Department of Neurosurgery, Alder Hey Children's NHS Foundation Trust, Liverpool, UK.
Department of Neurosurgery, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.
Childs Nerv Syst. 2023 Jul;39(7):1911-1920. doi: 10.1007/s00381-023-05883-7. Epub 2023 Mar 10.
Encephaloceles are considered to result from defects in the developing skull through which meninges, and potentially brain tissue, herniate. The pathological mechanism underlying this process is incompletely understood. We aimed to describe the location of encephaloceles through the generation of a group atlas to determine whether they occur at random sites or clusters within distinct anatomical regions.
Patients diagnosed with cranial encephaloceles or meningoceles were identified from a prospectively maintained database between 1984 and 2021. Images were transformed to atlas space using non-linear registration. The bone defect, encephalocele and herniated brain contents were manually segmented allowing for a 3-dimensional heat map of encephalocele locations to be generated. The centroids of the bone defects were clustered utilising a K-mean clustering machine learning algorithm in which the elbow method was used to identify the optimal number of clusters.
Of the 124 patients identified, 55 had volumetric imaging in the form of MRI (48/55) or CT (7/55) that could be used for atlas generation. Median encephalocele volume was 14,704 (IQR 3655-86,746) mm and the median surface area of the skull defect was 679 (IQR 374-765) mm. Brain herniation into the encephalocele was found in 45% (25/55) with a median volume of 7433 (IQR 3123-14,237) mm. Application of the elbow method revealed 3 discrete clusters: (1) anterior skull base (22%; 12/55), (2) parieto-occipital junction (45%; 25/55) and (3) peri-torcular (33%; 18/55). Cluster analysis revealed no correlation between the location of the encephalocele with gender (χ (2, n = 91) = 3.86, p = 0.15). Compared to expected population frequencies, encephaloceles were relatively more common in Black, Asian and Other compared to White ethnicities. A falcine sinus was identified in 51% (28/55) of cases. Falcine sinuses were more common (χ (2, n = 55) = 6.09, p = 0.05) whilst brain herniation was less common (χ (2, n = 55) = .16.24, p < 0.0003) in the parieto-occipital location.
This analysis revealed three predominant clusters for the location of encephaloceles, with the parieto-occipital junction being the most common. The stereotypic location of encephaloceles into anatomically distinct clusters and the coexistence of distinct venous malformations at certain sites suggests that their location is not random and raises the possibility of distinct pathogenic mechanisms unique to each of these regions.
脑膨出被认为是由于颅骨发育缺陷导致脑膜和潜在的脑组织疝出。这个过程的病理机制尚不完全清楚。我们旨在通过生成一组图谱来描述脑膨出的位置，以确定它们是随机发生在特定解剖区域内的还是在特定区域内聚集发生的。
从 1984 年至 2021 年期间前瞻性维护的数据库中确定诊断为颅裂或脑膜膨出的患者。使用非线性配准将图像转换到图谱空间。手动分割骨缺损、脑膨出和疝出的脑组织，以便生成脑膨出位置的三维热图。利用 K-均值聚类机器学习算法对骨缺损的质心进行聚类，使用肘部法确定最佳聚类数。
在确定的 124 名患者中，55 名患者有 MRI（48/55）或 CT（7/55）的容积成像，可用于图谱生成。脑膨出体积中位数为 14704（IQR 3655-86746）mm，颅骨缺损面积中位数为 679（IQR 374-765）mm。45%（25/55）的患者发现有脑疝入脑膨出，脑疝体积中位数为 7433（IQR 3123-14237）mm。应用肘部法发现有 3 个离散的簇：（1）前颅底（22%；12/55），（2）顶枕交界区（45%；25/55）和（3）眶周（33%；18/55）。聚类分析显示脑膨出的位置与性别之间没有相关性（χ（2，n=91）=3.86，p=0.15）。与预期的人群频率相比，黑人、亚洲人和其他种族的脑膨出相对更为常见，而白人的脑膨出则相对较少。在 51%（28/55）的病例中发现了镰状窦。镰状窦更为常见（χ（2，n=55）=6.09，p=0.05），而脑疝则较少见（χ（2，n=55）=0.16，p<0.0003）在顶枕交界区。
本分析揭示了脑膨出的三个主要位置簇，顶枕交界区是最常见的位置。脑膨出在解剖上明显的位置簇集中，以及在某些部位存在独特的静脉畸形，提示其位置不是随机的，并提出了其位置可能与每个特定区域独特的病理机制有关。
