Elsevier

World Neurosurgery

Volume 91, July 2016, Pages 582-591.e1
World Neurosurgery

Original Article
A Simple Scoring System to Predict the Resectability of Skull Base Meningiomas via an Endoscopic Endonasal Approach

https://doi.org/10.1016/j.wneu.2016.04.093Get rights and content

Objective

To identify clinico-radiologic factors associated with incomplete anterior cranial fossa (ACF) meningioma resection via an endoscopic endonasal approach.

Method

Patients undergoing endoscopic endonasal resection of an ACF meningioma were retrospectively accrued from two university-affiliated centers. Demographic profiles and radiologic findings, including tumor dimensions and morphology, anatomic location, and vascular involvement, were stratified according to the extent of resection.

Results

Twenty-five patients were included in this study. Factors associated with incomplete surgical resection via an endonasal route were: presence of hyperostosis (P = 0.04), cavernous internal carotid artery involvement (P = 0.001), maximal dural tail length in the transverse plane (P = 0.006), and its ratio to the inter-fovea ethmoidalis distance (P = 0.01). Using a multiple regression analysis, only cavernous internal carotid artery involvement (P = 0.002) and a large dural tail length to inter-foveal distance ratio (P = 0.04) were significant predictors of incomplete resection (multiple correlation coefficient = 0.71). The combination of predictive factors to determine the likelihood of complete endoscopic resection produced a scoring system with a sensitivity and specificity of 85.7% (95% confidence interval [CI], 42.1–99.6] and 100% (95% CI, 81.5–100), respectively.

Conclusion

The use of a simple scoring system outlined in our study can facilitate proper patient selection for endoscopic endonasal resection of ACF meningiomas.

Introduction

The addition of the endoscopic endonasal approach (EEA) to the armamentarium of approaches to skull base tumors has resulted in a paradigm shift in the management of anterior cranial fossa (ACF) meningiomas.1, 2, 3, 4 The lack of external incisions and direct access to the tumor under the frontal lobes together with an acceptable complication profile in contemporary series has enabled this transition.1, 2, 5 Nevertheless, several subtypes of ACF meningiomas remain challenging and potentially inappropriate for an EEA.6 Despite careful selection of patients for the EEA, as many as 25%–37% of ACF meningiomas are incompletely resected, based on a systematic review of the literature.7 A number of previously reported factors have been shown to influence surgical resectability, including significant lateral extension, vascular encasement,6, 8, 9 and a firm tumor consistency, which is difficult to predict radiologically.10, 11 Moreover, a clinically significant discrepancy exists in resection rates between open and endoscopic endonasal approaches to ACF meningiomas in the current literature.7, 12

To our knowledge, no clinical tool predicting success with the EEA for ACF meningiomas has been developed. In this study, we asked whether clinico-radiologic factors could predict which ACF meningiomas were appropriate for an endonasal endoscopic resection. To optimize patient selection for the EEA, we amalgamated significant clinico-radiologic factors associated with complete tumor resection into a simple scoring system to predict resectability via the EEA.

Section snippets

Study Design

A retrospective case series included patients undergoing endoscopic endonasal resection of ACF meningiomas at two Montreal tertiary care academic centers. The primary outcome measure in this study was the extent of tumor resection. Patients with complete (Simpson grade I/II) endoscopic endonasal resection were compared with patients with an incomplete initial resection. The goal of surgery in the majority of cases was to achieve gross tumor resection (GTR). For tumors invading into the

Clinico-Radiologic Factors

Previously studied clinico-radiologic features related to meningioma consistency and resectability via an EEA were identified with a literature review.11, 13, 14, 15, 16, 17, 18, 19 Subsequently, a panel of experts consisting of neurosurgeons (S.D., D.S.) and rhinologists (M.A., A.Z.) discussed and finalized a list of clinico-radiologic factors possibly associated with incomplete tumor resection. A total of 25 potential factors were included in the analysis (Supplementary Table 1).

The maximal

Results

Twenty-five patients undergoing endoscopic endonasal resection were analyzed, among a total of 30 ACF meningiomas treated during the same period. The 5 patients undergoing a primary transcranial route were due to significant lateral tumor extension. The series included 12 planum sphenoidale, 7 tuberculum sellae, and 6 olfactory groove meningiomas. In 18 (72%) patients, complete tumor resection (Simpson grade 1 or 2) was achieved (Figure 2). Among the 7 patients with subtotal or partial

Discussion

Despite careful patient selection and the performance of endoscopic endonasal resection of anterior cranial base meningiomas by high-volume centers of expertise, there is a significant rate of incomplete resection reported in the literature, ranging from 24% to 34%.6, 17 In a systemic review of the literature, Komotar and colleagues7 demonstrated an inferior rate of complete resection of ACF meningiomas compared with open transcranial approaches.7 This rate ranged from 63.2% for olfactory

Conclusion

Successful endoscopic endonasal resection of anterior cranial meningiomas in our study related to the extent of hyperostosis along the anterior cranial base, transverse dural tail length, particularly beyond the inter-fovea ethmoidalis, and any cavernous sinus dural invasion. These factors, when combined in a simple scoring system, can assist in the proper selection of ACF meningiomas for endoscopic endonasal resection. Further study is needed to validate this scoring system before widespread

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    Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

    Marco A. Mascarella and Marc A. Tewfik are co-first authors.

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