Characteristics of optic canal invasion in the large midline nontuberculum sellae anterior skull base meningiomas and the surgical outcomes

Acta Neurochirurgica (2025) 167:31

There is a lack of available data regarding the incidence and characteristics of optic canal invasion (OCI) in large midline non-tuberculum sellae anterior skull base meningiomas (NTSAM), specifically those originating predominantly from the olfactory groove and planum sphenoidale. This study aims to describe the incidence and characteristics of OCI as well as clinical and visual outcomes following extensive tumor resection with optic canal exploration in intra-optic canal tumor removal. In addition, the predictive performance of OCI by preoperative magnetic resonance imaging (MRI) is investigated.

Materials and methods From 2016 to 2024, we retrospectively reviewed 24 patients with large midline NTSAM who underwent extensive tumor resection in our institution. The OCI was evaluated and compared between preoperative MRI and intraoperative findings. The OCI was classified as follows. Type 1 represented no invasion, type 2 represented secondary invasion, type 3 represented partial wall invasion (two subtypes), and type 4 represented invasion into the superior-medialinferior walls of the optic canal. Visual functions were assessed before and after surgery.

Results Among 24 patients, a mean tumor size of 57.2 mm (range 39.0–79.0). The OCI was observed intraoperatively in 22 cases (91.7%), with 19 cases exhibiting bilateral OCI. Among the 48 optic canals in the 24 patients, 18 (37.5%) were type 4, 12 (25.0%) were type 3-inferomedial, 9 (18.8%) were type 3-superomedial, and 2 (4.2%) were type 2, where 7 (14.6%) optic canals were without OCI. A significant correlation was observed between intraoperative OCI and the tumors that exhibited involvement of the tuberculum sellae (TS) on MRI (p < 0.001). For patients with visual impairment, the vision in 27 of 38 (71.1%) eye sides showed improvement following the surgery. There was 1 (4.2%) case of tumor recurrence at the mean follow-up time of 27.3 months (range 4–73 months).

Conclusions A high incidence of OCI was observed in the large midline NTSAM. The identification of TS involvement on MRI can serve as a strong predictor of OCI. Therefore, optic canal exploration to remove the optic canal invasion during the surgical removal of these particular tumors should be contemplated to attain radical tumor resection to enhance the possibility of improving visual function and reduce the risk of recurrence.

Endoscopic endonasal approach for suprasellar meningiomas

J Neurosurg 135:113–125, 2021

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.

Endoscopic endonasal versus transcranial approach to tuberculum sellae and planum sphenoidale meningiomas

J Neurosurg 128:40–48, 2018

Planum sphenoidale (PS) and tuberculum sellae (TS) meningiomas cause visual symptoms due to compression of the optic chiasm. The treatment of choice is surgical removal with the goal of improving vision and achieving complete tumor removal. Two options exist to remove these tumors: the transcranial approach (TCA) and the endonasal endoscopic approach (EEA). Significant controversy exists regarding which approach provides the best results and whether there is a subset of patients for whom an EEA may be more suitable. Comparisons using a similar cohort of patients, namely, those suitable for gross-total resection with EEA, are lacking from the literature.

METHODS The authors reviewed all cases of PS and TS meningiomas that were surgically removed at Weill Cornell Medical College between 2000 and 2015 (TCA) and 2008 and 2015 (EEA). All cases were shown to a panel of 3 neurosurgeons to find only those tumors that could be removed equally well either through an EEA or TCA to standardize both groups. Volumetric measurements of preoperative and postoperative tumor size, FLAIR images, and apparent diffusion coefficient maps were assessed by 2 independent reviewers and compared to assess extent of resection and trauma to the surrounding brain. Visual outcome and complications were also compared.

RESULTS Thirty-two patients were identified who underwent either EEA (n = 17) or TCA (n = 15). The preoperative tumor size was comparable (mean 5.58 ± 3.42 vs 5.04 ± 3.38 cm3 [± SD], p = 0.661). The average extent of resection achieved was not significantly different between the 2 groups (98.80% ± 3.32% vs 95.13% ± 11.69%, p = 0.206). Postoperatively, the TCA group demonstrated a significant increase in the FLAIR/edema signal compared with EEA patients (4.15 ± 7.10 vs -0.69 ± 2.73 cm3, p = 0.014). In addition, the postoperative diffusion-weighted imaging signal of cytotoxic ischemic damage was significantly higher in the TCA group than in the EEA group (1.88 ± 1.96 vs 0.40 ± 0.55 cm3, p = 0.008). Overall, significantly more EEA patients experienced improved or stable visual outcomes compared with TCA patients (93% vs 56%, p = 0.049). Visual deterioration was greater after TCA than EEA (44% vs 0%, p = 0.012). While more patients experienced postoperative seizures after TCA than after EEA (27% vs 0%, p = 0.038), there was a trend toward more CSF leakage and anosmia after EEA than after TCA (11.8% vs 0%, p = 0.486 and 11.8% vs 0%, p = 0.118, respectively).

CONCLUSIONS In this small single-institution study of similarly sized and located PS and TS meningiomas, EEA provided equivalent rates of resection with better visual results, less trauma to the brain, and fewer seizures. These preliminary results merit further investigation in a larger multiinstitutional study and may support EEA resection by experienced surgeons in a subset of carefully selected PS and TS meningiomas.