Duane retraction syndrome: MRI features in two cases.

Area of Science:

• Ophthalmology
• Neurology
• Radiology

Background:

• Duane's retraction syndrome (DRS) is a congenital eye movement disorder.
• Previous neuroimaging studies suggested abducens nerve (VI) aplasia is linked to DRS types I and III.
• DRS type II was typically associated with a normal abducens nerve on MRI.

Observation:

• This study utilized brain MRI, specifically 3D T2 weighted images, to examine the cranial nerves in two pediatric patients with DRS.
• The patients presented with left-sided DRS type II and right-sided DRS type I.
• The abducens nerve (VI) and oculomotor nerve (III) were visualized, focusing on the brainstem region.

Findings:

• The abducens nerve (VI) was not observed on the affected side in both pediatric patients.
• The morphology of the third cranial nerves (oculomotor) was normal in both cases.
• Aplasia of the abducens nerve (VI) was identified in a patient with DRS type II.

Implications:

• The findings challenge the established understanding of DRS type II, suggesting abducens nerve (VI) aplasia can occur in this subtype.
• This expands the spectrum of neuroimaging findings associated with Duane's retraction syndrome.
• The results provide novel insights into the potential pathogenesis of DRS, highlighting nerve aplasia as a key factor across multiple types.