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Risk factors for the development of DJK in AIS patients undergoing posterior spinal instrumentation and fusion

Abstract

Purpose

Typically, selection of lowest instrumented vertebra (LIV) in Adolescent Idiopathic Scoliosis (AIS) is based on the coronal radiograph; however, increasing evidence suggests that fusions proximal to the stable sagittal vertebrae (SSV) on the lateral radiograph can result in distal junctional kyphosis (DJK). The purpose of this study is to compare rates of DJK in patients with AIS that have a discordance between the Lowest Touched Vertebra (LTV) and the SSV and to identify risk factors for developing DJK.

Methods

Patients with AIS Lenke type 1, 2 and 3 curves treated with a posterior spinal fusion were separated into two groups. Group 1 had SSV that was proximal to the LTV whereas group 2 had SSV that was distal to the LTV. Comparisons were made for patients that were fused to the SSV(a), LTV(b) or between(c). Distal junctional angle (DJA) > 5° and increasing kyphosis at the end of the fusion construct were evaluated as risk factors for DJK.

Results

The rate of DJK was 0.0% in group 1a, 1b, and 1c compared to 4.3%, 18.5% and 10.0% in groups 2a, 2b and 2c, respectively(p < 0.001). The rate of DJK was 22.9% when the distal junctional angle(DJA) > 5° versus 1.4% when the DJA < 5°(p < 0.001).

Conclusion

There was a low risk for progression of DJK when the SSV was proximal to the LTV, however, those with SSV distal to the LTV represent a high-risk group. Importantly, the development of DJK occurred almost exclusively in patients with LIV at the thoracolumbar junction which demonstrates that surgeons need to be cautious when ending fusions at T11, T12, and L1 in patients at high risk for DJK. Furthermore, having a distal junctional angle 5° or greater increased the risk of developing DJK by roughly 16-fold. At a minimum of 5-year follow-up, the development of DJK did not appear to adversely impact SRS outcomes or revision rates.

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Acknowledgements

Acknowledgement of Support: Setting Scoliosis Straight Foundation receives funding from DePuy Synthes Spine, EOS imaging, K2M, Medtronic, NuVasive, Zimmer Biomet and the Food and Drug Administration in support of Harms Study Group research. Harms Study Group: Setting Scoliosis Straight Foundation receives funding from DePuy Synthes Spine, EOS imaging, K2M, Medtronic, NuVasive, Zimmer Biomet and the Food and Drug Administration in support of Harms Study Group research. HSG Acknowledgements: This study was supported in part by grants to the Setting Scoliosis Straight Foundation in support of Harms Study Group research from DePuy Synthes Spine, EOS imaging, Stryker Spine, Medtronic, NuVasive, Zimmer Biomet and the Food and Drug Administration.

Harms Study Group Investigators: Aaron Buckland, MD; Royal Children’s Hospital – Melbourne Australia; Amer Samdani, MD; Shriners Hospitals for Children—Philadelphia; Amit Jain, MD; Johns Hopkins Hospital; Baron Lonner, MD; Mount Sinai Hospital; Benjamin Roye, MD; Columbia University; Burt Yaszay, MD; Rady Children’s Hospital; Chris Reilly, MD; BC Children’s Hospital; Daniel Hedequist, MD; Boston Children’s Hospital; Daniel Sucato, MD; Texas Scottish Rite Hospital; David Clements, MD; Cooper Bone & Joint Institute New Jersey; Firoz Miyanji, MD; BC Children’s Hospital; Harry Shufflebarger, MD; Paley Orthopedic & Spine Institute; Jack Flynn, MD; Children’s Hospital of Philadelphia; John Asghar, MD; Paley Orthopedic & Spine Institute; Jean Marc Mac Thiong, MD; CHU Sainte-Justine; Joshua Pahys, MD; Shriners Hospitals for Children—Philadelphia; Juergen Harms, MD; Klinikum Karlsbad-Langensteinbach, Karlsbad; Keith Bachmann, MD; University of Virginia; Lawrence Lenke, MD; Columbia University; Lori Karol, MD; Children’s Hospital, Denver Colorado; Mark Abel, MD; University of Virginia; Mark Erickson, MD; Children’s Hospital, Denver Colorado; Michael Glotzbecker, MD; Rainbow Children’s Hospital, Cleveland; Michael Kelly, MD; Washington University; Michael G. Vitale, MD, MPH; Columbia University; Michelle Marks, PT, MA; Setting Scoliosis Straight Foundation; Munish Gupta, MD; Washington University; Nicholas Fletcher, MD; Emory University; Noelle Larson, MD; Mayo Clinic Rochester Minnesota; Patrick Cahill, MD; Children’s Hospital of Philadelphia; Paul Sponseller, MD; Johns Hopkins Hospital; Peter Gabos, MD: Nemours/Alfred I. duPont Hospital for Children; Peter Newton, MD; Rady Children’s Hospital; Peter Sturm, MD; Cincinnati Children’s Hospital; Randal Betz, MD; Institute for Spine & Scoliosis; Stefan Parent, MD: CHU Sainte-Justine; Stephen George, MD; Nicklaus Children's Hospital; Steven Hwang, MD; Shriners Hospitals for Children—Philadelphia; Suken Shah, MD; Nemours/Alfred I. duPont Hospital for Children; Sumeet Garg, MD; Children’s Hospital, Denver Colorado ; Tom Errico, MD; Nicklaus Children's Hospital; Vidyadhar Upasani, MD; Rady Children’s Hospital

Funding

This study was supported in part by grants to the Setting Scoliosis Straight Foundation in support of Harms Study Group research from DePuy Synthes Spine, EOS imaging, Stryker Spine, Medtronic, NuVasive, Zimmer Biomet and the Food and Drug Administration.

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Contributions

DNS: Synthesis of idea, data analysis, manuscript writing, editing, approving work. JB: Synthesis of idea, data analysis, manuscript writing, editing, approving work. NDF: Synthesis of idea, manuscript editing, approving work. EY: Data analysis, manuscript writing, editing, approving work. TB: Data analysis, manuscript writing, editing, approving work. MGV: Synthesis of idea, manuscript editing, approving work. Harms Study Group: Synthesis of idea, manuscript editing, approving work.

Corresponding author

Correspondence to Nicholas D. Fletcher.

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IRB approval/research ethics committee

IRB approval for the multicenter study was obtained locally from each contributing institution’s review board, and consent was obtained from each patient prior to data collection.

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No copyrighted materials or patient information is included in this manuscript submission.

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Segal, D.N., Ball, J., Fletcher, N.D. et al. Risk factors for the development of DJK in AIS patients undergoing posterior spinal instrumentation and fusion. Spine Deform (2021). https://doi.org/10.1007/s43390-021-00413-4

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Keywords

  • Adolescent idiopathic scoliosis
  • Posterior spinal fusion
  • Distal junctional kyphosis
  • Stable sagittal vertebra