Endonasal Endoscopic Bony Decompression and Conservative Debulking of Invasive Parasellar Meningiomas

Background: Attempts at complete or near complete removal of invasive parasellar meningiomas involving the cavernous sinus, Meckel cave, sella, and clival/petroclival regions are challenging and may be associated with a relatively high rate of new cranial neuropathies and other complications. Herein, we evaluated a strategy of endonasal endoscopic parasellar skull base bony decompression and limited tumor removal followed by stereotactic radiotherapy (SRT), stereotactic radiosurgery (SRS), or observation.

Methods: From February 2009 to April 2014, 17 cases of invasive parasellar meningiomas of the cavernous sinus or Meckel cave were treated by an endonasal endoscopic approach. All patients underwent extensive bony skull base decompression and limited tumor removal or biopsy. All procedures utilized frameless navigation and Doppler for carotid artery and vertebral/basilar artery localization; 11 procedures [U1] utilized electrophysiological monitoring. Skull base reconstruction involved autologous fat grafts in all patients. A nasoseptal flap was used in six cases. Eight patients received postoperative SRT. Rates of tumor control, cranial neuropathy, and other complications were analyzed.

Results: The 17 patients included 11 women and 6 men with the mean age of 59 ± 10 years (range, 43–81 years). Previous surgery was noted in six patients and prior radiation in five patients: Single SRT (1), multiple SRS (2), and multiple SRS with single SRT (3). Two patients had a staged approach including craniotomy and endonasal debulking. The mean maximal tumor diameter was 3.4 ± 1.3 cm (range, 1.7–5.7 cm). Tumors involved the cavernous sinus (16), Meckel cave (14), the sella (11), the clival or petroclival region (10), and the sphenoethmoid or orbit (2). Fifteen tumors were WHO grade 1 and grade 2. Overall, 35 preoperative cranial neuropathies were observed in 14 patients, including: optic (seven), oculomotor (five), trochlear (two), ophthalmic (three), maxillary (five), mandibular (three), abducens (five), facial (two), and vestibulocochlear (three) nerves.

Postoperatively, tumor control was achieved in 13 of 17 patients (76%) whereas 4 patients (24%) had tumors that grew: all of whom had received between two and three rounds of SRS ±  SRT. Of the eight tumors treated with postoperative radiation, 100% achieved tumor control (median follow-up 31.5 months and range, 10–55 months) and 3 (38%) shrank. Tumor control was achieved in one patient who had preoperative radiotherapy (20%): the single patient receiving only prior SRT.

Overall, 15 (43%) cranial neuropathies improved after surgery and 19 (54%) were stable. Seven patients had preoperative pituitary dysfunction and three (43%) improved after surgery.

Complications: One patient developed a new abducens nerve palsy attributed directly to surgery and one patient developed postoperative cerebrospinal fluid leak and meningitis. No vascular injury or postoperative pituitary dysfunction related to surgery was encountered in our series.

Conclusion: Endonasal endoscopic bony decompression and limited debulking of invasive parasellar meningiomas appears to be a safe and feasible approach to stabilize and in some instances to resolve cranial nerve dysfunction. Combining this surgical approach with SRT appears to have a high tumor control rate although longer follow-up with more patients is needed.