The treatment of spondylolistheses with segmental reduction and interbody fusion by means of an internal fixator

In spondylolisthesis with an indication for fusion and with a slipping of more than 50 % at least a partial reposition should be reached in general because the incidence of pseudarthrosis would increase with a fusion in situ and a large disturbance of the spinal statics would persist. Hereby with almost all methods an enlarged operative morbidity and often a longer fusion range has to be taken in account compared to the fusion in situ. Therefore, in smaller slippages the fusion in situ will be favoured because the disturbance of the statics is not so important, that such an effort combined with such methods is necessary. If the operation method with small spondylolisthesis and pseudospondylolisthesis allows the reposition without much effort and if the operative morbidity in comparison with the fusion in situ is not higher, then it is reasonable to fuse the cases with a spondylolisthesis Meyerding grade 1 and 2 in the anatomic corrected position too. Because the spinal fixator we use fills out these criteria we combine the correction of the position with the fusion also in cases of small spondylolisthesis. The incidence of neurologic complications correlates with the amount of the reposition distance and can be caused by preforaminal or extraforaminal lesions. The reduction of small malpositions could only produce preforaminal lesions. Using the spine fixator with its reposition instruments linked outside the wound and with it's uninhibited access to the segment and to the preforaminal neural structures during the whole repositioning these lesions can be avoided.