The jigsaw sign. A reliable indicator of congenital aetiology in os odontoideum.

Autor: Fagan AB; Spinal Unit Department of Orthopaedics and Trauma, Royal Adelaide Hospital and the University of Adelaide, North Tce, 5000 Adelaide, Australia. andrew.fagan@adelaide.edu.au, Askin GN, Earwaker JW
Jazyk: angličtina
Zdroj: European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society [Eur Spine J] 2004 Jul; Vol. 13 (4), pp. 295-300. Date of Electronic Publication: 2004 Jul 01.
DOI: 10.1007/s00586-004-0732-2
Abstrakt: There is evidence in the literature for both a congenital and a post-traumatic aetiology for os odontoideum. In no series published to date has CT been used to aid in the diagnosis. This is a prospective study of the history of trauma and presence of diagnostic features on CT of 18 consecutive cases with os odontoideum. Our objective was to derive clinically useful radiological features enabling accurate differentiation between congenital and post-traumatic aetiologies. A mid-sagittal CT reconstruction of the atlanto-dens joint was obtained. Hypertrophy of the anterior arch of the atlas was quantified by measurement of the arch-peg-area ratio. The presence of dysplastic features (a positive "jigsaw" sign) of the atlanto-axial joint were noted. These included narrowing of the cartilage space and interdigitation of the two joint surfaces. A history of a potential traumatic aetiology was only obtained in one of the 18 (6%) in our series. A significant elevation of the arch-peg ratio was found when comparing this series to 85 controls. And a positive jigsaw sign was observed in 75% of cases. These features were not seen in paediatric cases of atlanto-axial instability, including odontoid non-union. In conclusion, an elevated arch-peg ratio and the presence of a jigsaw sign are sensitive and specific diagnostic criteria for os odontoideum. This series supports a congenital aetiology for this condition.
Databáze: MEDLINE
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