Retrospective exploration of risk factors for L5 XXXX following lumbar floating fusion surgery.

@entity1 @entity1183 @entity1347 @entity74 @entity158 @entity614
BACKGROUND: Lumbar floating fusion occasionally causes postoperative @entity1347 ( @entity1347 ) at lumbosacral level, causing L5 @entity74 by L5-S1 foraminal stenosis. The disorder is considered to be one of the major outcomes of L5-S1 @entity1347 , which has not been evaluated yet. The present study aimed to evaluate the incidence and risk factors of postoperative L5 @entity74 after lumbar interbody fusion extending to the L5 vertebra. METHODS: We evaluated 125 @entity1 with a diagnosis of spondylolisthesis who underwent floating fusion surgery with transforaminal lumbar interbody fusion with average postoperative period of 25.2  months. The @entity1 were regarded as symptomatic with postoperative L5 @entity74 such as @entity158 / @entity1183 in the lower limbs and/or motor dysfunction. We estimated and compared the wedging angle (frontal view) and height (lateral view) of the lumbosacral junction in pre- and postoperative plain X-ray images and the foraminal ratio (ratio of the narrower foraminal diameter to the wider diameter in the craniocaudal direction) in the preoperative magnetic resonance image. Risk factors for the incidence of L5 @entity74 were explored using multivariate logistic regression. RESULTS: Eight of the 125 @entity1 (6.4  %) were categorized as symptomatic, an average of 13.3  months after surgery. The wedging angle was significantly higher, and the foraminal ratio was significantly decreased in the symptomatic group (both P   <   0.05) compared to the asymptomatic group. Multivariate logistic regression analysis of possible risk factors revealed that the wedging angle, foraminal ratio, and multileveled fusion were statistically significant. CONCLUSIONS: Higher wedging angle and lower foraminal ratio in the lumbosacral junction were significantly predictive for the incidence of @entity614 as well as multiple-leveled fusion. These findings indicate that lumbosacral fixation should be considered for @entity1 with these risk factors even if they have few symptoms from the L5-S1 junction.
