Anterior Midline Skull Base Meningiomas: Interhemispheric Approach versus the Different Classical Surgical Approaches—Clinical Outcomes

Backgrounds: Different surgical approaches have been used to remove anterior skull base meningiomas (ASBMs) such as olfactory groove (OG) and tuberculum sellae (TS) meningiomas. These tumors are traditionally resected through pterional (PT), lateral supraorbital (LS) approaches. The endonasal endoscopic (EE) approach has gained some attention in recent years. The interhemispheric (IH) approach represents another option that has been rarely described and even more rarely compared with other approaches.

Objectives: To report clinical outcomes of the different approaches for the removal of midline ASBMs and to establish the efficacy of the IH approach compared with the traditional PT, LS, and EE approaches.

Methods: The medical chart of patients with an ASBMs were retrospectively analyzed. Patients with other ASBMs different from pure midline OG or TS meningiomas were excluded.

Results: 39 patients (30 women; 9 men; mean age 58.7y, range 25–80) had either an OGM (23) or a TSM (14). Mean symptoms time before diagnosis was 7.5 months (range 0- 60). Mean tumor size was 37 mm (range 10–77 mm). The most common symptom was visual deficit (n = 23; 59%). Tumors were attached to chiasm, optic nerves and to anterior cerebral arteries respectively in 48.7% (19 patients) 46.2% (18) and 46.2% (18 patients). The approaches used were respectively: IH (n = 15), PT (n = 17), SL (n = 4), and EE (n = 3) approaches. Median operative time was 300 minute; with a significantly shorter mean time for the PT (268 minute) over the IH (330 minute) (p = 0.04). Mean blood losses (440 cc) were not statistically significantly different when comparing the approaches. Gross total resection (Simpson ½) was achieved respectively in 93.3%, 76.5%, 75% and 66.7% of the cases through the IH, PT, SL, and EE approaches (p = 0.51). Visual improvement or stabilization was achieved in respectively 100%, 64.5%, 100%, 100% with a significant better outcome after an IH than a pterional approach (p = 0.01). Olfactory deterioration appeared respectively in 23.1%, 29.4%, 75%, and 33.3% (p = 0.31). CSF leakage developed in 3 patients (IH:1, PT: 1, EE; 1; p = 0.36). Memory problems were noted postoperatively in 6 patients (2 IH, 2 PT, 2 SF; p = 0.21), hemiparesis in 1 patient (PT) and dysphagia in 1 case (PT). Mortality rate was 0%. Tumor recurred in 2 patients: 47 months after one IH approach and 32 months after one PT approach with a Simpson 2 resection; both were treated with radiosurgery.

Conclusion: The IH approach can be used safely and routinely for midline ASBMs of all sizes with a high rate of gross total resection, an excellent visual outcomes and a low morbidity rate. The results of this limited series should be confirmed in larger studies.