Endonasal Endoscopic Bony Decompression, Limited Tumor Removal and Stereotactic Radiation Therapy in Invasive Parasellar Meningiomas to Improve Cranial Neuropathy and Endocrinopathy

Background: Invasive parasellar meningiomas pose a management challenge given their involvement with cranial nerves, pituitary and vascular structures. Treatment options range from aggressive resection to focused radiotherapy alone.

Objective: Our strategy of endonasal endoscopic bony decompression and selective tumor removal followed by selective stereotactic radiotherapy is assessed.

Methods: Data on tumor location, cranial neuropathies, pituitary dysfunction, complications, MRI-documented tumor control rates, clinical outcomes, prior treatments, and type/frequency of stereotactic radiosurgery (SRS) and radiotherapy (SRT) were evaluated.

Results: From 2009–2015, 20 patients (age 43–81 years; 65% women; 18 WHO grade I and 2 grade II meningiomas) underwent endonasal bony decompression and tumor removal including 7 with prior tumor debulking (6 of whom had prior SRS or SRT). The most common regions of tumor involvement were cavernous sinus (n = 19), Meckel’s cave (n = 15), and sella (n = 15).

The first two patients in the series underwent a microscopic approach with endoscopic assistance and the last 18 had a fully endoscopic approach. All patients underwent subtotal tumor removal; no patient had resection greater than 50% of overall tumor volume. Intraoperative CSF leaks were seen in 13 patients (65%): 2 grade I leaks, 2 grade II leaks, and 9 grade III leaks (69%); a nasoseptal flap was utilized in 10 patients for skull base reconstruction. Three of 20 patients underwent staged transcranial and endonasal debulkings of large meningiomas.

Average length of hospital stay was 2.9 days (range 1–6 days).

Median follow-up was 32.5 months (range 4–68 months). Of 14 patients without prior radiotherapy, 11 had postoperative SRT, with tumor shrinkage in 3 (27%). At last follow-up, tumor control was 100% in these 14 patients, compared with 33% in 6 patients with prior radiotherapy (p < 0.001). Three of 6 (50%) previously irradiated patients had new cranial neuropathies and one died from progressive tumor growth. In long-term follow-up, overall clinical status improved or remained stable in 15 (75%) patients; of the 5 patients who deteriorated neurologically, 4 had tumor progression (all of whom had at least 2 prior SRS treatments and prior surgery) and 1 had a new permanent postoperative abducens nerve palsy.

Overall, of the 29 pre-existing cranial neuropathies in the cohort, at last follow-up, 11 (38%) had resolved or improved, 16 (55%) were stable, 3 (10%) had worsened. No new pituitary dysfunction was noted, and 2/7 (28.5%) patients had resolution of preoperative endocrinopathy. There was one cerebrospinal fluid leak requiring reoperation; there were no other major complications including no vascular injuries, post-operative hematomas or meningitis.

Conclusions: Endonasal bony decompression and selective tumor removal followed by SRT appears to be a reasonable treatment option for invasive parasellar meningiomas. In patients who have failed prior surgery and radiotherapy, novel treatments are needed.