Recurrent trigeminal neuralgia: long-term outcome of repeat gamma knife radiosurgery

Objective: To date, the efficacy and safety of repeat radiosurgery (RS) for trigeminal neuralgia (TN) is mainly based on short-term results. Methods: Between 1994 and 2006, 93 patients were treated radiosurgically for TN at the Department of Neurosurgery in Graz, Austria. Twenty two patients underwent repeat GKRS mean 18.8 months after the initial treatment. The mean dose for repeat treatment was 74.3 Gy. Pain outcome was rated using the Barrow Neurological Institute (BNI) Pain Intensity Scale and facial numbness according to the BNI Facial Numbness Scale. Results: Mean follow-up after repeat RS was 5.4 years. Pain relief was noted in 72.7% (16/22), 6 patients had a second pain recurrence after mean 9.3 months and underwent medical, alternative and/or further RS. One patient was lost to follow-up, BNI pain scale evaluation for 21 patients indicated improvement in 76.2% (16/21) without medication (BNI I and II). Facial numbness was recorded in 73.7% (14/19), in only one classified as bothersome. Conclusions: Long-term observation of repeat GKRS for TN showed in more than two third a good pain relief. Despite a high percentage of facial numbness, most likely attributable to the higher delivered dose, repeat RS can still regarded as safe. However, further studies are needed to determine an optimized treatment protocol.