- 期刊
包坐骨式套筒簡介
Introduction to Ischial Ramus Containment Socket
摘要
第二次世界大戰以前，膝上截肢義肢的套筒約為塞入型((plug-fit)，二次世界大戰後，則逐漸被四邊形(quadrilateral)套筒所取代，然而近十年來，又出現革新型奔筒，起初是百家爭嗚如 NSNA、CAT-CAM、Narrowed M-L等，目前已由國際義肢裝具協會(ISPO)召開專題討論後，統一命名為包坐骨式套筒(Ischial Ramus Containment socket, IRC)。包坐骨式套筒的意義乃是，將大部份的坐骨包進套筒裡，以增強內外向的穩定(mediolateral stability)，而減少不正常步態的發生。它的特徵如下：(l)坐骨結節與骨支(ischial tuberosity & ramus)被包進套筒內，故內側壁與外側壁都比四邊形套筒相對地增高；(2)外側壁緊貼著股骨，故套筒的內外徑變窄而前後徑變寬；(3)套筒的四個轉角都變得十分圓滑，儘量符合肌肉的曲線，故近端截面的形狀顯得很自然而美觀；(4)嚴格要求套筒的內縮角度(adduction), 使其有利於股外展肌的收縮，並儘量限制股骨的外展趨勢；(5)設置套筒淤屈曲位置(initial flexion); (6)套筒與殘肢要完全接觸，以增加承近壓面積，減少殘肢水腫，並增加其本體感覺。膝上截肢義肢套筒的旋轉支點(fulcrum)，一般是位於坐骨結節的接觸點附近，比較四邊形套筒與包坐骨式套筒的坐骨結節位置，可知後者的旋轉支點比前者更靠近內側，亦即更接近地面反作用力線，故在步態週期的站立中期(midstance phase)，後者所受的內翻力距(varus moment)較小，換官之，包坐骨式套筒因外力而旋轉的趨勢降低。其次，包坐骨式套筒的最大特色，就是將大部份坐骨包進套筒內，以達到所謂的坐骨鎖定(ischial bony lock)效應，因為坐骨一旦被鎖定，好像形成一道牆，使套筒得以拮抗因內翻力距而旋轉的趨勢，同時也阻止了骨盆傾向健側的趨勢，故此設計在冠狀面的穩定性(M-L stabilty) 頗佳。此外，坐骨窩的設計使坐骨與套筒的接觸面積大增，局部壓力減少，病人倍感舒適，且套筒在矢狀面的穩定性(A-P stability)亦增加。作者認為包坐骨式套筒乃是融合過去兩種套筒的優點，再加上特殊的坐骨鎖定設計而成的，既美討又舒適，且有頗佳的前後及內外向之穩定性，以充分發揮其應有的功能，故包坐骨式套筒應是一個值得提倡的新設計。
並列摘要
The above-knee amputee had been fitted with plug-fit socket till the end of the World War II. In the past forty years, quadrilateral socket has been used as the routine socket for the above-knee amputee. But some drawbacks are found as the followings: 1) discomfort because the patients feel like sitting on the stone plate; 2) poor medio-lateral stability as shown by the lateral bending gait and the lateral gaping of the socket, which often needed the help of the hip joint with pelvic band. In order to correct the above drawbacks of the above-knee prosthetic socket, some new designs have been developed in recent ten years. They are: the Normal Shape Normal Alignment (NSNA), Contoured Adducted Trochanteric-Controlled Alignment Method (CAT-CAM), Narrowed ML, and Ischial Ramus Containment (IRC) sockets. In 1987, the IRC socket was endorsed for the name of the new above-knee prosthetic socket design. The characteristics of the IRC socket are: 1) ischial bony lock to prevent the pelvic tilt and the lateral gaping, which in turn provide excellent medio-lateral stability; 2) ischial fossa to have a good total contact with ischium, which increases contact surface, decreases pressure and increases comfort; 3) shifting the fulcrum of the socket medially, which decreases the varus moment at the midstatice phase. So the development of the IRC socket is a new milestone in the design of the above-knee prosthetic socket.