Utility of the Decubitus or the Supine Rather Than the Extension Lateral Radiograph in Evaluating Lumbar Segmental Instability — The International Society for the Study of the Lumbar Spine

Utility of the Decubitus or the Supine Rather Than the Extension Lateral Radiograph in Evaluating Lumbar Segmental Instability (#ZSP7)

Qingshuang Zhou 1 , Xu Sun 1 , Yong Qiu 1 , Zezhang Zhu 1
  1. Department of Spine Surgery, Medical School of Nanjing University, Nanjing, Jiangsu naniing, China

Utility of the Decubitus or the Supine Rather Than the Extension Lateral Radiograph in Evaluating Lumbar Segmental Instability

Abstract

Objective: To determine the superiority of decubitus and supine radiographs for the reduction of olisthesis instead of the extension radiograph, and the inconsistency of the CT scout view, 3D-reconstruction and MR image in evaluating segmental instability.

Methods: A cohort of 154 low-grade lumbar degenerative spondylolisthesis patients with the average age of (60.9±8.6) years were enrolled. Slip percentage was measured on the the flexion, upright and extension radiographs, the decubitus lateral radiograph, CT scout view, the supine median sagittal 3D-reconstruction and MR image.The translational range of motion was calculated, and segmental instability was defined as translational motion ≥ 8%.

Results: The flexion radiograph showed higher slip percentage than upright radiograph (p<0.001). The slip percentage of the MR image was lower than CT scout view (p=0.003) and CT sagittal radiograph (p=0.001) on the basis of statistical differences among three groups (p=0.002). The slip percentage of the CT scout view, decubitus radiograph, and extension radiograph was statistically different (p=0.01). The CT scout view and sagittal reconstruction had lower slip percentage than the extension radiograph (p=0.042; p=0.003, respectively). Both the flexion-supine and flexion-decubitus modality had larger translational motion than the flexion-extension modality (p=0.007; p<0.001, respectively).

Conclusion: Many modalities and techniques are used to show the vertebral displacement and its possible change and any cane used in the daily practice. In this study, supine and decubitus lateral radiography have larger reduction of olisthesis than the extension radiograph. The flexion radiograph coupled with a supine or decubitus radiograph reveals greater mobility than the flexion-extension modality.

Key words decubitus, supine, translational motion, segmental instability, lumbar degenerative spondylolisthesis

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