The Stanford stereotactic radiosurgery experience on 7000 patients over 2 decades (1999-2018): looking far beyond the scalpel

OBJECTIVE The CyberKnife (CK) has emerged as an effective frameless and noninvasive method for treating a myriad of neurosurgical conditions. Here, the authors conducted an extensive retrospective analysis and review of the literature to elucidate the trend for CK use in the management paradigm for common neurosurgical diseases at their institution. METHODS A literature review (January 1990-June 2019) and clinical review (January 1999-December 2018) were performed using, respectively, online research databases and the Stanford Research Repository of patients with intracranial and spinal lesions treated with CK at Stanford. For each disease considered, the coefficient of determination (r(2)) was estimated as a measure of CK utilization over time. A change in treatment modality was assessed using a t-test, with statistical significance assessed at the 0.05 alpha level. RESULTS In over 7000 patients treated with CK for various brain and spinal lesions over the past 20 years, a positive linear trend (r(2) = 0.80) in the system's use was observed. CK gained prominence in the management of intracranial and spinal arteriovenous malformations (AVMs; r(2) = 0.89 and 0.95, respectively); brain and spine metastases (r(2) = 0.97 and 0.79, respectively); benign tumors such as meningioma (r(2) = 0.85), vestibular schwannoma (r(2) = 0.76), and glomus jugulare tumor (r(2) = 0.89); glioblastoma (r(2) = 0.54); and trigeminal neuralgia (r(2) = 0.81). A statistically significant difference in the change in treatment modality to CK was observed in the management of intracranial and spinal AVMs (p < 0.05), and while the treatment of brain and spine metastases, meningioma, and glioblastoma trended toward the use of CK, the change in treatment modality for these lesions was not statistically significant. CONCLUSIONS Evidence suggests the robust use of CK for treating a wide range of neurological conditions.