Temporal Pattern of Pain Relief Using CyberKnife Radiosurgery for Trigeminal Neuralgia: A Preliminary Report

Abstract

Radiosurgery is a non-invasive alternative to treat medically refractory trigeminal neuralgia (TN) in selected patients. Several reports have described outcomes after gamma knife radiosurgery (GKR) for TN. We have recently treated a small cohort of patients with TN using a Linac-based frameless radiosurgical device, the CyberKnife (Accuray Inc., Sunnyvale, Calif., USA). Stereotactic irradiation is delivered by a compact 6-MV x-ray Linac moved and pointed by a precise and highly maneuverable robotic arm. Real-time image guidance using amorphous silicone detectors outlines the contour of the patient’s skull and provides accurate localization without requiring a rigid stereotactic frame. Preliminary results in 13 patients were encouraging; 7 patients (53.8%) developed pain relief within a week, and overall, 8 patients (61.5%) experienced a long-lasting satisfactory outcome. Reduced constraints on treatment planning due to the absence of a stereotactic ring, improved targeting accuracy produced by computed tomographic cisternography, and conformal dosimetry may explain the early onset of analgesia in a large subset of treated patients. These results should be considered preliminary, however, and need to be confirmed by a prospective study on a larger patient sample.