Nasal Encephalocele: Endoscopic Surgery

The major landmark in the management of this condition has been the development of endoscopic surgery consisting of resecting the meningocele and then sealing the anterior skull base defect without the morbidity of a transfacial or transcranial approach.

Indications for endoscopy include not only nasal meningoceles but also most other endonasal lesions and anterior skull base defects. Such procedures however should be done by experienced teams and in centers where neurosurgeons are available.

Contraindications include rare cases where the lesion extends in areas inaccessible to endoscopic surgery. These include extensions above and laterally to the orbits, superiorly in the frontal sinuses or within the cranial cavity. In those cases a combined approach or solely external approach can be necessary.

RevoLix® Thulium laser
RevoLix���® Thulium Laser
Rigid endoscope

The use of several superimposed materials increases the tightness of the skull base defect sealing. Different autologous or synthetic materials can be used. In this case we used an autologous cartilage graft (concha), temporal fascia, fibrin glue, and oxidized cellulose (Surgicel®, Ethicon, Issy-Les-Moulineaux, France). This reconstruction was then protected by an extra fibrin glue layer and a 1 mm thick reinforced Silastic® (Dow Corning, Michigan, United States). This sealing must be sufficiently distant from the nasofrontal duct in order to avoid its iatrogenic obstruction.

The preoperative workup is essentially based on imaging. CT-scan and MRI are complementary: the first technique better visualizes bony structures, especially the skull base defect, and the second one allows to differentiate meningoceles from encephaloceles and determines more accurately the extensions of the lesion. Preoperative biopsy of intranasal masses compatible with a meningocele on imaging is contraindicated due to risks of CSF leaks and bacterial meningitis.

The surgical anatomy must be carefully on pre-operative CT-scan and MRI in order to limit the risks of incidental intraoperative penetration of the orbit or cranial cavity. Endoscopic surgery can be performed even in case of altered anatomical landmarks.

Intra-operative: hemorrhage (nasal or intracranial), intra-cranial or intra-orbital injury. These must be prevented by careful planning of the procedure after having studied the patient���¢s anatomy on the CT-scan. During surgery, hemorrhage must be addressed immediately to stop the bleeding but also to maintain an optimal vision of surgical landmarks.
Short term: infection (meningitis, cerebral abscess). Careful surveillance is important before discharge.
Long term: frontal or ethmoid mucocele, recurrence of meningocele or CSF leak, obstruction of the nasofrontal duct with subsequent purulent frontal sinusitis. Although rare, these complications can occur even if the procedure was initially successful, and long term follow up is necessary.

Intra-operative: hemorrhage (nasal or intracranial), intra-cranial or intra-orbital injury. These must be prevented by careful planning of the procedure after having studied the patient���¢s anatomy on the CT-scan. During surgery, hemorrhage must be addressed immediately to stop the bleeding but also to maintain an optimal vision of surgical landmarks.
Short term: infection (meningitis, cerebral abscess). Careful surveillance is important before discharge.
Long term: frontal or ethmoid mucocele, recurrence of meningocele or CSF leak, obstruction of the nasofrontal duct with subsequent purulent frontal sinusitis. Although rare, these complications can occur even if the procedure was initially successful, and long term follow up is necessary.

1. Rawal RB, Sreenath SB, Ebert CS Jr et al. Endoscopic sinonasal meningoencephalocele repair: a 13-year experience with stratification by defect and reconstruction type. Otolaryngol Head Neck Surg. 2015;152(2):361-8. DOI: https://doi.org/10.1177/0194599814561437.

2. Gump WC. Endoscopic Endonasal Repair of Congenital Defects of the Anterior Skull Base: Developmental Considerations and Surgical Outcomes. J Neurol Surg B Skull Base. 2015;76(4):291-5. https://doi.org/10.1055/s-0034-1544120.

3. Di Rocco F, Couloigner V, Dastoli P, et al. Treatment of anterior skull base defects by a transnasal endoscopic approach in children. J Neurosurg Pediatr. 2010;6(5):459-63. DOI: https://doi.org/10.3171/2010.8.PEDS09325.