WHOLE SPINE MAGNETIC RESONANCE IMAGING (MRI) IN PATIENTS WITH ACHONDROPLASIA AND NEUROLOGICAL COMPROMISE

Abstract

Background: The incidence of neurological symptoms due to spinal stenosis in patients with achondroplasia is reported to be as great as 38%¹. These symptoms most commonly occur in the 4^th decade and myelography and CT myelography are most commonly described in evaluation of the stenosis. Difficulty arises in localisation of stenosis in patients presenting with neurological deficit². The value of MRI of the cervicomedullary junction has been reported in achondroplasia but it has not yet been evaluated in the investigation of spinal stenotic symptoms. The aim of this study was to review our experience of whole spine imaging in patients with achondroplasia that presented with symptoms and signs of neurological deficit.

Methods: We retrospectively reviewed the clinical notes and radiological imaging of 10 consecutive achondroplastic patients (3F:7M, mean age 31.7 years, range 13 to 60yrs) that presented to our unit with neurological compromise between 1998 and 2003. All patients had whole spine MRI at the time of presentation. Recorded from the notes were age and sex, and whether symptom pattern was radiculopathy, claudication or paresis. All radiological levels of stenosis on MRI were documented.

Results: Four patients presented with spinal paresis, four with neurogenic claudication, and two with radiculopathy. MRI confirmed that each patient had at least one region (cervical, thoracic or lumbar) of significant spinal stenosis. In six of the patients an additional region of significant stenosis was identified. All ten patients had lumbar stenosis but this was only the primary site in six of the ten. In the other four patients two had the dominant stenosis in the thoracic spine, one in the cervical spine and one at the foramen magnum – the clinical symptoms correlated with the dominant site in each of these four cases.

Conclusion: MRI was a useful tool for assessment of neurological compromise in the patients with achondroplasia in our study. All ten patients had classical lumbar stenosis on MRI but this was only the dominant site of stenosis in six of the ten cases. The MRI and clinical findings need to be evaluated together to ensure correct surgical treatment.