Analysis of imaging factors related to isthmic spondylolisthesis

English Keywords:Spondylolisthesis  Lower lumbar spine  Isthmus  Spino-pelvic balance parameters  relevant factors

English Abstract:

  【Abstract】 Objectives: To explore the imaging relevant factors of lumbar spondylolysis and isthmic spondylolisthesis in order to understand the occurrence and development mechanism of isthmic spondylolisthesis. Methods: A retrospective analysis of 34 normal patients who underwent full spine X-ray radiographs in our hospital from July 2018 to August 2020 were regarded as the normal group (group A), and their age was 18-35 (26.8±5.6) years old. In addition, 21 patients were selected in the lumbar isthmus fissure group (group B), 23 cases in the group with lumbar isthmic fissure with isthmic degeneration(group C), and 19 cases in the group with isthmic spondylolisthesis (group D), the isthmic fissures of group B, C, D are all located at L5. All images were determined by two senior radiologists. The spine-pelvic balance parameters and lower lumbar anatomical parameters of all images were observed. The spine balance parameters include thoracic kyphosis (TK), lumbar lordosis (LL), and sagittal axial vertical distance (sagittal vertical axis, SVA); pelvic balance parameters include: pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS); lower lumbar anatomical parameters include: lamina angle, intervertebral space angle were recorded and analyzed. One-way analysis of variance was used to compare the differences in imaging parameters between the 4 groups. The Logistic regression was used to analyze the revelant factors of lumbar spondylolysis and isthmic spondylolisthesie. The receiver operating characteristics curve(ROCC) and the Yorden index were used to determine the critical value. Results: The results of one-way analysis of variance showed that TK, SVA, PI, PT, SS, L3 lamina angle and L4 lamina angle were different among the four groups, and the differences was statistically significant(P<0.05). Logistic regression analysis results showed that SS, TK, L3/4 intervertebral space angle and L5/S1 intervertebral space angle(LSA) were closely related to the occurrence of lumbar spondylolysis. SS and TK were positively related to the occurrence of lumbar spondylolysis(P<0.05), L3/4 intervertebral space angle LSA was negatively correlated with the occurrence of lumbar spondylolysis (P<0.05); PI and SVA were positively correlated with the occurrence of isthmic spondylolisthesis(P<0.05). The results of ROCC and Yorden index showed that the critical values of the positive correlation factors SS and TK of lumbar spondylolysis were 28.4° and 25.8°, the critical values of the negative correlation factors L3/4 intervertebral space angle and LSA were 10.8° and 6.0°; The critical values of PI and SVA, which were positively relevant factors of lumbar spondylolisthesis, were 50.5° and 10.9mm. Conclusions: SS, TK, and L3/4 intervertebral space angle, LSA, PI, and SVA are closely related to the occurrence and development of isthmic spondylolisthesis. Increased SS and TK are prone to lumbar spondylolysis, while L3/4 intervertebral space angle and LSA are protective factors for lumbar spondylolysis; increased PI and SVA are prone to isthmic spondylolisthesis.