title: Cervical sagittal deformity develops after PJK in adult thoracolumbar deformity correction: radiographic analysis utilizing a novel global sagittal angular parameter, the CTPA.
abstract: To describe reciprocal changes in cervical alignment after adult spinal deformity (ASD) correction and subsequent development of proximal junctional kyphosis (PJK). This study also investigated these changes using two novel global sagittal angular parameters, cervical-thoracic pelvic angle (CTPA) and the T1 pelvic angle (TPA).
  
  
  
  Multicenter, retrospective consecutive case series of ASD patients undergoing thoracolumbar three-column osteotomy (3CO) with fusion to the pelvis. Radiographs were analyzed at baseline and 1 year post-operatively. Patients were substratified into upper thoracic (UT; UIV T6 and above) and lower thoracic (LT; UIV below T6). PJK was defined by >10° angle between UIV and UIV + 2 and >10° change in the angle from baseline to post-op.
  
  
  
  PJK developed in 29 % (78 of 267) of patients. CTPA was linearly correlated with cervical plumbline (CPL) as a measure of cervical sagittal alignment (R = 0.826, p < 0.001). PJK patients had significantly greater post-operative CTPA and SVA than patients without PJK (NPJK) (p = 0.042; p = 0.021). For UT (n = 141) but not LT (n = 136), PJK patients at 1 year had larger CTPA (4.9° vs. 3.7°, p = 0.015) and CPL (5.1 vs. 3.8 cm, p = 0.022) than NPJK patients, despite similar corrections in PT and PI-LL.
  
  
  
  The prevalence of PJK was 29 % at 1 year follow-up. CTPA, which correlates with CPL as a global analog of cervical sagittal balance, and TPA describe relative proportions of cervical and thoracolumbar deformities. Patients who develop PJK in the upper thoracic spine after thoracolumbar 3CO also develop concomitant cervical sagittal deformity, with increases in CPL and CTPA.
authors.affiliation: Department of Orthopedic Surgery, New York University School of Medicine, 306 East 15th St., New York, NY, 10003, USA. tprotopsaltis@gmail.com.
authors.forename: Themistocles
authors.initials: T
authors.lastname: Protopsaltis
authors.affiliation: Hopital Saint-Roch, Nice, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bronsard
authors.affiliation: Department of Orthopedic Surgery, New York University School of Medicine, 306 East 15th St., New York, NY, 10003, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Soroceanu
authors.affiliation: Department of Orthopedic Surgery, New York University School of Medicine, 306 East 15th St., New York, NY, 10003, USA.
authors.forename: Jensen K
authors.initials: JK
authors.lastname: Henry
authors.affiliation: Department of Orthopedic Surgery, New York University School of Medicine, 306 East 15th St., New York, NY, 10003, USA.
authors.forename: Renaud
authors.initials: R
authors.lastname: Lafage
authors.affiliation: Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Smith
authors.affiliation: Department of Orthopedic Surgery, University of California Davis, Sacramento, CA, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Klineberg
authors.affiliation: San Diego Center for Spinal Disorders, La Jolla, CA, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Mundis
authors.affiliation: Department of Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA.
authors.forename: Han Jo
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Baylor Scoliosis Center, Plano, TX, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Hostin
authors.affiliation: Department of Orthopedic Surgery, University of Oregon Health Sciences Center, Portland, OR, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Hart
authors.affiliation: Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Shaffrey
authors.affiliation: Department of Orthopedic Surgery, New York University School of Medicine, 306 East 15th St., New York, NY, 10003, USA.
authors.forename: Shay
authors.initials: S
authors.lastname: Bess
authors.affiliation: Department of Neurosurgery, University of California San Francisco, San Francisco, CA, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Ames
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging; D010027:Osteotomy; D010388:Pelvis / Q000000981:diagnostic imaging; D011859:Radiography; D012189:Retrospective Studies; D013131:Spine / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D013909:Thorax / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: Adult spinal deformity; Cervical alignment; Proximal junctional kyphosis; Sagittal alignment; Three-column osteotomy