外側型腰椎椎間板ヘルニア7例の検討

Clinical Features of Lateral Lumbar Disc Herniation : Report of Seven Cases

　抄録：外側型腰椎椎間板ヘルニアは画像診断の発達した現在もいまだ診断と治療に配慮の必要な疾患である．今回，われわれが経験した7例に検討を加え，診断に難渋した症例を呈示した．男性4例女性3例，年齢51～75歳，罹患高位はL3/4：2例，L4/5：3例，L5/S：2例，全例で当該椎間の上位の神経が障害されていた．L4/5の3例中2例にL4，L5の2根障害を認めた．下肢痛の程度は全例で強かった．術式はextra-foraminalと術前から診断された4例に対してWiltseの外側方アプローチを選択し，術後JOAスコアの平均は術前10.7点が26.5点に改善した．過去の報告でも外側型椎間板ヘルニアの頻度は，L4/5，L3/4の順に多く，L3，L4の根症状を呈する例が多い．L3とL4の神経所見は共通点が多く鑑別が困難なため，責任高位の決定に注意を要した．

　Lateral lumbar disc herniation (LLDH) has been diagnosed preoperatively with increasing frequency since the advent of CT and MRI, however, it is difficult to make an accurate diagnosis even now. We report seven cases of LLDH, three in females and four in males. The patients' average age was 64 years old, and the follow-up period ranged from 14 to 30months. The L3 root was affected by L3-4 herniation in two case, the L4 root by L4-5 herniation in three cases, and the L5 root by L5-S herniation in two cases. A double lesion of the L4 and L5 roots was present in two cases of L4-5 herniation. All patients had severe leg pain that required surgery, Wiltse's extra-spinal approach was used in four cases of extra-foraminal herniation. The average JOA score improved from 10.7 to 26.5 points. Compared with intraspinal disc herniations, LLDH tends to occur relatively more frequently at the L3-4 and L4-5 level. It is difficult to distinguish between L3 and L4 root signs because they are so similar.