Studies on the operative outcomes and mechanisms of microvascular decompression in treating typical and atypical trigeminal neuralgia.

OBJECTIVE: To evaluate the operative outcomes and mechanisms of microvascular decompression in treating typical and atypical trigeminal neuralgia. METHODS: A group of 45 patients with typical trigeminal neuralgia and 17 patients with atypical trigeminal neuralgia treated by micro-vascular decompression from 2000 to 2002 were reviewed, including their clinical presentations, operative findings, and outcomes. RESULTS: Of 45 patients with typical trigeminal neuralgia, the mean duration was 3.1 years, and the mean age of pain onset was 60.3 years. Single trigeminal division was involved in 20 patients (44.4%), and 2 or 3 divisions were involved in the other 25 patients (55.6%). During the operation, artery compression was found in 39 patients (86.7%), and the combined artery and venous compression was found in 6 patients (13.3%). Postoperatively, complete pain relief was achieved in 44 patients (97.8%), and significant pain relief was achieved in 1 patient (2.2%). As for 17 patients with atypical trigeminal neuralgia, the mean duration and the mean age of pain onset was 8.7 years and 55.5 years, respectively. Two or 3 trigeminal divisions were involved in all of these patients. During operation, artery compression occurred in 10 patients (58.8%), and the combined artery and venous compression was found in 7 patients (41.2%). Postoperatively, complete pain relief was achieved in 5 patients (29.4%), and partial pain relief was achieved in 10 patients (58.8%), and 2 patients showed no response to microvascular decompression. CONCLUSIONS: The operative outcome of microvascular decompression in patients with typical trigeminal neuralgia was better than that of patients with atypical trigeminal neuralgia, which perhaps related to short duration, late onset of pain, limited distribution, artery compression, and complete operative decompression.

Trigeminal neuralgia: what are the important factors for good operative outcomes with microvascular decompression.

BACKGROUND: Microvascular decompression has been widely used as the first choice in treating trigeminal neuralgia, but in a few patients, facial pain cannot be effectively controlled by microvascular decompression. We sought to clarify the important factors for good operative outcomes. METHODS: We reviewed 62 patients with trigeminal neuralgia treated by microvascular decompression during the period 2000 through 2002, including clinical presentation, operative findings, techniques, and outcomes. Neurovascular conflicts were divided into single contact, contact and indentation, single adhesion, adhesion and indentation, and trigeminal nerve atrophy. Operative outcomes were graded into immediate postoperative complete pain relief (excellent), delayed postoperative complete pain relief (better), significant pain relief (good), and no response to microvascular decompression (poor). RESULTS: All patients' presentations were typical at the time of pain onset, but the symptom in 17 patients changed to atypical before surgery. During operation, single contact and single adhesion was found in 14 patients and 15 patients, respectively; contact or adhesion in combination with indentation was found in 7 patients and 18 patients, respectively; atrophy occurred in 8 patients. Postoperatively, immediate and delayed complete pain relief was achieved in 32 (51.6%) patients and 17 (27.4%) patients, respectively; 11(17.7%) patients got significant pain relief; and 2 patients showed no response. The overall rate of complete pain relief in patients with shorter duration, typical presentation, artery compression and complete decompression was higher than that in patients with longer duration, atypical presentation, venous compression, and incomplete decompression. CONCLUSIONS: Shorter duration, typical presentation, single artery compression, and complete decompression are the positive factors for better operative outcomes with microvascular decompression. Worse outcomes are usually related to venous compression, longer duration, and atypical presentation.