Assessing Abnormal Proximal Junctional Angles in Adult Spinal Deformity: A Normative Data Approach to Define Proximal Junctional Kyphosis.

Abstract

Study design

Multicentric retrospective study of prospectively collected data.

Objective

Based on normative data from a cohort of asymptomatic volunteers, this study sought to determine the rate of abnormal values of proximal junctional angles (PJA) in adult spinal deformity (ASD) surgery patients, and compare it with PJK rate.

Summary of background data

Proximal junctional kyphosis (PJK) definition does not take the vertebral level into account.

Methods

This study included 721 healthy volunteers and 824 ASD surgery patients with 2-year postoperative follow-up. Normative values for each disc and vertebral body between T1 and T12 were analyzed, then normative values for PJA at each thoracic level were defined in the volunteer cohort as the mean±2 standard deviations. PJA abnormal values at the upper instrumented vertebra (UIV) were compared with Glattes' and Lovecchio's definitions for PJK in the ASD population at two years.

Results

Mean age was 37.7±16.3 in the volunteer cohort, with 50.5% of females. Mean thoracic kyphosis (TK) was -50.9±10.8°. Corridors of normality included PJA greater than 20° between T3 and T12. Mean age was 60.5±14.0 years in the ASD cohort, with 77.2% of females. Mean baseline TK was -37.4±19.9°, with a significant increase after surgery (-15.6±15.3°, P<0.001). There was 46.2% of PJK according to Glattes' versus 8.7% according to Lovecchio's and 22.9% of kyphotic PJA compared to normative values (P<0.001).

Conclusion

This study provides normative values for segmental and regional alignment of thoracic spine, used to describe abnormal values of PJA for each level. Using level-adjusted PJA values allows a more precise assessment of abnormal proximal angles and question the definition for PJK.

Level of evidence

II.

Department

Description

Provenance

Subjects

Citation

Published Version (Please cite this version)

10.1097/brs.0000000000005141

Publication Info

Khalifé, Marc, Renaud Lafage, Alan H Daniels, Bassel G Diebo, Jonathan Elysée, Christopher P Ames, Shay R Bess, Douglas C Burton, et al. (2024). Assessing Abnormal Proximal Junctional Angles in Adult Spinal Deformity: A Normative Data Approach to Define Proximal Junctional Kyphosis. Spine. 10.1097/brs.0000000000005141 Retrieved from https://hdl.handle.net/10161/31597.

This is constructed from limited available data and may be imprecise. To cite this article, please review & use the official citation provided by the journal.

Scholars@Duke

Shaffrey

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.


Unless otherwise indicated, scholarly articles published by Duke faculty members are made available here with a CC-BY-NC (Creative Commons Attribution Non-Commercial) license, as enabled by the Duke Open Access Policy. If you wish to use the materials in ways not already permitted under CC-BY-NC, please consult the copyright owner. Other materials are made available here through the author’s grant of a non-exclusive license to make their work openly accessible.