Krismer M, Haid C, Rabl W
Department of Orthopaedic Surgery, University of Innsbruck, Austria.
Spine (Phila Pa 1976). 1996 Nov 15;21(22):2551-7. doi: 10.1097/00007632-199611150-00004.
Anulus fibers of the intervertebral disc oriented in one direction were dissected, and oppositely directed fibers were left intact as a result of a newly developed dissection method. Motion segments were dissected by this way, and motion segments after bilateral facetectomy were loaded in torsion and compared with each other.
To assess the contribution of facets and anulus fibers to torque resistance.
Mathematical models predict that torsional stress is transmitted only to those collagene fibers of the anulus that are angled in the direction of the applied torque. Torsion and forward bending or torsion and compression are likely to cause anulus damage. No experimental study that we are aware of has confirmed that anulus fibers are the main structure to resist against torque.
Pure axial rotation moments were applied on 12 lumbar motion segments. The six components of motion were recorded. Six motion segments were investigated intact after dissection of anulus fibers directed in one direction and after additional bilateral facetectomy. In six motion segments, bilateral facetectomy was performed before anulus dissection.
With the application of an axial rotation moment of 8.5 Nm to the left, axial rotation increased 2 degrees after dissection of disc fibers in one direction, and 1.2 degrees after bilateral facetectomy (P = 0.002). In the opposite direction, there were no differences. After both injuries, axial rotation was 7.6 degrees to the left (direction of fiber dissection) and -3.3 degrees to the right (P = 0.0005).
In lumbar motion segments without degeneration, anulus fibers restrict axial rotation more than the facets.
采用一种新开发的解剖方法，将椎间盘单向排列的纤维环纤维进行解剖，而反向排列的纤维保持完整。采用这种方法对运动节段进行解剖，然后对双侧小关节切除后的运动节段施加扭转负荷并相互比较。
评估小关节和纤维环纤维对扭矩抵抗的作用。
数学模型预测，扭转应力仅传递至纤维环中与施加扭矩方向成一定角度的胶原纤维。扭转与前屈或扭转与压缩可能会导致纤维环损伤。据我们所知，尚无实验研究证实纤维环纤维是抵抗扭矩的主要结构。
对12个腰椎运动节段施加纯轴向旋转力矩。记录六个运动分量。在单向解剖纤维环纤维后以及额外进行双侧小关节切除后，对六个运动节段进行完整研究。另外六个运动节段，先进行双侧小关节切除，再进行纤维环解剖。
向左施加8.5 Nm的轴向旋转力矩时，单向解剖椎间盘纤维后轴向旋转增加2度，双侧小关节切除后增加1.2度（P = 0.002）。在相反方向上，无差异。两种损伤后，向左轴向旋转为7.6度（纤维解剖方向），向右为-3.3度（P = 0.0005）。
在无退变的腰椎运动节段中，纤维环纤维比小关节更能限制轴向旋转。
