Primary treatment of trigeminal neuralgia (TN) with Gamma Knife Surgery (GKS) is well established.  However a significant number of patients experience recurrence over time.  Currently the efficacy, safety, and appropriate dose of repeat GKS for TN is poorly defined.  

     In this study the authors report the largest series of long- term outcomes after repeat GKS for TN using a uniform treatment protocol.

     Between 1995 and 2009, 377 patients were treated with GKS for TN by the Department of Neurosurgery at Methodist University Hospital, Memphis TN, USA.  54 patients underwent repeat GKS.  Mean follow up after repeat GKS was 4.5 years, ranging from 6 months to 10 years.  The mean patient age at retreatment was 78 years.  

     During the initial treatment a uniform 80 Gy maximal dose was prescribed using a single isocenter; the 4 mm collimator was used. The second treatment prescribed a uniform 70 Gy maximal dose to the same single 4 mm isocenter directed at the trigeminal root entry zone. Pain outcomes were retrospectively reviewed and rated using the Barrow Neurological Institute (BNI) Pain Intensity Scale.

     Mean follow up after repeat GKS was 4.5 years, ranging from 6 months to 10 years.  Mean age at repeat GKS was approximately 78 years.  BNI pain scale evaluation indicated improvement in the majority of patients.  Second recurrence tended to be less severe and delayed.  Facial numbness correlated with better pain relief.  Few complications from repeat GKS were noted using our treatment protocol.

     This is a retrospective study.

     Long term observation of repeat GKS for TN demonstrates good pain relief in the majority of patients.

     Facial numbness may be an acceptable risk correlated with pain relief and may be related to the higher delivered dose. Repeat GKS for TN using this treatment protocol is safe. Further studies are needed to further define re-treatment timing and dosing.