title: The likelihood of reaching minimum clinically important difference and substantial clinical benefit at 2 years following a 3-column osteotomy: analysis of 140 patients.
abstract: OBJECTIVE
  Three-column osteotomies (3COs) are technically challenging techniques for correcting severe rigid spinal deformities. The impact of these interventions on outcomes reaching minimum clinically important difference (MCID) or substantial clinical benefit (SCB) is unclear. The objective of this study was to determine the rates of MCID and SCB in standard health-related quality of life (HRQOL) measures after 3COs in patients with adult spinal deformity (ASD). The impacts of location of the uppermost instrumented vertebra (UIV) on clinical outcomes and of maintenance on sagittal correction at 2 years postoperatively were also examined.
  
  
  METHODS
  The authors conducted a retrospective multicenter analysis of the records from adult patients who underwent 3CO with complete 2-year radiographic and clinical follow-ups. Cases were categorized according to established radiographic thresholds for pelvic tilt (> 22°), sagittal vertical axis (> 4.7 cm), and the mismatch between pelvic incidence and lumbar lordosis (> 11°). The cases were also analyzed on the basis of a UIV in the upper thoracic (T1-6) or thoracolumbar (T9-L1) region. Patient-reported outcome measures evaluated preoperatively and 2 years postoperatively included Oswestry Disability Index (ODI) scores, the Physical Component Summary and Mental Component Summary (MCS) scores of the 36-Item Short Form Health Survey, and Scoliosis Research Society-22 questionnaire (SRS-22) scores. The percentages of patients whose outcomes for these measures met MCID and SCB were compared among the groups.
  
  
  RESULTS
  Data from 140 patients (101 women and 39 men) were included in the analysis; the average patient age was 57.3 ± 12.4 years (range 20-82 years). Of these patients, 94 had undergone only pedicle subtraction osteotomy (PSO) and 42 only vertebral column resection (VCR); 113 patients had a UIV in the upper thoracic (n = 63) orthoracolumbar region (n = 50). On average, 2 years postoperatively the patients had significantly improved in all HRQOL measures except the MCS score. For the entire patient cohort, the improvements ranged from 57.6% for the SRS-22 pain score MCID to 24.4% for the ODI score SCB. For patients undergoing PSO or VCR, the likelihood of their outcomes reaching MCID or SCB ranged from 24.3% to 62.3% and from 16.2% to 47.8%, respectively. The SRS-22 self-image score of patients who had a UIV in the upper thoracic region reached MCID significantly more than that of patients who had a UIV in the thoracolumbar region (70.6% vs 41.9%, p = 0.0281). All other outcomes were similar for UIVs of upper thoracic and thoracolumbar regions. Comparison of patients whose spines were above or below the radiographic thresholds associated with disability indicated similar rates of meeting MCID and SCB for HRQOL at the 2-year follow-up.
  
  
  CONCLUSIONS
  Outcomes for patients having UIVs in the upper thoracic region were no more likely to meet MCID or SCB than for those having UIVs in the thoracolumbar region, except for the MCID in the SRS-22 self-image measure. The HRQOL outcomes in patients who had optimal sagittal correction according to radiographic thresholds determined preoperatively were not significantly more likely to reach MCID or SCB at the 2-year follow-up. Future work needs to determine whether the Schwab preoperative radiographic thresholds for severe disability apply in postoperative settings.
authors.affiliation: Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois;
authors.forename: Shayan
authors.initials: S
authors.lastname: Fakurnejad
authors.affiliation: Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois;
authors.forename: Justin K
authors.initials: JK
authors.lastname: Scheer
authors.affiliation: Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, New York, New York;
authors.forename: Virginie
authors.initials: V
authors.lastname: Lafage
authors.affiliation: Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia; 
authors.forename: Justin S
authors.initials: JS
authors.lastname: Smith
authors.affiliation: Departments of 4 Orthopaedic Surgery and.
authors.forename: Vedat
authors.initials: V
authors.lastname: Deviren
authors.affiliation: Department of Orthopaedic Surgery, Baylor Scoliosis Center, Plano, Texas;
authors.forename: Richard
authors.initials: R
authors.lastname: Hostin
authors.affiliation: San Diego Center for Spinal Disorders, La Jolla;
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Mundis
authors.affiliation: Department of Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, Kansas;
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Burton
authors.affiliation: Department of Orthopaedic Surgery, University of California, Davis, California;
authors.forename: Eric
authors.initials: E
authors.lastname: Klineberg
authors.affiliation: Department of Orthopaedic Surgery, University of California, Davis, California;
authors.forename: Munish
authors.initials: M
authors.lastname: Gupta
authors.affiliation: Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, Maryland; and.
authors.forename: Khaled
authors.initials: K
authors.lastname: Kebaish
authors.affiliation: Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia; 
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Shaffrey
authors.affiliation: Rocky Mountain Hospital for Children, Denver, Colorado.
authors.forename: Shay
authors.initials: S
authors.lastname: Bess
authors.affiliation: Department of Orthopaedic Surgery, New York University Hospital for Joint Diseases, New York, New York;
authors.forename: Frank
authors.initials: F
authors.lastname: Schwab
authors.affiliation: Neurological Surgery, University of California, San Francisco;
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Ames
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006304:Health Status; D006801:Humans; D008141:Lordosis / Q000000981:diagnostic imaging / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D011788:Quality of Life; D011859:Radiography; D012189:Retrospective Studies; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D011795:Surveys and Questionnaires; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
keywords: 3-column osteotomy; 3CO = 3-column osteotomy; ASD = adult spinal deformity; HRQOL = health-related quality of life; ISSG = International Spine Study Group; MCID = minimum clinically important difference; MCS = Mental Component Summary; ODI = Oswestry Disability Index; PCS = Physical Component Summary; PI-LL = mismatch between pelvic incidence and lumbar lordosis; PSO = pedicle subtraction osteotomy; SCB = substantial clinical benefit; SF-36 = 36-Item Short Form Health Survey; SRS-22 = Scoliosis Research Society-22 questionnaire; SVA = sagittal vertical axis; UIV = uppermost instrumented vertebra; VCR = vertebral column resection; minimum clinically important difference; pedicle subtraction osteotomy; spinal deformity; spinal disorders; substantial clinical benefit; vertebral column resection