Synchondrosis fracture in a pediatric patient
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* Christopher W. Reilly
* Fay Leung

We present the case of a 6-year-old boy with a fracture of the anterior arch of the atlas vertebra, treated with transoral closed reduction and external immobilization.

## Case report

A 6-year-old boy arrived at the emergency department three days after falling 51/2 metres (19 feet) from a balcony. Bystanders said that the child appeared to have landed on his forehead. The child complained of neck pain and held his head stiffly.

On examination, his C-spine movements were decreased and he held his head tilted to the left. The rest of the physical exam, including a neurological examination, was unremarkable. Extensive soft tissue swelling anteriorly and a widened atlanto-dental interval was seen on plain radiographs. Computed tomography revealed fractures through the synchondroses of the anterior arch of C1. The central portion of the C1 vertebra was displaced anteriorly by 6 mm on the left side and 1 mm on the right (Fig. 1, left scan).

![FIG. 1](http://canjsurg.ca/https://www.canjsurg.ca/content/cjs/48/2/158/F1.medium.gif)

[FIG. 1](http://canjsurg.ca/content/48/2/158/F1)

FIG. 1 
Computed tomographic images of synchondrosis disruption and displacement of the C1 vertebra at presentation (left), during transoral reduction (centre) and at follow-up (right, showing the healed anterior arch).

The patient was immobilized with a halo vest, and CT repeated under general anesthesia. With the boy in the CT scanner, reduction was achieved with digital compression applied transorally by the staff surgeon (Fig. 1, middle).

A follow-up CT scan demonstrated closure of the synchondrosis and maintenance of the reduction (Fig. 1, right). The child quickly returned to normal activities, with no further symptoms. Three years later his radiographs are normal, with no evidence of stenosis or C1 arch hypoplasia.

## Discussion

Excessive hyperextension has been cited as a possible mechanism of injury in anterior arch disruptions, as occurred in this case.1 In children, the signs of atlas fractures may be subtle. Suspicious clinical or radiographic signs should prompt further investigation with CT or MRI.

Fractures of the atlas in children must be distinguished from normal variants such as congenital arch malformations.2 Only 3 reports3–5 in the literature describe cases of disruption of the synchondrosis of the anterior arch of C1, with no consensus as to the recommended treatment: 2 patients were treated with a rigid collar,3,4 and the third underwent 3 weeks of cervical traction before 2 months of cervicothoracic bracing.5 Ours is the first report of transoral reduction.

Fractures of the atlas vertebra are rare in children. A history of trauma combined with the classical signs of neck pain, head tilt, diminished cervical range of motion and cervical muscle stiffness should alert the clinician to the possibility of an atlas fracture. Initial radiographs may be equivocal; further images should be made with CT and MRI if clinical suspicion is high. Imaging may also be used to verify post-immobilization reduction of the fracture. For stable fractures, excellent functional results may be obtained with immobilization by external fixation.

## Footnotes

*   **Competing interests:** None declared.

*   Accepted May 23, 2004.

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