Often, patients with trigeminal neuralgia first go to dentistry because of the presence of oral disorders at the same time, or even after the extraction of several teeth before they are diagnosed with trigeminal neuralgia and are then referred to neurosurgery. Trigeminal neuralgia surgery is more effective, but it may lead to adverse consequences if it is misdiagnosed as trigeminal neuralgia for other diseases. Trigeminal neuralgia is different from other intracranial diseases such as brain tumors, and the diagnosis is determined mainly by clinical symptoms. Trigeminal neuralgia is a transient, recurrent paroxysmal pain within the distribution of the facial trigeminal nerve, also known as a painful twitch. Trigeminal neuralgia can be divided into primary trigeminal neuralgia and secondary trigeminal neuralgia from the etiological point of view. Most of the trigeminal neuralgia that is commonly referred to by the public refers to primary trigeminal neuralgia. Primary trigeminal neuralgia mostly occurs in adults and the elderly, mostly unilateral, with pain starting from one maxillary or mandibular branch and gradually expanding to two or even all three branches. It has the following 4 characteristics: 1. episodic pain with painless intervals; 2. no clear positive neurological signs; 3. a trigger point; 4. pain strictly located in the trigeminal innervation area. So are all patients who meet the above symptoms primary trigeminal neuralgia? And what diseases should primary trigeminal neuralgia be differentiated from? First of all, primary trigeminal neuralgia should be distinguished from secondary trigeminal neuralgia: secondary trigeminal neuralgia is pain caused by other diseases involving the trigeminal nerve, mostly manifested as trigeminal nerve palsy and persistent headache, often combined with other cerebral nerve palsy, which can be caused by multiple sclerosis, neuritis and skull base tumor, and can be distinguished by cranial CT or MRI. 1.Tumor in pontocerebellar horn region: cholesteatoma, auditory neuroma, meningioma are common, which may only show trigeminal neuralgia in early stage, and other cranial nerve damage such as V, VII, VIII and IX may appear with the increase of tumor. 2.Arachnoiditis: Arachnoiditis at the base of skull may invade the trigeminal nerve and cause facial pain, mostly persistent dull pain, accompanied by sensory impairment at the painful area. 3, skull base malignant tumor: mostly oral cancer and nasopharyngeal cancer, accompanied by epistaxis and nasal congestion. Occasionally, metastatic carcinoma or sarcoma at the skull base is seen. The facial pain is widespread, often exceeding the trigeminal nerve distribution area, and the pain is persistent, and extensive cranial nerve damage is seen. 4.Tumor of trigeminal nerve hemianopia: it can be seen in ganglion cell tumor, chordoma and so on. Trigeminal nerve sensory and motor disorders are obvious, and imaging can show bone destruction at the skull base. 5.Multiple sclerosis: 1% of patients with multiple sclerosis can develop trigeminal neuralgia, and patients with bilateral trigeminal neuralgia should be alert to the possibility of multiple sclerosis. 6.Trigeminal neuralgia after herpes zoster: It mostly occurs in the area of the first branch of the trigeminal nerve and is a persistent burning pain. It can occur days, months, or even years after the herpes has subsided, and the painful area may have skin changes and sensory disturbances. In addition to secondary trigeminal neuralgia, primary trigeminal neuralgia should be differentiated from the following diseases: 1. oral and dental disorders, which need to be ruled out by stomatological consultation. 2. Glossopharyngeal neuralgia: the nature of pain is the same as trigeminal neuralgia, which is easily confused with the pain of the 3rd branch of the trigeminal nerve. The site of linguopharyngeal neuralgia is at the root of the tongue, soft palate, tonsils and pharynx, and a few of them show pain in the ear, but mostly located in the deep part of the ear and behind the ear. The diagnosis is confirmed by spraying cocaine on the pharynx and the pain disappears. However, sometimes glossopharyngeal neuralgia can be combined with trigeminal neuralgia, which needs to be judged correctly. 3. Intermediate neuralgia: It is manifested as burning pain in the external auditory canal and mastoid area on one side, and there is often localized herpes zoster, in addition to peripheral facial palsy and loss of taste and hearing. The pain is prolonged, and in severe cases, it radiates to the face, outer edge of the tongue, pharynx and neck. 4.Pterygopalatine neuralgia: the pain attacks with nasal mucosa congestion, obstruction and lacrimation, and the pain is limited to the lower part of the face and can radiate to the neck, shoulders and upper extremities, and the pain can disappear with the closure of the pterygopalatine ganglion. 5.Conglomerative pain: This disease also manifests as pain on one side of the face. It is mainly located in the eye and temporal region, and the attack time is long. It can be accompanied by facial flushing, conjunctival congestion, lacrimation, local sweating and slow pulse, and the superficial temporal artery pulsation is obvious. In summary, trigeminal neuralgia is mainly diagnosed by clinical symptoms and has similarities with many diseases, but its clinical manifestations have obvious characteristics, and an accurate diagnosis should be made at a professional hospital by asking medical history and combining with relevant auxiliary examinations. For patients who plan to have surgical treatment, they should be more cautious and should have a clear diagnosis and a trigeminal nerve thin layer scan (please refer to my article “The significance of preoperative magnetic resonance examination of trigeminal neuralgia”) to understand the responsible vascular situation before making a reasonable surgical plan in order to achieve excellent surgical results.