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 per sist. Hereby with almost all methods an enlarged operative morbidity a nd 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 imp ortant, that such an effort combined with such methods is necessary. I f the operation method with small spondylolisthesis and pseudospondylo listhesis allows the reposition without much effort and if the operati ve 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 spi nal fixator we use fills out these criteria we combine the correction of the position with the fusion also in cases of small spondylolisthes is. The incidence of neurologic complications correlates with the amou nt of the reposition distance and can be caused by preforaminal or ext raforaminal lesions. The reduction of small malpositions could only pr oduce preforaminal lesions. Using the spine fixator with its repositio n instruments linked outside the wound and with it's uninhibited acces s to the segment and to the preforaminal neural structures during the whole repositioning these lesions can be avoided.