Abstract：
OBJECTIVE: Reduced intracranial compliance (ICC) may be an important factor in the pathophysiology of Chiari malformation type I (CM-I). However, direct measurement of ICC is controversial because of its invasiveness, particularly in children. Instead, ICC may be estimated from continuous measurements of intracranial pressure (ICP), where the metric mean wave amplitude (MWA) has been found to be more useful as a surrogate marker of ICC than mean ICP. This observational study investigated the distribution of MWA and mean ICP in symptomatic children with CM-I, as well as their association with clinical and radiological findings.
METHODS: From a consecutive series of children treated for CM-I at a single institution between 2006 and 2023, the authors analyzed ICP scores in those who underwent an overnight preoperative ICP recording in which MWA was calculated. Clinical and radiological data were retrieved from the patient records.
RESULTS: Thirty-seven children (mean age 12.4 ± 3.6 years) with symptomatic CM-I were identified. From the overnight ICP measurements, the average MWA was 5.2 ± 1.3 mm Hg: 56% of children had an abnormal MWA (> 5 mm Hg) and 33% had a borderline MWA (4-5 mm Hg). In contrast, the average mean ICP was 9.7 ± 4.1 mm Hg: 8% of children had an abnormal mean ICP (> 15 mm Hg) and 41% had a borderline mean ICP (10-15 mm Hg). Thus, more children were found to have an abnormal MWA than an abnormal mean ICP (p < 0.001). MWA was significantly higher in the subgroup of children with medullary compression in the foramen magnum, as seen on MRI, than in those without (5.6 ± 1.0 mm Hg vs 4.7 ± 1.4 mm Hg, p = 0.03), whereas a similar difference was not observed for mean ICP (9.9 ± 4.6 mm Hg vs 9.7 ± 3.7 mm Hg, p = 0.889).
CONCLUSIONS: In this cohort of symptomatic children with CM-I, MWA was more frequently abnormal than mean ICP, with a clinically significant discrepancy in half of the patients. Moreover, MWA was significantly higher in patients with medullary compression. Based on these findings, the authors\' interpretation is that in children with CM-I, the ICC may be reduced, as indicated by increased MWA, even though the mean ICP is within normal thresholds.
METHODS: From a consecutive series of children treated for CM-I at a single institution between 2006 and 2023, the authors analyzed ICP scores in those who underwent an overnight preoperative ICP recording in which MWA was calculated. Clinical and radiological data were retrieved from the patient records.
RESULTS: Thirty-seven children (mean age 12.4 ± 3.6 years) with symptomatic CM-I were identified. From the overnight ICP measurements, the average MWA was 5.2 ± 1.3 mm Hg: 56% of children had an abnormal MWA (> 5 mm Hg) and 33% had a borderline MWA (4-5 mm Hg). In contrast, the average mean ICP was 9.7 ± 4.1 mm Hg: 8% of children had an abnormal mean ICP (> 15 mm Hg) and 41% had a borderline mean ICP (10-15 mm Hg). Thus, more children were found to have an abnormal MWA than an abnormal mean ICP (p < 0.001). MWA was significantly higher in the subgroup of children with medullary compression in the foramen magnum, as seen on MRI, than in those without (5.6 ± 1.0 mm Hg vs 4.7 ± 1.4 mm Hg, p = 0.03), whereas a similar difference was not observed for mean ICP (9.9 ± 4.6 mm Hg vs 9.7 ± 3.7 mm Hg, p = 0.889).
CONCLUSIONS: In this cohort of symptomatic children with CM-I, MWA was more frequently abnormal than mean ICP, with a clinically significant discrepancy in half of the patients. Moreover, MWA was significantly higher in patients with medullary compression. Based on these findings, the authors\' interpretation is that in children with CM-I, the ICC may be reduced, as indicated by increased MWA, even though the mean ICP is within normal thresholds.
摘要：
目的：颅内顺应性（ICC）降低可能是Chiari畸形I型（CM-I）病理生理的重要因素。然而,ICC的直接测量因其侵入性而引起争议，特别是在儿童中。相反，ICC可以通过颅内压（ICP）的连续测量来估计，其中已发现度量平均波振幅（MWA）作为ICC的替代指标比平均ICP更有用。这项观察性研究调查了有症状的CM-I儿童中MWA和平均ICP的分布，以及它们与临床和放射学结果的关联。
方法：从2006年至2023年期间在单一机构接受CM-I治疗的连续一系列儿童中，作者分析了接受隔夜术前ICP记录的患者的ICP评分，其中计算了MWA。从患者记录中检索临床和放射学数据。
结果：37名儿童（平均年龄12.4±3.6岁）有症状的CM-I。从夜间ICP测量结果来看，平均MWA为5.2±1.3mmHg:56%的儿童MWA异常(>5mmHg),33%的儿童MWA临界(4~5mmHg).相比之下,平均ICP为9.7±4.1mmHg:8%的儿童平均ICP异常(>15mmHg),41%的儿童平均ICP临界(10~15mmHg).因此，发现MWA异常的儿童多于平均ICP异常的儿童(p<0.001).在大孔髓质受压患儿亚组中，MWA明显增高，从核磁共振成像上看,比没有（5.6±1.0mmHgvs4.7±1.4mmHg，p=0.03),而平均ICP没有观察到类似的差异（9.9±4.6mmHgvs9.7±3.7mmHg，p=0.889)。
结论：在这个有症状的CM-I患儿队列中，MWA异常频率高于平均ICP，在一半的患者中具有临床意义的差异。此外，延髓受压患者的MWA明显更高。基于这些发现,作者的解释是，在患有CM-I的儿童中，国际商会可能会减少，如MWA增加所示，即使平均ICP在正常阈值内。
方法：从2006年至2023年期间在单一机构接受CM-I治疗的连续一系列儿童中，作者分析了接受隔夜术前ICP记录的患者的ICP评分，其中计算了MWA。从患者记录中检索临床和放射学数据。
结果：37名儿童（平均年龄12.4±3.6岁）有症状的CM-I。从夜间ICP测量结果来看，平均MWA为5.2±1.3mmHg:56%的儿童MWA异常(>5mmHg),33%的儿童MWA临界(4~5mmHg).相比之下,平均ICP为9.7±4.1mmHg:8%的儿童平均ICP异常(>15mmHg),41%的儿童平均ICP临界(10~15mmHg).因此，发现MWA异常的儿童多于平均ICP异常的儿童(p<0.001).在大孔髓质受压患儿亚组中，MWA明显增高，从核磁共振成像上看,比没有（5.6±1.0mmHgvs4.7±1.4mmHg，p=0.03),而平均ICP没有观察到类似的差异（9.9±4.6mmHgvs9.7±3.7mmHg，p=0.889)。
结论：在这个有症状的CM-I患儿队列中，MWA异常频率高于平均ICP，在一半的患者中具有临床意义的差异。此外，延髓受压患者的MWA明显更高。基于这些发现,作者的解释是，在患有CM-I的儿童中，国际商会可能会减少，如MWA增加所示，即使平均ICP在正常阈值内。
