Chiari malformation type I (CM1) is a common neurosurgical disorder. It often causes debilitation in the affected patients. CM1 is a herniation of the caudal cerebellum into the spinal canal. This study aimed to evaluate the clinical and radiological outcomes of posterior fossa decompression and duraplasty (PFDD) in treated CM1 patients. In retrospective design, we reviewed the medical records of diagnosed patients with CM1 at two neurosurgical centers spanning 8 years from 2010 to 2017. We selected all CM1 patients who underwent PFDD surgery (n = 72) as the core sample for this study. We used the Chicago Chiari Outcome Scale (CCOS) to evaluate clinical outcomes. Pre- and postoperatively, we assessed the syrinx/cord ratio, the syrinx length, and the improvement of aqueductal stroke volume (ASV) on CSF flow MRIs. The mean value of CCOS was 14.1 ± 2.1. On midsagittal MRIs, the mean regression in ectopia tonsils was 9.4 ± 1.9 mm (i.e., mean pre- and postoperative tonsil herniation was 13.1 ± 3.1 mm and 4.0 ± 1.6 mm, respectively; p < 0.001). On coronal MRIs, the mean regression in ectopia tonsils was 8.4 ± 1.5 mm (i.e., mean pre- and postoperative tonsil herniation was 13.9 ± 2.4 mm and 5.8 ± 1.0 mm, respectively; p < 0.001). A strong positive correlation was observed between clinical improvement and the increase in ASV values. CSF flow MRIs can help in the surgical decision and follow-up of CM1 patients. ASV ≤ 12 μl is a significant predictor for surgical intervention. Full clinical and radiological evaluation utilizing CSF flow MRI are essential. Most syrinx cavities have regressed following PFDD.

Chiari 畸形 I 型 (CM1) 是一种常见的神经外科疾病。它经常导致受影响的患者虚弱。CM1 是小脑尾部进入椎管的疝出。本研究旨在评估经治疗的 CM1 患者后颅窝减压和硬膜成形术 (PFDD) 的临床和放射学结果。在回顾性设计中，我们回顾了 2010 年至 2017 年 8 年间在两个神经外科中心确诊的 CM1 患者的病历。我们选择了所有接受 PFDD 手术的 CM1 患者（n = 72) 作为本研究的核心样本。我们使用芝加哥 Chiari 结果量表 (CCOS) 来评估临床结果。术前和术后，我们评估了 CSF 流 MRI 上的空洞/脊髓比率、空洞长度和导水管每搏输出量 (ASV) 的改善。CCOS 的平均值为 14.1 ± 2.1。在正中矢状位 MRI 上，异位扁桃体的平均消退为 9.4 ± 1.9 毫米（即，平均术前和术后扁桃体突出分别为 13.1 ± 3.1 毫米和 4.0 ± 1.6 毫米；p  < 0.001）。在冠状 MRI 上，异位扁桃体的平均退化为 8.4 ± 1.5 毫米（即，术前和术后的扁桃体突出平均分别为 13.9 ± 2.4 毫米和 5.8 ± 1.0 毫米；p < 0.001)。在临床改善和 ASV 值的增加之间观察到强烈的正相关。脑脊液流 MRI 可以帮助 CM1 患者的手术决策和随访。ASV ≤ 12 μl 是手术干预的重要预测指标。利用 CSF 流 MRI 进行全面的临床和放射学评估是必不可少的。大多数 syrinx 腔在 PFDD 后消退。