Redisplacement after Operative Reduction of Spondylolisthesis: Comparison between Pedicle screw system and Luque ring system

Cho, Jae Lim; Yoon, Won Koo; Park, Ye Soo; Choi, Kyeong Jin; Han, Joo Hee

Abstract

Operative reduction is not essential for mild to moderate spondylolisthesis, but some authors agree that reduction of spondylolisthesis is beneficial for widening of intervertebral canal and consequently for decompression of neural tissue even though the degree of slippage is grade I or II. In our institute, we sometimes reduced the slippage for these reasons. But at follow up study we would find redisplacement and the degree of it seemed to be associated with the kind of instruments. So we analyzed redisplacement rate according to the kind of instruments in 59 cases of spondylolisthesis that were followed more than one year. The conclusions were as follow; 1. There was no significant correlation between reduction and redisplacement rate with pathologic type, lesion site, age,iscectomy and clinical result at least in grade I or II spondylolisthesis (P>0.05). 2. The pedicle screw system was more useful in reduction and its maintenance than the Luque ring system (P<0.001). 3. Redisplacement was occurred mainly within 2 months after operation, 4. The cause of redisplacement after reduction seems to be associated with mechanical insecurity before consolidation of the grafted bone takes place.