L3 translation predicts when L3 is not distal enough for an 'ideal' result in Lenke 5 curves

摘要

PurposeDetermining whether to fuse a Lenke 5 curve to L3 or to L4 is often a difficult decision. The purpose of this study was to determine preoperative variables predictive of an ideal or less than ideal outcome for Lenke 5 curves instrumented to L3.MethodsA multicentre registry of adolescent idiopathic scoliosis patients was queried for surgically treated Lenke 5 curves with a lowest instrumented vertebra (LIV) of L3 and minimum 2years of follow-up. Five seasoned surgeons qualitatively rated the 2-year postoperative images as ideal or less than ideal with respect to correction and alignment. Preoperative and postoperative radiographic variables were compared between the two groups. Multivariate regression analysis was performed to determine variables most predictive of a less than ideal outcome.ResultsOne hundred and thirty-nine patients met criteria. Twenty-three were considered less than ideal by 3 surgeons; 81 were unanimously ideal. Preoperatively, the less than ideal group had significantly stiffer curves, greater apical translation, and greater LIV angulation and translation. Multivariate regression found that preoperative L3 translation (p=0.009) was the single most important predictor of a less than ideal outcome: 3.5cm risked a less than ideal result.ConclusionWhile multiple variables are important in achieving an ideal outcome in Lenke 5 curves, this study found preoperative L3 translation was the most important predictor of success with an L3 translation <3.5cm being a potential threshold for selecting L3 as the LIV.