Utility of Natural Sitting Lateral Radiograph in the Diagnosis of Segmental Instability for Patients with Degenerative Lumbar Spondylolisthesis

• Published in: Clinical orthopaedics and related research 2021-04, Vol.479 (4), p.817-825
• Main Authors: Zhou, Qing-shuang, Sun, Xu, Chen, Xi, Xu, Liang, Qian, Bang-ping, Zhu, Zezhang, Qiu, Yong
• Format: Article
• Language: English
• Subjects: Aged; Biomechanical Phenomena; Clinical Research; Female; Humans; Intervertebral Disc Degeneration - diagnostic imaging; Intervertebral Disc Degeneration - physiopathology; Intervertebral Disc Degeneration - surgery; Lumbar Vertebrae - diagnostic imaging; Lumbar Vertebrae - physiopathology; Lumbar Vertebrae - surgery; Lumbosacral Region; Magnetic Resonance Imaging; Male; Middle Aged; Patient Positioning; Predictive Value of Tests; Range of Motion, Articular; Reproducibility of Results; Retrospective Studies; Sitting Position; Spondylolisthesis - diagnostic imaging; Spondylolisthesis - physiopathology; Spondylolisthesis - surgery; Supine Position
• ISSN: 0009-921X; 1528-1132
• DOI: 10.1097/CORR.0000000000001542

Segmental instability in patients with degenerative lumbar spondylolisthesis is an indication for surgical intervention. The most common method to evaluate segmental mobility is lumbar standing flexion-extension radiographs. Meanwhile, other simple radiographs, such as standing upright radiograph, a supine sagittal magnetic resonance imaging (MRI) or supine lateral radiograph, or a slump or natural sitting lateral radiograph, have been reported to diagnose segmental instability. However, those common posture radiographs have not been well characterized in one group of patients. Therefore, we measured slip percentage in a group of patients with degenerative lumbar spondylolisthesis using radiographs of patients in standing upright, natural sitting, standing flexion, and standing extension positions as well as supine MRI. We asked: (1) Does the natural sitting radiograph have a larger slip percentage than the standing upright or standing flexion radiograph? (2) Does the supine sagittal MRI reveal a lower slip percentage than the standing extension radiograph? (3) Does the combination of the natural sitting radiograph and the supine sagittal MRI have a higher translational range of motion (ROM) and positive detection rate of translational instability than traditional flexion-extension mobility using translational instability criteria of greater than or equal to 8%? We retrospectively performed a study of 62 patients (18 men and 44 women) with symptomatic degenerative lumbar spondylolisthesis at L4 who planned to undergo a surgical intervention at our institution between September 2018 and June 2019. Each patient underwent radiography in the standing upright, standing flexion, standing extension, and natural sitting positions, as well as MRI in the supine position. The slip percentage was measured three times by single observer on these five radiographs using Meyerding's technique (intraclass correlation coefficient 0.88 [95% CI 0.86 to 0.90]). Translational ROM was calculated by absolute values of difference between two radiograph positions. Based on the results of comparison of slip percentage and translational ROM, we developed the diagnostic algorithm to evaluate segmental instability. Also, the positive rate of translational instability using our diagnostic algorithms was compared with traditional flexion-extension radiographs. The natural sitting radiograph revealed a larger mean slip percentage than the standing upright radiograph (21% ± 7.4% versus 17.