Treatment of trigeminal neuralgia with linear accelerator radiosurgery: initial results

Radiosurgery has emerged as an important treatment of trigeminal neuralgia. Substantial advantages have been demonstrated in safety and comfort over other modalities. Radiosurgical treatment of trigeminal neuralgia has been well investigated with gamma knife devices involving fixed cobalt sources. Few reports exist concerning trigeminal neuralgia treated using linear accelerator (LINAC)-based devices. In recent years these devices have reached the level of mechanical precision that is required for such functional treatments. The authors describe their initial experience with radiosurgical treatment of trigeminal neuralgia when using a BrainLAB Novalis LINAC device equipped with the commercially available 4-mm collimator.

A total of 32 patients were treated in a 12-month period between November 2002 and November 2003. The median patient age was 67 years (range 38-84 years). Facial pain was graded using the Barrow Neurological Institute (BNI) scoring system. All patients' pain was BNI Grade IV or V prior to treatment. Of these patients, 22 were undergoing initial treatment, and 10 were undergoing retreatment for recurrent pain following various treatments including percutaneous procedures, gamma knife surgery (GKS), or microvascular decompression. Two patients had multiple sclerosis. In patients undergoing initial radiosurgery, the most proximal segment of the cisternal portion of the trigeminal nerve received 85 to 90 Gy administered in a 5- or 7-noncoplanar arc single-isocenter plan with a 4-mm circular collimator. In patients undergoing repeated radiosurgery, the target received 60 Gy. Overall good and excellent results (BNI Grade I, II, or III) were achieved in 25 (78%) of 32 patients. The median time to pain relief was 6 weeks. Fair results (improvement in pain with BNI Grade IV) were achieved in three patients (9%), and poor results (no improvement in pain and BNI Grade IV or V) were seen in four (13%). Two patients demonstrated new trigeminal dysfunction following treatment. No other complications occurred.

High-precision imaging and LINAC instrumentation have allowed for treatment of trigeminal neuralgia with results and safety comparable to those achieved using GKS. Linear accelerator-based radiosurgery with the Novalis device is a safe and effective method of managing trigeminal neuralgia and may become the preferred means at centers where the technology is available.