胸腰椎圧迫骨折と診断された後，遅発性に転位が生じ，対麻痺を来した強直性脊椎骨増殖症の2例

Paraplegia due to Delayed Dislocation of the Spine after an Initial Diagnosis of Thoracolumbar Compression Fracture Complicating Ankylosing Spinal Hyperostosis : Report of Two Cases

　抄録：転倒などの比較的軽微な外傷により，胸腰椎に不安定型の骨折を生じた強直性脊椎骨増殖症の2例を経験した．いずれの症例も初診時にはほとんど転位がなく，圧迫骨折の診断を受けていたが，2～3週後に転位が生じて対麻痺を来した．ともに緊急手術により後方除圧・固定を行ったが，麻痺が残存してADLの低下につながった．強直性脊椎骨増殖症に合併した胸腰椎の骨折では，初診時に不安定性の有無を慎重に判断する必要があり，不安定型の骨折に対しては，厳重な経過観察と手術を含めた治療法の検討を要する．

　We report two cases of thoracolumbar spine fracture complicating ankylosing spinal hyperostosis. Because the fractures were caused by relatively minor trauma and there was minimal displacement, the initial diagnosis in both cases was compression fracture. A few weeks later, however, both patients developed rapidly progressive paraplegia due to delayed dislocation of the fractures. We managed both cases by posterior spinal arthrodesis, but the neurological deficit persisted. Fractures of the thoracolumbar spine complicating ASH must be carefully assessed for instability. If the fracture is found to be unstable, the patient must be strictly monitored, and indications for surgical treatment must be considered.