title: Revision Surgery After 3-Column Osteotomy in 335 Patients With Adult Spinal Deformity: Intercenter Variability and Risk Factors.
abstract: METHODS
  Multicenter, retrospective review.
  
  
  OBJECTIVE
  To assess rates, site variability, and risk factors for revision surgery (RS) after 3-column osteotomy (3CO).
  
  
  BACKGROUND
  Complex spinal osteotomies, including 3CO, are being increasingly performed in the setting of patients with adult spinal deformity with sagittal plane deformity. Three-column osteotomy procedures are associated with high complication and RS rates, but risk factors for complications and variability across centers for revision have not been well defined.
  
  
  METHODS
  The incidence and indications for RS in 335 patients with adult spinal deformity were analyzed. RS indications were classified as "mechanical" (MR: implant failure, pseudarthrosis, junctional failure, and loss/lack of correction) or "nonmechanical" (NMR: neurological deficit, infection, wound dehiscence, and stenosis). Risks factors for RS were analyzed using generalized linear models.
  
  
  RESULTS
  Three-month and 1-year RS incidences were 12.3% and 17.6%, respectively. Single-level 3CO (n = 311) had lower RS rates than multilevel 3CO (n = 24, 15.8% vs. 41.7%, P = 0.001). The 16.7% rate for single-level lumbar 3CO included 11.4% for MR and 5.7% for NMR. For all RS, 50% of MR and 78.6% of NMR occurred within 3 months of the index surgery. There was significant variation in rates across sites (range = 6.3%-31.9%, P = 0.001), however low- and high-volume sites had similar rates (18.2% vs. 16.2%, P = 0.503). Patients with MR were more likely to be sagittally undercorrected at 3 months (sagittal vertical axis = 7 cm vs. 3.2 cm, P = 0.003). Patients with NMR had more caudal 3CO levels (L4 vs. L3, P = 0.014) and larger 3CO bone resections than patients who did not (34°vs. 24.5°, P = 0.003).
  
  
  CONCLUSIONS
  Three-column osteotomy procedures for adult spinal deformity surgery can provide significant deformity correction and lead to marked improvement in function despite established complication and revision rates. This study shows that RS is associated with lower level osteotomy and higher residual sagittal vertical axis. There is significant variability in revision rates across sites independent of site volume, suggesting potential systems and practice variations that warrant further study.
  
  
  METHODS
  4.
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Maier
authors.affiliation: Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, VA.
authors.forename: Justin S
authors.initials: JS
authors.lastname: Smith
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Schwab
authors.affiliation: Bordeaux University Hospital, Bordeaux, France.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Obeid
authors.affiliation: San Diego Center for Spinal Disorders, La Jolla, CA.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Mundis
authors.affiliation: Department of Orthopaedic Surgery, University of California, Davis, Sacramento, CA.
authors.forename: Eric
authors.initials: E
authors.lastname: Klineberg
authors.affiliation: Department of Orthopaedic Surgery, Baylor Scoliosis Center, Plano, TX.
authors.forename: Richard
authors.initials: R
authors.lastname: Hostin
authors.affiliation: Department of Orthopaedic Surgery, Oregon Health and Science University, Portland, OR.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hart
authors.affiliation: Department of Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, KS.
authors.forename: Douglas
authors.initials: D
authors.lastname: Burton
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY.
authors.forename: Oheneba
authors.initials: O
authors.lastname: Boachie-Adjei
authors.affiliation: Department of Orthopaedic Surgery, University of California, Davis, Sacramento, CA.
authors.forename: Munish
authors.initials: M
authors.lastname: Gupta
authors.affiliation: Department of Neurosurgery, University of California, San Francisco Medical Center, San Francisco, CA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Ames
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY.
authors.forename: Themistocles S
authors.initials: TS
authors.lastname: Protopsaltis
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY.
authors.forename: Virginie
authors.initials: V
authors.lastname: Lafage