摘要目的:探讨单纯终丝牵张型脊髓拴系患者行终丝切断术后脊髓圆锥的漂移情况，分析脊髓圆锥漂移度与腰骶椎序列的关系及其意义。方法:回顾性分析2014年1月至2019年6月北京大学第三医院神经外科收治的20例单纯终丝牵张型脊髓拴系综合征患者的临床资料。所有患者均予终丝切断术治疗。行术前和术后腰骶部MRI平扫，测量腰骶角(LSA)、腰椎前凸角(LLA)以及腰骶椎间盘角(LSDA)以评估腰骶部脊柱序列情况。计算手术前、后脊髓圆锥弯曲角(BA)[脊髓圆锥长轴线与腰段脊髓长轴线之间所夹锐角]的差值(△BA)，即脊髓圆锥漂移度。比较腰骶部脊柱序列各角度手术前、后的差异。通过Pearson相关性分析探讨脊髓圆锥漂移度与腰骶部脊柱序列各角度之间的关系。结果:20例患者的术前LSA、LLA、LSDA分别为69.3°±7.4°、30.0°±9.5°、12.0°±4.5°，术后分别为69.8°±7.0°、30.3°±9.1°、11.9°±4.5°，手术前、后腰骶椎序列各角度的差异均无统计学意义(均 P>0.05)。术前、术后的BA分别为22.3°±6.8°和20.1°±6.7°，两者之间的差异有统计学意义( t＝9.353， P<0.001)。相关性分析结果提示，20例患者术前的LSA与术前LLA呈正相关( r＝0.576， P<0.01)；手术前、后的△BA为2.3°±1.1°，其与术前LSA呈负相关( r＝－0.610， P<0.01)，而与术前LLA呈高度负相关( r＝－0.812， P<0.01)。 结论:对于单纯终丝牵张型脊髓拴系患者，脊髓圆锥漂移度能在一定程度上反映终丝切断对脊髓拴系的松解情况；腰骶部脊柱序列对术后脊髓圆锥漂移存在影响，有助于术前预判终丝切断缓解脊髓拴系的程度。

abstractsObjectives:To investigate the drift of conus medullaris in patients with simple tethered cord syndrome after transection of filum terminale, and to analyze the relationship between the drift of conus medullaris and lumbosacral sagittal alignment and its significance.Methods:Clinical data of 20 patients with tethered cord syndrome admitted to Neurosurgery Department of Peking University Third Hospital from January 2014 to June 2019 were analyzed retrospectively. Lumbosacral angle (LSA), lumbar lordosis angle (LLA), lumbosacral disc angle (LSDA) were measured in all patients′ lumbosacral sagittal MRI before and after operation to evaluate the lumbosacral sagittal alignment. Bending angle (BA) was defined as the acute angle between the longitudinal axis of the conus medullaris and the longitudinal axis of the lumbar spinal cord. The change of BA (△BA) before and after operation was defined as the drift of conus medullaris. The differences of LSA, LLA, LSDA before and after surgery were compared. Pearson correlation was used to analyze the relationship among the △BA, LSA, LLA and LSDA.Results:The preoperative LSA, LLA and LSDA of 20 patients were 69.3°±7.4°, 30.0°±9.5°, 12.0°±4.5°, and the postoperative LSA, LLA, LSDA were 69.8°±7.0°, 30.3°±9.1°, 11.9°±4.5° respectively. There were no significant differences between the preoperative and postoperative angles (all P>0.05). BA was decreased from preoperative 22.3°±6.8° to 20.1°±6.7° after operation ( t=9.353, P<0.001). Preoperative LSA of 20 patients was positively correlated with LLA ( r=0.576, P<0.01). The △BA was 2.3°±1.1°, which was negatively correlated with preoperative LSA ( r=-0.610, P<0.01) and highly negatively correlated with preoperative LLA ( r=-0.812, P<0.01). Conclusions:To some extent, the drift of conus medullaris could reflect the release of tethered cord after transection of filum terminale in patients with single tethered cord syndrome. Lumbosacral sagittal alignment may affect the drift of conus medullaris, which is helpful for preoperative judgment of the release degree.