Assessment of Interobserver Variability for CT Scan–Based Evaluation of Posterior Ligament Complex Injury in Thoracolumbar Fractures: An International Multicenter Pilot Study

Abstract

Study Design: A multicenter, pilot study, for radiological assessment of thoracolumbar spine fractures was performed with the participation of 7 centers in Africa, Europe, Asia, and South America as a part of the AO Foundation network. Objectives: To determine the interobserver variability for computed tomography (CT) scan–based evaluation of posterior ligament complex (PLC) injury in thoracolumbar fractures. Methods: Forty-two observers including 1 principal investigator at each participating center performed variability assessment. Each center contributed toward a total of 91 patient images with A3 or A4 thoracolumbar burst fractures (T11-L2) with or without suspected PLC injury. Pathological fractures, multilevel injuries, obvious posterior bony element injury and translation/dislocation injuries were excluded. Ten patients were randomly selected and commonly reported CT parameters indicating PLC injury, including superior inferior endplate angle, vertebral body height loss, local kyphotic deformity, interspinous distance and interpedicular distance were assessed for variability. Observer values were compared with an experienced gold rater in spinal trauma. Analysis of variability was performed for all observers, between the principal investigators and also between observers participating in each center. Results: The studied parameters showed considerable variability in measurements among all observers and amongst all participating centers. The variability between the principal investigators was lower, but still substantial. The deviation of observer measurements from the gold rater were also significant for all CT parameters. Conclusions: CT-based radiological parameters previously reported to be suggestive of PLC injury showed considerable variability and magnetic resonance imaging verification of a PLC injury in all doubtful cases is suggested.

The AO Spine Thoracolumbar Injury Classification System and Treatment Algorithm in Decision Making for Thoracolumbar Burst Fractures Without Neurologic Deficit

“… 56 However, Maheswaran et al and Tang et al have demonstrated with increasingly high-quality CT scans that parameters such as local kyphosis, interspinous distance and interpedicular distance that can be used to determine PLC integrity without an MRI. 57 , 58 Ganjeifar et al 59 even argued that the diagnostic results of PLC injury with a CT scan were similar to those obtained by MRI in thoracolumbar burst fractures. 59…”

The Influence of Comminution and Posterior Ligamentous Complex Integrity on Treatment Decision Making in Thoracolumbar Burst Fractures Without Neurologic Deficit?

“…This study assessed comminution as the sole measure of bony instability without considering other indicators such as vertebral height loss, kyphotic angle, load-sharing classification, or canal compromise. 27 Initially, the study refrained from evaluating these radiographic parameters due to inherent measurement errors, variations in measurement methods, and poor reliability. However, on further discussion within the AO Spine Knowledge Forum Trauma, it was decided that studying the association of those parameters with decision-making could lead to a further depth of understanding.…”

How Often Would MRI Change the Thoracolumbar Fracture Classification or Decision-Making Compared to CT Alone?

“…The standardized definitions for CT findings could explain the high inter-reader reliability on CT classification reported in that study (k = .84). 16,23,34 We previously proposed defining criteria for each CT finding based on examining the diagnostic value of various morphological features of CT findings for PLC injury. 16 For instance, we used a threshold of ISW> 4 mm, which was shown to predict PLC injury independently in MRI previously.…”