Glossopharyngeal neuralgia is a severe paroxysmal pain that occurs in the region of the glossopharyngeal nerve division. The nature of the pain is very similar to that of trigeminal neuralgia and is divided into two main categories: primary and secondary. The pain occurs at the base of the tongue, throat, tonsils, root of the ear and the back of the lower jaw, sometimes with the pain at the root of the ear as the main manifestation.
The etiology and pathogenesis of the pain are not fully understood, but it may be the result of a “short circuit” between the afferent impulses of the linguopharyngeal nerve and the vagus nerve caused by demyelination of the nerve. It can also be caused by tumors in the jugular foramen, skull base, nasopharynx, tonsils, etc., local arachnoiditis or aneurysm, which are called secondary linguopharyngeal neuralgia. In recent years, the development of microvascular surgery has revealed that some patients have compression of the linguopharyngeal nerve by the vertebral artery or the posterior inferior cerebellar artery.
I. Clinical manifestations
It often starts after 35 years of age, and is more common in men than women. The sudden onset of pain, similar in nature to trigeminal neuralgia, is located in the tonsils, root of the tongue, pharynx, and deep part of the ear canal, etc. It is intermittent and lasts for a few seconds to 1 – 2 minutes each time. In some cases, it may be accompanied by pharyngeal spasm, cardiac rhythm disturbance, and hypotensive syncope.
Clinically, the symptoms exhibited by glossopharyngeal neuralgia can be basically divided into the following points.
1.Preferred age: 35 – 50 years old.
2. Site of onset: tonsillar region, pharynx, tongue root, neck, deep ear canal, and posterior mandibular region.
3.Pain nature: paroxysmal severe pain, such as knife-like, stabbing-like, painful convulsions.
4.Time of pain: frequent in the morning and morning, and there may be episodes during sleep, this point can be distinguished from trigeminal neuralgia.
5.Sense of foreign body and obstruction: there is a sense of foreign body and obstruction in the pharynx and larynx at the onset, and it leads to frequent coughing.
6. Pain-triggering factor: Palpation can cause pain, also called “trigger point”. It is commonly found in the tonsil area, external auditory canal and tongue root. Pain can be triggered whenever swallowing, chewing, yawning or coughing.
7. There are intermittent periods.
8. The patient has dehydration and wasting. It is caused by the fear of pain and less food intake.
9.Severe cases may have arrhythmia, cardiac arrest, fainting, convulsions, seizures, laryngeal spasms, and excessive secretion of parotid glands.
Second, the etiology of the disease
The etiology is unknown, and no pathological changes are found (except for rare cases with pontocerebellar horn tumors or neck tumors). Male cases are more frequent than female cases and usually develop after the age of 40. Similar to trigeminal neuralgia, intermittent episodes of brief, severe, unbearable pain occur, which can be spontaneous or triggered by certain movements (e.g., chewing, swallowing, speaking, or sneezing). The pain lasts from a few seconds to several minutes and usually begins in the tonsillar region or at the base of the tongue and may radiate to the ipsilateral ear. The pain is strictly unilateral. In 1 – 2 % of cases, hyperactivity of the vagus nerve can cause sinus arrest with syncope, and there can be a long interval between attacks and episodes.
Depending on the cause of the attack, glossopharyngeal neuralgia can also be divided into primary and secondary glossopharyngeal neuralgia.
1.Primary glossopharyngeal neuralgia
The etiology of primary glossopharyngeal neuralgia is still unclear, but it may be due to nerve desheathing. The age of onset is mostly above 40 years old, and there are more males than females.
The clinical manifestations are as follows
(1) Clinical manifestations and pain sites: Unlike primary trigeminal neuralgia, the pain occurs at the root of the tongue, pharynx, tonsils, root of the ear and the back of the lower jaw on one side, and sometimes the pain at the root of the ear is the main manifestation.
(2) Seizures and nature of pain: Same as trigeminal neuralgia, the pain usually comes on suddenly and stops suddenly, and the duration of each seizure is a few seconds or tens of seconds, usually not more than two minutes. It can also be severe pain like cutting, stabbing, tearing, burning and electric shock.
(3) Triggering factors: Pain is often triggered when swallowing, talking, coughing or yawning.
(4) Plate machine point: often have plate machine point, the part for more in the posterior pharyngeal wall, tonsils, tongue root, etc., a few can be in the external ear canal.
(5) Other symptoms: swallowing action often induces painful episodes, and although there is no abnormality between episodes, patients are afraid to eat for fear of inducing pain. Patients often have symptoms such as wasting, dehydration, laryngeal spasm feeling, cardiac arrhythmia and hypotensive fainting.
(6) Neurological examination: normal.
Most of the clinically common lingual-pharyngeal neuralgia belongs to primary lingual-pharyngeal neuralgia, and the temporary pain relief is not effective.
2.Secondary linguopharyngeal neuralgia
Some tumors of the cerebellopontine angle, spider retinitis, vascular diseases, nasopharyngeal tumors or hypertelorism can provoke the linguopharyngeal nerve and cause pain in the region of the linguopharyngeal nerve division, which is called secondary linguopharyngeal neuralgia. The clinical manifestations are.
(1) Pain in the region of the linguopharyngeal nerve division. The pain attack lasts for a long time or is persistent, the triggering factor and the point of the board machine are not obvious, and it is heavy at night. Symptoms of damage to the linguopharyngeal neuralgia. Paralysis of the jaw arch, hyperalgesia or loss of sensation in the soft palate and pharynx, impairment of taste and general sensation in the posterior third of the tongue, weakening or loss of the pharyngeal reflex, and abnormal secretion function of the parotid gland.
(2) Adjacent cerebral neuralgia. Jugular foramen syndrome and Horner’s symptom may appear; cerebellar pontine syndrome may also appear.
(3) If caused by nasopharyngeal carcinoma, a mass may be found in the nasopharynx and the lymph nodes in the neck may be enlarged.
Secondary lingual-pharyngeal neuralgia is mostly caused by intracranial tumors and foreign bodies, and is treated clinically by craniotomy.
Diagnostic examination
1.Inquire about the location and nature of the pain in the medical history, whether there is any relationship with diet, and whether the pain radiates to the ear.
2. Ask the patient to eat and observe the pain induced. Whether the trigger point is at the tonsillar trap, apply cocaine solution to the affected pharynx to understand whether the pain is relieved.
3.The nasopharynx and posterior group of cerebral nervous system should be examined for any positive signs.
4. Differential diagnosis should be differentiated from trigeminal neuralgia and cerebellopontocerebellar horn tumor.
Diagnosis of disease
1. Medical history and symptoms
It is common in middle-aged males. It is often triggered by swallowing, talking or coughing, and the episodes of severe pain in the tonsils, pharynx or deep part of the ear canal last for a few seconds each time, and some patients may have symptoms such as bradycardia, syncope and convulsion during the attack.
2. Physical examination findings
Except for the painful attacks, the neurological examination mostly has no abnormal findings. There may be trigger points at the root of the tongue and tonsillar fossa.
3.Differentiation
It is often distinguished from pain caused by trigeminal neuralgia, nasopharyngeal tumor invading the pharynx and skull base structures.
V. Treatment plan
1. Drug treatment
(1) Phenytoin sodium 0.1g, 3/d, orally.
(2) Vitamin B1, B12: etc.
(3) Carbamazepine 0.2g, 3/d, orally.
Drug treatment can often achieve relatively satisfactory clinical efficacy in the early stage of the disease, but as the pain increases, the drug often gradually loses its effect after several months or years.
2.Nerve block
The method is percutaneous perforation of the jugular vein hole radiofrequency treatment, applicable to.
(1) Those who are ineffective in drug treatment or cannot tolerate the adverse effects of drugs.
(2) those who are elderly or in poor general condition and cannot tolerate microvascular decompression surgery.
(3) cases with combined multiple sclerosis.
The main problems of this treatment method are the high recurrence rate of pain (23%-54%) and the difficulty of swallowing, choking and hoarseness caused by nerve damage.
3.Microvascular decompression surgery
Microvascular decompression surgery is the safest and most effective surgical treatment method, and its cure rate can reach 99%.
Surgical treatment is applicable to.
(1) Those who fail in drug or percutaneous puncture treatment.
(2) Patients in good general condition, without serious organic lesions, who can tolerate surgery.
(3) Those who exclude lesions such as multiple sclerosis or pontocerebellar horn tumors. Most patients’ pain disappears after surgery, and 99% of patients can be cured.
Microvascular decompression was first proposed by Prof. Jannatta in 1967, and later Haines et al. conducted a more in-depth anatomical study of the relationship between the linguopharyngeal nerve and microvessels and found that 92.5% of cases with compression of the linguopharyngeal nerve root by tiny vessels in the pontocerebellum showed symptoms of linguopharyngeal neuralgia. The blood vessels that compress the nerve and produce pain are called “responsible vessels”, and the common responsible vessels are.
(1) Superior cerebellar artery (55%), which can form a vascular loop extending caudally, is in contact with the entry of the linguopharyngeal nerve into the brainstem and mainly compresses the superior or superior medial aspect of the nerve root.
(2) The anterior inferior cerebellar artery (30%), which generally compresses the linguopharyngeal nerve from below, may also form a pinch compression on the linguopharyngeal nerve together with the superior cerebellar artery.
The basilar artery, with age and hemodynamic effects, may bend to both sides and compress the linguopharyngeal nerve root, generally to the side of the thinner vertebral artery.
④Other rare responsible vessels include posterior inferior cerebellar artery, variant vessels, transverse cerebral bridge vein, lateral veins and basilar plexus. The responsible vessel can be one or multiple, and can be either an artery or a vein.
Microvascular decompression is performed with the patient in a supine lateral head position with the healthy side on top and the upper body elevated about 20°. A transverse or longitudinal incision of about 4 cm is made behind the ear, and a posterior sigmoid sinus approach is used with a bony window of about 1.5 cm × 1.5 cm, and a “⊥” shaped incision is made to release some of the cerebrospinal fluid to allow the cerebellum to sink and then enter the pontocerebellar cerebellar horn. The surgery was performed endoscopically. The arachnoid membrane of the pontine pool was cut and the cerebral nerves VII, VIII, IX and X were explored. The arachnoid membrane around the linguopharyngeal nerve and vagus nerve roots were fully released, the responsible vessels of the linguopharyngeal nerve and vagus nerve roots were explored, the linguopharyngeal nerve was cut from the pontocerebral entry root area to the jugular foramen, the vagus nerve and the responsible vessels were freed, and decompression was performed. An appropriate amount of warm saline is instilled to replenish the cerebrospinal fluid, and the dura mater and all layers of the scalp are sutured to complete the procedure.
Microvascular decompression is the only treatment that targets the etiology of glossopharyngeal neuralgia and preserves the anatomical integrity of the glossopharyngeal nerve, so that normal neurological function of the glossopharyngeal nerve can be preserved. In some patients, it can also eliminate the hypertensive state caused by vascular compression of the brainstem and achieve a radical cure for hypertension. Because microvascular decompression has the advantages of obvious pain relief, non-destructive, few side injuries, and very low recurrence rate, it is currently the safest and most effective method internationally recognized for the treatment of glossopharyngeal neuralgia.
At present, microvascular decompression is the most popular and widely used method for the treatment of glossopharyngeal neuralgia by most experts and scholars at home and abroad, because it is the only method to treat glossopharyngeal neuralgia by targeting the “cause”. Compared with other treatments, the biggest advantage of microvascular decompression is that it can preserve the patient’s normal sensation and change the numbness and discomfort in the innervated area of the linguopharyngeal nerve after the previous treatment, which improves the quality of life of patients and makes them willing to accept the treatment.