Surgical Management of Sphenoid Ridge Meningioma

Sphenoid ridge meningiomas may extend to optic canal, cavernous sinus, orbit, and often encase major arteries. Due to these factors, surgical treatment for these tumors is complex, and may be associated with complications. Here, the authors reviewed surgical experience for these tumors.

Patients and Method: During the past 18 years, the authors operated on 45 cases of sphenoid ridge meningiomas (32 females, average 58 years of age). Six cases were recurrent. Average size of the tumor was 45 mm (17–92 mm). Eleven were located lateral, and 34 were medial (clinoidal 24, sphenoorbital 3, sphenocavernous 5, others 2).

Results: (1) Main presenting symptoms were headache (4), memory disturbance (2) in the lateral group, whereas those were visual disturbance (21), and memory disturbance (2) in the medial group. (2) Major artery (IC, MC) encasement was observed in 2 cases (18%) in the lateral group, and in 23 cases (67%) in the medial group, which was even higher in the clinoidal subgroup (18/24, 75%). (3) Surgical strategy was to remove as much as tumor while preserving function. In the lateral group, Simpson grade I-II removal was achieved in 10 cases except one with MC encasement. In the medial clinoidal type, grade I-II removal was possible in 13 cases, grade III in 8 cases, and grade IV in 3 cases. In the later two, thickened dura or residual tumor around the nerves or cavernous sinus was left untouched to preserve nerve function. In the other medial types exhibiting orbital or cavernous sinus invasion (n = 8), only optic canal decompression was performed (grade IV removal). (4) In the lateral group, no permanent neurological deficits were observed postoperatively. In the medial group, visual disturbance was improved in 67%, unchanged in 28%, and deteriorated in 5%. Major complications were observed in 2 cases. One patients harboring large recurrent tumor was maintained with warfarin, and exhibited large infarction due to IC occlusion postoperatively. Another patient exhibited postoperative delayed vasospasm, which led to large hemispheric infarction.

Conclusion: In sphenoid ridge meningiomas, gross total resection (Simpson grade I-III) of the extracavernous portion could be achieved in most of the cases with improvement of symptoms. In majority of these, cranial nerves and extra-cavernous major arteries/ perforators could be dissected when the arachnoid membrane was preserved. However, when arachnoid membrane is lost, care must be taken to avoid vascular and cranial nerve complications.