The incidence and risk factors of facial nerve dysfunction after acoustic neuroma surgery: A systematic review and meta-analysis

Abstract

Background: Facial nerve injury is a common complication after acoustic neuroma surgery, and there is currently a lack of clear evidence-based evidence. We conducted this systematic review and meta-analysis to explore the incidence and risk factors of facial nerve dysfunction (FNF) after acoustic neuroma (AN) surgery through meta-analysis, providing evidence-based basis for clinicians to predict and identify high-risk groups of FNF at an early stage.

Methods: We searched multiple databases including PubMed, Web of Science, Cochrane Library, CNKI, and Wan fang electronically for literatures on the incidence and risk factors of FNF after AN surgery from the establishment of the databases to December 2024. The quality of the literatures was evaluated, and statistical analysis was performed using R 4.4.1 software after data extraction.

Results: A total of 2,631 patients from 17 included literatures were analyzed. The results of meta-analysis showed that the incidence of FNF after AN surgery was 16% (95%CI: 0.11, 0.21). Larger tumor diameter [OR = 1.85, 95%CI (1.38 - 2.47), P < 0.0001], cystic tumors [OR = 2.22, 95%CI (1.43 - 3.45), P = 0.0004], a longer disease course [OR = 1.23, 95%CI (1.08 - 1.40), P = 0.0017], severe adhesion between the tumor and the facial nerve [OR = 5.45, 95%CI (3.67 - 81), P < 0.0001], peritumoral edema [OR = 3.22, 95%CI (1.71 - 6.07), P = 0.0003], total tumor resection [OR = 1.32, 95%CI (1.09 - 1.59), P = 0.0044], and preoperative gamma knife treatment [OR = 5.87, 95%CI (1.79 - 19.25), P = 0.0035] were the risk factors for FNF after AN surgery. The response of intraoperative facial nerve electromyography (EMG) to a 0.05 mA stimulation ≥ 100 microvolts [OR = 0.26, 95%CI (0.08 - 0.87), P = 0.0281] was a protective factor for FNF after AN surgery.

Conclusion: The existing evidence indicates that the incidence of FNF after AN surgery is 16%. Larger tumor diameter, cystic tumors, a longer disease course, severe adhesion between the tumor and the facial nerve, peritumoral edema, total tumor resection, and preoperative gamma knife treatment are the risk factors for FNF after AN surgery, while the response of intraoperative facial nerve EMG to a 0.05 mA stimulation ≥ 100 microvolts is a protective factor. Limited by the quantity and quality of the included literatures, the conclusions of this study still need to be confirmed by more high-quality studies.