Frame and frameless linear accelerator-based radiosurgery for idiopathic trigeminal neuralgia
Allan Y. Chen, Yen Hsieh, Steffanie McNair, Qijuan Li, Kevin Y. Xu and Conrad Pappas
Purpose: We report outcome of linear accelerator (Linac)-based stereotactic radiosurgery (SRS) for trigeminal neuralgia (TGN) utilizing rigid head frame (RF) and facemask (FM) immobilization.
Method: From November 2008 to October 2012, 48 patients with idiopathic TGN underwent primary SRS by a dedicated Linac. RF immobilization was utilized for 34 patients, and frameless image-guided radiosurgery (IGRS) with FM immobilization was performed in 14 patients. Treatment outcome was assessed by patient interviews with a 7-item questionnaire.
Results: Sub-millimeter targeting accuracy (0.71±0.31mm) was recorded for frameless IGRS by a novel hidden-target phantom method. With a follow-up of 26 months, significant pain relief was recorded in 43 (89%) patients, including 26 (54%) complete and 17 (35%) partial responses; with a significant reduction of 2.4±1.3 points (p < 0.01) on the 5-point Barrow Neurological Institute pain scale. No significant pain relief difference (p = 0.23) was detected between patients immobilized by RF and FM. Notable pin site problems were reported in 9 (26%) of 34 patients immobilized by RF.
Conclusion: Frameless IGRS with FM immobilization is more patient friendly and can achieve as excellent treatment outcome as with RF immobilization for idiopathic TGN.
Keywords: trigeminal neuralgia, radiosurgery, linear accelerator, targeting accuracy, frameless image-guided radiosurgery.