title: Comparison of best versus worst clinical outcomes for adult spinal deformity surgery: a retrospective review of a prospectively collected, multicenter database with 2-year follow-up.
abstract: OBJECTIVE
  Although recent studies suggest that average clinical outcomes are improved following surgery for selected adult spinal deformity (ASD) patients, these outcomes span a broad range. Few studies have specifically addressed factors that may predict favorable clinical outcomes. The objective of this study was to compare patients with ASD with best versus worst clinical outcomes following surgical treatment to identify distinguishing factors that may prove useful for patient counseling and optimization of clinical outcomes.
  
  
  METHODS
  This is a retrospective review of a prospectively collected, multicenter, database of consecutively enrolled patients with ASD who were treated operatively. Inclusion criteria were age > 18 years and ASD. For patients with a minimum of 2-year follow-up, those with best versus worst outcomes were compared separately based on Scoliosis Research Society-22 (SRS-22) and Oswestry Disability Index (ODI) scores. Only patients with a baseline SRS-22 ≤ 3.5 or ODI ≥ 30 were included to minimize ceiling/floor effects. Best and worst outcomes were defined for SRS-22 (≥ 4.5 and ≤ 2.5, respectively) and ODI (≤ 15 and ≥ 50, respectively).
  
  
  RESULTS
  Of 257 patients who met the inclusion criteria, 227 (88%) had complete baseline and 2-year follow-up SRS-22 and ODI outcomes scores and radiographic imaging and were analyzed in the present study. Of these 227 patients, 187 had baseline SRS-22 scores ≤ 3.5, and 162 had baseline ODI scores ≥ 30. Forthe SRS-22, best and worst outcomes criteria were met at follow-up for 25 and 27 patients, respectively. For the ODI, best and worst outcomes criteria were met at follow-up for 43 and 51 patients, respectively. With respect to the SRS-22, compared with best outcome patients, those with worst outcomes had higher baseline SRS-22 scores (p < 0.0001), higher prevalence of baseline depression (p < 0.001), more comorbidities (p = 0.012), greater prevalence of prior surgery (p = 0.007), a higher complication rate (p = 0.012), and worse baseline deformity (sagittal vertical axis [SVA], p = 0.045; pelvic incidence [PI] and lumbar lordosis [LL] mismatch, p = 0.034). The best-fit multivariate model for SRS-22 included baseline SRS-22 (p = 0.033), baseline depression (p = 0.012), and complications (p = 0.030). With respect to the ODI, compared with best outcome patients, those with worst outcomes had greater baseline ODI scores (p < 0.001), greater baseline body mass index (BMI; p = 0.002), higher prevalence of baseline depression (p < 0.028), greater baseline SVA (p = 0.016), a higher complication rate (p = 0.02), and greater 2-year SVA (p < 0.001) and PI-LL mismatch (p = 0.042). The best-fit multivariate model for ODI included baseline ODI score (p < 0.001), 2-year SVA (p = 0.014) and baseline BMI (p = 0.037). Age did not distinguish best versus worst outcomes for SRS-22 or ODI (p > 0.1).
  
  
  CONCLUSIONS
  Few studies have specifically addressed factors that distinguish between the best versus worst clinical outcomes for ASD surgery. In this study, baseline and perioperative factors distinguishing between the best and worst outcomes for ASD surgery included several patient factors (baseline depression, BMI, comorbidities, and disability), as well as residual deformity (SVA), and occurrence of complications. These findings suggest factors that may warrant greater awareness among clinicians to achieve optimal surgical outcomes for patients with ASD.
authors.affiliation: Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, Virginia;
authors.forename: Justin S
authors.initials: JS
authors.lastname: Smith
authors.affiliation: Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, Virginia;
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Shaffrey
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases;
authors.forename: Virginie
authors.initials: V
authors.lastname: Lafage
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases;
authors.forename: Frank
authors.initials: F
authors.lastname: Schwab
authors.affiliation: Department of Neurological Surgery, Northwestern University, Chicago, Illinois;
authors.forename: Justin K
authors.initials: JK
authors.lastname: Scheer
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases;
authors.forename: Themistocles
authors.initials: T
authors.lastname: Protopsaltis
authors.affiliation: Department of Orthopaedic Surgery, University of California Davis, Sacramento;
authors.forename: Eric
authors.initials: E
authors.lastname: Klineberg
authors.affiliation: Department of Orthopaedic Surgery, University of California Davis, Sacramento;
authors.forename: Munish
authors.initials: M
authors.lastname: Gupta
authors.affiliation: Department of Orthopaedic Surgery, Baylor Scoliosis Center, Plano, Texas; 
authors.forename: Richard
authors.initials: R
authors.lastname: Hostin
authors.affiliation: Department of Neurosurgery, Weill Cornell Medical College;
authors.forename: Kai-Ming G
authors.initials: KM
authors.lastname: Fu
authors.affiliation: San Diego Center for Spinal Disorders, La Jolla, California;
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Mundis
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York;
authors.forename: Han Jo
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Departments of 9 Orthopaedic Surgery and.
authors.forename: Vedat
authors.initials: V
authors.lastname: Deviren
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases;
authors.forename: Alex
authors.initials: A
authors.lastname: Soroceanu
authors.affiliation: Department of Orthopaedic Surgery, Oregon Health & Science University, Portland, Oregon;
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hart
authors.affiliation: Department of Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, Kansas and.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Burton
authors.affiliation: Department of Orthopaedic Surgery, Rocky Mountain Hospital for Children, Denver, Colorado.
authors.forename: Shay
authors.initials: S
authors.lastname: Bess
authors.affiliation: Neurosurgery, University of California San Francisco, California;
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Ames
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008141:Lordosis / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012189:Retrospective Studies; D012600:Scoliosis / Q000601:surgery*; D013123:Spinal Fusion; D016896:Treatment Outcome; D055815:Young Adult
keywords: ASA = American Society of Anesthesiology; ASD = adult spinal deformity; BMI = body mass index; CCI = Charlson Comorbidity Index; EBL = estimated blood loss; HRQOL = health-related quality of life; ISSG = International Spine Study Group; LL = lumbar lordosis; ODI = Oswestry Disability Index; PI = pelvic incidence; PT = pelvic tilt; SDSG = Spinal Deformity Study Group; SF-36 = 36-Item Short Form Health Survey; SRS-22 = Scoliosis Research Society-22 Patient Questionnaire; SVA = sagittal vertical axis; adult spinal deformity; complications; depression; outcomes; pelvic parameters; sagittal alignment; surgery