Comparison Of Two Methods Of Radiographic Evaluation Of Instability In Lumbar Spondylolisthesis

Summary: Instability in lumbar spondylolisthesis is a reason for low back pain and sciatica, and is a key condition for spinal fusion and fixation. Evaluating potential instability in lumbar spondylolisthesis is signifcant to its treatment. Although radiographical evaluation of instability in lumbar spondylolisthesis is extensively performed, the diagnostic criteria of segmental instability remains controversial. Currently, with the flexion-extension standing radiograph(FESR) judgment of instability in lumbar spondylolisthesis different scholars use different methods to judge, so far there is no completely uniform standard for clinical diagnosis. Recently, some scholars combine a variety of imaging changes in posture for comparative analysis to determine the instability of lumbar spondylolisthesis. It has been reported that sagittal translation(ST) on standing lateral X-ray- supine MRI / CT measured is larger than that on FESR.Objective: To compare the use of 2 diagnostic modalities in the evaluation of instability in lumbar spondylolisthesis. To investigate whether upright-supine lateral radiograph(USLR) can better predict segmental instability of the lumbar spondylolisthesis as diagnosed than with FESR.Methods:In the single hospital from January 2014 to January 2016, demographic date were collected from 64 patients(25 men and 39women) with primary diagnosis of a I/II-grade lumbar spondylolisthesis. Allpatients received radiographs in FESR and USLR. Vertebral body depth(VBD), sagittal translation(ST), sagittal rotational angle(SRA) of the listhetic segment were measured and slip percentage(SP) and Intervertebral motion(IM) were calculated on FESR and USLR. Using USLR was compared with that using FESR. In addition, the relationships between mobility determined using FESR or USLR and sex, age, height, weight, body mass index(BMI), primary symptom(with or without low back pain), nature of spondylolisthesis(degenerative or isthmic), listhetic segment, and slippage grade were analyzed.Results: The mean age of 64 patients was 61.3±9.9 years. The mean of IM revealed 5.70 ± 3.83% in FESR and 7.69 ± 5.33% in USLR. Overall, the assessment of IM in USLR was significantly higher than that in FESR(P<0.05). The number of cases of instability in lumbar spondylolisthesis using USLR were more than that using FESR(26/64 VS 17/64, P <0.05). Comparison of SRA showed the highest rotation in FESR(6.8°±3.5°), however, compared to USLR(4.3°±3.2°), P <0.05.Female patients demonstrated higher mobility in FESR than male patients, and low back pain, isthmic spondylolisthesis, and slippage grade also showed some relevance with mobility and statistical significance(P<0.05).Conclusion: USLR can diagnose much more cases of instability in lumbar spondylolisthesis than FESR; USLR is a simple, low-cost method to diagnose instability in lumbar spondylolisthesis.