Electrical stimulation of the trigeminal tract in chronic, intractable facial neuralgia

In this paper the treatment of patients with chronic, intractable trigeminal neuralgia by invasive electrical stimulation of the Gasserion ganglion is reviewed. Two different surgical techniques are employed in this treatment. Most frequently, a method similar to the traditional technique for percutaneous glycerol and radiofrequency trigeminal rhizolysis is used: a small percutaneous stimulation electrode is advanced under fluoroscopic control through a thin needle via the foramen ovale to the Gasserian cistern. Some neurosurgeons use an open surgical technique by which the Gasserian ganglion is approached subtemporally and extradurally, and the bipolar pad electrode is sutured to the dura. When percutaneous test stimulation is successful (at least 50% pain relief) the electrode is internalized and connected to a subcutaneous pulse generator or RF-receiver. Data from 8 clinical studies, including 267 patients have been reviewed. Of all 233 patients with medication-resistant atypical trigeminal neuralgia 48% had at least 50% long term pain relief. The result of test stimulation is a good predictor of the long term effect, because 83% of all patients with successful test stimulation had at least 50% long term relief, and 70% had at least 75% long term relief. Patients generally preferred this invasive method over TENS. The success rate in patients with postherpetic trigeminal neuralgia was very low (less than 10%). It is suggested that the likelihood of pain relief by electrical stimulation is inversely related to the degree of sensory loss. It is concluded that invasive stimulation of the Gasserian ganglion is a promising treatment modality for patients with chronic, intractable, atypical trigeminal neuralgia.