Brain Herniation Through the Cribriform Plate: Review and Comparison to Encephaloceles in the Same Region

Abstract

Herniations of the brain and/or meninges through an opening of the skull often occur through the foramen magnum, e.g., Chiari malformations and encephaloceles. The herniation of brain matter through the cribriform plate is a rare incident and has not been reported frequently. The presence of such an occurrence still requires attention and anatomical understanding. This review will examine the potential causes of cribriform plate herniation and its distinguishability to nasal encephaloceles. The sloping of brain tissue toward potential space/opening in response to elevated pressures in the cranium to accommodate for the added pressure are features seen in herniation. The presence of a pedicle and stalk seen in an encephalocele define its characteristics, which are not visible in a ‘classical’ herniation. Cerebrospinal fluid (CSF) fistula commonly occurs at the cribriform plate, and due to the structural weakness, a pathway is formed. This is often seen in conjunction with meningoceles. Delineating between herniation and encephaloceles is important for both clinicians and neurosurgeons.

Potential neuroinvasive pathways of SARS‐CoV‐2: Deciphering the spectrum of neurological deficit seen in coronavirus disease‐2019 (COVID‐19)

“…[88][89][90][91][92][93][94][95][96][97][98][99][100] As CSF is present in the subarachnoid space of the meninges directly supporting the olfactory nerves, the virus can reach the CNS without breaching the BBB. [101][102][103][104] [CNS, central nervous system; CSF, cerebrospinal fluid; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2]…”

“…It is well established that the OE via ON directly access the olfactory bulb (OB) through a horizontal segment of the ethmoid bone called the cribriform plate ( Figure 3A). [101][102][103][104] As the ON travel through the olfactory foramina in the cribriform plate, they also pass directly through the three layers of the cranial meninges (dura mater, arachnoid mater, and pia mater) before reaching the OB ( Figure 3A). [101][102][103][104] Consequently, the rupturing of infected cells through the subarachnoid space could directly release virion into the CSF ( Figure 3A, blue zone).…”

“…[101][102][103][104] As the ON travel through the olfactory foramina in the cribriform plate, they also pass directly through the three layers of the cranial meninges (dura mater, arachnoid mater, and pia mater) before reaching the OB ( Figure 3A). [101][102][103][104] Consequently, the rupturing of infected cells through the subarachnoid space could directly release virion into the CSF ( Figure 3A, blue zone). As evidence of the presence of CSF in the meninges that support the OB above, is the phenomenon of CSF rhinorrhea resulting from a fracture of the cribriform plate in trauma involving the base of the skull.…”

Middle Fossa Encephaloceles Treated via the Transmastoid Approach: A Case Series and Review of the Literature

“…30 Continued pressure forces dural thinning and tearing, leading to brain herniation and CSF egress. [21][22][23][24][25][26][27][28][29][30][31] A spontaneous etiology presents challenges to the treating physician. Decompression of intracranial contents through the defect may delay a diagnosis of elevated ICP.…”

Delayed forebrain syndrome due to presumptive traumatic intranasal meningoencephalocele in a cat

“…Thus, MRI is the preferred imaging technique for evaluation of brain parenchymal pathology, including haematoma or haemorrhage, parenchymal contusion, oedema,37 and apparently MEC itself. Moreover, distinguishing between a true MEC and brain herniation can be challenging; however the presence of a pedicle (containing brain and meninges) with a stalk between the cranial and the frontal sinus cavity in the MRI of the current case, was a strong criterion to support the scenario of MEC 38. Thus, the MRI of our case was consistent with a frontoethmoidal MEC accompanied by mild meningeal contrast uptake of the protruding tissue and meningeal uptake in the adjacent brain in the calvarium, and secondary dilated superior frontal sulcus mainly on the right and mildly on the left.…”