第5腰神経のダブルクラッシュ症候群

“Double-crush” Syndrome of the 5th Lumbar Spinal Nerve as a New Clinical Entity

　第4-5腰椎(L4-5)高位の脊柱管内の除圧で，ある一定の症状の改善がみられるも，完治にはいたらず，L5-S1高位の椎間孔外狭窄病変に対して，サルベージ手術を追加し，遺残する下肢の根性坐骨神経痛および間欠跛行が消失した15例の臨床経過について報告した．このような症例が存在するという事実は，腰部神経根症においても上肢と同様に，ダブルクラッシュ症候群が存在する可能性を示唆している．今後，第5腰神経根症の手術成績向上のためには，脊柱管内だけでなく，脊柱管外も含めたすべての神経圧迫部位を考慮に入れた手術計画を立案すべきである．

　We reported 15 surgical failure cases of 5th lumbar radiculopathy due to residual sciatica and intermittent claudication in spite of adequate decompression at L4-5 level.　The effects of first operations were somewhat effective, but not satisfactory for these patients.　The causes of failed back surgery were unrecognition of extraforaminal stenosis at L5-S1 level in all cases.　Their symptoms were completely relieved after extraforaminal decompression.　This fact suggests that double crash syndrome may exist in cases of 5th lumbar radiculopathy in the same way as the nerve entrapment syndrome in the upper extremity.　We named this disease condition the double crush syndrome of the 5th lumbar spinal nerve as a new clinical entity.　In order to improve surgical outcome of lumbar spinal stenosis, treatment should be applied to all the compression sites along the course of the 5th lumbar spinal nerve from the intra-spinal canal to the extra-foraminal area.