² = 0.91), respectively. The ossification center-to-vertebral body volume ratio was gradually decreasing with age. On the right and left, the neural ossification centers revealed the following models: y = −15.188 + 6.332 × ln(age) ± 0.629 (R² = 0.72) and y = −15.991 + 6.600 × ln(age) ± 0.629 (R² = 0.74) for length, y = −6.716 + 2.814 × ln(age) ± 0.362 (R² = 0.61) and y = −7.058 + 2.976 × ln(age) ± 0.323 (R² = 0.67) for width, y = −5.665 + 0.591 × age ± 1.251 (R² = 0.86) and y = −11.281 + 0.853 × age ± 1.653 (R² = 0.78) for CSA, and y = −9.279 + 0.849 × age ± 2.302 (R² = 0.65) and y = −16.117 + 1.155 × age ± 1.832 (R² = 0.84) for volume, respectively.

Conclusions

Neither sex nor laterality differences are found in the morphometric parameters of evolving T6 vertebra and its three ossification centers. The growth dynamics of the T6 vertebral body follow logarithmically for its height, and both sagittal and transverse diameters, linearly for its CSA, and four-degree polynomially for its volume. The three ossification centers of T6 vertebra increase logarithmically in both transverse and sagittal diameters, and linearly in both CSA and volume. The age-specific reference intervals for evolving T6 vertebra present the normative values of potential relevance in the diagnosis of congenital spinal defects.

Cross-sectional study of the neural ossification centers of vertebrae C1-S5 in the human fetus

Purpose

An understanding of the normal evolution of the spine is of great relevance in the prenatal detection of spinal abnormalities. This study was carried out to estimate the length, width, cross-sectional area and volume of the neural ossification centers of vertebrae C1–S5 in the human fetus.

Materials and methods

Using the methods of CT (Biograph mCT), digital-image analysis (Osirix 3.9) and statistics (the one-way ANOVA test for paired data, the Kolmogorov–Smirnov test, Levene’s test, Student’s t test, the one-way ANOVA test for unpaired data with post hoc RIR Tukey comparisons) the size for the neural ossification centers throughout the spine in 55 spontaneously aborted human fetuses (27 males, 28 females) at ages of 17–30 weeks was studied.

Results

The neural ossification centers were visualized in the whole pre-sacral spine, in 74.5 % for S1, in 61.8 % for S2, in 52.7 % for S3, and in 12.7 % for S4. Neither male–female nor right–left significant differences in the size of neural ossification centers were found. The neural ossification centers were the longest within the cervical spine. The maximum values referred to the axis on the right, and to C5 vertebra on the left. There was a gradual decrease in length for the neural ossification centers of T1–S4 vertebrae. The neural ossification centers were the widest within the proximal thoracic spine and narrowed bi-directionally. The growth dynamics for CSA of neural ossification centers were found to parallel that of volume. The largest CSAs and volumes of neural ossification centers were found in the C3 vertebra, and decreased in the distal direction.

Conclusions

The neural ossification centers show neither male–female nor right–left differences. The neural ossification centers are characterized by the maximum length for C2–C6 vertebrae, the maximum width for the proximal thoracic spine, and both the maximum cross-sectional area and volume for C3 vertebra. There is a sharp decrease in size of the neural ossification centers along the sacral spine. A decreasing sequence of values for neural ossification centers along the spine from cervical to sacral appears to parallel the same direction of the timing of ossification. The quantitative growth of the neural ossification centers is of potential relevance in the prenatal diagnosis and monitoring of achondrogenesis, caudal regression syndrome, diastematomyelia and spina bifida.

Cross-sectional study of the ossification center of the C1-S5 vertebral bodies

Purpose

Knowledge on the normative growth of the spine is relevant in the prenatal detection of its abnormalities. This study describes the size of the ossification center of C1–S5 vertebral bodies.

Materials and methods

Using CT, digital-image analysis, and statistics, the size of the ossification center of C1–S5 vertebral bodies in 55 spontaneously aborted human fetuses aged 17–30 weeks was examined.

Results

No sex significant differences were found. The body ossification centers were found within the entire presacral spine and in 85.5 % of S1, in 76.4 % of S2, in 67.3 % of S3, in 40.0 % of S4, and in 14.5 % of S5. All the values for the atlas were sharply smaller than for the axis. The mean transverse diameter of the body ossification center gradually increased from the axis to T12 vertebra, so as to stabilize through L1–L3 vertebrae, and finally was intensively decreasing to S5 vertebra. There was a gradual increase in sagittal diameter of the body ossification center from the axis to T5 vertebra and its stabilization for T6–T9 vertebrae. Afterward, an alternate progression was observed: a decrease in values for T10–T12 vertebrae, an increase in values for L1–L2 vertebrae, and finally a decrease in values for L3–S5 vertebrae. The values of cross-sectional area of ossification centers were gradually increasing from the axis to L2 vertebra and then started decreasing to S5 vertebra. The following cross-sectional areas were approximately equivalent to each other: for L5 and T3–T5, and for S4 and C1. The volumetric growth of the body ossification center gradually increased from the axis to L3 vertebra and then sharply decreased from L4 to S5.

Conclusions

No male–female differences are found in the size of the body ossification centers of the spine. The growth dynamics for morphometric parameters of the body ossification centers of the spine follow similarly with gestational age.

New anatomical data on the growing C4 vertebra and its three ossification centers in human fetuses

PURPOSE

Detailed knowledge on the normative growth of the spine is of great relevance in the prenatal diagnosis of its abnormalities. The present study was conducted to compile age-specific reference data for vertebra C4 and its three ossification centers in human fetuses.

MATERIALS AND METHODS

With the use of CT (Biograph mCT), digital image analysis (Osirix 3.9) and statistical analysis (Wilcoxon signed-rank test, Kolmogorov-Smirnov test, Levene's test, Student's t test, one-way ANOVA, post hoc RIR Tukey test, linear and nonlinear regression analysis), the normative growth of vertebra C4 and its three ossification centers in 55 spontaneously aborted human fetuses (27 males, 28 females) aged 17-30 weeks was examined.

RESULTS

Significant differences in neither sex nor laterality were found. The height and transverse and sagittal diameters of the C4 vertebral body increased logarithmically as: y = -3.866 + 2.225 × ln(Age) ± 0.238 (R(2) = 0.69), y = -7.077 + 3.547 × ln(Age) ± 0.356 (R(2) = 0.72) and y = -3.886 + 2.272 × ln(Age) ± 0.222 (R(2) = 0.73), respectively. The C4 vertebral body grew linearly in cross-sectional area as y = -7.205 + 0.812 × Age ± 1.668 (R(2) = 0.76) and four-degree polynomially in volume as y = 14.108 + 0.00007 × Age(4) ± 6.289 (R(2) = 0.83). The transverse and sagittal diameters, cross-sectional area and volume of the ossification center of the C4 vertebral body generated the following functions: y = -8.836 + 3.708 × ln(Age) ± 0.334 (R(2) = 0.76), y = -7.748 + 3.240 × ln(Age) ± 0.237 (R(2) = 0.83), y = -4.690 + 0.437 × Age ± 1.172 (R(2) = 0.63) and y = -5.917 + 0.582 × Age ± 1.157 (R(2) = 0.77), respectively. The ossification center-to-vertebral body volume ratio gradually declined with age. On the right and left, the neural ossification centers showed the following growth: y = -19.601 + 8.018 × ln(Age) ± 0.369 (R(2) = 0.92) and y = -15.804 + 6.912 × ln(Age) ± 0.471 (R (2) = 0.85) for length, y = -5.806 + 2.587 × ln(Age) ± 0.146 (R(2) = 0.88) and y = -5.621 + 2.519 × ln(Age) ± 0.146 (R(2) = 0.88) for width, y = -9.188 + 0.856 × Age ± 2.174 (R(2) = 0.67) and y = -7.570 + 0.768 × Age ± 2.200 (R(2) = 0.60) for cross-sectional area, and y = -13.802 + 1.222 × Age ± 1.872 (R(2) = 0.84) and y = -11.038 + 1.061 × Age ± 1.964 (R(2) = 0.80) for volume, respectively.

CONCLUSIONS

The morphometric parameters of vertebra C4 and its three ossification centers show no sex differences. The C4 vertebral body increases logarithmically in height and both sagittal and transverse diameters, linearly in cross-sectional area, and four-degree polynomially in volume. The three ossification centers of vertebra C4 grow logarithmically in both transverse and sagittal diameters, and linearly in both cross-sectional area and volume. The age-specific reference intervals for evolving vertebra C4 may be useful in the prenatal diagnosis of congenital spinal defects.

Quantitative description of the morphology and ossification center in the axial skeleton of 20-week gestation formalin-fixed human fetuses using magnetic resonance images

OBJECTIVES

Human tissues are usually studied using a series of two-dimensional visualizations of in vivo or cutout specimens. However, there is no precise anatomical description of some of the processes of human fetal development. The purpose of our study is to develop a quantitative description of the normal axial skeleton by means of high-resolution three-dimensional magnetic resonance (MR) images, collected from six normal 20-week-old human fetuses fixed in formaldehyde.

METHODS

Fetuses were collected after spontaneous abortion and subsequently fixed with formalin. They were imaged using a 1.5 T MR scanner with an isotropic spatial resolution of 200 µm. The correct tissue discrimination between ossified and cartilaginous bones was confirmed by comparing the images achieved by MR scans and computerized axial tomographies. The vertebral column was segmented out from each image using a specially developed semi-automatic algorithm.

RESULTS

Vertebral body dimensions and inter-vertebral distances were larger in the lumbar region, in agreement with the beginning of the ossification process from the thoracolumbar region toward the sacral and cephalic ends.

CONCLUSION

In this article, we demonstrate the feasibility of using MR images to study the ossification process in formalin-fixed fetal tissues. A quantitative description of the ossification centers of vertebral bodies and arches is presented.

Intra-articular meniscoid folds in thoracic zygapophysial joints

STUDY DESIGN

A descriptive morphologic anatomic study was performed.

OBJECTIVE

The study aimed to investigate intra-articular meniscoids (folds) and cartilage quality in the thoracic zygapophysial joints (ZAJs), and to discuss them in the context of possible causes of thoracic back pain.

SUMMARY OF BACKGROUND DATA

The clinical relevance of the intra-articular meniscoid structures described in the cervical and lumbar spine is unclear, particularly in relation to ZAJ blockades. Corresponding data for the thoracic joints are not available.

METHODS

A total of 297 ZAJs between C7 and L1, obtained from 12 human cadavers (7 female, 5 male; mean age 81 years), were studied. The intra-articular folds were described and classified morphologically. The characteristics of the folds and their association with zygapophysial cartilage quality were investigated. Thirteen example folds were studied histologically.

RESULTS

In all, 268 intra-articular meniscoid folds were found in 183 joints. Three types were identified: type 1 (90%; mean length 3.1 mm) were thin, solid folds originating from a connective-tissue base, with multiple vessels at the joint capsule, extending between the joint surfaces. Type 2 folds (6%) were soft structures of fat and loose connective tissue including multiple vessels, located in the joint recess and not extending between the joint surfaces. The remaining folds (type 3, 4%) were circumscribed thickenings of the joint capsule. Three folds showed chronic hemorrhage, with dilated vessels at the base, and this was associated with severe cartilage lesions. In 16 folds, the base had direct tissue connection to the fat tissue of the epidural space.

CONCLUSION

This study for the first time systematically classifies intra-articular meniscoid folds in human thoracic ZAJs. These folds may represent an anatomic correlate for thoracic back pain. The chronic hemorrhage observed may be an important factor leading to arthritis.

Sexual dimorphism in degenerative disorders of the spine

Sexual dimorphism is evident during formation, growth, and development of the spine. Pregnancy alters spine physiology and is a risk factor for back pain. The processes of aging and spinal degeneration adversely affect men and women slightly differently. Although degenerative changes are observed at similar rates in both sexes, women seem to be more susceptible to degenerative changes leading to instability and malalignment, structural deterioration, such a stenosis or disc degeneration. Surgical satisfaction is greater in men, which has been attributed to poorer preoperative function secondary to more advanced disease at time of surgery and lower patient expectations for clinical improvement, both observed in women.