Trigeminal neuralgia is the most common clinical neurological disorder, often characterized by recurrent paroxysmal “electric shock-like”, “knife-like”, “tear-like” severe pain in the distribution area of the trigeminal nerve on one side of the face. The main manifestation of trigeminal neuralgia is pain. According to domestic and international statistics, the incidence rate of trigeminal neuralgia is 52.2 per 100,000, and it is common among middle-aged and elderly women, with the incidence rate of women significantly higher than that of men, and the incidence rate generally increases with age. So how is trigeminal neuralgia caused? In clinical practice, patients often ask, “Why do I get trigeminal neuralgia? In terms of the etiology of trigeminal neuralgia, in the past hundred years, scholars at home and abroad have conducted a lot of animal experiments and clinical epidemiological research, but so far there is no consensus. At present, only a few hypotheses can be put forward: First, the central etiology of trigeminal neuralgia, the central part of the trigeminal nervous system of the brain nucleus accumbens, the thalamus and the brain dysfunction and organic lesions, will lead to trigeminal neuralgia. It has been found that herpes and herpes simplex virus infection can invade into the skull along any pathway of the trigeminal nervous system (mainly through the olfactory nerve and trigeminal nerve) and lurk in the trigeminal ganglion and the spinal ganglion, which can cause trigeminal neuralgia episodes when invading the cerebral cortex that innervates the trigeminal nerve. Second, the theory of compression 1, vascular compression theory vascular mechanical compression of the trigeminal nerve, the brain bridge anterior ventral lateral is the trigeminal nerve sensory root into the area, where the sensory root around the common compression of the main blood vessels are: superior cerebellar artery, cerebellar anterior inferior cerebellar artery, cerebellar posterior inferior cerebellar artery, vertebral artery, rock vein, and so on. The compressed vessels can be a single artery, multiple arteries, multiple arteries combined with a single vein, multiple veins combined with multiple arteries, and so on. It is an important cause of pain and the most common cause of trigeminal neuralgia, so the surgical method of vascular decompression is often used to treat the disease. 2.Bone compression theory This kind of compression can be divided into two categories: congenital and acquired. The main cause of compression is due to the elevation of the bony angle, the narrowing of the foramen ovale and the variation of the suprachiasmatic sinus to trigeminal neuralgia. Elevation of the petrous humeri is mostly congenital, generally more on the right side than on the left. Bone foraminal stenosis is also mostly congenital, while acquired causes of bone foraminal stenosis are mostly due to skull base fractures from craniocerebral injuries. The extent of their trigeminal nerve pain is consistent with the narrowed bony foramen, as in the case of stenosis of the foramen ovale, where the pain occurs within the mandibular distribution area. Bone hyperplasia and hyperplasia caused by inflammation of the periosteum can narrow the foramen ovale. This condition is mostly acquired, and mostly for elderly patients. Third, the theory of allergic reaction, some people believe that the cause of primary trigeminal neuralgia is due to neurophysiological and chemical dysfunction. The principle of this allergic reaction is still unclear, may be because of allergic patients, due to the lack of gastric acid and lead to abnormal protein digestion, histamine-like substances are absorbed into the bloodstream, with the blood circulation to the root of the trigeminal nerve and the semilunar ganglion, resulting in edema of the tissues of the Department, compression and stimulation of the trigeminal nerve and cause pain attacks. Fourth, the theory of local stimulation Inflammatory foci occur in the tissues and organs innervated by the trigeminal nerve, such as paranasal sinusitis, odontogenic inflammation, etc., or traumatic foci, the formation of long-term chronic stimulation, which can make the nerve inflammation, fibrosis, semilunar ganglion toxicity, and further distribution of trophoblastic blood vessels in trigeminal nerve roots, dysfunction, spasm, and finally secondary ischemia, leading to sensory root demyelination lesions, which causes Trigeminal neuralgia. Fifth, the theory of dental factors dental factors are also considered to be the possible causes of trigeminal neuralgia. In clinical practice, dentists often find that trigeminal neuralgia occurs mostly in the maxillary and mandibular branches, and such patients are often accompanied by malocclusion, such as early contact, severe locking, deep overdenture, most of the posterior teeth missing as well as low vertical distance due to excessive abrasion of the occlusal surfaces, and poor restorations (long fixed bridges across the region). All of these problems with the occlusal relationship of the teeth can cause muscle spasm and muscle dysfunction around the joints. This condition creates a small amount of abnormal impulses and constantly transmits them to the center, making the center lose its dynamic balance and dysfunction occurs. Sixth, dystrophy theory in the study of scholars have used vasodilator drugs to treat trigeminal neuralgia patients, and achieved some efficacy. After the expansion of blood vessels, trigeminal nerve root ischemia can be partially lifted, terminating the onset of pain. In recent years, there are also studies that ischemia can not be alone as a cause of disease, but can be used as a cofactor. Ischemia of the trigeminal nervous system, so that the system of local malnutrition, thereby reducing the nerve vitality and local resistance; and then under the action of other factors, trigeminal nerve pain can occur. Trigeminal neuralgia also has many triggers, such as fatigue, too little sleep, nervousness, emotional instability, cold environment, as well as certain foods and drugs induced. Examples include cheese containing aminopyralid, meats and cured products containing nitrites, and food additives containing monosodium glutamate. In addition, certain medications can trigger trigeminal neuralgia, such as long-term oral contraceptives and vasodilators.