In Reply: Residual and Recurrent Disease Following Endoscopic Endonasal Approach as a Reflection of Anatomic Limitation for the Resection of Midline Anterior Skull Base Meningiomas.

Abstract

To the Editor: Drs McGahan, Magill, and Prevedello have provided a very thoughtful and logical algorithm1 for approaching 1 group of tumors discussed in our article.2 Their proposed approach selection for olfactory groove meningiomas demonstrates their experience and skill with all options, which is the ultimate goal of any skull base surgeon. We were glad to see that this article stimulated such a response, as it was written with the hope of clarifying the anatomic boundaries of the endonasal approach as 1 small step in elucidating the “right” approach for any given patient. The authors state that they prefer a “craniotomy” when olfaction is preserved. As they allude, the type of craniotomy may be critical, evidenced by the small series referenced by Jang et al,3 which showed improved olfactory outcomes compared with bifrontal craniotomy in the 21 patients who were selected for frontotemporal craniotomy based largely on unilateral dysfunction and lateral extension. Unspoken in this is that there is inevitably a less radical tumor removal inherent in leaving the cribriform plate (and olfactory fibers) untouched. This must also be considered in the context that the majority of patients with olfactory groove meningiomas have absent or severely impacted olfaction at presentation. For tumors not amenable to endonasal resection, a single-stage resection using a modified subfrontal transbasal approach allows complete tumor resection, including skull base/sinonasal invasion with pericranial flap reconstruction, while minimizing brain manipulation. This approach is mostly extradural with barely any brain exposure. Often, going back to traditional and properly done skull base approaches is the preferred choice. We agree completely with the authors of this letter with respect to the role of olfaction in approach selection for these tumors, but we believe that visual compromise should also be considered, given growing evidence that midline tumors presenting with vision loss may have better outcomes when treated with a midline approach. This is especially important for tuberculum and planum meningiomas, key groups in this article. In addition, neurosurgeons as a group have largely ignored the impact of anterior base meningiomas and surgical approach on neurocognitive outcomes. At a minimum, endonasal approaches minimize radiographic impact on the frontal lobes,3 and further study is needed to understand if there is a cognitive tradeoff for the potential olfactory preservation provided by craniotomy. Indeed, the staged approach discussed in this letter considers this and is an excellent option, especially when there is significant edema. Staging may also occasionally demonstrate an unexpected medial attachment with only pushing borders laterally on the skull base (rather than a true lateral attachment). It is our hope that the conversation that is ongoing via this paper and the resultant letter will continue to help all of us fully understand the impact of various approaches on the multiplicity of critical functions that midline anterior skull base meningiomas involve and how to balance radicality of resection with preservation of these functions. Funding This study did not receive any funding or financial support. Disclosures The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.