Lightning Podiums: Adult Spinal Deformity - Room 801A

Presented by: R. Lafage

Author(s):

R. Lafage(1), F. Schwab(1), E. Klineberg(2), D. Burton(3), S. Bess(4), H.J. Kim(1), J. Smith(5), C. Ames(6), R. Hostin(7), C. Shaffrey(5), G. Mundis(8), V. Lafage(1), International Spine Study Group (ISSG)

(1) Hospital for Special Surgery, New York, NY, United States
(2) University of California, Davis, Sacramento, CA, United States
(3) University of Kansas Medical Center, Kansas City, KS, United States
(4) Denver International Spine Center, Denver, CO, United States
(5) University of Virginia, Charlottesville, VA, United States
(6) University of California, San Francisco, San Francisco, CA, United States
(7) Baylor Scoliosis Center, Plano, TX, United States
(8) San Diego Center for Spinal Disorders, La Jolla, CA, United States

Abstract

Introduction: Junctional failure following ASD correction has gained much attention recently. While realignment goals have been published, there are concerns that dramatic spinal realignment surgery poses elevated risks of proximal junctional kyphosis (PJK) and failure. Several studies have established independent risk factors for PJK but a pragmatic scoring system remains elusive. The objective of the study was to establish a simple scoring system to permit the physician and patient to pragmatically assess the likelihood of PJK following surgical realignment

Purpose: To create a simple pragmatic scoring system through literature review that can predict the risk of PJK in the after adult spinal deformity (ASD). Design: Retrospective analysis of a prospective multicenter database of ASD patients

Methods: In this clinical and radiographic analysis, 417 surgical ASD patients (80% female, mean age 57.8 years old) with 2 years post-operative follow up were included. After radiographic analysis, PJK was identified when a >10 degree kyphotic angulation existed between the upper instrumented vertebra (UIV) and the vertebrae two levels above it. Based on a literature review of the risk-factors for PJK, the following point score was attributed for parameters likely to impact PJK development (Liu, ESJ, 2016): Age > 55 (1pt), fusion to S1/ilium (1pt), UIV in the upper thoracic spine (1pt), UIV in the lower thoracic region (2pts), peri-operative reduction in kyphosis across fused segments greater than 10 degrees (1pt).

Results: At 2 years, the PJK rate was 43%. The odds ratio for each risk factor was determined to be: Age > 55 (2.52), fusion to S1/ilium (5.17), UIV in the upper thoracic spine (6.63), UIV in the lower thoracic region (8.24), and a >10 degree surgical reduction in kyphosis across fused segments (1.59). Analysis by risk factor revealed a significant impact on PJK (no pjk vs. pjk): Age >55 (28% vs 51% p < 0.001), LIV S1/ilium (16.3% vs 51.4% p< 0.001), UIV in lower thoracic spine (12.0% vs 52.9% p< 0.001), and a >10 degree surgical reduction in kyphosis (40.0% vs 51.5% p < 0.025). The PJK rate by point score was: 1=17%, 2=29%, 3=40%, 4=53%, and 5=69%.

Conclusion: This study confirms the impact of published factors linked to PJK. A pragmatic scoring system was developed that is tied to the increasing risk of proximal junctional kyphosis. The findings from this study will permit enhanced shared decision making and patient counseling pre-operatively. Additionally, based upon the results of this investigation, surgeons may consider varying their surgical strategy to mitigate the post-operative development of PJK.

PJK rates by increasing risk score