MRI of Glossopharyngeal Neuralgia Caused by Neurovascular Compression

Compressive lesions of the head and neck: Common and uncommon must-know entities

There are many lesions that cause compression of nerves and vessels in the head and neck, and they can often be overlooked in the absence of adequate history or if not suspected by the radiologist. Many of these lesions require a high index of suspicion and optimal positioning for imaging. While a multimodality approach is critical in the evaluation of compressive lesions, an MRI utilizing high-resolution (heavily weighted) T2-weighted sequence is extremely useful as a starting point. In this review, we aim to discuss the radiological features of the common and uncommon compressive lesions of the head and neck which are broadly categorized into vascular, osseous, and miscellaneous etiologies.

Glossopharyngeal Neuralgia Characterized by Otalgia: A Retrospective Study

Glossopharyngeal neuralgia (GPN) is an uncommon facial pain syndrome and is characterized by paroxysms of excruciating pain in the distributions of the auricular and pharyngeal branches of cranial nerves IX and X. Glossopharyngeal neuralgia characterized by otalgia alone is rare. Herein, the authors analyzed 2 patients with GPN with otalgia as the main clinical manifestation. The clinical features and prognosis of this rare group of patients with GPN were discussed. They both presented with paroxysmal pain in the external auditory meatus and preoperative magnetic resonance imaging suggested the vertebral artery were closely related to the glossopharyngeal nerves. In both patients, compression of the glossopharyngeal nerve was confirmed during microvascular decompression, and the symptoms were relieved immediately after surgery. At 11 to 15 months follow-up, there was no recurrence of pain. A variety of reasons can cause otalgia. The possibility of GPN is a clinical concern in patients with otalgia as the main complaint. The authors think the involvement of the glossopharyngeal nerve fibers in the tympanic plexus via Jacobson nerve may provide an important anatomic basis for GPN with predominant otalgia. Surface anesthesia test of the pharynx and preoperative magnetic resonance imaging is helpful for diagnosis. Microvascular decompression is effective in the treatment of GPN with predominant otalgia.

Percutaneous radiofrequency thermocoagulation and microvascular decompression for treating glossopharyngeal neuralgia: a retrospective clinical study

OBJECTIVES

This study aimed to investigate the differences in the effectiveness of percutaneous radiofrequency thermocoagulation (PRT) and microvascular decompression (MVD) in treating glossopharyngeal neuralgia (GPN).

METHODS

Medical records of patients were reviewed to investigate their baseline characteristics and immediate postoperative prognosis. Long-term outcomes of these patients were obtained through telephone interviews. Visual analog scale (VAS) and Pittsburgh sleep quality index (PSQI) scores at 1 day and 1, 4, 12, 24, and 48 weeks after surgery were compared between the MVD and PRT groups, in addition to complete pain relief rate, effective rate, adverse reactions, length of hospital stay, and economic indicators.

RESULTS

The VAS and PSQI scores of the two groups at 1 day and 1, 4, 12, 24, and 48 weeks after surgery were significantly lower (P < 0.05) than those before surgery. At 48 weeks, the complete remission rate was significantly higher (P < 0.05) in the MVD group than in PRT group. No significant difference in adverse reactions was observed between the two groups. The length of hospital stay, operative time, and cost were significantly higher (P < 0.05) in the MVD group than in the PRT group.

CONCLUSIONS

Both PRT and MVD can significantly reduce patients' degree of pain and improve their sleep quality. In the medium term, MVD is better than PRT in terms of the complete curative effect. In young patients with GPN, MVD is more often recommended than PRT; however, MVD is costlier than PRT.

Glossopharyngeal Neuralgia Secondary to COVID-19: A Case Report

Glossopharyngeal neuralgia (GPN) is a painful condition characterized by stabbing pain throughout the glossopharyngeal nerve distribution. Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, we have learned that COVID-19 may induce neurological symptoms and complications. This case report presents a 54-year-old patient diagnosed with GPN, potentially secondary to COVID-19. The pain resolved spontaneously in three months without the need for medication. We discuss our diagnostic approach for this patient and propose a possible theory about the relation between cranial neuralgias and COVID-19.

Vestibular paroxysmia: Clinical features and imaging findings; a literature review

According to the definition of neurovascular compression syndromes (NVCS), a vascular structure in direct contact with a cranial nerve is causing mechanical irritation of the neural tissue producing correlating symptoms. Vestibular paroxysmia is an example of a neurovascular compression which is caused by neurovascular contact between the eighth cranial nerve and a vessel. It is crucial to understand the unique anatomy of the vestibulocochlear nerve in order to study the syndrome which is the result of its compression. More specifically, the long transitional zone between central and peripheral myelin plays a central role in clinical significance, as the transitional zone is the structure most prone to mechanical injury. Imaging techniques of the eighth cranial nerve and the surrounding structures are substantial for the demonstration of clinically significant cases and potential surgical decompression. The goal of the current review is to present and study the existing literature on vestibular paroxysmia and to search for the most appropriate imaging technique for the syndrome. An extensive literature search of PubMed database was performed, and the studies were ranked based on evidence-based criteria, followed by descriptive statistics of the data. The present analysis indicates that 3D CISS MRI sequence is superior to any other sequence, in the most studies reviewed, regarding the imaging of neurovascular compression of the eighth cranial nerve.

Study of the Anatomical Features of the Offending Arteries Involved in Glossopharyngeal Neuralgia

BACKGROUND

The anatomic features of the posterior inferior cerebellar arteries (PICAs) and the anterior inferior cerebellar arteries (AICAs) as offending arteries involved in glossopharyngeal neuralgia (GPN) are important to dictate the best surgical approach.

OBJECTIVE

To study and classify the anatomic features of the offending arteries.

METHODS

All clinical data and surgical videos from 18 GPN cases that were surgically treated during the past 10 yr were retrospectively reviewed.

RESULTS

Among these 18 patients, the offending arteries involved were the PICA in 12 (66.7%), AICA in 4 (22.2%), and both PICA and AICA in 2 (11.1%). The PICA were then classified into the following groups based on their anatomic features: type I: the PICA formed an upward loop at the level of the glossopharyngeal nerve and passed between the glossopharyngeal and vestibulocochlear nerves; type II: the PICA formed an upward loop at the level of the glossopharyngeal nerve and passed between the glossopharyngeal and vagus nerves or between the rootlets of the vagus nerve; and type III: the PICA passed between the glossopharyngeal and vestibulocochlear nerves without forming a loop. The AICA had only one running pattern.

CONCLUSION

The offending arteries involved in GPN, mainly the PICA and/or AICA, were classified into 4 different types based on their anatomic features.

A segmentation-independent volume rendering visualisation method might reduce redundant explorations and post-surgical complications of microvascular decompression

OBJECTIVES

This study aimed to investigate the feasibility of segmentation-independent volume rendering (SI-VR) in visualising the root entry zone (REZ), and to explore the influence on the management of vascular compression syndromes (VCSs).

METHODS

Two hundred and twenty patients with VCSs were recruited in this prospective study from July 2015 to May 2019. SI-VR was reconstructed based on inverted 3D fast spin echo T2WI. They were assigned to the experimental group and control group randomly. Patients in the experimental group would accept extra evaluation based on SI-VR before microvascular decompression. Image quality and diagnostic accuracy between SI-VR and 3D fast spin echo T2WI in the experimental group were compared by Mann-Whitney U test and chi-square test, separately. Interobserver agreement was performed with intraclass correlation coefficient. Postsurgical outcomes and complications between two groups were compared by chi-square test.

RESULTS

SI-VR had a better interobserver agreement (0.82 vs 0.68) and diagnostic accuracy (95.5% vs 83.6%, p = 0.004) than that of 3D fast spin echo T2WI. Especially, significantly improved diagnostic accuracy was reached in detecting the multi-vascular branches compression (100% vs 15.4%, p < 0.001). There were fewer complications (7.1% vs 26.8%, p = 0.004) and less operation time (20.7 min vs 14.5 min, p = 0.007) but no significant difference of pain relief (p = 0.19) in the experimental group than in the control group.

CONCLUSIONS

The SI-VR method is feasible for the precise demonstration of the anatomy structure along the REZ, with high reliability and reproducibility. Unbiased pre-surgical visualisation could reduce redundant explorations and post-surgical complications in patients who undergo microvascular decompression.

KEY POINTS

• Visualisation of the root entry zone by the segmentation-independent volume rendering is in accordance with the landscape by the neuro-endoscopy. • Segmentation-independent volume rendering has an advantage over 3D fast spin echo T2WI in the visualisation of multi-vascular branches compression. • Presurgical 3D visualisation of the neurovascular compression at the root entry zone leads to less postsurgical complications from the decrease of redundant exploration.

Glossopharyngeal Neuralgia Treatment Outcomes After Nerve Section, Microvascular Decompression, or Stereotactic Radiosurgery: A Systematic Review and Meta-Analysis

BACKGROUND

Glossopharyngeal neuralgia (GPN) is a rare neuralgic pain syndrome amenable to neurosurgical treatments, including nerve section (NS), microvascular decompression (MVD), and stereotactic radiosurgery (SRS). However, thorough comparisons of the modalities have not been performed to date. The objective of the present study was to compare the pain and complication outcomes after these approaches to GPN.

METHODS

Searches of 7 electronic databases from inception to June 2018 were conducted following the appropriate guidelines. The incidence rates (IRs) of short-term (≤3 months) and long-term (≥12 months) pain relief and complications were extracted and analyzed using a meta-analysis. Meta-regression was used to assess for heterogeneity.

RESULTS

A total of 792 GPN cases managed by NS, MVD, or SRS were described by 6, 11, and 6 studies, reporting outcomes for 282 (36%), 446 (56%), and 67 (8%) cases. The short-term pain relief rate was highest after NS postoperatively (IR, 94%; 95% confidence interval [CI], 88%-98%) and lowest after SRS at 3 months postoperatively (IR, 80%; 95% CI, 68%-96%). The postoperative complication rate was greatest after MVD (IR, 26%; 95% CI, 16%-38%) and lowest after SRS (IR, 0%; 95% CI, 0%-4%). The long-term pain relief rate was greatest after NS (IR, 96%; 95% CI, 91%-99%) and lowest after SRS (IR, 82%; 95% CI, 67%-94%). Statistically significant differences between the approaches were found for each outcome.

CONCLUSION

Neurosurgical treatment of GPN is frequently performed by 1 of 3 modalities with unique outcomes profiles. NS might provide the most favorable treatment response, with respect to short- and long-term pain relief and postoperative outcomes.

Guidelines for radiographic imaging of cranial neuropathies

Disruption of the complex pathways of the 12 cranial nerves can occur at any site along their course, and many, varied pathologic processes may initially manifest as dysfunction and neuropathy. Radiographic imaging (computed topography or magnetic resonance imaging) is frequently used to evaluate cranial neuropathies; however, indications for imaging and imaging method of choice vary considerably between the cranial nerves. The purpose of this review is to provide an analysis of the diagnostic yield and the most clinically appropriate means to evaluate cranial neuropathies using radiographic imaging. Using the PubMed MEDLINE NCBI database, a total of 49,079 articles' results were retrieved on September 20, 2014. Scholarly articles that discuss the etiology, incidence, and use of imaging in the context of evaluation and diagnostic yield of the 12 cranial nerves were evaluated for the purposes of this review. We combined primary research, guidelines, and best practice recommendations to create a practical framework for the radiographic evaluation of cranial neuropathies.

Trigeminal Neuralgia, Glossopharyngeal Neuralgia, and Myofascial Pain Dysfunction Syndrome: An Update

Neuropathic pain is a common phenomenon that affects millions of people worldwide. Maxillofacial structures consist of various tissues that receive frequent stimulation during food digestion. The unique functions (masticatory process and facial expression) of the maxillofacial structure require the exquisite organization of both the peripheral and central nervous systems. Neuralgia is painful paroxysmal disorder of the head-neck region characterized by some commonly shared features such as the unilateral pain, transience and recurrence of attacks, and superficial and shock-like pain at a trigger point. These types of pain can be experienced after nerve injury or as a part of diseases that affect peripheral and central nerve function, or they can be psychological. Since the trigeminal and glossopharyngeal nerves innervate the oral structure, trigeminal and glossopharyngeal neuralgia are the most common syndromes following myofascial pain dysfunction syndrome. Nevertheless, misdiagnoses are common. The aim of this review is to discuss the currently available diagnostic procedures and treatment options for trigeminal neuralgia, glossopharyngeal neuralgia, and myofascial pain dysfunction syndrome.

Imaging of the Posterior Skull Base

The posterior skull base can be involved by a variety of pathologic processes. They can be broadly classified as: traumatic, neoplastic, vascular, and inflammatory. Pathology in the posterior skull base usually involves the lower cranial nerves, either as a source of pathology or a secondary source of symptoms. This review will categorize pathology arising in the posterior skull base and describe how it affects the skull base itself and surrounding structures.

Imaging of Neurovascular Compression Syndromes: Trigeminal Neuralgia, Hemifacial Spasm, Vestibular Paroxysmia, and Glossopharyngeal Neuralgia

Neurovascular compression syndromes are usually caused by arteries that directly contact the cisternal portion of a cranial nerve. Not all cases of neurovascular contact are clinically symptomatic. The transition zone between the central and peripheral myelin is the most vulnerable region for symptomatic neurovascular compression syndromes. Trigeminal neuralgia (cranial nerve V) has an incidence of 4-20/100,000, a transition zone of 4 mm, with symptomatic neurovascular compression typically proximal. Hemifacial spasm (cranial nerve VII) has an incidence of 1/100,000, a transition zone of 2.5 mm, with symptomatic neurovascular compression typically proximal. Vestibular paroxysmia (cranial nerve VIII) has an unknown incidence, a transition zone of 11 mm, with symptomatic neurovascular compression typically at the internal auditory canal. Glossopharyngeal neuralgia (cranial nerve IX) has an incidence of 0.5/100,000, a transition zone of 1.5 mm, with symptomatic neurovascular compression typically proximal. The transition zone overlaps the root entry zone close to the brain stem in cranial nerves V, VII, and IX, yet it is more distal and does not overlap the root entry zone in cranial nerve VIII. Although symptomatic neurovascular compression syndromes may also occur if the neurovascular contact is outside the transition zone, symptomatic neurovascular compression syndromes are more common if the neurovascular contact occurs at the transition zone or central myelin section, in particular when associated with nerve displacement and atrophy.

Intraoperative neurophysiological monitoring of microvascular decompression for glossopharyngeal neuralgia

PURPOSE

To evaluate if adding cranial nerves (CNs) V and VI to standard intraoperative neurophysiological monitoring (IONM) of microvascular decompressions for glossopharyngeal neuralgia improve its efficacy.

METHODS

We reviewed all patients who received a microvascular decompression for glossopharyngeal neuralgia at our institution between January 2008 and August 2012. All received upper extremity somatosensory evoked potentials, brainstem auditory evoked potentials, and free-running electromyography of muscles innervated by ipsilateral CNs VII, IX, and X. The sample was divided into 12 patients who received additional monitoring of CNs V and VI and 15 who did not.

RESULTS

No difference on neurotonic activity presence was found on CN V (standard IONM: 0% versus additional CNs IONM: 8.33%; p = 0.423), CN VI (never present on the additional CN patients), CN VII (standard IONM: 73.33% versus additional CNs IONM: 66.64%; p = 0.973), CN IX (standard IONM: 40.0% versus additional CNs IONM: 25.0%; p = 0.683), or CN X (standard IONM: 46.67% versus additional CNs IONM: 33.33%; p = 0.701) between groups. Additionally, no differences of brainstem auditory evoked potentials wave V's delay, and amplitude at the end of the decompression, or closing of the case were found between groups.

CONCLUSIONS

Monitoring free-running electromyography of additional CNs V and VI does not improve the efficacy of IONM of microvascular decompressions for glossopharyngeal neuralgia.

The lower cranial nerves: IX, X, XI, XII

The lower cranial nerves innervate the pharynx and larynx by the glossopharyngeal (CN IX) and vagus (CN X) (mixed) nerves, and provide motor innervation of the muscles of the neck by the accessory nerve (CN XI) and the tongue by the hypoglossal nerve (CN XII). The symptomatology provoked by an anomaly is often discrete and rarely in the forefront. As with all cranial nerves, the context and clinical examinations, in case of suspicion of impairment of the lower cranial nerves, are determinant in guiding the imaging. In fact, the impairment may be located in the brain stem, in the peribulbar cisterns, in the foramens or even in the deep spaces of the face. The clinical localization of the probable seat of the lesion helps in choosing the adapted protocol in MRI and eventually completes it with a CT-scan. In the bulb, the intra-axial pathology is dominated by brain ischemia (in particular, with Wallenberg syndrome) and multiple sclerosis. Cisternal pathology is tumoral with two tumors, schwannoma and meningioma. The occurrence is much lower than in the cochleovestibular nerves as well as the leptomeningeal nerves (infectious, inflammatory or tumoral). Finally, foramen pathology is tumoral with, outside of the usual schwannomas and meningiomas, paragangliomas. For radiologists, fairly hesitant to explore these lower cranial pairs, it is necessary to be familiar with (or relearn) the anatomy, master the exploratory technique and be aware of the diagnostic possibilities.

3D Computer graphics simulation to obtain optimal surgical exposure during microvascular decompression of the glossopharyngeal nerve

The affected artery in glossopharyngeal neuralgia (GPN) is most often the posterior inferior cerebellar artery (PICA) from the caudal side or the anterior inferior cerebellar artery (AICA) from the rostral side. This technical report describes two representative cases of GPN, one with PICA as the affected artery and the other with AICA, and demonstrates the optimal approach for each affected artery. We used 3D computer graphics (3D CG) simulation to consider the ideal transposition of the affected artery in any position and approach. Subsequently, we performed microvascular decompression (MVD) surgery based on this simulation. For PICA, we used the transcondylar fossa approach in the lateral recumbent position, very close to the prone position, with the patient's head tilted anteriorly for caudal transposition of PICA. In contrast, for AICA, we adopted a lateral suboccipital approach with opening of the lateral cerebellomedullary fissure, to visualize better the root entry zone of the glossopharyngeal nerve and to obtain a wide working space in the cerebellomedullary cistern, for rostral transposition of AICA. Both procedures were performed successfully. The best surgical approach for MVD in patients with GPN is contingent on the affected artery--PICA or AICA. 3D CG simulation provides tailored approach for MVD of the glossopharyngeal nerve, thereby ensuring optimal surgical exposure.

An uncommonly common: Glossopharyngeal neuralgia

Glossopharyngeal neuralgia is a relatively rare condition characterized by severe, paroxysmal episodes of pain localized to the external ear canal, the base of the tongue, the tonsil or the area beneath the angle of the jaw. This pain is many a times confused with Trigeminal Neuralgia and mistreated. There are various diagnostic and management dilemmas which are herein addressed in this review.

High-resolution STIR for 3-T MRI of the posterior fossa: visualization of the lower cranial nerves and arteriovenous structures related to neurovascular compression

OBJECTIVE

Preoperative evaluation of small vessels without contrast material is sometimes difficult in patients with neurovascular compression disease. The purpose of this retrospective study was to evaluate whether 3D STIR MRI could simultaneously depict the lower cranial nerves--fifth through twelfth--and the blood vessels in the posterior fossa.

MATERIALS AND METHODS

The posterior fossae of 47 adults (26 women, 21 men) without gross pathologic changes were imaged with 3D STIR and turbo spin-echo heavily T2-weighted MRI sequences and with contrast-enhanced turbo field-echo MR angiography (MRA). Visualization of the cranial nerves on STIR images was graded on a 4-point scale and compared with visualization on T2-weighted images. Visualization of the arteries on STIR images was evaluated according to the segments in each artery and compared with that on MRA images. Visualization of the veins on STIR images was also compared with that on MRA images. Statistical analysis was performed with the Mann-Whitney U test.

RESULTS

There were no significant differences between STIR and T2-weighted images with respect to visualization of the cranial nerves (p > 0.05). Identified on STIR and MRA images were 94 superior cerebellar arteries, 81 anteroinferior cerebellar arteries, and 79 posteroinferior cerebellar arteries. All veins evaluated were seen on STIR and MRA images. There were no significant differences between STIR and MRA images with respect to visualization of arteries and veins (p > 0.05).

CONCLUSION

High-resolution STIR is a feasible method for simultaneous evaluation of the lower cranial nerves and the vessels in the posterior fossa without the use of contrast material.

Focal deformity of the cranial nerves observed on multislice motion-sensitized driven equilibrium (MSDE) in patients with neurovascular compression

OBJECTIVE

Our purpose is to demonstrate the deformity of the cranial nerves by arterial compression using a novel technique, multislice motion-sensitized driven equilibrium (MSDE).

METHODS

Subjects were 10 patients with neurovascular compression (5 patients with trigeminal neuralgia and 5 patients with hemifacial spasm). We observed the existence and extent of deformity of nerves by MSDE. Afterward, we compared operative findings with preoperative imaging findings and evaluated the validity of the latter.

RESULTS

All compressing, blood vessels could be correctly identified through preoperative evaluation. Of all patients, 7 showed deformity of the cranial nerves, which was consistent with operative findings except in one case. In postoperative evaluation, patients' neurological symptoms improved and the deformity disappeared. Three patients did not show deformity on preoperative MSDE images. In these patients, neural compression was also not observed during the operation.

CONCLUSIONS

The deformity of cranial nerves in patients with neurovascular compression was clearly shown using MSDE.

Transcondylar fossa (supracondylar transjugular tubercle) approach: anatomic basis for the approach, surgical procedures, and surgical experience

The authors clarify the anatomic basis and the usefulness of the transcondylar fossa approach (T-C-F A), in which the posterior portion of the jugular tubercle is removed extradurally through the condylar fossa with the atlanto-occipital joint intact. The authors first performed an anatomic study to identify the area to be removed using cadaveric specimens and then applied the T-C-F A to foramen magnum surgeries. The surgeries included clipping a vertebral artery-posterior inferior cerebellar artery aneurysm in 11 cases, microvascular decompression for glossopharyngeal neuralgia in 15 cases, and removing intradural foramen magnum tumors in 17 cases. Only the condylar fossa was removed, but the approach offered very good visualization of the lateral part of the foramen magnum and sufficient working space. These surgeries were performed safely without major complications. This skull base approach is minimally invasive and is not difficult. Therefore, it can be a standard approach for accessing intradural lesions of the foramen magnum. It can be combined with the transcerebellomedullary fissure approach from the lateral side and can also be easily changed to the transcondylar approach, if necessary.

Microvascular decompression for glossopharyngeal neuralgia through the transcondylar fossa (supracondylar transjugular tubercle) approach

OBJECTIVE

Our surgical results were reviewed to clarify the cause of glossopharyngeal neuralgia (GPN) and the effects of the microvascular decompression (MVD) procedure.

METHODS

Fourteen cases of idiopathic GPN were operated on through the transcondylar fossa (supracondylar transjugular tubercle) approach. Their clinical data and operative records were retrospectively reviewed.

RESULTS

In every case, vascular compression on the glossopharyngeal nerve was found and MVD was performed without any major complications. In 13 of the 14 cases the neuralgia completely disappeared postoperatively. Recurrence of pain was found in 1 case. Offending vessels were the posterior inferior cerebellar artery (PICA) in 10 cases, the anterior inferior cerebellar artery (AICA) in 2 cases, and both arteries in 2 cases. In 10 of the 14 cases, the high-origin PICA formed an upward loop between the glossopharyngeal and vagus nerves, compressing the glossopharyngeal nerve upward. In those cases, the PICA was transposed and fixed to the dura mater by the stitched sling retraction technique, and MVD was very effective.

CONCLUSION

The offending artery was the PICA in most cases. MVD is expected to be very effective, especially when the radiological images show the following 3 findings: 1) high-origin PICA, 2) the PICA making an upward loop, and 3) the PICA coursing the supraolivary fossette. The transcondylar fossa approach is suitable for transposing the PICA by the stitched sling retraction technique, and provides sufficient surgical results.