title: Changes in thoracic kyphosis negatively impact sagittal alignment after lumbar pedicle subtraction osteotomy: a comprehensive radiographic analysis.
abstract: METHODS
  Consecutive, multicenter retrospective review.
  
  
  OBJECTIVE
  To evaluate if change in thoracic kyphosis (TK) has a positive or negative impact on spinopelvic alignment after lumbar pedicle subtraction osteotomy (PSO) with short fusions.
  
  
  BACKGROUND
  In the setting of sagittal malalignment, the effect of large vertebral resections can now be anticipated in long fusions, but their impact on unfused segments (reciprocal changes [RC]) remains poorly understood.
  
  
  METHODS
  A total of 34 adult patients (mean age = 54 years; SD = 12) who underwent lumbar PSO with upper instrumented vertebra below T10 were included. Radiographic analysis included pre- and postassessment of TK, lumbar lordosis (LL), sagittal vertical axis (SVA), T1 spinopelvic inclination (T1SPI), pelvic tilt (PT), and pelvic incidence (PI). Final SVA and PT were analyzed to determine successful realignment. RC in the thoracic spine was designated favorable or unfavorable on the basis of impact on final SVA and PT.
  
  
  RESULTS
  Mean PSO resection was 26°. LL increased from 20° to 49° (P < 0.001). SVA improved from 14 to 4 cm (P < 0.001), and PT improved from 33° to 25° (P < 0.001). Mean increase in TK was 13° (P = 0.002) but was unchanged in 11 patients. Five patients had a favorable RC, and 18 patients had an unfavorable RC. Unfavorable RC was attributed to junctional failure in 6 of 18 patients. Significant differences in the unfavorable RC group included age and greater preoperative PT, PI, SVA, and T1SPI.
  
  
  CONCLUSIONS
  Significant postoperative alignment changes can occur through unfused thoracic spinal segments after lumbar PSO. Unfavorable RC may limit optimal correction and lead to clinical failures. Risk factors for unfavorable thoracic RC include older patients, larger preoperative PI and PT, and worse preoperative T1SPI and are not simply due to junctional failure. Care should be taken with selective lumbar fusion and PSO in older patients and in those with severe preoperative spinopelvic parameters.
authors.affiliation: NYU Hospital for Joint Diseases, New York, NY, USA. virginie.lafage@gmail.com
authors.forename: Virginie
authors.initials: V
authors.lastname: Lafage
authors.forename: Christopher
authors.initials: C
authors.lastname: Ames
authors.forename: Frank
authors.initials: F
authors.lastname: Schwab
authors.forename: Eric
authors.initials: E
authors.lastname: Klineberg
authors.forename: Behrooz
authors.initials: B
authors.lastname: Akbarnia
authors.forename: Justin
authors.initials: J
authors.lastname: Smith
authors.forename: Oheneba
authors.initials: O
authors.lastname: Boachie-Adjei
authors.forename: Douglas
authors.initials: D
authors.lastname: Burton
authors.forename: Robert
authors.initials: R
authors.lastname: Hart
authors.forename: Richard
authors.initials: R
authors.lastname: Hostin
authors.forename: Christopher
authors.initials: C
authors.lastname: Shaffrey
authors.forename: Kirkham
authors.initials: K
authors.lastname: Wood
authors.forename: Shay
authors.initials: S
authors.lastname: Bess
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011859:Radiography; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000379:methods*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome