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Neurosurgery. 2018 Oct 1;83(4):675-682. doi: 10.1093/neuros/nyx479.

Cervical Alignment Changes in Patients Developing Proximal Junctional Kyphosis Following Surgical Correction of Adult Spinal Deformity.

Author information

Department of Orthopaedic Surgery, NYU Langone Orthopedic Hospital, NYU Langone Medical Center, New York, New York.
Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York.
Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, Virginia.
Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Department of Orthopaedic Surgery, University of Calgary, Alberta, Canada.
Department of Neurological Surgery, University of California, San Francisco, San Francisco, California.
Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
Division of Orthopaedic Surgery, Scripps Clinic, La Jolla, California.
Department of Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, Kansas.
Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri.
Rocky Mountain Scoliosis and Spine, Denver, Colorado.



Proximal junctional kyphosis (PJK) following adult spinal deformity (ASD) surgery is a well-documented complication, but associations between radiographic PJK and cervical malalignment onset remain unexplored.


To study cervical malalignment in ASD surgical patients that develop PJK.


Retrospective review of prospective multicenter database. Inclusion: primary ASD patients (≥5 levels fused, upper instrumented vertebra [UIV] at T2 or above, and 1-yr minimum follow-up) without baseline cervical deformity (CD), defined as ≥2 of the following criteria: T1 slope minus cervical lordosis < 20°, cervical sagittal vertical axis < 4 cm, C2-C7 cervical lordosis < 10°. PJK presence (<10° change in UIV and UIV + 2 kyphosis) and angle were identified 1 yr postoperative. Propensity score matching between PJK and nonPJK groups controlled for baseline alignment. Preoperative and 1-yr postoperative cervical alignment were compared between PJK and nonPJK patients.


One hundred sixty-three patients without baseline CD (54.9 yr, 83.9% female) were included. PJK developed in 60 (36.8%) patients, with 27 (45%) having UIV above T7. PJK patients had significantly greater baseline T1 slope in unmatched and propensity score matching comparisons (P < .05). At 1 yr postoperative, PJK patients had significantly higher T1 slope (P < .001), C2-T3 Cobb (P = .04), and C2-T3 sagittal vertical axis (P = .02). New-onset CD rate in PJK patients was 15%, and 16.5% in nonPJK patients (P > .05). Increased PJK magnitude was associated with increasing T1 slope and C2-T3 SVA (P < .05).


Patients who develop PJK following surgical correction of ASD have a 15% incidence of development of new-onset CD. Patients developing PJK following surgical correction of ASD tend to have an increased preoperative T1 slope. Increased progression of C2-T3 Cobb angle and C2-T3 SVA are associated with development of PJK following surgical correction of thoracolumbar deformity.


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