L5/S1椎間孔狭窄によるL5神経根症状の病態―L4/5脊柱管狭窄によるL5神経根症状と比較して

Pathogenesis of L5 Radiculopathy Secondary to Lumbar Foraminal Stenosis. Clinical Features Compared with L5 Radiculopathy Secondary to L4/5 Lumbar Canal Stenosis

　目的：L5/S1椎間孔の病態の特徴を検討する．

　対象と方法：片側のL5神経根症状を呈し，L5/S1椎間孔狭窄の診断で，椎間孔部の除圧と固定により下肢痛が消失した29例と，通常のL4/5脊柱管内狭窄の診断でL5神経根症状を呈し，L4/5の除圧術により下肢痛が消失した70例の臨床所見・画像所見を調査し比較した．

　結果：臨床所見として安静時下肢痛，下肢痛VAS，画像所見としてL5/S1椎間可動角，後屈時L5後方すべり，L5/S1楔状化について，L5/S1椎間孔狭窄群とL4/5脊柱管狭窄群との間で有意差を認めた．

　まとめ：安静時下肢痛，下肢痛VAS，L5/S1椎間可動角，後屈時L5後方すべり，L5/S1楔状化がL5/S1椎間孔狭窄の病態に特徴的と考えられた．MRI所見のみではL5/S1椎間孔狭窄を診断することは困難と考えられた．

　Background：The aim of this study is to investigate the clinical features of lumbar foraminal stenosis.

　Methods：We compared the clinical and imaging findings of 29 patients with L5 radiculopathy secondary to L5/S1 foraminal stenosis who were successfully treated by foraminal decompression and posterior interbody fusion of L5/S1, with the clinical and imaging findings of 70 patients with L5 radiculopathy secondary to L4/5 central canal stenosis who were successfully treated by L4/5 decompression with or without fusion.

　Outcome：Statistical significant inter-group differences were noted in the presence of symptoms of L5 radiculopathy at rest, a high visual analog scale (VAS) score for the pain of L5 radiculopathy, a high L5/S1 intervertebral mobile angle, retrolisthesis of the L5 lumbar vertebra, and L5/S1 wedging.

　Conclusion：This study revealed that statistical analysis revealed that the presence of symptoms of L5 radiculopathy at rest, a high VAS score for the pain of L5 radiculopathy, a high L5/S1 intervertebral mobile angle, retrolisthesis of the L5 lumbar vertebra, and L5/S1 wedging were important clinical features of lumbar foraminal stenosis, and it was difficult to differentiate foraminal stenosis from canal stenosis on the basis of the MRI findings alone.