REVIEW ARTICLE - TUMOR - MENINGIOMA Recurrence of surgically treated parasagittal meningiomas: a meta-analysis of risk factors Vladimir Balik 1,2 & Pavla Kourilova 1 & Igor Sulla 3 & Jana Vrbkova 1 & Josef Srovnal 1 & Marian Hajduch 1 & Katsumi Takizawa 4 Received: 29 February 2020 /Accepted: 7 April 2020 # Springer-Verlag GmbH Austria, part of Springer Nature 2020 Abstract Background As the predictive role of many risk factors for parasagittal meningioma (PM) recurrence remains unclear, the objective of the meta-analysis was to make a comprehensive assessment of the predictive value of selected risk factors in these lesions. Methods Studies including data on selected risk factors, such as histology, tumor and sinus resection, sinus invasion, tumor localization, and immediate postoperative radiotherapy for PMs recurrence, were searched in the NCBI/NLM PubMed/ MEDLINE, EBM Reviews/Cochrane Central, ProQuest, and Scopus databases, and analyzed using random effects modeling. Results Thirteen observational studies involving 1243 patients met the criteria for inclusion in the meta-analysis. WHO grading of meningiomas was identified as the most powerful risk factor for recurrence. WHO grade II meningiomas (OR 11.61; 95% CI 4.43–30.43; P < .01; I 2 = 31%) or composite group of WHO grades II and III (OR 14.84; 95% CI 5.10–43.19; P < .01; I 2 = 48%) had a significantly higher risk of recurrence than benign lesions. Moreover, an advanced sinus involvement (types IV–VI according to the Sindou classification) (OR 3.49; 95% CI 1.30–9.33; P = .01; I 2 = 0%) and partial tumor resection (Simpson grades III–V) (OR 2.73; 95% CI 1.41–5.30; P = .03; I 2 = 52%) were associated with a significantly higher risk of recurrence than their counterparts. Conclusion Among the selected risk factors, high-grade WHO lesions, advanced sinus invasion, and partial tumor resection were associated with a higher risk of PM recurrence, with WHO grading system being the most powerful risk factor. Keywords Meta-analysis . Parasagittal meningioma . Recurrence . Risk factors Introduction Parasagittal meningiomas (PMs) per se along with achieving their low recurrence rate still present a unique set of challenges to neurosurgeons. Since the lesions, accounting for 20% to 30% of all intracranial meningiomas [10] and having one of the highest recurrence rates among all meningiomas ranging from 13 to 40% [8], invade the superior sagittal sinus (SSS) and frequently also structures in the eloquent area [41], the risk of a neurological deficit must be weighed carefully against the risk of recurrence when considering their removal, especially since the extent of tumor resection (EOR) was gen- erally accepted as a critical predictive factor for their recur- rence [2, 7, 25, 29, 35, 36]. Even some view discrepancies among recurrence rates likely due to differences in EOR rather than histological types [36]. In addition, several other prog- nosticators have been proposed, including extent of sinus re- section (ESR) [11, 22, 36], sex [9, 23], tumor size [11], This article is part of the Topical Collection on Tumor – Meningioma. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00701-020-04336-3) contains supplementary material, which is available to authorized users. * Vladimir Balik balik.vladimir@gmail.com 1 Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hněvotínská 1333/5, I. P. Pavlova 6, 779 00 Olomouc, Czech Republic 2 Department of Neurosurgery, Svet Zdravia Hospital Michalovce, Michalovce, Slovak Republic 3 Institute of Neurobiology, Slovak Academy of Sciences, Kosice, Slovak Republic 4 Department of Neurosurgery, Japanese Red Cross Asahikawa Hospital, Asahikawa, Hokkaido, Japan Acta Neurochirurgica https://doi.org/10.1007/s00701-020-04336-3