Introduction: The identification of risk factors of recurrence of skull base meningiomas remains an important goal in neurosurgery. The purpose of the research is outcome analysis of surgical treatment and reliable prognosis scale designing.

Methods: A total of 325 patients with skull base meningiomas were studied. Each patient underwent surgery between 1996 and 2015. The mean patient age was 51.8 years. Clinical data, magnetic resonance imaging studies, angiographic data, operative reports, histological findings were examined in patients. Mean follow-up was 76 months (6-18 months). Functional outcomes were determined using the KPS.

Results: Total removal was obtained in 271 patients (83.4%); subtotal was achieved in 31 patients (9.5%). In the 325 patients, mean preoperative and follow-up Karnofsky performance scale (KPS) scores were 75.9±7 and 83±5 respectively. The median MIB-1 index was 2.7% (range: 0-41.6%). 31 patients (9.5%) had tumor regrowth. As predictors of meningiomas regrowth we define the following: earlier radiation therapy, tumor localization, tumor size, cranial nerve affection, brain invasion, grade of tumor removal, histological structure of tumor and MIB-1 index. As a result we offer numerical recurrence rate scale of meningiomas: low recurrence rate – 0-3 score, moderate – 4-6 score, high – more than 7.

Conclusions: The identification of predictors and predicting the probability of recurrence of skull base meningiomas allows choosing the correct combination of treatment options. Combined therapy is indicated for patients with high recurrence rate: microsurgery with following radiosurgery.

Patient Care: The identification of predictors and predicting the probability of recurrence of skull base meningiomas allows choosing the correct combination of treatment options.

Learning Objectives: The purpose of the research is outcome analysis of surgical treatment and reliable prognosis scale designing.

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