An aneurysmal cyst (AC) is a rare benign bony tumor with a possible aggressive extension. We present a complication following the surgical ablation of an ethmoidal AC. CLINICAL HISTORY AND FINDINGS: A 40-year-old man with a left ethmoidal AC extending to the orbital roof underwent 2 surgeries. After the second one involving a neuro-surgical approach, a bilateral palsy of the superior oblique muscles (SO) appeared. The diplopia did not improve following a bilateral asymmetrical recession of the inferior recti muscles done elsewhere. There was an excyclotorsion up to 20 degrees in down gaze and a vertical deviation of 10 degrees in primary position.
We performed a bilateral tucking of the anterior SO fibres with, on the left, an advancement of the inferior rectus and a resection of the medial rectus muscles. Two weeks after surgery the absence of cyclotorsional deviation allowed a binocular vision.
The double vision due to the excyclotorsion, which was the main complaint, could be alleviated by an anterior strengthening of the SO. A precise measurement of the cyclotorsion is required for the surgical procedure.