[Olfactory groove meningiomas. Radical microsurgical treatment through the bifrontal approach]

To describe the microsurgical technique for the radical removal of olfactory groove meningiomas through the bifrontal approach. To review the diagnostic elements to be taken into account in the selection of the surgical approach to these tumours.

A microsurgical series of 35 olfactory groove meningiomas operated on through a bifrontal craniotomy is reviewed.

The mean tumoral volume was 85cc (4.4cm diameter). A relevant peritumoral brain edema was found in 65.7% of cases, hyperostosis in the implantation base in 80% and paranasal sinus invasion in 28.6%. A Sipmson grade 1 resection was achieved in every case. A patient died due to a postoperative pneumonia. Postoperative hospitalization time was between 3 and 20 days and at discharge all patients had a Glasgow Outcome Scale grade 4-5. The mean follow-up was 55.2 months. Two patients had postoperative transient rhinolicuorrhea and an additional patient developed hydrocephalus. An asymptomatic recurrence have been identified in a patient four years after surgery.

In our experience the bifrontal approach allowed the radical removal of huge olfactory groove meningiomas. The microdissection of the anterior cerebral artery A2 segments is possible thanks to the arachnoidal plane between vessels and tumor. Tumoral blood flow is secured by the early approaching of the base of the tumor and preoperative embolization is not necessary. Bifrontal approach allows an aggressive treatment of the hyperostosis, bone infiltration and paranasal sinus invasion. Anterior fossa reconstruction is done using a vascularized periosteal flap.