Quantification of pediatric cervical spine growth at the cranio-vertebral junction

Measuring the shape and dimensions of normal the bony structures in the craniovertebral junction from computed tomography images of the pediatric age group

BACKGROUND

The aim of this study is to contribute to the literature by determining the morphometric reference values of the bony structures in the craniovertebral junction (CVJ) from computer tomography (CT) images of the pediatric age group.

METHODS

In this study, CT's of 151 simple trauma patients aged between 3 and 15 years between 2016 and 2020 were evaluated. All CT examinations were performed using a 32-slice CT and included images of the skull base and C1-C2 junction. A total of 10 measurements were obtained from these images, including Wachenheim clivus canal angle (WCA), Welcher basal angle (WBA), Cran-iocervical tilt angle (CCT), power ratio (PR), Atlantodens interval, McRae Line (MRL), McRae - Dens distance, basion-dens interval (BDI), basion-axis interval (BAI), and atlantooccipital measurement (AOM).

RESULTS

In comparison between gender groups, MRL (p=0.011) and AOM (p<0.001) measurements were found to be significantly higher in males. McRae-Dens distance, BDI, and AOM were significantly higher in patients aged 3-9 years (respectively, p=0005, p=0.003, p<0.001), and BAI (p=0.001) was significantly higher in patients aged 10-15 years. The McRae - Dens distance (p=0.119) was similar between patients with and without terminal ossicle in odontoid apex. But BDI of patients without terminal ossicle was significantly higher (p=0.048). All parameters, except the WCA, WBA, CCT, and PR, were statistically significantly correlated with the patient age (respectively, p=0.21, p=0.13, p=0.70, p=0.99).

CONCLUSION

In this study, the morphometric reference values of the bone structures at the CVJ were determined from the CT images of the pediatric age group.

Increase in clivo-axial angle is associated with clinical improvement in children undergoing occipitocervical fusion for complex Chiari malformation: patient series

BACKGROUND

The authors analyzed the pre- and postoperative morphometric properties of pediatric patients with complex Chiari malformation undergoing occipitocervical fusion (OCF) to assess clinical outcomes and morphometric properties that might influence postoperative outcomes.

OBSERVATIONS

The authors retrospectively reviewed 35 patients younger than 22 years with Chiari malformation who underwent posterior fossa decompression and OCF with or without endoscopic endonasal odontoidectomy at their institution (13 with and 22 without odontoidectomy). Clivo-axial angle (CXA), pB-C2, atlantodental interval, basion-dens interval, basion-axial interval, and canal diameter at the level of C1 were measured on preoperative and approximately 3-month postoperative computed tomography or magnetic resonance imaging. The authors further stratified the patient cohort into three age groups and compared the three cohorts. The most common presenting symptoms were headache, neck/shoulder pain, and dysphagia; 80% of the cohort had improved clinical outcomes. CXA increased significantly after surgery. When stratified into those who showed postoperative improvement and those who did not, only the former showed a significant increase in CXA. After age stratification, the significant changes in CXA were observed in the 7- to 13-year-old and 14- to 21-year-old cohorts.

LESSONS

CXA may be the most important morphometric predictor of clinical outcomes after OCF in pediatric patients with complex Chiari malformation.

Pediatric dens anatomy and its implications for fracture treatment: an anatomical and radiological study

PURPOSE

Separation of C2 growth plates and dens fractures are the most common types of injuries to the axis (C2) in children. Operative treatment of these injuries with the use of direct osteosynthesis requires a profound knowledge of detailed anatomy and dimensions of the axis. The main issue addressed by the study was the age at which the size of the dens is adequate at all levels to accommodate two screws, and the size of the posterior dens angulation angle (PDAA) in a healthy child in individual age periods.

METHODS

Dimensions and angles of the dens and C2 in individual age categories in both boys and girls were measured in a series of 203 CT scans of individuals 0-18 years old and on anatomical specimens (42 samples). In addition, 5 histological series of this region from the fetal period were reviewed.

RESULTS

Dimensions of the dens gradually increase with age, with a considerable acceleration during growth spurt periods that are different in boys and girls. PDAA is markedly changing with age; in the fetal period, the dens shows a slight anterior angulation which gradually transforms into posterior angulation, as early as between 4 and 6 years of age. The screw insertion angle changes accordingly.

CONCLUSION

During growth, there occur changes in PDAA that should be respected in evaluation of transformation of anterior into posterior angulation, as shown by imaging methods. Dens dimensions theoretically allow insertion of two 3.5 mm screws as early as from the age of 1 year.

Morphometric changes at the craniocervical junction during childhood

OBJECTIVE

Current understanding of how the pediatric craniocervical junction develops remains incomplete. Measurements of anatomical relationships at the craniocervical junction can influence clinical and surgical decision-making. The purpose of this analysis was to quantitatively define clinically relevant craniocervical junction measurements in a population of children with CT scans that show normal anatomy.

METHODS

A total of 1458 eligible patients were identified from children between 1 and 18 years of age who underwent cervical spine CT scanning at a single institution. Patients were separated by both sex and age in years into 34 groups. Following this, patients within each group were randomly selected for inclusion until a target of 15 patients in each group had been reached. Each patient underwent measurement of the occipital condyle-C1 interval (CCI), pB-C2, atlantodental interval (ADI), basion-dens interval (BDI), basion-opisthion diameter (BOD), basion-axial interval (BAI), dens angulation, and canal diameter at C1. Mean values were calculated in each group. Each measurement was performed by two teams and compared for intraclass correlation coefficient (ICC).

RESULTS

The data showed that CCI, ADI, BDI, and dens angulation decrease in magnitude throughout childhood, while pB-C2, PADI, BAI, and BOD increase throughout childhood, with an ICC of fair to good (range 0.413-0.912). Notably, CCI decreases continuously on coronal CT scans, whereas on parasagittal CT scans, CCI does not decrease until after age 9, when it shows a continuous decline similar to measurements on coronal CT scans.

CONCLUSIONS

These morphometric analyses establish parameters for normal pediatric craniocervical spine growth for each year of life up to 18 years. The data should be considered when evaluating children for potential surgical intervention.

Biodistribution and Dosimetry of Intraventricularly Administered 124I-Omburtamab in Patients with Metastatic Leptomeningeal Tumors

Radiation dose estimations are key for optimizing therapies. We studied the role of ¹²⁴I-omburtamab (8H9) given intraventricularly in assessing the distribution and radiation doses before ¹³¹I-omburtamab therapy in patients with metastatic leptomeningeal disease and compared it with the estimates from cerebrospinal fluid (CSF) sampling. Methods: Patients with histologically proven malignancy and metastatic disease to the central nervous system or leptomeninges who met eligibility criteria for ¹³¹I-omburtamab therapy underwent immuno-PET imaging with ¹²⁴I-8H9 followed by ¹³¹I-8H9 antibody therapy. Patients were imaged with approximately 74 MBq of intraventricular ¹²⁴I-omburtamab via an Ommaya reservoir. Whole-body PET images were acquired at approximately 4, 24, and 48 h after administration and analyzed for dosimetry calculations. Peripheral blood and CSF samples were obtained at multiple time points for dosimetry estimation. Results: Forty-two patients with complete dosimetry and therapy data were analyzed. ¹²⁴I-omburtamab PET-based radiation dosimetry estimations revealed mean (±SD) absorbed dose to the CSF for ¹³¹I-8H9 of 0.62 ± 0.40 cGy/MBq, compared with 2.22 ± 2.19 cGy/MBq based on ¹²⁴I-omburtamab CSF samples and 1.53 ± 1.37 cGy/MBq based on ¹³¹I-omburtamab CSF samples. The mean absorbed dose to the blood was 0.051 ± 0.11 cGy/MBq for ¹²⁴I-omburtamab samples and 0.07 ± 0.04 cGy/MBq for ¹³¹I-omburtamab samples. The effective whole-body radiation dose for ¹²⁴I-omburtamab was 0.49 ± 0.27 mSv/MBq. The mean whole-body clearance half-time was 44.98 ± 16.29 h. Conclusion: PET imaging with ¹²⁴I-omburtamab antibody administered intraventricularly allows for noninvasive estimation of dose to CSF and normal organs. High CSF-to-blood absorbed-dose ratios are noted, allowing for an improved therapeutic index to leptomeningeal disease and reduced systemic doses. PET imaging-based estimates were less variable and more reliable than CSF sample-based dosimetry.

Morphometric analysis of the developing pediatric cervical spine

OBJECTIVE Our understanding of pediatric cervical spine development remains incomplete. The purpose of this analysis was to quantitatively define cervical spine growth in a population of children with normal CT scans. METHODS A total of 1458 children older than 1 year and younger than 18 years of age who had undergone a cervical spine CT scan at the authors' institution were identified. Subjects were separated by sex and age (in years) into 34 groups. Following this assignment, subjects within each group were randomly selected for inclusion until a target of 15 subjects in each group had been measured. Linear measurements were performed on the midsagittal image of the cervical spine. Twenty-three unique measurements were obtained for each subject. RESULTS Data showed that normal vertical growth of the pediatric cervical spine continues up to 18 years of age in boys and 14 years of age in girls. Approximately 75% of the vertical growth occurs throughout the subaxial spine and 25% occurs across the craniovertebral region. The C-2 body is the largest single-segment contributor to vertical growth, but the subaxial vertebral bodies and disc spaces also contribute. Overall vertical growth of the cervical spine throughout childhood is dependent on individual vertebral body growth as well as vertical growth of the disc spaces. The majority of spinal canal diameter growth occurs by 4 years of age. CONCLUSIONS The authors' morphometric analyses establish parameters for normal pediatric cervical spine growth up to 18 years of age. These data should be considered when evaluating children for potential surgical intervention and provide a basis of comparison for studies investigating the effects of cervical spine instrumentation and fusion on subsequent growth.

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.