Syndromic Atlanto-axial Instability: WFNS Consensus on Screening and Surveillance, Sports Clearance, and Treatment Options.

Study design: Systematic review plus expert opinion framed on Delphi Method.

Objective: Define criteria to on (i) how to screen for instability of cranio-vertebral CVJ in a high-risk population, especially in Down or Morquio syndrome, (ii) if or when which surgical procedure is indicated, and (iii) whether syndromic patients can safely participate in sports activities.

Summary background data: Syndromic abnormalities of CVJ may lead to potentially devastating neurological deficits. As of now, there is no international consensus on how to handle syndromic patients with atlanto-axial instability.

Methods: International spine specialists of the WFNS spine committee reviewed statements from articles published between 2012 and 2022 to reach an expert agreement. Each statement was voted for on a Likert scale. The Delphi method was used to achieve a high level of validity.

Results: Because of the high incidence of craniovertebral instability in Down's patients, close neurological and radiologic screening is advocated. In Morquio's patients older than 5 years, it is recommended to perform an annual neurological examination and imaging studies to detect cervical stenosis or instability. For atlanto-axial instability (AAI), the recommended screening should include cervical spine lateral radiograph in controlled flexion/extension projections. In asymptomatic Down and Morquio syndrome patients with proven AAI, preventive stabilization might be considered. Neurological symptoms deriving from AAI are an indication for stabilization through Goel-Harms C1-C2 technique.Patients without AAI and intact neurological status are cleared to unrestricted sports. Down syndrome patients with symptoms but without AAI or spinal cord compression can participate in most Special Olympics sports competition activities.

Conclusions: Consent was achieved on treatment recommendations for patients with syndromic disorders of the CVJ, with special focus laid on participation in physical activity and sports competitions. This should help spine surgeons and sports medicine doctors decide on a management path for each individual patient.