Oculomotor palsy treated by microvascular decompression.

Background: Oculomotor palsy is well known to be due to diabetes mellitus, or aneurysmal compression, or cavernous sinus lesion. Only few reports presented that arterial compression was the reason for oculomotor palsy.

Methods: We performed a surgical treatment for a 76-year-old man with left oculomotor palsy. During surgical clipping of the left IC-PC aneurysm, it became clear that the left IC-PC aneurysm had not been compressing the third cranial nerve. The left oculomotor nerve was being pinched between the arteriosclerotic PCA and the SCA. Microvascular decompression was carried out, and the oculomotor nerve palsy improved.

Conclusions: Arteriosclerotic PCA and SCA may compress the oculomotor nerve. Microvascular decompression is effective in this type of oculomotor palsy.