Trigeminal neuralgia may be caused by abnormality of the trigger zone

Trigeminal neuralgia is a painful unilateral neuralgia of the trigeminal nerve characterized by agonizing, paroxysmal, and lancinating facial pain with unidentified causes. Usually it is triggered by stimuli at specific area in head or neck which is called trigger zone clinically. The pathophysiology of trigeminal neuralgia is thought to be focal mechanical compression of the trigeminal nerve at a point close to the brain stem, but also not quite clear. Unclear causes lead to unidentified treatments. Most therapeutic methods are simply symptomatic treatment. Many medicine and treatment methods have been proved effective, such as carbamazepine, gabapetin, phenytoin, microvascular decompression, percutaneous techniques and radiosurgery methods, but their long term efficiency remains a matter of dispute. Therefore, novel etiological and therapeutic concepts are urgently needed. According to our clinical observation and some facts that do not favor the mechanical compression theory, such as epidemiological analysis, clinical manifestation and pathoanatomical characters of trigeminal neuralgia, we can conclude that not all trigeminal neuralgia is related to mechanical compression, some may be caused by abnormality of receptors or nerve endings in the trigger zone. Based on this hypothesis, we make the hypotheses that subcutaneous or submucous injection of carbamazepine at the position of trigger zone might be more effective than taking carbamazepine orally as we usually do. We also make further hypotheses that destruction of trigger zone such as by laser, freezing or surgery may be a novel and effective treatment methods for trigeminal neuralgia. (C) 2009 Elsevier Ltd. All rights reserved.