Do you modify your target volume for treatment of trigeminal neuralgia confined to a single branch of CN V?

Short answer: NO.

Target is preferable to the cisternal segment and we have always cusped into the DREZ on the first treatment. Distal treatment nearer the Meckel's Cave and even beyond becomes more akin to a Rhizotomy and will have more likelihood of sensory loss and ultimately deafferentation pain or atypical face pain - 'anesthesia dolorosa' - which is a nightmare to manage - patients can be suicidal.

We target the Cisternal portion of the nerve with the Gamma Knife as follows:

1. Enclose the nerve in the 80% IDL of a single 4 mm collimator (Yale experience with two shots resulted in more numbness - de Lotbiniere et al., PMID 10853104) on the coronal plane.

2. Change gamma angle to align the 35% IDL to the long axis of the CN V in the sag...