Farfan H F, Osteria V, Lamy C
Clin Orthop Relat Res. 1976 Jun(117):40-55.
There are 3 mechanisms that may result in failure of the neural arch with or without displacement of the vertebral body of the pathological vertebral: flexion overload, unbalanced shear forces and forced rotation. It is understood that all types of overload may be applied simultaneously and in various combinations. Of all the forces acting on the lumbar spine torsional violence is the most disruptive of the neural arch. Besides causing olisthesis, it is also capable of producing lysis of the pars especially if the dorsal spine has the added restraint of high tensile stresses in the posterior ligamentous system. Under normal conditions, the L5-S1 intervertebral joint is subject to the highest forces and it therefore receives the first damage. However, in the presence of antiverse process, damaging stress occurs in the next higher joint. While the antitorsional large transverse process may protect the L5-S1 joint from torsion, it may not protect the L5 vertebra from excessive flexional strains that may fracture the pars. Though lysis may occur in both instances, paradoxically spondylolysis and spondylolisthesis are mutually exclusive conditions. It has long been thought that shear force imbalance was the causative agent in olisthesis. This mechanism remains unconvincing except possibly in instances where there is a pathological condition affecting the skeletal tissue.
有3种机制可能导致病变椎体的椎弓失败，椎体有无移位均可：屈曲过载、不平衡剪切力和强制旋转。可以理解，所有类型的过载可能同时以各种组合形式出现。在作用于腰椎的所有力中，扭转暴力对椎弓的破坏最大。除了导致椎体滑脱外，它还能够产生椎弓峡部裂，特别是如果后柱在后部韧带系统中受到高拉伸应力的额外约束时。在正常情况下，L5-S1椎间关节承受的力最大，因此首先受到损伤。然而，在存在反折突的情况下，损伤应力会出现在更高一级的关节。虽然抗扭转的大横突可能保护L5-S1关节免受扭转，但它可能无法保护L5椎体免受可能导致椎弓峡部骨折的过度屈曲应变。虽然在这两种情况下都可能发生峡部裂，但矛盾的是，椎弓峡部裂和椎体滑脱是相互排斥的情况。长期以来，人们一直认为剪切力不平衡是椎体滑脱的致病因素。这种机制仍然难以令人信服，除非可能在存在影响骨骼组织的病理状况的情况下。
