title: Analysis of risk factors for loss of lumbar lordosis in patients who had surgical treatment with segmental instrumentation for adolescent idiopathic scoliosis.
abstract: OBJECTIVE
  Iatrogenic flattening of lumbar lordosis in patients with adolescent idiopathic scoliosis (AIS) was a major downside of first generation instrumentation. Current instrumentation systems allow a three-dimensional scoliosis correction, but flattening of lumbar lordosis remains a significant problem which is associated with decreased health-related quality of life. This study sought to identify risk factors for loss of lumbar lordosis in patients who had surgical correction of AIS with the use of segmental instrumentation.
  
  
  METHODS
  Patients were included if they had surgical correction for AIS with segmental pedicle screw instrumentation Lenke type 1 or 2 and if they had a minimum follow-up of 24 months. Two groups were created, based on the average loss of lumbar lordosis. The two groups were then compared and multivariate analysis was performed to identify parameters that correlated to loss of lumbar lordosis.
  
  
  RESULTS
  Four hundred and seventeen patients were analyzed for this study. The average loss of lumbar lordosis at 24 months follow-up was an increase of 10° lordosis for group 1 and a decrease of 15° for group 2. Risk factors for loss of lumbar lordosis included a high preoperative lumbar lordosis, surgical decrease of thoracic kyphosis, and the particular operating surgeon. The lowest instrumented vertebra or spinopelvic parameters were two of many parameters that did not seem to influence loss of lumbar lordosis.
  
  
  CONCLUSIONS
  This study identified important risk factors for decrease of lumbar lordosis in patients who had surgical treatment for AIS with segmental pedicle screw instrumentation, including a high preoperative lumbar lordosis, surgical decrease of thoracic kyphosis, and factors attributable to a particular operating surgeon that were not quantified in this study.
authors.affiliation: Orthopädische Universitätsklinik Magdeburg, Leipziger Str. 44, 39120, Magdeburg, Germany. pertrobisch@gmail.com
authors.forename: Per D
authors.initials: PD
authors.lastname: Trobisch
authors.forename: Amer F
authors.initials: AF
authors.lastname: Samdani
authors.forename: Randal R
authors.initials: RR
authors.lastname: Betz
authors.forename: Tracey
authors.initials: T
authors.lastname: Bastrom
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Pahys
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Cahill
mesh_terms: D000293:Adolescent; D001863:Bone Screws; D005260:Female; D006801:Humans; D008141:Lordosis; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008161:Lumbosacral Region / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods