Bogdanov E I
Kazan State Medical University, Kazan, Russia.
Zh Vopr Neirokhir Im N N Burdenko. 2022;86(3):92-98. doi: 10.17116/neiro20228603192.
Cerebellar tonsil dislocation into foramen magnum exceeding 5 mm is traditionally considered as Chiari malformation type 1. This disease requires surgical treatment in case of severe clinical manifestations. In patients with hypoplasia of posterior cranial fossa (PCF), subthreshold tonsil dislocations or tonsil position inside the foramen magnum can result clinical signs identical to Chiari malformation type 1. These disorders are presumably referred to phenotypic variant of Chiari malformation type 1 (Chiari malformation type 0). The authors discuss the data on the prevalence and mechanisms of cerebellar tonsil ectopia into foramen magnum, the role of hereditary and environmental factors in development of PCF hypoplasia and its role in Chiari malformation type 1 and 0. Significance of MR-based morphometry of PCF in identifying the primary forms (Chiari malformation type 1 and 0), clinical and radiological signs of malformation type 0, as well as data on surgical treatment of Chiari malformation type 0 combined and non-combined with syringomyelia are analyzed. Literature data confirm validity of the concept of Chiari malformation type 0. We emphasize the need for further analysis of this problem to identify sensitive and specific diagnostic signs of Chiari malformation type 0 and determine optimal treatment strategy.
传统上认为小脑扁桃体疝入枕骨大孔超过5mm为Chiari I型畸形。若临床表现严重，该病需手术治疗。在后颅窝（PCF）发育不全的患者中，阈下扁桃体疝或扁桃体位于枕骨大孔内可导致与Chiari I型畸形相同的临床症状。这些病症可能被归为Chiari I型畸形（Chiari 0型畸形）的表型变异。作者讨论了小脑扁桃体疝入枕骨大孔的患病率和机制的数据，遗传和环境因素在PCF发育不全发生中的作用及其在Chiari I型和0型畸形中的作用。分析了基于磁共振成像（MR）的PCF形态测量在识别主要类型（Chiari I型和0型畸形）、0型畸形的临床和放射学征象以及Chiari 0型畸形合并和不合并脊髓空洞症的手术治疗数据方面的意义。文献数据证实了Chiari 0型畸形概念的有效性。我们强调需要进一步分析该问题，以识别Chiari 0型畸形的敏感和特异诊断征象并确定最佳治疗策略。
