Intraoperative Spinal Cord Monitoring for Ossification of the Spinal Ligaments

1.脊髄刺激,脊髄記録による脊髄誘発電位(SpEP)を用いて,術中脊髄モニタリングを施術した脊柱靭帯骨化症手術症例14例の術中SpEP変化と術前後神経症状の推移につき検討した。2.SpEP基本波形(コントロール波形)はスパイク成分とそれに続く多相性成分とが明確に識別できるtype Iと,多相性成分のみからなるtype IIとに分類でき, type Iが7例,type IIが7例であった。また術前神経症状が重篤な症例はtype IIとなりやすい傾向があった。3.除圧操作完了直後にSpEPの振幅増大をみとめた症例の多くは,術後神経症状が著明に改善した。またそのうちの2例において,SpEP頂点潜時の明らかな短縮をみとめた。4.除圧操作中にSpEPの振幅が減少し,手術終了時まで回復傾向がみられなかった2症例において,術後一過性に神経症状の悪化をみた。5.以上より脊柱靭帯骨化症手術に際し,SpEPの振幅を指標とする術中脊髄モニタリング法は,術中脊髄機能の評価および予後の推定に有効な方法と考えられた。
Relationship between intraoperative spinal cord evoked potentials (SpEP) and neurological symptoms was studied in 14 patients suffering from ossification of spinal canal ligaments. The basic wave pattern of SpEP was classified into two groups: type I showed both an initial spike and a polyphasic component, and type II showed only a polyphasic component. The type I SpEP was observed in 7 cases, while the type II in 7 cases. The cases showing the type II SpEP had preoperatively more serious symptoms than those showing the type I SpEP. Marked neurological improvements were postoperatively observed in most of the cases which showed increased peak amplitude of SpEP after the completion of surgical decompression maneuvers. However, two cases, in which peak amplitude decreased by 25% or more and showed no tendency to recover, had transient neurological deterioration posto