Clinical profile and magnetic resonance imaging characteristics of Duane retraction syndrome

To describe the clinical profile and magnetic resonance imaging findings of the brain in Duane retraction syndrome (DRS) and determine whether there is an association between clinical presentation and magnetic resonance imaging (MRI) brain characteristics.

This was a cross-sectional study done at a tertiary care center in South India. We recruited and analyzed the clinical characteristics of 54 patients with DRS. MRI of the brain with fast imaging employing steady-state acquisition (FIESTA) was performed in 41 cases, and the cisternal segment of the sixth nerve was studied. Statistical analysis was done to determine any association between the radiological and clinical features.

Type 1 DRS was predominant, followed by Type 3 DRS and Type 2 DRS. 9.3% of cases were bilateral and 11.1% were familial. Orthotropia was most common, followed by esotropia and exotropia. The MRI brain showed the absence of the cisternal part of the sixth nerve on the affected side in 82% of Type 1 and 75% of Type 3 unilateral DRS. Both the abducens nerves were visualized in 19.5% of the patients with unilateral DRS. There was no statistically significant association between MRI brain findings and the clinical features.

MRI brain with FIESTA shows absent or hypoplastic sixth nerve in most cases of Type 1 and Type 3 DRS. However, around 20% of DRS cases may show the presence of the cisternal part of the sixth nerve. Hence, clinicians must be cautious when ruling out DRS on the basis of MRI brain findings. Although aplasia of the sixth nerve is the most frequent MRI finding, it may not be the sole etiologic factor.