Olfactory groove meningiomas: clinical outcome and recurrence rates after tumor removal through the frontolateral and bifrontal approach.

Objective: Olfactory groove meningiomas account for 8 to 13% of all intracranial meningiomas. Surgical removal is often performed through the bifrontal, unilateral subfrontal (frontolateral), or pterional approach. We report on the clinical outcome and recurrence rate after surgical treatment of olfactory groove meningiomas in our neurosurgical department.

Methods: A retrospective study was conducted by analyzing the charts of the patients, including surgical records, discharge letters, histological records, follow-up records, and imaging studies.

Results: A total of 1800 meningiomas were operated on between 1978 and 2002 in our department. There were 82 patients with olfactory groove meningiomas, including 63 women and 19 men with a mean age of 57.8 years (age range, 33-91 yr). Most patients presented with mental disturbance. Tumors were operated through the bifrontal (n = 46), frontolateral (n = 34), and pterional (n = 2) approaches. Total tumor removal (Simpson Grade 1 or 2) was achieved in most cases (91.2% frontolateral, 93.5% bifrontal). Perioperative mortality was 4.9% (four out of 82 patients, all operated through the bifrontal approach). The overall recurrence rate was 4.9%, with four patients requiring surgery. The mean follow-up period was 63.4 months (range, 4-270 mo).

Conclusion: Olfactory groove meningiomas were removed mainly through two different surgical approaches. Even in large tumors, high rates of total tumor resection could also be achieved with low recurrence rates using the simple and minimally invasive frontolateral approach. In recent years, we have preferred to use the frontolateral approach, which provides quick access to the tumor with less brain exposure while still enabling total tumor removal with a low morbidity rate and no mortality.