Endoscopic endonasal approach to the ethmoidal planum: anatomic study

Abstract

The endoscopic endonasal technique is currently used by otolaryngologists for the management of different extradural lesions located below the ethmoidal planum. The cooperation between ENTs and neurosurgeons has recently pushed the use of such approach also in the removal of some intradural lesions, which has promoted the interest for an anatomic study to identify the anatomical landmarks and the dangerous points during the endoscopic approach to this area. In six fresh cadaver heads, unilateral and bilateral measurements between the main landmarks of the approach were performed by means of an endoscopic endonasal approach. A wide exposure of the midline anterior skull base was realized. The maximum of lateral extension was obtained between the two medial orbital walls, at the middle of the cribriform plate (mean distance 25,33 mm), while the mean distance between the anterior and posterior ethmoidal arteries at the level of the lamina papyracea was 16 mm. The endoscopic endonasal route can be considered a minimally invasive technique to approach the ethmoidal planum. It requires adequate anatomical knowledge and endoscopic skill for its realization. Due to the wide window realizable through this corridor, it could be considered in selected cases for the removal of intradural lesions such as meningiomas or estesioneuroblastomas.

Endoscopic transnasal resection of anterior cranial fossa meningiomas

“…Since only selected lesions can be considered suitable for a low-route approach, preoperative neuroradiological workup, providing vital information related to the features of the tumor and relative distances between the surgical landmarks, 16 has significant impact on the choice of the best surgical approach. In most patients complete removal can be accomplished with a low morbidity rate and good recovery of neurological function.…”

Morphological Characteristics of the Anterior Ethmoidal Artery in Ethmoid Roof and Endoscopic Localization

“…Stammberger 18 used the junction of the posterior wall of the frontal recess with the roof of the anterior ethmoidal cell as a reference point, and reported the artery was 1 to 2 mm posterior to this skull base junction. Simmen et al 14 measured the average distance between the AEA and the posterior wall of the frontal recess as 11 mm (range, 6 to 15 mm), and de Notaris et al 17 measured the distance between the AEA and the anterior margin of the frontal recess as 10 mm. Our dissection showed that not all AEAs were located behind the posterior wall of the frontal recess.…”

“…7,13,17 Floreani et al 16 measured the range of the posterolateral to anteromedial angle as 30 degrees to 45 degrees as it passed from the orbit to the anterior cranial fossa. Cankal et al 15 observed that AEC left the orbit at an angle of 12 to 50 degrees anteriorly, and the angle was superiorly 0 to 45 degrees and inferiorly 0 to 20 degrees on coronal images.…”

Rhino-Neurochirurgie

“…Endoskopische, endonasale Tumoroperationen mit ihren anatomischen Grundlagen sind dem HNO-Arzt grundsätzlich vertraut als Teil einer "erweiterten endonasalen Nasennebenhöhlenchirurgie" oder in Kombination von endoskopischen endonasalen Eingriffen mit transkraniellen Zugängen [73,[427][428][429][430]. Im Fokus rhino-neurochirurgischer Interventionen stehen ausgedehnte Malignome mit massiver Infiltration der Dura ("transcribriforme Kraniektomie"), Meningeome, Olfaktoriusschwannome oder große Meningoenzephalozelen, Dermoidzysten bzw.…”