Neurosurg Focus. 2023 Mar;54(3):E11. doi: 10.3171/2022.12.FOCUS22623.
The surgical treatment for Chiari I malformation and basilar invagination has been discussed with great controversy in recent years. This paper presents a treatment algorithm for these disorders based on radiological features, intraoperative findings, and analyses of long-term outcomes.
Eight-five operations for 82 patients (mean ± SD age 40 ± 18 years; range 9-75 years) with basilar invagination were evaluated, with a mean follow-up of 57 ± 55 months. Apart from the radiological features and intraoperative findings, findings on neurological examinations before and after surgery were analyzed. Long-term outcomes were evaluated with Kaplan-Meier statistics. All 77 patients with a Chiari I malformation underwent foramen magnum decompression with arachnoid dissection and duraplasty. Patients with ventral compression by the odontoid peg were managed with posterior realignment and C1-2 fusion. Patients without ventral compression did not undergo C1-2 fusion unless radiological or clinical signs of instability were detected.
Thirty-three patients without ventral compression or instability underwent foramen magnum decompression without additional fusion, whereas 52 operations on 49 patients involved posterior fusion at C0-2 or C1-2 after realignment of ventral compression and/or treatment of C1-2 instability. Postoperatively, gait ataxia, swallowing functions, and suboccipital pain improved significantly in both treatment groups. In total, 79% and 73% of patients reported that their condition improved after foramen magnum decompression alone and after fusion with or without foramen magnum decompression, respectively. Progression-free survival rates at 10 years were 83% and 81%, respectively.
Among the patients with basilar invagination, a subgroup consisting of 40.2% of the included patients underwent successful long-term treatment with foramen magnum decompression alone and without additional fusion. This subgroup was characterized by the absence of a ventral compression and no atlantoaxial dislocation or other signs of craniocervical instability. The remainder of patients underwent C1-2 fusion with posterior realignment of ventral compression if required. In the presence of basilar invagination, Chiari I malformation should be treated with foramen magnum decompression and duraplasty.
Chiari I 畸形和颅底凹陷症的手术治疗近年来一直存在很大争议。本文基于影像学特征、术中发现和长期结果分析，为这些疾病提供了一种治疗方案。
对 82 例（平均年龄 40 ± 18 岁，范围 9-75 岁）颅底凹陷症患者的 85 次手术进行评估，平均随访 57 ± 55 个月。除了影像学特征和术中发现外，还分析了手术前后的神经检查结果。采用 Kaplan-Meier 统计法评估长期结果。所有 77 例 Chiari I 畸形患者均行枕骨大孔减压术，蛛网膜松解和硬脑膜成形术。对于齿状突压迫的患者，行后路复位和 C1-2 融合术。对于没有齿状突压迫的患者，除非发现不稳定的影像学或临床征象，否则不进行 C1-2 融合术。
33 例无齿状突压迫或不稳定的患者行单纯枕骨大孔减压术，而 49 例 52 次手术中，52 例患者在复位齿状突压迫和/或治疗 C1-2 不稳定后，行 C0-2 或 C1-2 后路融合术。术后两组患者步态共济失调、吞咽功能和枕下部疼痛均明显改善。单纯行枕骨大孔减压术和融合术（伴或不伴枕骨大孔减压术）后，分别有 79%和 73%的患者报告病情改善。10 年无进展生存率分别为 83%和 81%。
在颅底凹陷症患者中，40.2%的患者经单纯枕骨大孔减压术治疗后取得了长期成功，无需进一步融合。该亚组的特点是没有齿状突压迫，没有寰枢椎脱位或其他颅颈不稳定的迹象。如果需要，其余患者需要行后路复位齿状突压迫和 C1-2 融合术。对于颅底凹陷症患者，Chiari I 畸形应采用枕骨大孔减压术和硬脑膜成形术治疗。
