Abstract

At present time we have increasing posterior interbody fusion number for spine restabilization in cases of it's degenerative disease. All cages variety for posterior and posterior-lateral stabilization can be divided in four big groups: cylindrical, trapezoidal, flexed and expandable cages. In that abstract we shall consider technology of implantation of the most progressive - trapezoidal cages with the concept of the open window. During posterior interbody instrumentation one of the important elements of implantation is cage carrying out through the vertebral canal with minimal trauma of spinal structures. Now there are essentially three technologies of cages implantation: twisting, turn on 90 degrees, and direct introduction. In our two universities were performed x-ray morphometrical and biomechanical researches of interarch geometry and its interaction during cage implantation. During PLIF procedure the area between two arches should not be less than 250-300 square mm , and its cross-section size 19-20 mm, width of the cage should be between 10-12 mm, i.e. a proportion - an interarch interval: the width of cage is optimum at its value 1,6 or size close to it. In case of reduction of this proportion up to 1,3-1,2 - cage implantation becomes more traumatic for spinal structures (pressure and deformation of the nerve root), but proportion increasing up to two and more expands opportunities of implantation, and also leads to a significant resection of facet joint. In this situation it is expedient to choose TLIF technology. Conclusion: During PLIF planning it is necessary to consider not only anatomic parameters of interbody space, but also the distance between two arches generated during decompression of spinal structures.