Xi Chen1, Qing-Shuang Zhou1, Liang Xu1, Zhong-Hui Chen1, Ze-Zhang Zhu1, Song Li1, Yong Qiu1, Xu Sun2. 1. Department of Spine Surgery, Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China. 2. Department of Spine Surgery, Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China. Electronic address: drsunxu@163.com.
Abstract
OBJECTIVE: To investigate the segmental instability of degenerative lumbar spondylolisthesis (DLS) with a kyphotic configuration at the involved segment, and to determine the most useful diagnostic modalities in the evaluation of instability. PATIENTS AND METHODS: This study reviewed a consecutive series of patients with L4/5 DLS between July 2010 and May 2016. The enrolled patients were divided into two groups based on preoperative neutral radiographs: the kyphotic group (Group K) and non-kyphotic group (Group NK). Translational and angular motion was determined by comparing upright lateral radiograph (U) with a supine sagittal MR image(S) (Combined, US) or flexion/extension radiographs (FE). RESULTS: There were 26 and 201 patients in Groups K and NK, respectively. In comparison to Group NK, Group K demonstrated significantly higher translational motion (12.4% vs. 7.0%, P < 0.001) on US analysis, but significantly lower translational motion (4.2% vs. 6.4%, P < 0.001) on FE analysis. Angular motion was detected to be significantly lower in US versus FE in Group NK (1.2° vs. 7.8°, P < 0.001), while of no difference in Group K (P > 0.05). In Group K, "instability" was recognized in 84.6% of patients using US versus 11.5% patients using FE (P < 0.001); While in Group NK, no significant difference was observed in the incidence of "instability" between FE and US (31.3% vs. 27.8%, P = 0.444). Overall, Group K had a significantly higher incidence of instability than Group NK (84.6% vs. 31.3%, P < 0.001). CONCLUSION: DLS with a kyphotic configuration is a distinct subgroup associated with segmental instability. The modality of US is shown to be superior to traditional FE in measuring translational motion and identifying instability for DLS patients with a kyphotic configuration.
OBJECTIVE: To investigate the segmental instability of degenerative lumbar spondylolisthesis (DLS) with a kyphotic configuration at the involved segment, and to determine the most useful diagnostic modalities in the evaluation of instability. PATIENTS AND METHODS: This study reviewed a consecutive series of patients with L4/5 DLS between July 2010 and May 2016. The enrolled patients were divided into two groups based on preoperative neutral radiographs: the kyphotic group (Group K) and non-kyphotic group (Group NK). Translational and angular motion was determined by comparing upright lateral radiograph (U) with a supine sagittal MR image(S) (Combined, US) or flexion/extension radiographs (FE). RESULTS: There were 26 and 201 patients in Groups K and NK, respectively. In comparison to Group NK, Group K demonstrated significantly higher translational motion (12.4% vs. 7.0%, P < 0.001) on US analysis, but significantly lower translational motion (4.2% vs. 6.4%, P < 0.001) on FE analysis. Angular motion was detected to be significantly lower in US versus FE in Group NK (1.2° vs. 7.8°, P < 0.001), while of no difference in Group K (P > 0.05). In Group K, "instability" was recognized in 84.6% of patients using US versus 11.5% patients using FE (P < 0.001); While in Group NK, no significant difference was observed in the incidence of "instability" between FE and US (31.3% vs. 27.8%, P = 0.444). Overall, Group K had a significantly higher incidence of instability than Group NK (84.6% vs. 31.3%, P < 0.001). CONCLUSION: DLS with a kyphotic configuration is a distinct subgroup associated with segmental instability. The modality of US is shown to be superior to traditional FE in measuring translational motion and identifying instability for DLS patients with a kyphotic configuration.
Authors: Jonathan Charles Elysee; Francis Lovecchio; Renaud Lafage; Bryan Ang; Alex Huang; Mathieu Bannwarth; Han Jo Kim; Frank Schwab; Virginie Lafage Journal: Global Spine J Date: 2020-09-25