Summary and conclusion
The normal ossification patterns and timing of synchondrosis fusion of cervical vertebrae are variable. Knowledge of these patterns and time of closure of synchondrosis is important to better differentiate a normal variant from a traumatic injury. Recently, an increasing use of computed tomography images makes this knowledge can be identified more frequently.
The aim of this work was to record the normal variations of timing of appearance of ossification centers of cervical vertebrae and time of closure of synchondrosis in normal Egyptian individuals in relation to age and sex by using plain x-ray and CT scan.
This present study was carried out on two hundred & forty healthy living Egyptian individuals of both sexes with exclusion of any individual with clinical evidence of congenital or developmental disease, neoplastic growth, adverse neurological conditions, vertebral and muscular abnormalities, fracture or dislocation, epiphyseal injury, spine surgery, and scoliosis that might affect normal vertebral growth from this study.
The individuals were divided into 3 groups according to thier age as following: Group I: Their ages ranged from 1 year up to less than 6 years and they included 40 males and 40 females. Group II: Their ages ranged from 6 years up to less than 12 years and they included 40 males and 40 females. Group III: Their ages ranged from 12 years up to 20 years and they included 40 males and 40 females. The cases have been examined by using axial, sagittal and coronal CT scanning (Reconstruction) & antero posterior (Open Mouth) plain X-ray of the cervical spine at Benha university hospital and other private radiological centers in Benha. Through these cervical spines CT and plain x-ray films, Ossification of atlas, axis and other cervical vertebrae was detected. The presence or absence of synchondrosis was also identified. Normal closing age of synchondrosis was defined. A CT scanner was used to obtain spine images at 2.5 mm intervals according to the established clinical protocols. The resolution was 512 × 512 pixels. The obtained data were collected and analyzed statistically.
Results: The present study showed that the atlas vertebra was formed by three primary ossification centers; the anterior arch and the two neural arches, which surround the anterior arch. The ossification centers became visible by 1 year of age. The axis vertebra was formed by four primary ossification centers; one for each neural arch, one for the body and one for the odontoid process. All were visible by 1 year of age. Cervical vertebrae from C3 to C7 were formed by three primary ossification centers; the body arises from a single ossification center and one center for each neural arch. The three primary ossification centers were also visible by 1 year of age. This study was carried out on healthy individuals aged from 1year up to 20 years and by the age of 1 year all ossification centers of the cervical vertebrae had appeared. The atlas vertebrae began to close at the age of 3.75±1.53 years and had completed their closure by the age of 15.71±2.84 years with a maximum closure occurring at the age of 8.75±1.53 years. The posterior synchondrosis had closed earlier than the RT & LT. neurocentral synchondrosis.
The axis vertebra began to close at the age of 3.75±1.53 years and completed their closure by the age of 15.71±2.84 years with a maximum closure occurring at the age of 8.75±1.53 years. The posterior synchondrosis had closed completely at the age of 8.75±1.53 years. The apicodental synchondrosis might still be opened after the age of 20 years.
The cervical vertebrae from C3 to C7 began to close at the age of 3.75±1.53 years and had completed their closure by the age of 8.75±1.53 years. Ossification of the cervical vertebrae had occurred from below upwards since the cervical vertebrae from C3 to C7 were the first to ossify followed by the axis vertebra then the atlas vertebra, which was the last one to ossify.
There was difference in the percentile of closure of the synchondrosis of the cervical vertebrae between males & females in the three age groups but this difference was statistically insignificant. In addition, there was no statistical difference between RT. neurocentral synchondrosis closure & LT. neurocentral synchondrosis closure of the cervical vertebrae.
Conclusion: From this study, we can conclude that the radiological study of the normal ossification patterns and timing of synchondrosis fusion of cervical vertebrae is a valuable index in determination of age in the living individuals. Also, we can conclude that the patterns of ossification and time of fusion of synchondrosis are not related to sex.
Recommendation: The knowledge of ossification milestones of cervical vertebrae and time of closure of synchondrosis is essential, especially for medical professionals and radiologists for discriminating between normal anatomy, variants and true osseous lesions. The synchondrosis may be misread as fractures and proper CT imaging could help differentiation.
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