title: Maintenance of radiographic correction at 2 years following lumbar pedicle subtraction osteotomy is superior with upper thoracic compared with thoracolumbar junction upper instrumented vertebra.
abstract: OBJECTIVE
  The goal of this study was to characterize the spino-pelvic realignment and the maintenance of that realignment by the upper-most instrumented vertebra (UIV) for adult deformity spinal (ASD) patients treated with lumbar pedicle subtraction osteotomy (PSO).
  
  
  METHODS
  ASD patients were divided by UIV, classified as upper thoracic (UT: T1-T6) or Thoracolumbar (TL: T9-L1). Complications were recorded and radiographic parameters included thoracic kyphosis (TK, T2-T12), lumbar lordosis (LL, L1-S1), sagittal vertical axis (SVA), pelvic tilt, and the mismatch between pelvic incidence and LL. Patients were also classified by the Scoliosis Research Society (SRS)-Schwab modifier grades. Changes in radiographic parameters and SRS-Schwab grades were evaluated between the two groups. Additional analyses were performed on patients with pre-operative SVA ≥ 15 cm.
  
  
  RESULTS
  165 patients were included (UT: 81 and TL: 84); 124 women, 41 men, with average age 59.9 ± 11.1 years (range 25-81). UT had a lower percentage of patients above the radiographic thresholds for disability than TL. UT had a significantly higher percentage of patients that improved in SRS-Schwab global alignment grade than the TL group at 2 years. Within the patients with pre-operative SVA ≥ 15 cm, TL developed significantly increased SVA and had a significantly higher percentage of patients above the SVA threshold at 3 months, and 1 and 2 years than UT.
  
  
  CONCLUSIONS
  Patients undergoing a single-level PSO for ASD who have fixation extending to the UT region (T1-T6) are more likely to maintain sagittal spino-pelvic alignment, lower overall revision rates and revision rate for proximal junctional kyphosis than those with fixation terminating in the TL region (T9-L1).
authors.affiliation: Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, 676 N. St. Clair Street, Suite 2210, Chicago, IL, 60611, USA, jscheer@ucsd.edu.
authors.forename: Justin K
authors.initials: JK
authors.lastname: Scheer
authors.forename: Virginie
authors.initials: V
authors.lastname: Lafage
authors.forename: Justin S
authors.initials: JS
authors.lastname: Smith
authors.forename: Vedat
authors.initials: V
authors.lastname: Deviren
authors.forename: Richard
authors.initials: R
authors.lastname: Hostin
authors.forename: Ian M
authors.initials: IM
authors.lastname: McCarthy
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Mundis
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Burton
authors.forename: Eric
authors.initials: E
authors.lastname: Klineberg
authors.forename: Munish
authors.initials: M
authors.lastname: Gupta
authors.forename: Khaled
authors.initials: K
authors.lastname: Kebaish
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Shaffrey
authors.forename: Shay
authors.initials: S
authors.lastname: Bess
authors.forename: Frank
authors.initials: F
authors.lastname: Schwab
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Ames
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D011859:Radiography; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D013121:Spinal Curvatures / Q000601:surgery; D013123:Spinal Fusion; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*