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Year : 2022  |  Volume : 28  |  Issue : 1  |  Page : 57-61

Facial palsy following onyx embolization of a glomus tympanicum tumor: A case report and literature review

1 Department of Otorhinolaryngology-Head and Neck Surgery, Imam AbdulRahman Bin Faisal University, King Fahd Hospital of the University, Khobar, Saudi Arabia
2 Department of Otorhinolaryngology-Head and Neck Surgery, Prince Sultan Military Medical City, Saudi Arabia
3 Department of Emergency, Qariyat Al Ulya General Hospital, Saudi Arabia
4 Department of Radiology, Imam AbdulRahman Bin Faisal University, King Fahd Hospital of the University, Khobar, Saudi Arabia

Date of Submission07-Oct-2020
Date of Decision01-Jan-2021
Date of Acceptance03-Feb-2021
Date of Web Publication25-Apr-2022

Correspondence Address:
Dr. Abdulaziz AlEnazi
Department of Otolaryngology - Head and Neck Surgery
Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/indianjotol.indianjotol_220_20

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The embolization of a glomus tumor (GT) is a known preoperative procedure aimed at decreasing the blood supply to the tumor and reducing operative time and blood loss. Liquid embolic material is the preferable embolic agent. However, the incidence of cranial neuropathy due to denaturation with Onyx is not well established. This report seeks to illustrate the outcomes of a combined preoperative Onyx embolization of a glomus tympanicum tumor and highlight the related complications of facial palsy. A 49-year-old woman developed left-sided facial palsy following the preoperative embolization of a left-sided GT with selective transarterial embolization using ethylene vinyl alcohol (EVOH; Onyx 18), which was complicated with left-sided facial weakness 1 h post embolization. An additional uneventful surgical resection of the GT was performed successfully 72 h later. Embolization material poses a risk of cranial neuropathy. Further studies are recommended to support the knowledge of well-established embolization agents that will provide maximal occlusion while minimizing the risk of complications.

Keywords: Embolization, glomus tympanicum, Onyx, paraganglioma

How to cite this article:
AlEnazi A, Alshawi Y, Alnasser H, AlAftan M, AlQahtani M. Facial palsy following onyx embolization of a glomus tympanicum tumor: A case report and literature review. Indian J Otol 2022;28:57-61

How to cite this URL:
AlEnazi A, Alshawi Y, Alnasser H, AlAftan M, AlQahtani M. Facial palsy following onyx embolization of a glomus tympanicum tumor: A case report and literature review. Indian J Otol [serial online] 2022 [cited 2022 Nov 29];28:57-61. Available from: https://www.indianjotol.org/text.asp?2022/28/1/57/343760

  Introduction Top

A glomus tympanicum tumor is a benign, slow-growing, and common primary neoplasm of the middle ear.[1],[2] Glomus tumors (GTs) account for only 0.03% of all neoplasms and 0.5% of head-and-neck tumors.[3] The embolization of a GT is a preoperative procedure that aims to reduce surgical complications by using agents, such as polymerized glue, polyvinyl alcohol (PVA), and ethylene vinyl alcohol (Onyx, eV3 Inc).[4]

Preoperative embolization was first reported in 1973 for paragangliomas.[5] However, from the 1980s onward, surgical resection preceded by embolization became the treatment of choice.[6] In 2005, the Food and Drug Administration approved ethylene vinyl alcohol copolymer (EVOH) (Onyx, eV3 Inc.) for interventional procedures, and because of its unique physical properties, it is injectable, nonadhesive, and nonabsorbable.[7],[8] Liquid embolic material is the preferable embolic agent, but it has a risk of complications, such as ischemia, hemorrhage, peritumoral edema, and nontarget embolization and influences the risk of developing cranial neuropathy.[9],[10] Onyx is known to take a longer period of time to solidify than other agents. Although this property is beneficial in preventing microcatheter gluing, in the presence of tortuous vessels or vasospasm, it can lead to migration of the material to the vasa vasorum of cranial nerves prior to completing solidification.[11] Nevertheless, the risk of severe complications is generally low, ranging from 0% to 13%.[12] There is no consensus on the indications for the preoperative embolization of head-and-neck paragangliomas.

We report a rare case of facial palsy following an Onyx embolization of a glomus tympanicum tumor to illustrate the outcomes and personal experience of a combined preoperative Onyx embolization and highlight the related complications.

  Case Report Top

A 49-year-old woman with no known medical illnesses presented to the otolaryngology clinic with a yearlong history of left-sided pulsatile tinnitus and nonprogressive ipsilateral hearing loss. A physical examination under a microscope revealed a pale reddish mass involving the lower half of the middle ear. Cranial nerve examination revealed no deficits. The Weber test was centralized, and the Rinne test was negative for the left ear. An audiogram [Figure 1]a and [Figure 1]b indicated mild left-sided conductive hearing loss with normal hearing in the right ear. All laboratory findings were normal, including that for vanillylmandelic acid and serum metanephric. A high-resolution computed tomography (HRCT) of the temporal bone revealed a soft-tissue mass in the middle ear lateral to the cochlear promontory encasing the middle ear ossicles, especially the stapes and the incus. A postcontrast administration showed homogeneous enhancement of the middle ear mass. A computed tomography (CT) scan after the surgery showed no evidence of tumoral residual or significant intracranial involvement [Figure 2]a,[Figure 2]b,[Figure 2]c,[Figure 2]d. The magnetic resonance image (MRI) finding axial T2 fat sat showed a hyperintense mass lesion in the left middle ear and the T1 postcontrast showed homogeneous enhancement of the left middle ear mass lesion [Figure 3]a and [Figure 3]b.
Figure 1: (a) Pure tone audiometry showed right ear hearing within normal limits. Left ear moderate hearing loss. (b) Right ear hearing within normal limits, left ear mild conductive hearing loss

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Figure 2: (a-e) Computed tomography (a-c) thin slices with bone window in different reconstructions showed soft-tissue mass in the middle ear lateral to cochlear promontory encasing ossicles of the middle ear, especially the stapes and the incus. (d) Postcontrast computed tomography showed homogeneous enhancement of middle ear mass. (e) Computed tomography scan follow-up after surgery showed surgical clips with no evidence of tumral residual

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Figure 3: (a) Axial T2 fast sat show hyper intense mass lesion in the left middle ear. (b) T1 postcontrast show homogeneous enhancement of left middle ear mass lesion

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Preoperative embolization was scheduled 24 h before surgery. An angiogram of the left common carotid artery demonstrated a tumoral blush at the left petrous bone. An angiogram of the left external carotid artery again showed the tumoral blush. An angiogram of the left internal carotid artery showed no tumoral supply or anastomosis. A microcatheter was advanced by ascending the pharyngeal artery with an almost tumoral blush. Another tumoral blush was seen from the small branches of the occipital artery. The embolization of the left ascending pharyngeal and occipital artery feeders was performed using Onyx 18. The final postembolization angiogram demonstrated complete tumor devascularization [Figure 1]a,[Figure 1]b,[Figure 1]c. The patient developed House–Brackmann Grade V FN paralysis immediately after the embolization with Onyx, with no lower cranial nerve deficits. After 24 h, an uneventful surgical removal was performed. The tumor was completely excised [Figure 2]e using a retro-auricular incision via a canal wall-up mastoidectomy and posterior tympanotomy with an extended facial recess approach. Intraoperatively, Onyx was seen to fill the stylomastoid artery and scattered segments of the vasa nervosa of the FN. The postembolization deficit did not resolve after the 1st month of clinical follow-up.

Materials and methods

In May 2018, a tympanic paraganglioma was treated with a preoperative embolization with Onyx 18 and a total surgical resection with the intent of preserving function in the otology unit of the territory medical hospital in collaboration with the department of interventional radiology on a 49-year-old woman. The tympanic paraganglioma was categorized according to the Fisch classification: class B 2. A micro-otoscopic examination and an evaluation of the cranial nerves were performed before and after treatment. Pre- and post-operative audiograms were obtained. An HRCT of the petrous bone and an MRI of the inner ear and posterior fossa were performed. FN paralysis occurred immediately after the embolization with Onyx, with no lower cranial nerve deficits; it was Grade IV, according to the House–Brackmann grading system. After 24 h, the tumor was completely excised. Regular follow-up was continued.

Embolization procedure

The procedures were performed under generalized anesthesia as per the departmental protocol. The right common femoral artery was punctured under ultrasound guidance using an 18-gauge needle followed by advancing the 8Fr vascular sheath using the Seldinger technique. The selection of bilateral common carotid, internal carotid, and external carotid arteries was performed and followed by an angiogram.

The angiogram showed a vascular mass lesion in the left tympanic region with a vascular supply mainly from the left ascending pharyngeal artery and left occipital artery [Figure 4]a,[Figure 4]b,[Figure 4]c,[Figure 4]d,[Figure 4]e.
Figure 4: (a) Angiogram through the left common carotid artery demonstrate tumoral blush at the left petrous bone. (b) Tumoral blush seen in the left external carotid artery. (c) Angiogram through the left internal carotid artery show no tumoral supply or anastomosis. (d) Microcaheter was advanced through ascending pharyngeal artery with show almost tumoral blush. (e) Post embolization angiogram show no tumroal blush

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The left ascending pharyngeal artery and two feeding branches of the left posterior occipital arteries were selectively catheterized using a microcatheter. Two detachable Apollo microcatheters were introduced into the ascending pharyngeal artery and one of the branches of the occipital artery feeding this tumor. A third microcatheter (marathon) was introduced into the third feeding branch. The total volume of liquid embolic Onyx injected into the tumor was 1.3 ml. The tympanic paraganglioma was delineated with a typical homogeneous hypervascular blush. After each injection, a super-selective control angiography demonstrated the gradual disappearance of the tumor blush. Once denudation of the tumor artery was achieved, the embolization was stopped. All microcatheters were removed, the catheter systems were retrieved, and the femoral artery was sealed with an Angio-seal (closure device). The final angiogram showed a satisfactory obliteration of the major feeding vessels.

  Discussion Top

Most paragangliomas are benign, slow-growing tumors with the potential to remain stable over the years, and they commonly appear in females aged 40–50 years.[8],[13] Our patient was in this age group. The gold standard for the treatment of glomus tympanicum is complete surgical resection with preoperative embolization.[14] Patients usually desire symptom control and the prevention of neurological compromise. Tympanic paragangliomas are symptomatic at an early stage, presenting with very disturbing pulsatile tinnitus and progressive hearing loss, requiring treatment.[15] Our case was a typical example of tympanicum paraganglioma. An HRCT and an MRI are diagnostic tests for the GTs. An HRCT offers a very sensitive evaluation of the extent of bone erosion, which is useful in differentiating glomus tympanicum from glomus jugular tumors and monitoring tumor progression.[16] In the early phase, these tumors appear as small soft-tissue nodules located at the cochlear promontory and are confined to the middle ear on a thin-section CT. An MRI helps to define the extension of a large tumor and understanding the soft-tissue involvement. A T1-weighted MRI may show a “salt and pepper” appearance of paragangliomas. However, a gadolinium-enhanced MRI can reveal small tumors in the middle ear.[17] The introduction of preoperative super-selective embolization (SSE) has provided a means to reduce complication risks during the surgical removal of vascular tumors by decreasing operative time and blood loss.[18]

Caution must be taken when utilizing Onyx near branches of the neuromeningeal trunk of the ascending pharyngeal artery to avoid a lower cranial neuropathy.[19] Various embolic agents have been used, including PVA, polymerized glue, and more recently, ethylene vinyl alcohol (Onyx, eV3 Inc.). Onyx is a liquid embolic agent comprised EVOH dissolved in dimethyl sulfoxide.[7],[20]

The facial nerve has a different course that results in a different blood supply. From the origin of the facial nerve to the internal auditory canal, it takes the supply from the anterior inferior cerebellar artery. In the facial canal, it takes blood supply from the petrosal (a branch from the middle meningeal artery) and the stylomastoid (a branch from an occipital artery), and below the stylomastoid foramen, it takes blood supply from the stylomastoid and parotid gland branches.[21] Understanding cranial nerve blood supply is essential when considering deficits after SSE. With respect to the facial nerve, the tympanic and mastoid segments receive overlapping blood supply from the stylomastoid artery and the petrosal branch of the middle meningeal artery.

Valavanis proposed the concept of “dangerous” and “safe” vessels when choosing embolization agents. Safe arteries are not involved in supplying a cranial nerve, while those feeding a functional nerve are termed dangerous.[10],[21] In our case, the dangerous vessels had a risk of causing nerve injury.

The authors propose using Onyx with caution when embolizing dangerous vessels known to supply cranial nerves. The likelihood of a nonreversible neuropathy may be higher with Onyx than with other nonpermanent agents. Lv et al. reported two cases of facial palsy after embolization of intradural arteriovenous fistulas with Onyx, neither of which displayed full recovery with time.[22] In addition, the recanalization rate of Onyx is not currently known, making it difficult to define its use as a nonpermanent or more lasting agent. Most cases of cranial neuropathy reported in the literature after embolization with PVA are temporary with full or partial recovery. In our patient, complete facial nerve recovery was achieved over 6 months. However, the case series provides three new cases of cranial neuropathy with Onyx, none of which achieved full recovery of at least one involved nerve.[23] Different theories have been presented about why the patients had these unpredictable side effects. One is that Onyx is a liquid embolic agent that is nonadhesive and has more penetration in the tissue, and thus, it may reflux into the other side of the arterial supply. A more convincing theory is that aggressive embolization of occipital artery branches leads to reflux of the Onyx embolizing the stylomastoid artery, which supplies the facial nerve.[24] In general, the literature does not advocate its use for tympanic paragangliomas that are confined to the middle ear cavity (Fisch Class A) because the risk of potential complications with this invasive procedure outweighs the advantages.[23] Criteria for successful tumor control include no recurrence of symptoms, a normal microscopic evaluation of the middle ear, and normal imaging when available, all of which were successfully applied in our case.

Literature review

Preoperative embolization has been proven to reduce operative time and postoperative complications.[5],[9] Several authors have reported an increased risk of tumor growth and aggravated edema after embolization. However, the use of onyx has been reported as a safe and efficient material for head-and-neck tumors.[17] It also shows potential in endovascular bleeding management.[8]

In general, the rate of preoperative embolization complications is low, from 0% to 9%,[5] including tumor swelling, peritumoral edema, ischemia, and hemorrhage. However, because of Onyx's ability to penetrate the vasa vasorum of the cranial nerves, it can cause cranial nerve palsies.[26] Many studies have reported the most common is ipsilateral facial palsy.[26] Severe complications such as stroke, blindness, and death have also been reported.[5]

Jugulotympanic paragangliomas are the most common primary neoplasms of the middle ear.[25] Preoperative embolization for paragangliomas was first reported in 1973 by Manelfe et al.[5] Surgery remains the only curative treatment option to eradicate the tumor. Embolization is meant to facilitate surgery by reducing operative blood loss and tumor size.[4] Thus, preoperative embolization is usually performed with embolic materials within a few days of the surgical resection to assure the complete thrombosis of the embolized vessels and avert the reconstitution of the tumor's blood supply through recanalization and neovascularization.

Embolization should be started when angiographic features confirm the feeder supply of the tumor and go more distally to the tumor.[11],[27] Various embolic agents are used for embolization, including PVA, Embospheres, N-butyl-2-cyanoacrylate (NBCA, Cordis Neurovascular Inc.), and more recently, ethylene vinyl alcohol (Onyx, eV3 Inc.).[7],[22] There are two techniques for tumor embolization: direct arterial catheterization and direct puncture of the main tumor artery.[28] There are two viscidities of Onyx: 6% EVOH (Onyx 18) and 8% EVOH (Onyx 34), and it has two formulations: 1.5 ml and 6 ml.[8] Some advantageous properties of Onyx are that it is nonadhesive to the vessel wall, only filling the vascular lumen and solidifying over a longer period than other agents and that it permits greater penetration of intratumoral vasculature. Moreover, it has a weak inflammatory effect on the endothelium.[28],[8]

Compared with other agents, for example, NBCA and PVA agents, Onyx allows a more controlled injection to increase embolization management and better permits cessation and restarting administration. Onyx is easy to deliver due to its low risk of gluing to a microcatheter. PVA is highly dependent on the patient's coagulation status, whereas Onyx acts independently of underlying coagulopathies or a low platelet count. It is radiopaque and can be seen on fluoroscopy, while the reflux of PVA particles can be missed.[8],[26]

  Conclusion Top

The indications for the preoperative embolization of head-and-neck tumors include monitoring the risk of potential complications that may outweigh the advantages. The embolization agent influences the risk of cranial neuropathy. Further studies are recommended to support the knowledge of embolization agents that will provide maximal occlusion while minimizing the risk of complications. Understanding tumoral endovascular embolization principles is important for avoiding unpredictable completion.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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