セメントレス人工股関節置換術における臼蓋スクリュー設置の安全域の検討―臼蓋側からみた骨盤部血管の解剖学的研究

Safety Zone for Acetabular Screw Fixation in Cementless Total Hip Arthroplasty. A Study of Pelvic Vascular Anatomy

　セメントレス人工股関節置換術での重篤な合併症の一つに，臼蓋インプラントのスクリュー設置操作に伴う骨盤部血管の損傷がある．今回，われわれは骨盤部血管損傷を予防するため，臼蓋側からみた骨盤部血管の位置を解剖学的に検討して，臼蓋スクリューの設置操作における安全域を明らかにした．臼蓋の中央部分を除いた臼蓋後方の領域においては，臼蓋の裏側に骨盤部血管は一部にしか存在しなかった．また，臼蓋の裏側に骨盤部血管が存在していても骨盤血管までの距離は31mm以上であった．すなわち，中央部分を除く臼蓋の後方部分が，臼蓋スクリュー設置の安全域といえる．しかし，骨盤の形態や骨盤部血管の走行には個人差があるため，骨盤部血管損傷を回避して安全に手術を行うためには，短いドリルやスクリューを使用して，細心の注意を払い操作する必要がある．

　Pelvic vascular injury is one of the serious complications associated with acetabular component setting in cementless total hip arthroplasty (THA). In order to prevent intrapelvic vascular injury during cementless THA, each individual's unique intrapelvic morphology must be fully understood. Therefore, in the present study we investigated the location of intrapelvic blood vessels in order to establish a safety zone for acetabular screw fixation in cementless THA. Few intrapelvic blood vessels were located in the posterior area except in the acetabular center, and when intrapelvic blood vessels were found there, they were typically located 31 mm from the acetabular surface. We therefore concluded that the posterior area, except the acetabular center, is a safe area for screw fixation. Because of the possibility of intrapelvic vascular anomalies and the heterogeneity of pelvic morphology, the possibility of intrapelvic blood vessel injury and the use shorter screws and drills to prevent intrapelvic vascular injury must be borne in mind.