Paradoxical subfalcine brain herniation

Case contributed by Dr René Pfleger

Presentation

Patient history temporarily withheld.

Patient Data

Age: 65
Gender: Male
Modality: CT

3D surface volume rendering 3D VR illustrates marked concavity of the skin in greater parts of right frontal, parietal and temporal surface areas.

Slightly different settings of 3D VR from the same imaging series as before

Modality: CT

.

Axial and coronal MPR from same imaging series

Modality: CT

Demarcated right MCA infarction with loss of substance and secondary dilatation of right lateral ventricle (i.e. chronic phase). S/p right-sided decompressive hemicraniectomy, left-sided VP-shunt with tip in 3rd ventricle near left foramen Monroi. Marked concavity of parts of right hemisphere with slight displacement of the cingulate gyrus beneath the free edge of the falx cerebri without evidence of external mass effect, representing paradoxical subfalcine herniation to the left. Simultaneously slight right-sided transcalvarial herniation of a minor part of right parietal lobe, most likely caused by gravity effects and organized hematoma. 

Conclusion
Paradoxical subfalcine herniation

Head CT obtained in ER 4 months before

Modality: CT

Non-contrast CT of the head reveals dense right MCA (M1-3 segments), hypoattenuating brain tissue with sulcal effacement in the territory of the right MCA, obscuration of right lentiform nucleus and loss of right insular ribbon. No significant mass-effect, no hemorrhage. 

Conclusion
Right-sided complete MCA infarction without actual significant mass-effect.

Modality: Annotated image

In chronological order.

Case Discussion

Case key points:

  • the rare and potentially fatal complication of decompressive hemicraniectomy, paradoxical brain herniation, requires early recognition and urgent treatment
  • growing indications for decompressive craniectomy requires the radiologist to be cognizant of the clinical characteristics and imaging appearances of paradoxical brain herniation
  • symptoms and imaging findings that may raise concern/constitute the syndrome are 
    • acute postoperative deterioration after hemicraniectomy with or without temporal association with external ventricular drainage or lumbar puncture
    • sinking skin flap
    • marked concavity at the craniotomy site accompanied by subfalcine and/or transtentorial herniation

What is more, this case illustrates the time course of space-occupying MCA infarction including hemorrhagic transformationWallerian degeneration, decompressive surgery complicated by above mentioned and subgaleal abscess and is a textbook example of the controversy regarding optimal timing of cranioplasty. 

 

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Case Information

rID: 34550
Case created: 25th Feb 2015
Last edited: 19th Sep 2015
Inclusion in quiz mode: Included

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