Appropriate Risk Stratification and Accounting for Age-Adjusted Reciprocal Changes in the Thoracolumbar Spine Reduces the Incidence and Magnitude of Distal Junctional Kyphosis in Cervical Deformity Surgery.


Study design

Retrospective cohort study of a prospective cervical deformity (CD) database.


Identify factors associated with distal junctional kyphosis (DJK); assess differences across DJK types.

Summary of background data

DJK may develop as compensation for mal-correction of sagittal deformity in the thoracic curve. There is limited understanding of DJK drivers, especially for different DJK types.


Included: patients with pre- and postoperative clinical/radiographic data. Excluded: patients with previous fusion to L5 or below. DJK was defined per surgeon note or DJK angle (kyphosis from LIV to LIV-2)<-10°, and pre- to postoperative change in DJK angle by<-10°. Age-specific target LL-TK alignment was calculated as published. Offset from target LL-TK was correlated to DJK magnitude and inclination. DJK types: severe (DJK<-20°), progressive (DJK increase>4.4°), symptomatic (reoperation or published disability thresholds of NDI ≥ 24 or mJOA≤14). Random forest identified factors associated with DJK. Means comparison tests assessed differences.


Included: 136 CD patients (61 ± 10 yr, 61%F). DJK rate was 30%. Postop offset from ideal LL-TK correlated with greater DJK angle (r = 0.428) and inclination of the distal end of the fusion construct (r = 0.244, both P < 0.02). Seven of the top 15 factors associated with DJK were radiographic, four surgical, and four clinical. Breakdown by type: severe (22%), progressive (24%), symptomatic (61%). Symptomatic had more posterior osteotomies than asymptomatic (P = 0.018). Severe had worse NDI and upper-cervical deformity (CL, C2 slope, C0-C2), as well as more posterior osteotomies than nonsevere (all P < 0.01). Progressive had greater malalignment both globally and in the cervical spine (all P < 0.03) than static. Each type had varying associated factors.


Offset from age-specific alignment is associated with greater DJK and more anterior distal construct inclination, suggesting DJK may develop due to inappropriate realignment. Preoperative clinical and radiographic factors are associated with symptomatic and progressive DJK, suggesting the need for preoperative risk stratification.Level of Evidence: 3.





Published Version (Please cite this version)


Publication Info

Passias, Peter G, Cole Bortz, Katherine E Pierce, Nicholas A Kummer, Renaud Lafage, Bassel G Diebo, Breton G Line, Virginie Lafage, et al. (2021). Appropriate Risk Stratification and Accounting for Age-Adjusted Reciprocal Changes in the Thoracolumbar Spine Reduces the Incidence and Magnitude of Distal Junctional Kyphosis in Cervical Deformity Surgery. Spine, 46(21). pp. 1437–1447. 10.1097/brs.0000000000004033 Retrieved from

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Peter Passias

Instructor in the Department of Orthopaedic Surgery

Christopher Ignatius Shaffrey

Professor of Orthopaedic Surgery

I have more than 25 years of experience treating patients of all ages with spinal disorders. I have had an interest in the management of spinal disorders since starting my medical education. I performed residencies in both orthopaedic surgery and neurosurgery to gain a comprehensive understanding of the entire range of spinal disorders. My goal has been to find innovative ways to manage the range of spinal conditions, straightforward to complex. I have a focus on managing patients with complex spinal disorders. My patient evaluation and management philosophy is to provide engaged, compassionate care that focuses on providing the simplest and least aggressive treatment option for a particular condition. In many cases, non-operative treatment options exist to improve a patient’s symptoms. I have been actively engaged in clinical research to find the best ways to manage spinal disorders in order to achieve better results with fewer complications.

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