Cranio-Vertebral Junction Anomalies

Introduction. The published literature on Cranio-vertebral Junction (CVJ) anomalies lacks a comprehensive appraisal that integrates common diagnostic, management and treatment concepts for different conditions, such as Chiari Malformation (CM), Basilar Invagination (BI), Os Odontoideum (OO) and Syndromic Malformations. The authors aimed to fill this knowledge gap offering guidelines and recommendations with a global outreach and applicability. Methods. A group of expert spine surgeons and WFNS Spine Committee members, most of which extensively published on CVJ anomalies in the past, reviewed the literature issued from 2011 to 2022. Following a common methodology, based on the Delphi method, the authors analyzed the strength of the literature and voted statements concerning diagnosis and management of these conditions. Results. A total of eight papers were produced: (1) Chiari Malformation diagnosis, classifications, natural history, and conservative management, (2) Chiari malformation: indications for surgery and surgical options, (3) Pediatric Chiari malformation, (4) Syndromic atlanto-axial instability, (5) Os odontoideum, (6) Basilar invagination: diagnosis, radiology, and classification, (7) Surgical treatment of Basilar Invagination, and (8) Basilar invagination with associated Chiari malformation. Conclusions. Despite grey zones on natural history of CVJ anomalies and controversies on timing and type of surgical treatments, whenever atlantoaxial instability is present, C1-C2 stabilization through instrumentation and fusion is necessary. If only recurrent pain and neurological dysfunction occurs, surgical decompression is appropriate. If no atlantoaxial instability is present, Down’s patients can participate in competitive sports. In general, contact sports are not recommended.