Early Postoperative Results of Microsurgery of Anterior Clinoidal Meningiomas - Russian (Siberian) Experience

Objective: To assess the radicality and neurological deficit in the early postoperative period after microsurgery of anterior clinoid process meningiomas.

Materials and Methods: From 2013 to present 29 patients with anterior clinoidal meningiomas were operated on. There were 23 (79%) females and 6 (21%) males. The average age was 52.44 years (from 35 to 72). Based on All-Mefty classification - type A tumor (up to 2 cm) were observed in 4 cases (13.8%), type B (2–4 cm) - 8 (27.6%) and type C (more than 4 cm) - in 17 cases (58.6%). The tumor involved: in 5 patients the internal carotid, middle, anterior cerebral artery, in 4 - the internal carotid, anterior cerebral, and anterior communicating artery, in 3 -internal carotid and middle cerebral artery, in 5 - the cavernous sinus; in 8 - tumor dislocated the internal carotid artery and 4 patients had subtentorial growth. Thus, in 16 cases (55.2%) the major cerebral arteries were involved in a tumor stroma. Headache, dizziness, memory loss and other cerebral symptoms were reported in all 29 patients, vision lost, diplopia were presented in 12 (41.4%) cases, seizures - in 5 patients (17.2%) .

Results: Pterional approach was used in 8 patients (27.6%), 21 patients (72.4%) were operated on via the lateral supraorbital approach. The Gross Total Removal (Simpson II) were achieved in 23 cases (79.3%), subtotal removal (Simpson IV) - in 6 patients (21.7%) due to dens stroma. Histology showed benign tumor (Grade I) in all cases. From all the16 patients with the involvement of the main arteries in the tumor parenchima good extention of resection (Simpson II) was achieved in 11 patients (68.8%) because of the soft density of the tumor and good arachnoid plane between the tumor and involved vessels. In 13 patients (44.8%) the cerebral symptoms were completely regressed, in 2 patients (16.7%) the visual acuity was improved, in 8 patients (27.6%) symptoms remained unchanched. 4 patients (13.8%) had the III nerve palsy associated with the spread of the tumor in the cavernous sinus, in 1 case (3.4%) - severe hemiparesis and motor aphasia due to intraoperative injury of the left middle cerebral artery. The mortality rate was 3.4% (1 patient) associated with spasm of the internal carotid artery, its main branches and perforators resulted in ischemia of hemisphere, upper brain stem and the hypothalamic region due to hard density with no good dissection plane between the arteries and the tumor.

Conclusions: Microsurgery of anterior clinoidal meningiomas is challenging because of the location of the tumor, involvement of the main arteries, close connection with the optic nerve and chiasm, large and giant size and the presence of hyperostosis. From our experience, the degree of radicality depends on the density of the tumor: in the cases of soft meningiomas it is possible to achieve the gross total removal and good functional outcome. When the tumor is hard, the attempts of radical removal can cause trauma to the main arteries and ischemia with a high mortality rate or a significant decrease of the patients life quality