Micro-vascular decompression for primary Trigeminal Neuralgia (typical or atypical). Long-term effectiveness on pain; prospective study with survival analysis in a consecutive series of 362 patients.
BACKGROUND: Few publications on primary Trigeminal Neuralgia treated by Micro-Vascular Decompression (MVD) report large series, with long-term follow-up, using Kaplan-Meier (K-M) analysis. None was specifically directed to the comparative study of MVD effectiveness on Trigeminal Neuralgia with typical (i.e., with paroxysmal pain only) and atypical features (i.e., with association of a permanent background of pain). METHOD: The authors report a series of 362 patients having clearcut vascular compression and treated with pure MVD - i.e., without any additional cut or coagulation of the adjacent root fibers. Follow-up was 1 to 18 y (8 y on average, with a median of 7.2 y). Results were considered overall, then separately for patients with typical (237 (65.5%)) and atypical (125 (34.5%)) clinical presentation. FINDINGS: One year after operation, (294 (81.2%) of patients were totally-free - of paroxysmal pain, and also of permanent background pain - and not needing any medication) 13 (3.6%) still had a background of pain but without the need for medication which 55 patients (15.2%), treatment had failed. At latest review (8 y on average) the corresponding rates were 80, 4.9 and 15.1%, respectively. Kaplan-Meier analysis estimated the probability of total cure at 15 y to be 73.4%. There was no difference in the cure rate between patients with typical and atypical features at one year: 81 and 81.16%, respectively. The probability of cure at 15 y was identical for the two clinical presentations. CONCLUSIONS: Pure MVD offers patients affected by Trigeminal Neuralgia due to vascular compression a long-lasting cure in three-fourths of the cases. Both typical and atypical presentations respond well to MVD, view in contrast to the classical view that an atypical presentation has an adverse effect on outcome after surgery.