Supplementary Material for: Late prenatal development of hindbrain herniation in open spina bifida

Introduction: We describe four cases of open spina bifida initially presumed to be “closed” defects in which serial prenatal ultrasound examinations documented the occurrence of sac rupture and development of Chiari II malformation later in the pregnancy.
Case presentation: In each case, the ultrasound examinations starting from 19-24 weeks’ gestation, showed spinal cystic lesions containing neural elements, but no evidence of Chiari II malformation. The lack of hindbrain herniation rendered them ineligible for prenatal surgical repair; but follow-up imaging at 24-32 weeks’ gestation, demonstrated the cystic lesions no longer visible or visible but decompressed, with the additional development of de novo hindbrain herniation.
Conclusion: We conclude by recommending serial ultrasound surveillance of presumed “closed” spina bifida as these may be in fact open defects, with confirmatory diagnosis only possible later in pregnancy. This detection is important because it may change counseling since prenatal repair or planned delivery may be warranted

引言：我们描述了4例初始被认为是“闭合性缺陷（closed defects）”的开放性脊柱裂（open spina bifida）病例，系列产前超声检查记录了妊娠后期囊破裂及Chiari II畸形（Chiari II malformation）的发生。

病例报告：每例患者在妊娠19-24周开始的超声检查中，均显示含神经成分的脊柱囊性病变，但无Chiari II畸形证据。由于缺乏后颅窝疝（hindbrain herniation），这些病例不符合产前手术修复的条件；然而，妊娠24-32周的随访影像显示，囊性病变已消失或虽可见但已减压，同时出现新发的（de novo）后颅窝疝。

结论：我们建议对疑似“闭合性”脊柱裂进行系列超声监测，因为这些病变实际上可能为开放性缺陷，确诊仅能在妊娠后期实现。这种检测至关重要，因其可能改变咨询方案——产前修复或计划分娩或许是必要的。