Intradiploic encephalocele of the primary motor cortex in an adult patient: electrophysiological implications during surgery

Abstract

Encephaloceles are herniations of brain parenchyma through congenital or acquired osseous-dural defects of the skull base or cranial vault. Different types of symptoms, due to CSF fistulas, meningitis, or seizures, are often associated with this condition. The authors present a rare case of spontaneous right frontal parasagittal encephalocele in a 70-year-old man who was experiencing a spastic progressive paresis of his left lower limb. Results of routine electrophysiological workup (motor evoked potentials, somatosensory evoked potentials, and electroneuromyography), as well as those of MRI of the spinal cord, were normal. A brain MRI study detected a partial herniation of the right precentral gyrus through a meningeal defect into the diploe, embedding corticospinal fibers. The patient underwent navigated craniotomy. Intraoperative neuromonitoring of motor function with transcranial electrical stimulation and direct cortical stimulation indicated the presence of motor cortex inside the encephalocele. Thus, the brain parenchyma was carefully released without resection to preserve motor function and, finally, a cranioplasty was performed. After a few months, the patient demonstrated considerable improvement in his left lower-limb function and, after 1 year, he had fully recovered. Intraoperative electrophysiological monitoring and mapping allowed for the determination of the best surgical strategy for the isolation of the encephalocele and correlated well with preoperative multimodal MRI.

Tissue damage in herniated brain parenchyma into giant arachnoid granulations: demonstration with high resolution MRI

“…One of them was shown incidentally in the parietal lobe, and no association with the patient’s symptom was detected (21). In another study, spastic progressive paresis of his left lower limb due to damage in the frontal lobe herniation was shown (22). In the present study, damage of the herniated parenchyma into GAG was seen in 41% of cases.…”

A red herring CVA with unexpected outcome: illustrative case

“…This is caused by neural tube defects that occur during development hypothesized to be due to failure of these structures to close during neurulation. [5][6][7] Commonly, the defects occur along a cranial suture. Secondary encephaloceles occur more commonly in adulthood and are precipitated by infections, trauma, tumor, or surgery.…”

“…The Nager classification is more complex in terms of the number of metrics. 5 Typical presentations of patients with encephaloceles include palsies, seizures, CSF leakage, and meningitis. 5,[8][9][10][11] Neurological deficits are relatively uncommon, and those that have been cited include hearing loss, visual deficits, facial nerve palsy, and hemiparesis.…”

“…5 Typical presentations of patients with encephaloceles include palsies, seizures, CSF leakage, and meningitis. 5,[8][9][10][11] Neurological deficits are relatively uncommon, and those that have been cited include hearing loss, visual deficits, facial nerve palsy, and hemiparesis. This case was unique in that our patient was older and experienced only neurological deficits with the expressive aphasia and right upper extremity deficits.…”

Intradiploic encephalocele following linear skull fracture: a rare evolution of growing skull fracture

“…The treatment option of IE mainly depends on the relationship between the radiological findings and the clinical symptoms [15]. If there is a convincing relationship between the parenchymal hernia and the symptoms, surgery can be performed [8,11,13].…”