Malignant Cerebral Edema After Cranioplasty: A Case Report and Literature Insights

Abstract

BACKGROUND Decompressive craniectomy is a common life-saving intervention in the setting of elevated intracranial pressure. Cranioplasty restores the calvarium and intracranial physiology once swelling recedes. Cranioplasty is often thought of as a low-risk intervention. However, numerous reports indicate that malignant cerebral edema (MCE) is an often-fatal complication of an otherwise uneventful cranioplasty. A careful review of the literature is needed to better understand this devastating condition. CASE REPORT A 41-year-old man presented after suffering a gunshot wound to the right frontal lobe. Upon initial evaluation, the patient had grossly visible brain matter, left-sided hemiparesis with a Glascow Coma Score (GCS) of 11, and vital signs concerning for elevated intracranial pressure. Computed tomography (CT) showed right-sided intraparenchymal and subarachnoid hemorrhage with a 5 mm leftward midline shift. The patient was taken to the operating room (OR) for right fronto-parietal craniectomy. Over the next 3 months, he recovered steadily and underwent PEEK cranioplasty on post-operative day 83. Pre-operative CT showed sunken skin flap syndrome with an 8-mm midline shift. Following an uneventful cranioplasty, he failed to regain consciousness. Examination revealed absent brainstem reflexes. CT showed global diffuse cerebral edema. The patient was declared brain dead. CONCLUSIONS Continued research is needed to better understand the pathophysiology of malignant cerebral edema so that future incidences may be prevented. A combination of negative-pressure suction drainage, sunken skin flap syndrome, and delayed time to cranioplasty likely play a significant role in the evolution of MCE. We urge neurosurgeons to consider the likelihood of MCE and adapt surgical planning accordingly.

Figure 1.

Non-contrast CT head scan on initial presentation to the Emergency Department. Imaging shows right-sided mixed intraparenchymal and subarachnoid hemorrhage with a leftward midline shift of 5 mm and pneumocephalus along the path of the penetrating gunshot wound with retained ballistic fragments.

Figure 2.

Non-contrast head CT scan following decompressive craniotomy. (A) Significant subdural hemorrhage noted at the falx cerebri. (B) Right frontal EVD and superior sagittal sinus thrombus. (C) Subdural hemorrhage present along the right tentorium. (D) Packing material present in the right middle cranial fossa.

Figure 3.

Non-contrast CT head scan series illustrating VP shunt settings. (A) Initial development of post-traumatic hydrocephalus 2 weeks after EVD removal, demonstrated by rightward midline shift measuring up to 9 mm and an increase in ventricle size. (B) Persistent expanded ventricles 1 week after shunt placement. (C) Concern for over-shunting after 1 month, with decompression of the left ventricle and associated 5-mm leftward midline shift.

Figure 4.

Non-contrast CT head scan prior to cranioplasty shows evidence of sunken skin flap with leftward midline shift measuring up to 8 mm.

Figure 5.

Immediate post-operative imaging studies. (A) Non-contrast CT brain scan with new diffuse sulcal effacement, indistinct gray-white matter differentiation, and rightward midline shift measuring up to 6 mm. (B) CT brain scan with contrast perfusion demonstrating decreased blood flow and prolonged mean transit time.