Endoscopic Superior Ethmoidal Approach for Anterior Cranial Base Resection: Tailoring the Approach for Maximum Exposure with Preservation of Nasal Structures

Background

Traditional endoscopic anterior cranial base resection involves the total removal of the ethmoidal cells, including the middle and superior turbinates. This is associated with increased volume of the nasal cavity postoperatively, with increased crusting and permanent change of the nasal airflow. Here we provide a step-by-step description of the technique and evaluate the feasibility of the superior ethmoidal approach for anterior cranial base resection with maximum exposure of the anterior cranial base while keeping the middle turbinates, uncinate processes, and ostiomeatal complexes intact.

Methods

Three fresh cadaveric heads were used for dissections. This technique was successfully performed in 2 consecutive cases of large olfactory groove meningiomas.

Results

In all anatomic dissections, satisfactory exposure of the cranial base was achieved while keeping the middle turbinate, uncinate process, ethmoid bulla, and middle meatus intact bilaterally. Successful resection of 2 consecutive cases of olfactory groove meningioma was performed using this approach.

Conclusions

The endoscopic superior ethmoidal approach for anterior cranial base resection is a feasible and safe approach that maximizes preservation of the nasal structures while providing optimal access to the anterior skull base. It can be used in pathologies that involve the anterior cranial base and do not involve the nasal structures.

Introduction

Traditional endoscopic anterior cranial base resection involves complete removal of the ethmoidal cells, including the middle and superior turbinates, to achieve good exposure of the slope of the anterior cranial base. In the past decade, teams of endoscopic cranial base surgeons have been successfully using this approach to treat a variety of pathologies, including olfactory groove meningiomas, meningoencephaloceles, reconstructions after skull base trauma, sinonasal malignancies, and other tumors involving the anterior cranial base.1, 2, 3, 4, 5, 6, 7

Complete removal of the ethmoidal cells, including the middle and superior turbinates, is associated with an increased volume of the nasal cavity postoperatively and permanent changes in nasal airflow. These factors predispose the patient to chronic nasal crusting and the need for long-term follow-up for nasal debridement.8, 9

In cases of malignant tumors involving the nasal cavity, the ethmoidal cells are usually resected for margins, and thus their preservation is not recommended.¹⁰ However, for purely intracranial pathologies, such as olfactory groove meningiomas, traditional endoscopic endonasal resection entails near-total ethmoidectomy as part of the approach to gain access to the skull base. Any attempt to decrease nonessential resection of nasal structures is of great value when this technique is used exclusively for intracranial tumors.

In this study, we evaluated a technique aimed at decreasing nasal trauma during endoscopic endonasal anterior cranial base approaches to intracranial pathologies. The endoscopic superior ethmoidal approach is envisioned to maximize the preservation of nasal structures while maintaining sufficient access for endoscopic anterior cranial base surgery (Figure 1).