Effect of gamma knife surgery for primary orbital optic nerve sheath meningioma upon visual control and influencing factors thereof

Objective: To investigate the effect of gamma knife surgery (GKS) in treatment of primary orbital optic nerve sheath meningioma (PONSM) upon visual control and to explore the factors influencing the visual acuity changes after GKS. Methods: Totally 26 PONSM patients, 3 males and 23 females, aged 35.5 (4-66) years old, 2 pathologically confirmed and 24 confirmed by MRI, underwent GKS, and were followed up for 20.2 months (6-62 months). The efficacy of GKS was evaluated by the change of tumor volume and visual acuity. The relations between the change of visual acuity and different clinical features were analyzed. Results: The vision control rate was 65.4%, and the tumor control rate was 96.2%. The onset age, onset speed, and preoperative shape of PONSM were significantly correlated with the visual change after GKS (P = 0.034, 0.014, and 0.034 respectively). Conclusions: The efficacy of GKS in patients with PONSM is fine, which depends on the onset age, onset speed, as well as the degree of radiation-induced side effect after GKS. (authors)