[Neurosurgical therapy of facial neuralgias]

Neuralgias of the face, especially trigeminal neuralgia and glossopharyngeal neuralgia are indications for surgical interventions after failed medical therapy. In contrast to other forms of headache or atypical facial pain, where surgical measures are considered to be contraindicated, percutaneous procedures or microvascular decompression are able to produce immediate and longstanding pain relief. Careful preoperative evaluation is essential to confirm the clinical diagnosis and to rule out other causes as multiple sclerosis or tumors afflicting the cranial nerves. The following study will summarize the common surgical techniques and their role considering a mechanism-based therapy as well as document long-term results of these measures.

Between 1977 and 1997 316 thermo-controlled radiofrequency trigeminal rhizotomies (TK) and 379 microvascular decompressions (MVD) were performed in our hospital to treat trigeminal neuralgia; additional 6 MVDs for glossopharyngeal neuralgia and one MVD of the intermediate facial nerve were carried out. Questionnaires were sent out to all patients still living in 1981, 1982, 1992 and 1998. For all other patients, interviews with relatives or the general practitioners were conducted. A retrospective analysis of postoperative pain relief was performed using Kaplan-Meier curves at the latest follow-up. Additionally 80 patients underwent careful quantitative sensory testing with Von-Frey-hairs.

225 patients who underwent microvascular decompression and 206 with radiofrequency trigeminal rhizotomies were further analyzed. There was a 50% risk for pain recurrence two years after radiofrequency rhizotomy. On the other hand 64% of patients who underwent microvascular decompression remained painfree 20 years postoperatively. Patients with microvascular decompression without sensory deficit were painfree significantly longer than patients with postoperative hypesthesia.

Etiology and pathogenesis of facial neuralgias are far from understood despite several hypotheses. Based on current models there is no explanation for the immediate pain relief especially after microvascular decompression. Some authors even discuss surgical trauma as the only cause for postoperative pain relief.