title: Delayed Visual Loss and Its Surgical Rescue Following Extracranial-Intracranial Arterial Bypass and Native Internal Carotid Artery Sacrifice.
abstract: BACKGROUND
  High-flow extracranial-intracranial (EC-IC) bypass followed by sacrifice of the native internal carotid artery (ICA) is a recognized treatment option for giant ICA aneurysm and skull base tumor involving the ICA. Distal clipping at the supraclinoid portion of the ICA is technically straightforward, but it can potentially compromise ophthalmic artery (OA) perfusion. Because of the extensive EC-IC anastomoses with the OA, visual symptoms are fortunately uncommon. We report a patient who developed complete blindness after distal trapping of the supraclinoid ICA; it was reversed after emergency clip removal.
  
  
  METHODS
  Our patient is a 47-year-old man with recurrent nasopharyngeal carcinoma in close proximity to the left petrosal ICA. The first stage of the procedure involved an EC-IC bypass using radial artery graft, followed by a second stage with combined craniofacial excision. Trapping of the native ICA was achieved using a permanent aneurysm clip placed at the supraclinoid ICA distal to the origin of the OA. He complained of a new onset of complete left eye visual loss approximately 6 hours after the distal aneurysm clip was applied. He was immediately sent to the operating theatre for the removal of the supraclinoid aneurysm clip. On the next day, his vision improved and left pupil became reactive again.
  
  
  CONCLUSIONS
  OA flow following ICA trapping is complicated and precarious. Delayed onset of visual loss is possible. Prompt action by direct exploration and clip removal is needed and can be effective in reversing blindness.
authors.affiliation: Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China. Electronic address: llfrandom@gmail.com.
authors.forename: Lai-Fung
authors.initials: LF
authors.lastname: Li
authors.affiliation: Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors.forename: Gilberto Ka-Kit
authors.initials: GK
authors.lastname: Leung
authors.affiliation: Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors.forename: Wai-Man
authors.initials: WM
authors.lastname: Lui
mesh_terms: D015901:Angiography, Digital Subtraction; D002277:Carcinoma / Q000601:surgery; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000601:surgery*; D002548:Cerebral Revascularization / Q000009:adverse effects*; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging / Q000473:pathology; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology*; D014786:Vision Disorders / Q000209:etiology*
keywords: Blindness; Cerebral revascularization; Ischemic; Optic neuropathy