中間位すべり度と前後への椎体動揺度が腰椎の臨床症状に与える影響の比較

Influence of the Amount of Slip in the Neutral Position and Sagittal Translation on Lumbar Symptoms

　抄録：腰下肢症状を呈する880例について中間位でのすべり度と前後への椎体動揺度が臨床症状に与える影響について調査した．方法は，単純X線側面像で中間位すべり度および前後への椎体動揺度を計測し，3mm以上と未満で4群に分類して，各群の臨床評価点数（JOAスコア）を比較した．結果は，中間位ですべりを有する群は有意に年齢が高く，すべりの発生には加齢的変化が影響していると考えられた．中間位すべりを有する群は動揺度の有無に関わらず有意に点数が低かった．また動揺度の有無での有意差はないが，中間位すべりを合併すると症状に影響していた．すなわち中間位でのすべりは前後への椎体動揺性よりもより強く臨床症状に影響を与えていた．以上の結果から，臨床症状に関与する腰椎の不安定性の指標としては，中間位でのすべりが前後への動揺性よりも重要であると証明された．

　Purpose：The purpose of this study was to assess the clinical significance of two radiologic factors, slip in neutral position and sagittal translation, in relation to lumbar symptoms.

　Methods：Between 1996 and 1997, 1,647 outpatients with low back disorders were examined radiologically. After excluding the 767 patients with trauma, compression fractures, spondylolysis and spondylolisthesis, scoliosis, retrolisthesis, or unsuitable radiographs, the radiographs of 880 patients were examined for amount of slip in the neutral position and sagittal translation at segment L4/5. The patients were divided into four groups according to whether a 3mm slip in neutral position and 3mm sagittal translation were detected. There were 32 patients with 3mm or more neutral slip and 3mm or more sagittal translation, 38 with 3mm or more neutral slip and less than 3mm sagittal translation, 106 with less than 3mm neutral slip and more than 3mm sagittal translation, and 704 with less than 3mm neutral slip and less than 3mm sagittal translation. The symptoms in the four groups were compared on the basis of their Japanese Orthopaedic Association lumbar scores.

　Results：The group with 3mm or more neutral slip was older than the other groups. The scores of the patients with 3mm or more neutral slip were significantly lower than those of the other groups, and symptom severity was not correlated with the amount of sagittal translation,indicating that a 3mm or more neutral slip had a greater impact on lumbar symptoms than sagittal translation. Sagittal translation, however, influenced symptoms when combined with 3mm or more neutral slip.

　Conclusion：Because of the elderly population with neutral slip, slip in the neutral position was concluded to be the final stage of disc degeneration. The slip in neutral position was a more important radiological factor than the sagittal translation on lumbar symptoms, therefore earlier intervention, such as by trunk-muscle exercise, should be recommended to patients with such evidence of disc degeneration in the minimal stage.