Brain Pathology Case of the Month - April 2012


A diffuse paradoxical cerebral air embolism of cortical veins.


The gross evaluation shows diffuse cortical air embolism. Microscopic evaluation also shows air within veins and excluded pulmonary microemboli.

Prolonged prone position, large tissues opening and hydrogen peroxide pressure irrigation represent well known risk factors for pulmonary air embolism in spine surgery (1, 2, 4). Paradoxical cerebral air embolism, without pulmonary involvement, is a rare complication during spine surgery and to date it has been always associated to patency of foramen ovale (3,5). Nevertheless, in our case, post-mortem examination excluded with certainty any cardiac or vascular defects. Then we can speculate that air bubbles would have reached cerebral veins starting from the venules of muscles and overlying teguments along the infected wound; they would have reached the posterior extra-spinal venous plexus and from there, through the lumbar ascending veins and the azygos-hemiazygos vein system, they would have entered the superior vena cava, bypassing the pulmonary circulation. Finally in a retrograde manner, through the jugular veins, air bubbles would have filled dural venous sinuses and cortical cerebral vein system, causing the patient death (Figure 4).

This is the first and unique case describing a fatal paradoxical air venous cerebral embolism in a pediatric patient undergone spine surgery without cardiac defects.


  1. Brown J, Rogers J, Soar J (2001) Cardiac arrest during surgery and ventilation in the prone position: a case report and systematic review. Resuscitation 50:233-238.
  2. Despond O, Fiset P (1997) Oxygen venous embolism after the use of hydrogen peroxide during lumbar discectomy. Can J Anaesth 44:410-413.
  3. Eck JC, Humphreys SC, Patil VD, Hodges SD, Clarke SE, Davare JR (2006) Paradoxical embolus causing transient bilateral blindness following spinal surgery. Am J Orthop 35:527-529.
  4. Morikawa H, Mima H, Fujita, Mishima S (1995) Oxygen embolism due to hydrogen peroxide irrigation during cervical spinal surgery. Can J Anaesth 42:231-233.
  5. Pham Dang C, Péréon Y, Champin P, Delécrin J, Passuti N (2002) Paradoxical air embolism from patent foramen ovale in scoliosis surgery. Spine 27:E291-E295.

Contributed by Fabio De-Giorgio, MD, PhD, Vincenzo Arena, MD, Francesco Turturro, MD, Ernesto d'Aloja, MD, PhD and Massimo Miscusi, MD, PhD

International Society of Neuropathology