Abstract
Aim: To evaluate the necessity for further radiological investigation in patients with suspicion of rotatory subluxation of the atlanto-axial complex on plain radiography following acute cervical trauma. To outline guidelines for assessment of patients with atlanto-axial asymmetry on plain radiography.
Methods: A retrospective review of all patients who had undergone atlanto-axial CT scanning as a result of radiographic C1–C2 asymmetry following cervical spine trauma in the 3 year period from January 1999 to December 2001. The plain X-ray and CT images were reviewed retrospectively and correlated with their clinical presentation and outcome by the senior author.
Results: Twenty-eight patients were included in the study. Acute cervical spine trauma had occurred most commonly following a road traffic accident. No patient was found to have acute cervical spine torticollis or severe cervical pain. Patients age ranged from 21–44 years (M:F – 15:13). All patients were found to have atlanto-odontoid asymmetry on initial plain X-ray. No patients were found to have rotatory subluxation on CT images. 3 patients were found to have minor degrees (< 10°) of rotation on the CT scan which is within normal limits. 9 patients (32%) were found to have congenital odontoid lateral mass asymmetry. All patients were treated conservatively and had no further intervention. All plain radiographs were then assessed to determine the underlying reason for asymmetry. In 19 cases the orientation of the radiographic beam in combination with head rotation was found to be at fault.
Conclusion: Rotatory subluxation of the cervical spine is a rare but serious condition in the adult. The condition is suspected radiologically in the presence of odontoid lateral mass asymmetry on open mouth view. The application of ATLS principles in the initial assessment of trauma patients has resulted in a significant increase in the number of radiological examinations performed. This has led inevitably to an increase in the number of anomalies identified. An average of 400 c-spine X-rays per year are performed for trauma in our casualty department. In this study, we have identified 9 patients out of a total of 29 with congenital odontoid lateral mass asymmetry over a 3 year period. This represents approximately 0.75% of the cervical spine X-rays and should be considered in the differential diagnosis following acute cervical trauma. We outline guidelines for recognising benign atlanto-axial asymmetry.
The abstracts were prepared by Mr Ray Moran. Correspondence should be addressed to him at Irish Orthopaedic Associaton, Secretariat, c/o Cappagh National Orthopaedic Hospital, Finglas, Dublin 11.
