Flexion stressが頚椎部脊髄症の病態に及ぼす影響

Effects of Flexion Stress on the Development of Cervical Myelopathy

　抄録：頚椎部脊髄症の病態にflexion stressが及ぼす影響を調べるため，過去10年間における手術例で後弯を伴った症例を検討した．対象は頚椎症性脊髄症257例中23例（9％），頚椎OPLL 85例中9例（11％），neuropathic spine 3例の合計35例であった．神経症状の多変量解析では構築学的事項に関連して，脊髄後弯角が10°以上のもの，15°以上の限局性角状頚椎変形は運動麻痺優位の脊髄症に有意に関与した．脊髄後弯はsegmental myelopathyの発現に大きく影響し，かつ術後成績，特に弛緩性運動麻痺の改善に影響した．脊髄後弯とflexion stressは術後の脊髄expansion rateの低下を来した．頚椎柱のmechanical flexionは，脊髄のlongitudinal stressを高めて脊髄機能障害を起こす閾値を低下させ，病変のanterior impingementの影響力を高める．

　We studied the effects of flexion stress of the cervical spine in terms of development of myelopathy. Thirty-five surgical cases were analyzed with respect to clinical presentation, kyphotic alignment, modalities of the anterior impingement of the cord, and surgical outcome. Kyphotic alignment of the cervical spine had potentially increased flexion stress of the cord with a presumable presentation of segmental motor-dominant myelopathy. It is recommended that the treatment option must be individual based upon reduction of each flexion stress.