title: Can a Minimal Clinically Important Difference Be Achieved in Elderly Patients with Adult Spinal Deformity Who Undergo Minimally Invasive Spinal Surgery?
abstract: BACKGROUND
  Older age has been considered a relative contraindication to complex spinal procedures. Minimally invasive surgery (MIS) techniques to treat patients with adult spinal deformity (ASD) have emerged with the potential benefit of decreased approach-related morbidity.
  
  
  OBJECTIVE
  To determine whether a minimal clinically important difference (MCID) could be achieved in patients ages ≥ 65 years with ASD who underwent MIS.
  
  
  METHODS
  Multicenter database of patients who underwent MIS for ASD was queried. Outcome metrics assessed were Oswestry Disability Index (ODI) and visual analog scale (VAS) scores for back and leg pain. On the basis of published reports, MCID was defined as a positive change of 12.8 ODI, 1.2 VAS back pain, and 1.6 VAS leg pain.
  
  
  RESULTS
  Forty-two patients were identified. Mean age was 70.3 years; 31 (73.8%) were women. Preoperatively, mean coronal curve, pelvic tilt, pelvic incidence to lumbar lordosis mismatch, and sagittal vertical axis were 35°, 24.6°, 14.2°, and 4.7 cm, respectively. Postoperatively, mean coronal curve, pelvic tilt, pelvic incidence to lumbar lordosis, and sagittal vertical axis were 18°, 25.4°, 11.9°, and 4.9 cm, respectively. A mean of 5.0 levels was treated posteriorly, and a mean of 4.0 interbody fusions was performed. Mean ODI improved from 47.1 to 25.1. Mean VAS back and leg pain scores improved from 6.8 and 5.9 to 2.7 and 2.7, respectively. Mean follow-up was 32.1 months. For ODI, 64.3% of patients achieved MCID. For VAS back and leg pain, 82.9% and 72.2%, respectively, reached MCID.
  
  
  CONCLUSIONS
  MCID represents the threshold at which patients feel a meaningful clinical improvement has occurred. Our study results suggest that the majority of elderly patients with modest ASD can achieve MCID with MIS.
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan. Electronic address: ppark@umich.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: David O
authors.initials: DO
authors.lastname: Okonkwo
authors.affiliation: San Diego Center for Spinal Disorders, La Jolla, California.
authors.forename: Stacie
authors.initials: S
authors.lastname: Nguyen
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 Neurosurgery, University of California, San Francisco, California.
authors.forename: Khoi D
authors.initials: KD
authors.lastname: Than
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, California.
authors.forename: Vedat
authors.initials: V
authors.lastname: Deviren
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan.
authors.forename: Frank
authors.initials: F
authors.lastname: La Marca
authors.affiliation: Weill Cornell Brain and Spine Center, New York, New York.
authors.forename: Kai-Ming
authors.initials: KM
authors.lastname: Fu
authors.affiliation: Department of Neurological Surgery, University of Miami, Miami, Florida.
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, University of South Florida, Tampa, Florida.
authors.forename: Juan S
authors.initials: JS
authors.lastname: Uribe
authors.affiliation: Cedars-Sinai Spine Center, Los Angeles, California.
authors.forename: Neel
authors.initials: N
authors.lastname: Anand
authors.affiliation: Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois.
authors.forename: Richard
authors.initials: R
authors.lastname: Fessler
authors.affiliation: Spine Institute of Louisiana, Shreveport, Louisiana.
authors.forename: Pierce D
authors.initials: PD
authors.lastname: Nunley
authors.affiliation: Department of Neurosurgery, University of California, San Francisco, California.
authors.forename: Dean
authors.initials: D
authors.lastname: Chou
authors.affiliation: Department of Neurosurgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Kanter
authors.affiliation: Department of Neurosurgery, University of Virginia, Charlottesville, Virginia.
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Shaffrey
authors.affiliation: San Diego Center for Spinal Disorders, La Jolla, California.
authors.forename: Behrooz A
authors.initials: BA
authors.lastname: Akbarnia
authors.affiliation: Department of Orthopaedic Surgery, NYU Medical Center Hospital for Joint Diseases, New York, New York.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Passias
authors.affiliation: Department of Orthopaedic Surgery, Scripps Clinic Torrey Pines, La Jolla, California, USA.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Eastlack
authors.affiliation: Department of Neurosurgery, University of California, San Francisco, California.
authors.forename: Praveen V
authors.initials: PV
authors.lastname: Mummaneni
mesh_terms: D000367:Age Factors; D000368:Aged; D001416:Back Pain / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae; D008297:Male; D019060:Minimally Invasive Surgical Procedures; D011859:Radiography; D020127:Recovery of Function; D012447:Sacrum; D013121:Spinal Curvatures / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion; D016896:Treatment Outcome
keywords: Adult spinal deformity; Elderly; Minimally invasive surgery; Spine