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Case report
Detection of inferolateral trunk syndrome by neuromonitoring during catheter angiography with provocative testing
  1. Scheherazade Le1,
  2. Robert Dodd2,
  3. Jaime López1,
  4. Viet Nguyen1,
  5. S Charles Cho1,
  6. Leslie Lee1
  1. 1Department of Neurology and Intraoperative Neuromonitoring, Stanford University Medical Center, Stanford, California, USA
  2. 2Department of Neurosurgery and Radiology, Stanford University School of Medicine, Stanford, California, USA
  1. Correspondence to Dr S Le, Department of Neurology, Stanford University Medical Center, 300 Pasteur Drive, A343, Stanford, CA 94305, USA; schele{at}


Background and importance It is not uncommon that endovascular balloon test occlusion (BTO) is performed to assess collateral blood flow and risk of injury of permanent occlusion of the internal carotid artery (ICA). This case is the first reported of detection and reversal of the inferolateral trunk (ILT) syndrome in an awake patient during provocative BTO; prompt recognition of the syndrome effectively prevented permanent neurologic deficits.

Clinical presentation The case of a 42-year-old woman is reported who had a left sphenoid wing meningioma with extension into the cavernous sinus and who underwent awake catheter angiography with provocative BTO of the ICA. Serial examinations by intraoperative monitoring neurologists and neurointerventionalists detected acute progressive left retro-orbital pressure followed by sudden inability to adduct the left eye, or a left medial rectus palsy, indicative of the ILT syndrome which led to immediate balloon deflation and resolution of the deficits. The hypothesis was that hypoperfusion of the ILT, an arterial branch of the ICA which provides blood supply to several cranial nerves (CN) III, CN V1 and CN V2, caused her acute symptoms.

Conclusion Although cerebral ischemia is a well known complication of endovascular procedures, CN ischemia is a rare potential risk. Knowledge of cerebrovascular anatomy and serial examinations prevented neurologic deficits; this case underscores the added utility of examinations by intraoperative monitoring neurologists and interdisciplinary collaboration.

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  • Competing interests None.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.