Paresis of the Oculomotor nerve due to neurovascular conflict with Superior Cerebellar Artery

Abstract

Background: Neurovascular conflict between the Oculomotor nerve (CN III) and any of the posterior circulation cerebral arteries is a relatively frequent radiological finding, however, it does not manifest clinically or manifests itself only minimally (slowly reacts to light on the ipsilateral side). Sustained paresis of CN III arose directly due to neurovascular conflict between the Superior Cerebral Artery (SCA) and CN III, resolved after microvascular decompression, is extremely rare and has not yet been published. Aim: This case report aims to present a case of a scarce clinical condition caused by a generally common anatomical variation. This variation was proved to be the only cause of the clinical status and the symptoms did resolve after microsurgical restoration of the neuroanatomy. Case description: A 34-year-old female patient presented with an advancing ptosis and a downward gaze on one side. Differential diagnostics ruled out all other causes of the Oculomotor paresis, MRI showed significant oppression of the Oculomotor nerve by an aberrant SCA on the ipsilateral side. Neurovascular decompression performed microsurgically has resulted in near complete resolution of the symptoms. Conclusions: Oculomotor nerve paresis caused directly by neurovascular conflict is an extremely rare diagnosis, but microvascular decompression should be considered in these cases, especially if other reasons have been excluded.