The glossopharyngeal nerve is a mixed nerve. The special visceral efferent fibers, which innervate the stylopharyngeus muscle of the pharynx, originate in the nucleus ambiguus. The general visceral efferent fibers which supply the parasympathetic innervation to the parotid gland arise in the inferior salivatory nucleus and terminate in the otic ganglion. The general somatic afferent fibers supply the sensation to the back of the ear; their cell bodies are in the superior ganglion, and the central connections terminate in the spinal nucleus of the trigeminal nerve. The general visceral afferent fibers supply sensation to the carotid sinus, carotid body, eustachian tube, pharynx and tongue. The cell bodies are in the inferior (petrosal) ganglion and the central connections terminate in the tractus solitarius.

The special visceral afferent fibers from the taste receptors of the posterior one-third of the tongue in like manner have cell bodies in the inferior (petrosal) ganglion and terminate in the tractus solitarius. The glossopharyngeal nerve emerges from the medulla. dorsal to the inferior olivary nucleus and passes through the jugular foramen in its cephalic portion, being separated from the fibers of the tenth and eleventh cranial nerves by a distinct dural septum. The ganglia of the glossopharyngeal nerve lie within the jugular foramen.

Clinical Presentation and Diagnosis

Glossopharyngeal neuralgia was defined as a clinical entity by Harris in 1921. It is characterized by paroxysms of pain in the sensory distribution of the ninth cranial nerve. Except for the location of the pain and the sensory stimuli which induce it. the attacks are identical to those of trigeminal tic douloureux. The incidence of glossopharyngeal neuralgia is one-seventieth that of trigeminal neuralgia' The typical pain is a severe lancinating repetitive series of electric-like stabs in the region of the tonsil or posterior one-third of the tongue unilaterally. Bilateral glossopharyngeal neuralgia was never encountered in Dandy's series or in Mayo Clinic experience. The pain may either radiate to or originate in the ear.

The sensory stimulus which induces the pain is swallowing and during severe attacks the patient may sit motionless. head flexed forward,  allowing saliva to freely drool from the mouth. Although remissions may occur for months or years. spontaneous cure has never been reported. Associated with attacks of glosso­pharyngeal neuralgia have been cardiac arrest, syncope, and seizures. Cardiac arrest occurring during an attack of glossopharyngeal neuralgia has been attributed to hypersensitivity of the dorsal motor nucleus of the vagus caused by repetitive afferent impulses from the pharynx. tragus and ear. These impulses. occurring during an attack of neuralgia or secondary to surgical manipulation. may also be conveyed to the dorsal motor nucleus via collaterals from the nucleus solitarius of the ninth nerve causing asystole. Carotid sinus syncope and seizures occur by this latter mechanism. causing reduced cardiac output and cerebral hypoxia.

Almost all cases of glossopharyngeal neuralgia are idiopathic. although a certain number have been ascribed to entities such as ossification of the stylohyoid ligament nasopharyngeal and cerebellopontine angle tumors, an atheromatous vertebral artery causing compression of the ninth nerve, anomalous vascular lesions, tortuous vertebral and basilar arteries. and arterial loops. Historically. Weisenburg in 1910 first described glossopharyngeal neuralgia in a patient harboring an extra-axial posterior fossa tumor.

When ear pain is predominant. Svien et al. pointed out that five separate nerves must be considered: the tympanic branches of the glossopharyngeal. the auriculotemporal branch of the trigeminal. the nervus intermedius. the auricular branch of the vagus. and the upper fibers of the cervical nerves. Robson and Bonica emphasized the overlapping of sensory neuralgias and the rare diagnostic dilemmas posed by pain at junctional sites between the pharynx and ear. Cocainization of the pharynx alleviates the ninth nerve component of pain. and cocainization of the pyriform fossa relieves neuralgia of the superior laryngeal branch of the vagus. By blocking the foramen ovale with bupivacaine. it is possible to determine the component of pain due to the third division of the trigeminal nerve. Tetracaine block of the jugular foramen will block all afferent impulses via the ninth and tenth nerves and help to sort out the rare pain mediated only by the nervus intermedius component of the seventh cranial nerve.


Adson reported temporary relief in two patients in whom he sectioned the glossopharyngeal nerve extracranially but encountered great technical difficulty because of its close proximity to the vagus nerve and jugular bulb. He later performed cadaver dissections and described a suboccipital approach to intracranial ninth nerve sectioning, but in 1927 Dandy reported the first intracranial ninth nerve section for the relief of glossopharyngeal neuralgia. Dandy, Fay and others in earlier report, stressed the need for sectioning the upper one-sixth to one-eighth of the vagus rootlets to prevent recurrence of pain. It has later been reemphasized that the superior laryngeal branch of the vagus and the tympanic plexus component of the vagus may be not infrequent concomitant of glossopharyngeal neuralgia.

Since, section of the ninth cranial nerve and the upper rootlet of the tenth leaves the patient with no discernible sequelae, it would seem unwise to subject the patient needlessly to the possibility of recurrence by microvascular decompression of the ninth nerve alone.

The percutaneous radiofrequency lesions which have been suggested in the past seem fraught with an inordinate risk of injury to the tenth cranial nerve. Tew described percutaneous radiofrequency procedures carried out in nine patients with pharyngeal pain secondary to neoplasms of the head and neck and in two patients with idiopathic glossopharyngeal neuralgia. Excellent relief was obtained from the pain of malignant disease: however, vocal cord paralysis occurred after rhizotomy in both patients treated for idiopathic pain and aspiration pneumonia in one. When malignant disease has already altered the swallowing mechanism. radiofrequency lesions seem tenable: however, when tenth nerve preservation is mandatory, the procedure is undesirable.

Operative Approach

The patient is placed in the upright sitting position in the pinion headrest. with the head acutely flexed and rotated to the side of the glossopharyngeal neuralgia. A central right atrial catheter for monitoring and aspiration of possible air emboli is placed before the patient is placed in the sitting position. Either an S-shaped or a hockey stick-shaped incision is made over the ipsilateral occipital bone. The 4-cm craniectomy is done inferiorly to incorporate the portion of the occipital bone which lies directly adjacent to the foramen magnum and which is oriented in a tranverse plane directly above the lamina of the first cervical segment. The dura is opened in a cruciate fashion and tacked back over the edge of the craniectomy. The cerebellar hemisphere is elevated to expose the arachnoid of the cisterna magna. which is opened. allowing the egress of spinal fluid and relaxation of the cerebellum. By identifying the sigmoid sinus as it traverses the posterior fossa floor. the surgeon can achieve precise retractor position for identification of the jugular foramen. Once the self-retaining retractor has been fixed in position. illumination by the overhead surgical lights and operating loupes is usually sufficient. The operating microscope may enhance visualization at this point. The ninth cranial nerve in the jugular foramen is always separated by the dural septum from the tenth and eleventh cranial nerves and jugular vein.

The ninth nerve and upper one-sixth to one-eighth of the filaments of the tenth nerve are sectioned with the aid of a black spatula or blunt hook and bipolar coagulation. The dural opening may then be closed by any of various methods. either with or without the aid of a fascia lata or homologous dural graft.

Intra- and Postoperative Considerations

While sensation is diminished over the pharynx and the gag reflex is abolished on the side of the divided nerve and while discrete neurological testing reveals absence of taste over the ipsilateral posterior one-third of the tongue, it is seldom to note more than a transient disturbance in swallowing.

Intraoperative cardiovascular complications during suboccipital craniectomy for glossopharyngeal nerve section and decompression have been well documented. Jannetta described one case of microvascular decompression which was followed by a hypertensive crisis and a fatal intracerebellar hemorrhage. In another case he described significant hypertension lasting for 1 week postoperatively.

Nagashima et al. summarized the physiologic intraoperative changes in a case report. During an intracranial procedure for sectioning the ninth cranial nerve. they noted that an extrasystole occurred each time the vagus nerve was touched and that acute hypotension followed. which responded to atropine. During the hypotensive episodes there was electrocardiographic evidence of a right bundle branch block secondary to coronary artery insufficiency and myocardial ischemia with progressive ST segment depression.

With section of the ninth and upper rootlets of the tenth cranial nerves. auricular flutter. tachycardia. hypertension. ectopic ventricular contractions and cardiac arrhythmias have been noted. Medical therapy with phenytoin or carbamazepine is of considerable use in some patients to afford temporary and short-term pain relief. Although there are obvious operative risks. as previously mentioned. the operative results with sectioning of the ninth cranial nerve and a portion of the tenth cranial nerve are uniformly excellent for total pain relief from glossopharyngeal neuralgia. Unless there are unusual circumstances. this is not only the procedure of choice.



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