Acute Spontaneous Paradoxical Herniation After Large Cerebral Meningioma Resection and Decompressive Craniectomy: A Case Report and Systematic Review of the Literature.

background and importanceParadoxical herniation (PH) is a rare but life-threatening complication after decompressive hemicraniectomy (DHC) performed to treat refractory intracranial hypertension. Although most cases occur subacutely or after cerebrospinal fluid (CSF) diversion, acute presentations without preceding CSF manipulation are uncommon and may be underrecognized. CLINICAL PRESENTATION: We report the case of a 45-year-old woman who developed acute PH after undergoing DHC for severe vasogenic edema after resection of a parieto-occipital meningioma. After initial postoperative neurological improvement, she experienced rapid neurological deterioration. Imaging demonstrated cerebellar tonsillar herniation and brain shift away from the craniectomy site, consistent with PH. Trendelenburg positioning resulted in prompt neurological improvement, confirming the diagnosis. We additionally performed a systematic review of reported cases of PH after tumor resection.

conclusionPH should be considered in patients with fluctuating or worsening neurological status after DHC, even in the absence of prior CSF diversion. Early recognition is critical, as standard intracranial pressure-lowering therapies may exacerbate herniation. Management requires immediate cessation of such therapies, initiation of intracranial pressure-augmenting measures, and prompt cranioplasty as definitive treatment.