Cavernous Malformation From Cranial Nerves: A Systematic Review With a Novel Classification and Patient-Level Analysis

BACKGROUND AND OBJECTIVES:Cavernous malformations (CMs) occurring in the cranial nerve (CN) are extremely rare, and there is currently no comprehensive review on CN CMs, leading to a lack of sufficient understanding of CN CMs. We aimed to systematically review all published CN CM cases; summarize the epidemiology, clinical manifestations, treatment, and prognosis of CN CMs; and identify factors influencing the prognosis of CN CMs. METHODS:This systematic review identified all cases potentially diagnosed with CN CM through a systematic search of PubMed, SCOPUS, Web of Science, and Cochrane databases. This represents the most comprehensive systematic review to date. We classified CN CMs based on their anatomic origins. Patient characteristics, disease manifestations, treatment approaches, and prognosis were summarized descriptively. Further analysis was conducted to identify factors influencing the prognosis of CN CMs. RESULTS:The final analysis included 108 articles (127 individual patient cases). The optic nerve (49/128, 38.3%) is the most commonly affected nerve. Notably, CN CMs can be categorized into 3 types: Intraneural, Perineural, and Extraneural. Preoperative nerve function status and novel classification were associated with the prognosis of CN CMs (P = .001; P < .001). The postoperative neurological deterioration rate for the Intraneural type was 19/37 (51.4%); for the Extraneural type, it was 13/69 (18.8%); and for the Perineural type, it was 1/22 (4.5%) (P < .001). CONCLUSION:We reviewed all the published CN CMs to date, offering a comprehensive description of CN CMs for the first time and identifying prognostic factors. The classification of CN CMs proposed in this study could serve as guidance for the selection of intraoperative treatment regimens. The findings of this systematic review are expected to provide a foundation for clinical decision-making in this crucial rare disease and lay the groundwork for developing relevant clinical guidelines.