前方スクリュー固定および後方固定を同時施行した軸椎歯突起骨折の2例

Anterior Screw Fixation Combined with Posterior Interlaminar Fusion for Fracture of Axis : report of two cases

I．はじめに

　軸椎歯突起骨折の治療の選択は骨折のタイプと転位の程度によってなされるが，年齢や合併損傷なども重要で，個々の症例にあわせた治療法の選択が重要である^11,13）．

　最近当施設においても転位の強い2例の軸椎骨折を経験した．1例ではハローベストによる固定にも関わらず不安定性が持続したため，他の1例は来院時に既に外傷後8週経過していたため，両症例とも手術による内固定を施行した．手術法としては一期的に前方スクリュー固定と後方環軸椎椎弓間固定を併用した方法を用いた．各症例を呈示し，今回施行した方法について他の手術法と比較検討する．

Two cases of axis fracture are reported. Traffic accidents were the cause of injury in both cases. Theodontoid process was dislocated anterolaterally with fracture of the lateral mass of the axis in both cases.In Case 1 good alignment of the atlas and axis could not be maintained even with a Halo-vest. The case 2patient with spinal cord compression caused by dislocation of the axis was referred to our hospital 8 weeksafter the accident. Both cases were surgically treated in a similar fashion. Because of the lateral mass frac-ture and lateral displacement of the atlas relative to the axis, posterior screw fixation with interlaminarfixation (Magerl) was thought to carry a risk of causing damage to the vertebral artery. Because of this,anterior screw fixation combined with posterior wiring was conducted. First, the odontoid process was fix-ed anteriorly by a screw because it was able to be placed back in good alignment while the patient was inthe supine position. Then, the posterior C1-2 interlaminar wiring with iliac bone graft was added. Rigidfixation was obtained without any complication.

Various kinds of fixation, such as posterior interlaminar wiring, odontoid screw fixation and Magerl'sfixation, have been reported for the treatment of unstable axis fracture. Among them Magerl's method hasbeen regarded as the most stable. When it is not applicable, combination of the first two methods can bean alternative way of treatment for this odontoid process fracture.