title: Prevalence of atlanto-occipital and atlantoaxial instability in adults with Down syndrome.
abstract: OBJECTIVE
  This study sought to evaluate the presence of atlanto-occipital and atlantoaxial instabilities as well as their clinical significance in patients with Down syndrome.
  
  
  METHODS
  The present study retrospectively evaluated 80 adults with Down syndrome for the presence of atlanto-occipital and atlantoaxial instability in lateral craniocervical radiographic images. Atlanto-occipital instability was defined by the Rules of 12 or Harris measurements, using the values of the basion-dens interval or the basion-axial interval. Atlantoaxial instability was radiologically identified by the space between the anterior border of the odontoid apophysis and the posterior border of the atlas arch, as well as by the Wiesel-Rothman line.
  
  
  RESULTS
  Eighty patients were assessed; 14 (17.5%) presented with atlanto-occipital instability and 9 (11.2%) with atlantoaxial instability. Only 3 patients (3.8%) had specific symptoms for cervical instability. There was no statistical correlation with patient age or gender.
  
  
  CONCLUSIONS
  High cervical instability in patients with Down syndrome can also be observed among adults, and there is a low correlation between the radiological findings and symptoms. These findings emphasize the importance of periodic follow-up on these patients, particularly when sports activities are considered.
authors: Institute of Physical Medicine and Rehabilitation of Hospital das Clínicas of the University of São Paulo, São Paulo, Brazil.
authors: Marcelo
authors: M
authors: El-Khouri
authors: Institute of Physical Medicine and Rehabilitation of Hospital das Clínicas of the University of São Paulo, São Paulo, Brazil.
authors: Marcelo Alves
authors: MA
authors: Mourão
authors: Institute of Physical Medicine and Rehabilitation of Hospital das Clínicas of the University of São Paulo, São Paulo, Brazil.
authors: Andrea
authors: A
authors: Tobo
authors: Institute of Physical Medicine and Rehabilitation of Hospital das Clínicas of the University of São Paulo, São Paulo, Brazil; School of Medicine in São Paulo, University of São Paulo, São Paulo, Brazil.
authors: Linamara Rizzo
authors: LR
authors: Battistella
authors: Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
authors: Carlos Fernando Pereira
authors: CF
authors: Herrero
authors: Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil. Electronic address: mriberto@usp.br.
authors: Marcelo
authors: M
authors: Riberto
mesh_terms: D000328:Adult; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging*; D001269:Atlanto-Occipital Joint / Q000000981:diagnostic imaging*; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004314:Down Syndrome / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000150:complications / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D008297:Male; D015995:Prevalence; D011859:Radiography; D013177:Sports; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Adult; Atlanto-occipital instability; Atlantoaxial instability; Down syndrome; Prevalence