強直性脊椎炎に伴う頚椎骨折の1例

Fracture of the Cervical Spine in Ankylosing Spondylitis. A Case Report

Ⅰ．は じ め に

　強直性脊椎炎は，脊柱の関節や仙腸関節を主に障害する全身の炎症性疾患である．若年で発症し，椎体間が癒合し，脊柱の可動性や弾力性が失われる．さらに骨粗鬆症を合併し，軽微な外傷で脊椎骨折を生じやすい^8,11,18)．骨折部の不安定性や偽関節により遅発性に脊髄麻痺を生じる危険性が高く，強固な固定を要する^1,15)．今回，強直性脊椎炎に伴うC7頚椎骨折に対して手術治療を行った症例を報告する．本病態では通常の頚椎骨折とは異なる臨床像を示す．本報告では，画像上の特徴と手術方法について検討する．

　We report a case of a 61-year-old man with ankylosing spondylitis who showed cervical spine fracture. The patient had fallen down on the floor and presented with severe neck pain. He was treated conservatively with a hard neck collar in an emergency hospital because of C7 body fracture without dislocation. However, the follow-up radiographs demonstrated a progressive C6-7 anterior dislocation. He was referred to our hospital 6 weeks after the trauma. The 3D-CT reconstruction imaging revealed that the fracture extended from the C7 vertebral body to the C6 lamina via the bilateral C6/7 facet joints. The patient underwent C2-Th3 posterior fixation using pedicle and lateral mass screw techniques. The postoperative course was uneventful. He was discharged without any complication at 1 month postoperatively. The radiograph 3 months after surgery showed good bone fusion. Spine fracture with ankylosing spondylitis usually shows significant instability because of the long lever-arm of the fused vertebrae at the fracture level. Solid spinal fusions such as long posterior fusion or anterior-posterior simultaneous fusion are needed in such cases.