Update on anterior clinoid process removal in anterior clinoid meningioma surgery: literature review, and a new didactical concept

Purpose Anterior clinoidal meningioma (ACM) remains a challenging lesion to treat surgically due to its intricate neurovascular relationships with surrounding anatomy and often presents with ipsilateral visual loss. Anterior clinoidectomy (AC) by skilled skull base surgeons enables early optic nerve (ON) decompression, tumor devascularization, and radical tumor resection. The authors provide an update on ACM surgery, current views on the role of AC and its impact on outcomes in surgical treatment, as well as a new 2 stage 4 by 4 step concept of ON decompression involving AC. Methods A systematic review of PubMed and meta-regression of surgically treated ACMs was performed. Results In total, 908 patients were analyzed; 415 (45.7%) underwent routine AC (performed in all cases) and 493 (54.3%) underwent selective AC (planned preoperatively). The routine AC cohort showed higher risk for new cranial-nerve (CN) deficits (12.5% vs. 3.0%; p < 0.001), vascular complications (6.7% vs. 3.3%; p = 0.02), and new focal neurological deficits (5.5% vs. 2.3%; p = 0.04). No differences were found in visual outcomes, gross-total resection, mortality, recurrence, or other major complications. Random-effects meta-regression of routine AC showed increased odds of new CN deficit (odds ratio [OR], 3.34; 95% confidence interval [95% CI], 1.51–7.38; p = 0.005; heterogeneity [I2] = 60.5%) and vascular complication (OR, 2.59; 95% CI, 1.05–6.38; p = 0.04; I2 = 47.8%), with moderate and substantial heterogeneity among routine AC studies, respectively. Conclusions In experienced hands, AC remains an invaluable tool for ACM treatment as it offers more consistent tumor devascularization, prevention of tumor recurrence, optic nerve decompression, and increased working space, which facilitates optimal tumor resection and better long‐term control and functional outcome. We propose a new didactical structured concept of routine AC via 2-stage, 4 by 4 steps to improve the utility of AC and decrease associated operative risks compared to selective AC. Supplementary Information The online version contains supplementary material available at 10.1007/s00701-025-06742-x.