J Neurosurg (Suppl 2) 121:222–225, 2014

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GlossopharynGeal neuralgia is a disorder of crani-al nerve IX, characterized by severe, paroxysmal episodes of pain localized to the posterior tongue,

tonsil, throat, or external ear canal. The pain is similar to that experienced by patients with trigeminal neuralgia and can be triggered by eating, swallowing, and speaking.7,18 The pain can also be associated with hemodynamic insta-bility and syncopal episodes;2 it represents 0.2%–1.3% of facial pain syndromes.1 The overall incidence of glosso-pharyngeal neuralgia is estimated to be between 0.2 and 0.7 cases per 100,000 person-years, much lower than the incidence of trigeminal neuralgia, which is 28.9 cases per 100,000 person-years.9 Glossopharyngeal neuralgia oc-curs more commonly on the patient’s left side (left/right

ratio 3:2), and involvement is bilateral (usually sequen-tially and not simultaneously) for 2% of patients.15

Surgery is reserved for patients whose pain continues despite medical treatment or who experience significant side effects. Rhizotomy of the glossopharyngeal nerve and upper roots of the vagus nerve4 or microvascular de-compression3 is associated with high rates of pain relief (80%–90%),5,11,15 but persistent lower cranial nerve dam-age has been reported for 8%–19% of patients.11,14,23

On the basis of results obtained using by using Gam-ma Knife surgery (GKS) to treat trigeminal neuralgia,6,13,17 we have used GKS to treat glossopharyngeal neuralgia in a series of patients since 2007. Our study objective was to demonstrate the usefulness of this procedure for treating glossopharyngeal neuralgia, including for patients who had previously undergone surgery. We also describe a simple way to treat this condition.

Glossopharyngeal neuralgia and radiosurgery

Clinical articleRobeRto MaRtínez-ÁlvaRez, M.D., Ph.D., nuRia MaRtínez-MoReno, M.D., Ph.D., M. elena KusaK, M.D., anD GeRMÁn Rey-PoRtolés, M.sc., Ph.D.Department of Functional Neurosurgery and Gamma Knife Radiosurgery, Ruber International Hospital, Madrid, Spain

Object. Glossopharyngeal neuralgia is difficult to treat. On the basis of results obtained by using Gamma Knife surgery (GKS) to treat trigeminal neuralgia, the authors have used GKS to treat glossopharyngeal neuralgia in a series of patients since 2007. Their objectives with this study were to demonstrate the usefulness and safety of GKS for treating glossopharyngeal neuralgia and to describe a simple treatment method.

Methods. From 2007 through 2013, the authors treated glossopharyngeal neuralgia in 5 patients (4 women and 1 man), who ranged in age from 36 to 74 years. One patient had previously undergone treatment for trigeminal neu-ralgia at the Ruber International Hospital, Department of Functional Neurosurgery and Gamma Knife Radiosurgery. For all patients, before GKS, medical management did not control the pain. Three patients had previously undergone surgery (2 microvascular decompression and 1 rhizotomy) without improvement. For the GKS procedure, the nerve was localized by MRI and CT under stereotactic conditions and the target was located at the level of the glossopha-ryngeal meatus of the jugular foramen. For 1 patient, a maximum dose of 80 Gy was administrated with a 4-mm collimator, and for the others, the maximum dose was 90 Gy. The nerves located near the glossopharyngeal nerve received between 63 and 10 Gy, and the brainstem received less than 10 Gy. The mean follow-up time was 43 months (range 14–83 months).

Results. All patients improved within 3–6 months after undergoing GKS. All 5 are without pain; 3 patients take no medication, but the other 2 patients continue to take medication. No neurological deficits after GKS were observed.

Conclusions. GKS is useful and safe for treating glossopharyngeal neuralgia, even for patients who have previ-ously undergone surgery. GKS should be considered as the initial therapy for glossopharyngeal neuralgia.(http://thejns.org/doi/abs/10.3171/2014.8.GKS141273)

Key WoRDs      •      glossopharyngeal neuralgia      •      Gamma Knife surgery      •      pain      •      stereotactic radiosurgery

Abbreviation used in this paper: GKS = Gamma Knife surgery.

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MethodsFrom 2007 through 2013, we treated glossopharyn-

geal neuralgia in 5 patients (4 women and 1 man) with respective ages of 37, 56, 62, 66, and 73 years. One pa-tient had previously received treatment in our unit (De-partment of Functional Neurosurgery and Gamma Knife Radiosurgery) for trigeminal neuralgia (Table 1). For all patients, medical management did not control the pain. Three patients had previously undergone surgery (2 mi-crovascular decompression and 1 lower cranial nerve rhi-zotomy) without improvement; after these surgeries, 2 pa-tients experienced partial lower cranial nerve neuropathy without sensory deficit.

For all patients, we performed 3D 1-mm thickness T2-weighted series MRI (FIESTA series, General Elec-tric) without the frame; 1-mm thickness 3D T1-weight-ed series MRI, including contrast-enhanced series; and 0.6-mm thickness CT scanning under stereotactic con-ditions. The FIESTA images were coregistered with the stereotactic pictures by using Leksell GammaPlan soft-ware (Elekta AB). As indicated by other studies,8,10,12,24 we chose the distal part of the glossopharyngeal nerve at the level of the glossopharyngeal meatus of the jugular foramen (Fig. 1) as a radiosurgical target because that is a good place for visualizing the nerve and because we wanted to lower the radiation dose to the brainstem and the rest of the lower cranial nerves.8,16 The first patient received a maximum dose of 80 Gy administered with a 4-mm collimator, and the other 4 patients received a maximum dose of 90 Gy. The nerves located at the vicin-ity of the glossopharyngeal nerve received 10–63 Gy, and the brainstem received less than 10 Gy.

Clinical progression after GKS was assessed every 6 months by interview and by neurological examination conducted by neurologists who were not directly involved in the care of these patients. Outcomes were expressed in terms of persistence or increasing pain, pain improve-ment, and no pain with or without medication; pain was documented on the visual analog scale (score range 0–100). A complete response (no pain) was scored as 0. The patient’s neurological status before GKS was used for the baseline data, and subsequent findings were de-scribed in terms of change from this baseline (improved, unchanged, or worse). Neurological status of asympto-matic patients without posterior deficits was considered unchanged.

Beginning 12 months after GKS and every year there-

after, follow-up MR images, including contrast-enhanced series, were acquired to evaluate changes in the anatomical structures treated. Images were assessed by a neuroradi-ologist not directly involved in the care of the patient.

ResultsThe median follow-up time after GKS was 43 months

(range 14–83 months). After surgery (microvascular de-compression or lower cranial nerve rhizotomy), 2 patients experienced partial lower cranial nerve neuropathy that did not affect the sensitive part of the glossopharyngeal nerve. Beginning 2–10 months after GKS, all patients showed improvement. Three patients are currently with-out pain and have not taken medication for 12 months (2 patients) and 18 months (1 patient). The other 2 patients, the first and last patients to undergo treatment, have been

TABLE 1: Clinical data for patients and outcomes at last follow-up visit*

Case No.

Patient Age (yrs), Sex Dose (Gy) Previous Surgery Outcome

Pain Control Duration (mos)

Follow-Up (mos)

1 56, F 80 none pain free, w/ medication 10 832 73, F 90 (+TN) rhizot pain free, w/o medication 2 713 62, F 90 MVD pain free, w/o medication 6 314 66, M 90 none pain free, w/o medication 10 195 37, F 90 MVD pain free, w/ medication 4 14

* Target for all patients was the glossopharyngeal meatus. MVD = microvascular decompression; rhizot = rhizotomy; +TN = prior trigeminal neuralgia.

Fig. 1. Fused 3D T2-weighted 1-mm thickness (FIESTA) and con-trast-enhanced 3D T1-weighted (fast spoiled gradient echo [FSPGR]) images showing the 63-Gy and 10-Gy isodose lines (circles) on the glossopharyngeal meatus of the jugular foramen. The maximum dose is 90 Gy.

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224 J Neurosurg / Volume 121 / December 2014

followed up for 83 and 14 months, respectively, and do not have pain but continue to take medication (Table 1).The neurological status of patients did not change after GKS, and follow-up imaging revealed no changes after GKS.

DiscussionRhizotomy of the vagus and glossopharyngeal nerves

for glossopharyngeal neuralgia is associated with adverse effects such as hoarseness and dysphagia; the rate of per-manent neurological deficits after this procedure has been reported to be 17.8%.19 For patients who undergo rhizoto-my, the mean possibility of remaining pain free is 87.3%, and pain recurs for 8.2%.4,19 For patients who undergo microvascular decompression (a nondestructive surgical technique used to treat glossopharyngeal neuralgia), the mean possibility of complete pain relief is 84.7% and of pain recurrence is 7%; permanent complications of lower cranial nerves occur in an average of 5.5% of patients af-ter microvascular decompression.3,5,11,14,20

The efficacy of GKS for trigeminal neuralgia report-ed in the literature seems to be similar to that for mi-crovascular decompression, and GKS is most commonly indicated for treatment of trigeminal neuralgia.6,13,17,18 To the best of our knowledge, we report the first patient to undergo GKS for trigeminal neuralgia with good results, followed by GKS for glossopharyngeal neuralgia also with good results. This finding suggests that the patho-physiology of typical trigeminal and glossopharyngeal neuralgia is similar and that therefore that the response of both entities to GKS will be comparable.

Because the glossopharyngeal nerve is smaller than the trigeminal nerve, it is more difficult to localize. When planning treatment for glossopharyngeal neuralgia, to avoid artifacts we obtain a FIESTA series of images with-out the frame, and later we coregister the images with the 3D T1-weighted series of images and CT scans obtained under stereotactic conditions in such a way as to render it possible to recognize the glossopharyngeal nerve at the level of the glossopharyngeal meatus of the jugular fora-men (Fig. 1). The rest of the lower cranial nerves converge in the anterior part of the jugular foramen, and we have not observed adverse effects after irradiation of the glos-

sopharyngeal nerve, consistent with previously reported findings.8,10,12,21,22,24,25

Our results are consistent with those observed in pre-viously reported series (Table 2), in that 87% of patients treated with radiosurgery for glossopharyngeal neuralgia exhibit significant and sustained improvement.10 For most reported cases, a maximum dose of 80 Gy was effec-tive.8,10,12,22,24 For 4 patients in the series reported here, we increased the maximum dose to 90 Gy with good results and no side effects.

In our unit, 3 of 5 patients who underwent GKS for glossopharyngeal neuralgia had previously undergone surgery. We confirm the finding previously described in a case report21 that GKS is feasible for treating glosso-pharyngeal neuralgia after surgery, either microvascular decompression or rhizotomy.

Many neurologists still consider GKS as a secondary treatment for glossopharyngeal neuralgia. We report that GKS is effective and safe for this indication and should be considered as initial therapy for many of these infre-quent cases.

ConclusionsOur experience confirms that treating glossopharyn-

geal neuralgia with GKS, either as initial treatment or after surgery, is an effective and safe therapeutic option.

Disclosure

Dr. Martínez-Álvarez is a consultant with Elekta AB.Author contributions to the study and manuscript preparation

include the following. Conception and design: Martínez-Álvarez. Acquisition of data: Martínez-Moreno. Analysis and interpreta-tion of data: Martínez-Álvarez, Rey-Portolés. Drafting the article: Martínez-Álvarez. Critically revising the article: Kusak. Reviewed submitted version of manuscript: Martínez-Álvarez, Kusak, Rey-Portolés. Approved the final version of the manuscript on behalf of all authors: Martínez-Álvarez. Study supervision: Martínez-Moreno.

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TABLE 2: Reported cases and outcome of patients with glossopharyngeal neuralgia treated with stereotactic radiosurgery*

Authors & YearNo. of

Patients Age (yrs); Sex Target Dose (Gy) OutcomeFollow-Up

(mos)

Stieber et al., 2005 1 unknown; F cistern 80 pain free, w/o medication 6Lévêque et al., 2011 7 36–83; 5 M, 2 F cistern (2), GPM (5) 60 (1), 70 (2), 75 (1),

80 (3)pain free, w/o medication (3); pain free, w/ medication (4)

17; 7–32

Pollock & Boes, 2011 5 61; 3 M, 2 F GPM 80 pain free, w/o medication (3); pain unchanged (2)

16; 13–19

Williams et al., 2010 1 47; F GPM 80 pain free, w/o medication 11O’Connor & Bidiwala, 2013 1 99; F GPM 80 pain free, w/o medication 16Martínez-Álvarez et al., 2014 (present series)

5 37–73; 1 M, 5 F GPM 80 (1), 90 (4) pain free, w/o medication (3); pain free, w/ medication (2)

43; 14–83

* Numbers in parentheses indicate the number of patients. GPM = glossopharyngeal meatus.

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Manuscript submitted June 10, 2014.Accepted August 1, 2014.Please include this information when citing this paper: DOI:

10.3171/2014.8.GKS141273.Address correspondence to: Roberto Martínez-Álvarez, M.D.,

Department of Gamma Knife Radiosurgery, Hospital Ruber Inter-nacional, Calle La Masó, 38, Madrid 28034, Spain. email: rob.martinez@telefonica.net.

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