1.Utility of Seated Lateral Radiographs in the Diagnosis and Classification of Lumbar Degenerative Spondylolisthesis
Tariq Z. ISSA ; Yunsoo LEE ; Emily BERTHIAUME ; Mark J. LAMBRECHTS ; Caroline ZAWORSKI ; Qudratallah S. QADIRI ; Henley SPRACKLEN ; Richard PADOVANO ; Jackson WEBER ; John J. MANGAN ; Jose A. CANSECO ; Barrett I. WOODS ; I. David KAYE ; Alan S. HILIBRAND ; Christopher K. KEPLER ; Alexander R. VACCARO ; Gregory D. SCHROEDER ; Joseph K. LEE
Asian Spine Journal 2023;17(4):721-728
Methods:
We assessed baseline neutral upright, standing flexion, seated lateral radiographs, and magnetic resonance imaging (MRI) for patients identified with spondylolisthesis from January 2021 to May 2022 by a single spine surgeon. DS was classified by Meyerding and Clinical and Radiographic Degenerative Spondylolisthesis classifications. A difference of >10° or >8% between views, respectively, was used to characterize angular and translational instability. Analysis of variance and paired chi-square tests were utilized to compare modalities.
Results:
A total of 136 patients were included. Seated lateral and standing flexion radiographs showed the greatest slip percentage (16.0% and 16.7%), while MRI revealed the lowest (12.2%, p <0.001). Standing flexion and lateral radiographs when seated produced more kyphosis (4.66° and 4.97°, respectively) than neutral upright and MRI (7.19° and 7.20°, p <0.001). Seated lateral performed similarly to standing flexion in detecting all measurement parameters and categorizing DS (all p >0.05). Translational instability was shown to be more prevalent when associated with seated lateral or standing flexion than when combined with neutral upright (31.5% vs. 20.2%, p =0.041; and 28.1% vs. 14.6%, p =0.014, respectively). There were no differences between seated lateral or standing flexion in the detection of instability (all p >0.20).
Conclusions
Seated lateral radiographs are appropriate alternatives for standing flexion radiographs. Films taken when standing up straight do not offer any more information for DS detection. Rather than standing flexion-extension radiographs, instability can be detected using an MRI, which is often performed preoperatively, paired with a single seated lateral radiograph.