Brain Herniation into the Subdural Space: Rare Iatrogenic Complication of Treatment of a Giant Calcified Subdural Hematoma.

Background: Chronic subdural hematoma associated with dural calcifications in previously pediatric shunted patients is a rare condition. The inner dural membrane opening can lead to progressive brain herniation into the subdural space due to brain reexpansion.

Case Description: A 15-year-old boy, previously shunted at birth for congenital hydrocephalus, presented with a giant chronic right hemispheric subdural hematoma. After 2 surgical procedures in which the subdural calcified neomembrane was opened and a subdural shunt was implanted, he developed a cortical brain herniation into the subdural space, resulting in brain ischemia and upper limb weakness and vomiting. The final surgical treatment consisted of an extensive wide peeling of visceral calcified membrane mutually to programmable valve placement along the subduroperitoneal shunt, in order to create a positive gradient between the subdural space and the ventricles. The patient experienced a prompt clinical improvement.

Conclusions: This case illustrates a rare complication of the treatment of a chronic subdural hematoma caused by insufficient opening of the calcified inner mambrane of the hematoma and encouraged by gradient pressure between the ventricular and subdural compartments. To avoid this complication, it is preferable to not open a thick, calcified, unelastic inner membrane. However, in case of lack of clinical and radiologic improvement, it may become necessary to open it: a wide opening should be attempted, in order to prevent brain strangulation.