Continuously Progressive Abducens Palsy after Coil Embolization

ABSTRACT

Purpose@#To report a case of continuously progressive abducens palsy after transarterial coil embolization.Case summary: A 42-year-old male was referred to the clinic due to binocular horizontal diplopia. The patient had a history of left direct carotid cavernous fistula (CCF) after head trauma, and his ocular symptoms developed 15 months after coil embolization for CCF. Visual acuity and pupil reaction of both eyes were normal. The ocular motility examination showed 14 prism diopters (PD) of left esotropia in the primary gaze with abduction limitation; therefore, the patient was diagnosed with left abducens palsy. There was no evidence of fistula recanalization or new abnormal lesions in follow-up brain imaging. After strabismus was stabilized with 35 PD of esotropia, strabismus surgery including left medial rectus muscle recession and lateral rectus resection was performed, and ocular alignment was normalized in the primary position. However, 2 years after surgery, left abducens palsy recurred and abduction limitation worsened to -4 over 10 months. Finally, the patient underwent superior rectus transposition and medial rectus re-recession, which improved his ocular alignment at primary position. Binocular diplopia was resolved at primary position. @*Conclusions@#Late-onset abducens palsy can occur after coil embolization and is likely to continue to progress. Because spontaneous regression is rare in late-onset palsy compared with acute-onset palsy, surgery should be considered when the strabismus becomes stabilized.