title: The lumbar lordosis index: a new ratio to detect spinal malalignment with a therapeutic impact for sagittal balance correction decisions in adult scoliosis surgery.
abstract: OBJECTIVE
  Sagittal malalignment is frequently observed in adult scoliosis. C7 plumb line, lumbar lordosis and pelvic tilt are the main factors to evaluate sagittal balance and the need of a vertebral osteotomy to correct it. We described a ratio: the lumbar lordosis index (ratio lumbar lordosis/pelvic incidence) (LLI) and analyzed its relationships with spinal malalignment and vertebral osteotomies.
  
  
  METHODS
  53 consecutive patients with a surgical adult scoliosis had preoperative and postoperative full spine EOS radiographies to measure spino-pelvic parameters and LLI. The lack of lordosis was calculated after prediction of theoretical lumbar lordosis. Correlation analysis between the different parameters was performed.
  
  
  RESULTS
  All parameters were correlated with spinal malalignment but LLI is the most correlated parameter (r = -0.978). It is also the best parameter in this study to predict the need of a spinal osteotomy (r = 1 if LLI <0.5).
  
  
  CONCLUSIONS
  LLI is a statistically validated parameter for sagittal malalignment analysis. It can be used as a mathematical tool to detect spinal malalignment in adult scoliosis and guides the surgeon decision of realizing a vertebral osteotomy for adult scoliosis sagittal correction. It can be used as well for the interpretation of clinical series in adult scoliosis.
authors: Unité chirurgie rachis1, Université Bordeaux CHU, 33076, Bordeaux, France. boissierelouis@yahoo.fr
authors: Louis
authors: L
authors: Boissière
authors: Anouar
authors: A
authors: Bourghli
authors: Jean-Marc
authors: JM
authors: Vital
authors: Olivier
authors: O
authors: Gille
authors: Ibrahim
authors: I
authors: Obeid
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008141:Lordosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion; D013131:Spine / Q000000981:diagnostic imaging* / Q000601:surgery*; D016896:Treatment Outcome