Endoscopic endonasal approach for suprasellar meningiomas: introduction of a new scoring system to predict extent of resection and assist in case selection with long-term outcome data

Abstract

Objective: The endoscopic endonasal approach (EEA) has gained increasing popularity for the resection of suprasellar meningiomas (SSMs). Appropriate case selection is critical in optimizing patient outcome. Long-term outcome data are lacking. The authors systematically identified preoperative factors associated with extent of resection (EOR) and determined the relationship between EOR and long-term recurrence after EEA for SSMs.

Methods: In this retrospective cohort study, the authors identified preoperative clinical and imaging characteristics associated with EOR and built on the recently published University of California, San Francisco resectability score to propose a score more specific to the EEA. They then examined the relationship between gross-total resection (GTR; 100%), near-total resection (NTR; 95%-99%), and subtotal resection (STR; < 95%) and recurrence or progression with Kaplan-Meier survival analysis.

Results: A total of 51 patients were identified. Radiographic GTR was achieved in 40 of 47 (85%) patients in whom it was the surgical goal. Significant independent risk factors for incomplete resection were prior surgery (OR 25.94, 95% CI < 2.00 to 336.49, p = 0.013); tumor lateral to the optic nerve (OR 13.41, 95% CI 1.82-98.99, p = 0.011); and complete internal carotid artery (ICA) encasement (OR 15.12, 95% CI 1.17-194.08, p = 0.037). Tumor size and optic canal invasion were not significant risk factors after adjustment for other variables. A resectability score based on the multivariable model successfully predicted the likelihood of GTR; a score of 0 had a positive predictive value of 97% for GTR, whereas a score of 2 had a negative predictive value of 87.5% for incomplete resection. After a mean follow-up of 40.6 ± 32.4 months (mean ± SD), recurrence was 2.7% after GTR (1 patient with atypical histology), 44.4% after NTR, and 80% after STR (p < 0.0001). Vision was stable or improved in 93.5% and improved in 67.4% of patients with a preoperative deficit. There were 5 (9.8%) postoperative CSF leaks, of which 4 were managed with lumbar drains and 1 required a reoperation.

Conclusions: The EEA is a safe and effective approach to SSMs, with favorable visual outcomes in well-selected cases. The combination of postoperative MRI-based EOR with direct endoscopic inspection can be used in lieu of Simpson grade to predict recurrence. GTR dramatically reduces recurrence and can be achieved regardless of tumor size, proximity or encasement of the anterior cerebral artery, or medial optic canal invasion. Risk factors for incomplete resection include prior surgery, tumor lateral to the optic nerve, and complete ICA encasement.

Keywords: endoscopic endonasal approach; meningioma; planum sphenoidale; skull base; suprasellar; transsphenoidal; tuberculum.

FIG. 1.

Optic nerve laterality score. A: The optic nerve laterality score was determined based on the maximal lateral extension of the tumor on the anterior skull base relative to the optic nerve on either side. We assigned a score of 0 if the maximal lateral extension on either side was medial to the optic nerve; 1 if lateral < 50%; 2 if lateral ≥ 50% but < 100%; and 3 if it was completely (≥ 100%) lateral to the optic nerve. B: The optic nerve laterality score was measured on coronal MRI. The coronal image demonstrates lateral extension above the optic nerve at the bony edge of the optic canal on the anterior skull base. ***Optic nerve laterality score of 3 was associated with a significantly increased risk of not achieving GTR. Panel A: Copyright Matthew Holt. Published with permission.

FIG. 2.

Optic nerve laterality scores (superior view). An intracranial, superior-to-inferior view of SSMs in each category of the optic nerve laterality score. Scores were assigned as described in Fig. 1. ***Optic nerve laterality score of 3 was associated with a significantly increased risk of not achieving GTR. Copyright Matthew Holt. Published with permission.

FIG. 3.

EOR by the Weill Cornell resectability score. The number of patients in whom GTR and non-GTR was achieved is stratified by the Weill Cornell resectability score. A score of 0 had a positive predictive value of 97% for GTR, whereas a score of 2 had a negative predictive value of 87.5%.

FIG. 4.

Progression-free survival by EOR. Progression-free survival after radiographic and surgical GTR (100%), NTR (95%–99% radiographic resection and/or small residual tumor noted intraoperatively), and STR (< 95%). Hash marks represent censored data due to the end of the follow-up period for each patient. Log-rank test, p < 0.0001. Figure is available in color online only.

FIG. 5.

Examples of GTR with bilateral optic canal invasion, incomplete ICA encasement, and complete ACA encasement. A and B: Preoperative coronal T2-weighted MR image (A) demonstrates significant bilateral optical canal invasion and a Weill Cornell optic nerve laterality score of 2, and postoperative T2-weighted MR image (B) reveals GTR. C and D: Preoperative coronal T1-weighted MR image with contrast (C) demonstrates incomplete (> 50% but < 99%) intracavernous ICA encasement (Weill Cornell ICA score of 2), and postoperative T1-weighted MR image with contrast (D) reveals GTR. E and F: Preoperative coronal T1-weighted MR image with contrast (E) demonstrates complete encasement of the bilateral ACAs (Weill Cornell ACA score of 3), and postoperative coronal T1-weighted MR image with contrast (F) demonstrates GTR.