Excavating meningoencephaloceles: A newly recognized entity

Area of Science:

• Neurosurgery
• Rhinology
• Skull Base Surgery

Background:

• Spontaneous cerebrospinal fluid (CSF) leaks are typically linked to intracranial hypertension and present as skull base defects.
• A distinct subset of spontaneous CSF leaks, characterized by bone excavation, has been observed in clinical practice.

Purpose of the Study:

• To define and discuss a newly classified, challenging-to-treat subset of spontaneous CSF leaks.
• To describe leaks presenting as a tunnel- or canal-like excavation of skull base bone by a meningocele or meningoencephalocele.

Main Methods:

• Retrospective review of patients with CSF leaks at a tertiary rhinology practice.
• Identification of patients with excavating/canal-like skull base defects via CT, MRI, or endoscopic visualization.

Main Results:

• 8 patients (7 female, 1 male, average age 53.6) presented with CSF rhinorrhea, most commonly at the cribriform/upper septum.
• 6 patients had multiple/progressive defects; 5 required multiple repairs. Cisternography was needed for 7 patients due to leak complexity.
• The excavating nature of these leaks posed diagnostic and therapeutic challenges.

Conclusions:

• An excavating pattern should be considered in spontaneous CSF leaks that are difficult to identify or recur post-repair.
• Failure to recognize and fully address the excavating nature, meningocele, and origin site leads to recurrence.
• Proper identification and surgical management of this specific CSF leak type are crucial for successful outcomes.