骨盤形態角と脊椎矢状面アライメントの関係

Pelvic Morphologic Angle and Sagittal Spinal Alignment

　腰椎・骨盤アライメントは，加齢や脊椎変性による影響を受け，腰痛疾患の発生に影響を及ぼすことが報告されている．若年成人54人に対して，C7 plumb lineから仙骨後方隅角までの距離(SVA)，腰椎前弯角(LLA)，仙骨傾斜角(SS)，骨盤回旋角(PA)，hip axisと仙椎後上隅を結ぶ線と仙椎の上縁とがなす角(PRS1角，骨質形態角)について計測し，それぞれのパラメータ間の相関係数を計測した．今回の結果から，PRS1角が大きい場合にはSSは小さく，PRS1角が小さい場合には仙骨傾斜が急峻で骨盤が後傾している骨盤形態である傾向がみられた．骨盤傾斜とSVAは，骨盤傾斜の大小に関わらずSVAは一定に保たれる傾向があった．

　We investigated the relation between the pelvic morphologic angle (PRS1) and total sagittal spinal alignment in 54 healthy adult volunteers.　The following parameters were measured on lateral whole-spine standing radiographs：distance between the C7 plumb line and the posterior superior corner on the superior margin of S1 (SVA), lumbar lordotic angle (LLA), sacral slope (SS), pelvic tilting angle (PA), and pelvic morphologic angle (PRS1).　The coefficient for the correlations between PRS1 and SS and LLA was r＝－0.81 (p＜0.01) and r＝－0.50 (p＜0.05), respectively.　The close results clearly showed a relationship between the pelvic and the spinal parameters.　LLA is closely related to the orientation of the pelvis, which is expressed by the SS, which, in turn, is strongly influenced by the PRS1.　Our results showed that PRS1 had a high correlation coefficient between both of PA and SS, and the relationship to LLA was statistically significant.