Syrinx resolution has been associated with an increase in the size of the posterior subarachnoid space (pSAS) after foramen magnum decompression (FMD) for type I Chiari malformation (CM1). The present study investigated the influence of pSAS increase on syrinx resolution and symptom improvement after FMD. 32 patients with CM1 with syrinx were analyzed retrospectively. FMD was performed for the 24 patients with CM1 with syrinx. pSAS areas were measured on sagittal magnetic resonance images. Neurological symptoms were grouped into three clinical categories and scored. The rates of symptom improvement in the CM1 patients with syrinx after FMD was 19.7% ± 12.9%. The mean times to the improvement of neurological symptoms in CM1 patients with syrinx after FMD was 23.4 ± 50.2 months. There were no significant differences between the patients with and without improvement of syrinx after FMD with regard to the age, length of tonsillar herniation, BMI, and preoperative pSAS areas. The rate of increase in the pSAS areas was significantly higher in the group with syrinx improvement within 1 year (p < 0.0001). All patients with a > 50% rate of increase in the pSAS area showed syrinx improvement. Our results suggested that the increasing postoperative pSAS area accelerated the timing of syrinx resolution.

Syrinx 分辨率与 I 型 Chiari 畸形 (CM1) 枕骨大孔减压 (FMD) 后蛛网膜下腔后间隙 (pSAS) 的大小增加有关。本研究调查了 pSAS 增加对 FMD 后空洞的消退和症状改善的影响。回顾性分析了 32 名 CM1 与 syrinx 患者。对 24 名 CM1 与 syrinx 患者进行了 FMD。pSAS 面积是在矢状磁共振图像上测量的。神经系统症状分为三个临床类别并进行评分。FMD 后有 syrinx 的 CM1 患者的症状改善率为 19.7% ± 12.9%。FMD 后有 syrinx 的 CM1 患者神经系统症状改善的平均时间为 23.4 ± 50.2 个月。FMD后有和没有改善的患者在年龄、扁桃体突出长度、BMI和术前pSAS面积方面没有显着差异。pSAS 区域的增加率在 1 年内有空洞改善的组中显着更高（p < 0.0001）。pSAS 面积增加率 > 50% 的所有患者都显示出空洞改善。我们的结果表明，增加的术后 pSAS 面积加速了空洞消退的时间。pSAS 面积增加 50% 的速度显示了空洞的改善。我们的结果表明，增加的术后 pSAS 面积加速了空洞消退的时间。pSAS 面积增加 50% 的速度显示了空洞的改善。我们的结果表明，增加的术后 pSAS 面积加速了空洞消退的时间。