Diagnostic significance of carbamazepine and trigger zones in trigeminal neuralgia

Objective. To investigate the relationship between the efficacy of carbamazepine (CBZ) and the presence of the trigger zone for diagnosis of trigeminal neuralgia (TN). Study design. CBZ was administered to 61 patients with suspected TN. All patients underwent intracranial examination by magnetic resonance imaging or computed tomography. The final diagnosis was established by oral and maxillofacial surgeon and neurosurgeon. Results. Of the 61 patients, 50 were finally diagnosed as having TN and 6 as having atypical facial pain. CBZ was effective for pain relief in 45 of the 50 TN patients (90%), and in 5 of the 11 patients (45%) with other diseases (P < .005). However, CBZ also relieved pain in some patients other than TN. Thirty of the 31 patients (97%) with a distinct trigger zone and 20 of the 30 (67%) without a trigger zone were diagnosed as having TN (P<0.005). Conclusion. The efficacy of CBZ is an auxiliary indicator of TN and the presence of a distinct trigger zone is a strong indicator of TN.