A low score on the National Institutes of Health Stroke Scale with eye movement disorder may indicate a good candidate for acute mechanical thrombectomy for posterior circulation large vessel occlusion: illustrative cases

BACKGROUND: Basilar artery occlusion (BAO) accounts for 1% of all strokes, and its natural prognosis is extremely poor. There is no consensus on the treatment strategy for mild BAO. OBSERVATIONS: Between August 2015 and May 2021, 429 patients received mechanical thrombectomy (MT) in the authors’ hospital. Three patients had a BAO with a National Institutes of Health Stroke Scale (NIHSS) score of ≤6 and showed eye movement disorder as the main symptom. MT immediately improved ocular symptoms in all three cases, and the patients were discharged with a modified Rankin Scale ≤2. LESSONS: Lesions responsible for the eye movement disorder are distributed from the midbrain to the pontine tegmentum. These lesions are supplied by the arteries of the interpeduncular fossa, which is impaired by BAO. Symptoms due to problems with the arteries of the interpeduncular fossa can be rapidly improved by MT, and it is useful for preventing neurological deterioration in mild cases. BAO with a low NIHSS score in the presence of eye movement disorder as the main symptom may be a good indication for MT.