The aim of this study is to assess the feasibility of deep brain stimulation for refractory trigeminal neuralgia due to a pontine lesion, as is usually seen in the context of multiple sclerosis. These patients usually have severe intractable facial pain and current medical and surgical options generally fail to achieve long lasting pain relief. Hoping to improve pain control in this population, the investigators of this trial propose a novel technique consisting of implanting a deep brain stimulation lead within the pontine lesion to modulate the generation of pain signals.