title: Results of Revision Surgery for Proximal Junctional Kyphosis Following Posterior Segmental Instrumentation: Minimum 2-Year Postrevision Follow-Up.
abstract: METHODS
  A retrospective cohort study.
  
  
  OBJECTIVE
  The aim of this study was to evaluate radiographic and patient-reported outcomes at minimum 2 years after revision surgery for proximal junctional kyphosis (PJK), correlating these results with PJK etiology.
  
  
  BACKGROUND
  There are no studies detailing the results of revision surgery for PJK following posterior segmental instrumentation.
  
  
  METHODS
  Thirty-two consecutive patients treated with revision surgery after PJK above posterior fusions (25 women/7 men, average age at surgery 60.6 yrs) were reviewed for radiographic and patient-reported outcomes (mean follow-up, 4.5 yrs; range, 2-10 yrs). Patients were subdivided into fracture (F) and nonfracture (NF) groups on the basis of PJK etiology.
  
  
  RESULTS
  Radiographic severity of PJK improved significantly with revision surgery and was maintained at ultimate follow-up (P < 0.001). However, initial sagittal vertical axis (SVA) correction was not maintained through ultimate follow-up (P = 0.04). There were significant postrevision improvements in mean Oswestry scores (P < 0.001) and SRS total scores (P < 0.001) in all patients. In patients with pelvic incidence-lumbar lordosis (PI-LL) mismatch < 11°, final PJK measurement was smaller than in patients with mismatch ≥11° (9.4° vs. 19.8°, P = 0.009). Six patients (19%) developed new postrevision PJK, with two (6%) requiring additional surgery. Patients who sustained PJK through a fracture had greater improvements in Oswestry (P = 0.004), total SRS (P = 0.04), pain (P < 0.001), and satisfaction (P = 0.05) scores, although the fracture patients had less maintained SVA correction (P = 0.002).
  
  
  CONCLUSIONS
  Revision surgery for PJK following posterior instrumentation achieved acceptable radiographic and clinical outcomes at minimum 2-year follow-up. Patients with PI-LL mismatch <11° experienced more ultimate PJK correction than patients with mismatch ≥11°. Although the NF group experienced more sustained correction of sagittal balance, the F group reported greater improvements in patient-reported outcomes. Ultimate clinical outcomes after revision surgery for PJK were similar between patients with and without compression fractures.
  
  
  METHODS
  3.
authors.affiliation: Department of Orthopaedic Surgery, Spine Center, Hallym University Sacred Heart Hospital, Hallym University, School of Medicine, Anyangsi, South Korea.
authors.forename: Yong-Chan
authors.initials: YC
authors.lastname: Kim
authors.affiliation: Department of Orthopedic Surgery, Columbia University Physicians and Surgeons, New York City, NY.
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lenke
authors.affiliation: Department of Orthopedic Surgery, Washington University, School of Medicine, St. Louis, MO.
authors.forename: Keith H
authors.initials: KH
authors.lastname: Bridwell
authors.affiliation: Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University, College of Medicine, Seongnam, South Korea.
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Hyun
authors.affiliation: Department of Orthopaedic Surgery, Spine Center, Hallym University Sacred Heart Hospital, Hallym University, School of Medicine, Anyangsi, South Korea.
authors.forename: Ki-Han
authors.initials: KH
authors.lastname: You
authors.affiliation: Department of Orthopaedic Surgery, Hallym University Dongtan Sacred Heart Hospital, Hallym University, Hwasungsi, South Korea.
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, Hallym University Dongtan Sacred Heart Hospital, Hallym University, Hwasungsi, South Korea.
authors.forename: Ho-Guen
authors.initials: HG
authors.lastname: Chang
authors.affiliation: Department of Orthopedic Surgery, Washington University, School of Medicine, St. Louis, MO.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kelly
authors.affiliation: Department of Neurological Surgery, Washington University, School of Medicine, St. Louis, MO.
authors.forename: Linda A
authors.initials: LA
authors.lastname: Koester
authors.affiliation: Department of Orthopedic Surgery, Columbia University Physicians and Surgeons, New York City, NY.
authors.forename: Kathy M
authors.initials: KM
authors.lastname: Blanke
authors.affiliation: University of Arkansas for Medical Sciences, Little Rock, AR.
authors.forename: David B
authors.initials: DB
authors.lastname: Bumpass
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007738:Kyphosis / Q000209:etiology* / Q000601:surgery; D008141:Lordosis / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D012086:Reoperation; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000379:methods; D013904:Thoracic Vertebrae / Q000601:surgery*; D016896:Treatment Outcome