The incidence of nerve root sedimentation sign (SedSign) was evaluated to explore potential pathogenesis in patients with severe lumbar spinal stenosis (LSS). In a total of 209 patients with severe LSS, 290 intervertebral levels were narrow, among which 248 showed a positive SedSign, giving a prevalence of 85.52%. Those levels with a positive SedSign were further analyzed relative to those with a negative SedSign. There was no significant difference between the two groups for the cross-sectional area (CSA) or the posteroanterior diameter (PAD). In contrast, there was a significant difference between the groups for the grade of degenerative facet joint (DFJ) (p < 0.05), the thickness of ligamentum flavum (TLF) (p < 0.01), and the cross-sectional area difference (CSAD) (p < 0.01). In addition, receiver operating characteristic (ROC) curves were used to identify associated factors. The area under the ROC curve for PAD was 0.608 (p < 0.05), for DFJ was 0.634 (p < 0.05), for TLF was 0.74 (p < 0.01), and for CSAD was 0.911 (p < 0.01). In summary, a positive SedSign has notable advantages in assisting with the diagnosis of severe LSS. Compression of the dural sac from the rear may be the main risk factors of a positive SedSign.

评估神经根沉降征（SedSign）的发生率，以探讨严重腰椎管狭窄症（LSS）患者的潜在发病机制。209例重度LSS患者中，290例椎间节段狭窄，其中248例SedSign呈阳性，患病率为85.52%。相对于具有负 SedSign 的那些水平，进一步分析具有正 SedSign 的那些水平。两组之间的横截面积 (CSA) 或后前径 (PAD) 没有显着差异。相比之下，退行性小关节 (DFJ) 的等级 ( p  < 0.05)、黄韧带厚度 (TLF) ( p  < 0.01) 和横截面积差 (CSAD)的组间存在显着差异) ( < 0.01)。此外，接受者操作特征 (ROC) 曲线用于识别相关因素。PAD 的 ROC 曲线下面积为 0.608 ( p  < 0.05)，DFJ 为 0.634 ( p  < 0.05)，TLF 为 0.74 ( p  < 0.01)，CSAD 为 0.911 ( p  < 0.01)。总之，SedSign 阳性在辅助重度 LSS 诊断方面具有显着优势。从后面压迫硬膜囊可能是 SedSign 呈阳性的主要危险因素。