Department of Paediatric Endocrinology, Evelina London Children's Hospital, London, UK
Department of Clinical Genetics, Guy's and St Thomas' NHS Foundation Trust, London, UK.
Arch Dis Child. 2021 Feb;106(2):180-184. doi: 10.1136/archdischild-2020-319625. Epub 2020 Sep 3.
Achondroplasia is associated with foramen magnum stenosis (FMS) and significant risk of morbidity and sudden death in infants. A sensitive and reliable method of detecting infants who require decompressive surgery is required. This study aims to describe the incidence and severity of FMS in an unselected, sequential series of infants using a novel MRI score and retrospectively correlate severity with clinical examination and cardiorespiratory sleep (CRS) studies.
The Achondroplasia Foramen Magnum Score (AFMS) was developed and scores were retrospectively correlated with clinical and CRS data over a 3-year period.
Of 36 infants (M:F, 18:18), 2 (5.6%) did not have FMS (AFMS0); 13 (36.1%) had FMS with preservation of the cerebrospinal fluid (CSF) spaces (AFMS1); 3 (8.3%) had FMS with loss of the CSF space but no spinal cord distortion (AFMS2); 13 (36.1%) had FMS with flattening of the cervical cord without signal change (AFMS3); and 5 (13.9%) had FMS resulting in cervical cord signal change (AFMS4). Mean Total Apnea and Hypopnea Index (TAHI) for AFMS0-4 was 3.4, 6.41, 2.97, 10.5 and 25.8, respectively. Severe TAHI had a specificity of 89% but only a 59% sensitivity for AFMS3-4. Neurological examination was normal in 34/36 (94%) patients. Overall, 9/36 (25%) infants required neurosurgery with minimal surgical complications.
Clinical examination and CRS have a low sensitivity for predicting the effects of foramen stenosis on the spinal cord. Routine screening with MRI using AFMS can aid in detecting early spinal cord changes and has the potential to reduce infant morbidity and mortality.
成骨不全症与颅后窝狭窄（FMS）有关，并且在婴儿中存在显著的发病和猝死风险。因此需要一种敏感且可靠的方法来检测需要减压手术的婴儿。本研究旨在使用一种新的 MRI 评分，描述未经选择的连续系列婴儿中 FMS 的发生率和严重程度，并回顾性地将严重程度与临床检查和心肺睡眠（CRS）研究相关联。
开发了成骨不全症颅后窝评分（AFMS），并在 3 年期间回顾性地将评分与临床和 CRS 数据相关联。
在 36 名婴儿（男：女，18：18）中，2 名（5.6%）没有 FMS（AFMS0）；13 名（36.1%）有 FMS，伴有脑脊液（CSF）空间保留（AFMS1）；3 名（8.3%）有 FMS，伴有 CSF 空间丢失但无脊髓变形（AFMS2）；13 名（36.1%）有 FMS，颈髓变平但无信号改变（AFMS3）；5 名（13.9%）有 FMS 导致颈髓信号改变（AFMS4）。AFMS0-4 的平均总呼吸暂停和低通气指数（TAHI）分别为 3.4、6.41、2.97、10.5 和 25.8。严重的 TAHI 对 AFMS3-4 的特异性为 89%，但敏感性仅为 59%。36 名患者中有 34 名（94%）神经检查正常。总体而言，9/36（25%）的婴儿需要神经外科手术，手术并发症极少。
临床检查和 CRS 对预测 FMS 对脊髓的影响的敏感性较低。使用 AFMS 进行常规 MRI 筛查有助于早期发现脊髓变化，并有可能降低婴儿发病率和死亡率。
