Jugular foramen syndrome

INTRODUCTION

Jugular foramen syndrome (JFS) is an uncommon clinical entity that often presents a diagnostic and management challenge to the otolaryngologist. The purpose of this section is to define this syndrome and elucidate the epidemiology, pathogenesis, clinical manifestations, diagnostic workup, and general treatment options for the syndrome.

DEFINITION

Various combinations of palsies of cranial nerves IX, X, and XI resulting from lesions in the area of the jugular foramen have been referred to as JFS. Eponyms include Vernet's and Collet-Sicard syndromes (36,37).

ETIOLOGY AND EPIDEMIOLOGY

Etiologies of JFS can be classified as neoplastic (primary and metastatic), traumatic, vascular, and infectious.

Primary lesions of the jugular foramen include glomus jugulare tumors, schwannomas, and meningiomas. Metastatic lesions to the jugular foramen are more common than primary neoplasms (36,38-42). Glomus jugulare tumors are the most common primary neoplasms of the jugular foramen. These are vascular tumors arising from neuroectodermally derived paraganglia present at the jugular fossa, the inferior tympanic canaliculus, the promontory, and within the vagus nerve. Paraganglia are very similar histologically and embryologically to the adrenal medulla. They, along with their derivative glomus tumors (jugulare and tympanicum), are typically supplied by the inferior tympanic branch of the ascending pharyngeal artery (43); however, the blood supply to glomus tumors may be very extensive, originating from the external carotid, the internal carotid, and the vertebral arteries (44). These tumors are more common in females (6:1 female-to-male ratio) and usually present in middle age. Functional tumors occur in 1% to 3% of cases with secretion of dopamine, serotonin, or norepinephrine. In such cases, patients may experience headache, labile blood pressure, sweating, and flushing (43). Approximately 3% of glomus jugulare tumors are malignant and develop metastases. Although hearing loss occurs in 80% and PT occurs in 60% of patients with glomus jugulare tumors, only 10% have cranial neuropathies.

Schwannomas are the second most common primary neoplasms. They most often involve the vagus nerve and originate from schwann cells. Malignant schwannomas are extremely rare. Sensorineural hearing loss may occur when schwannomas encroach on the cochlea and/or the internal auditory canal.

Meningiomas are the third most common primary neoplasms. They originate from arachnoid cap cells and may be associated with prior trauma, radiotherapy, or foreign body, although the nature of this association is not known. Like glomus jugulare, these tumors have a female predilection (2:1 female-to-male ratio). They also tend to present in middle age and can become metastatic in approximately 7% of the cases. These tumors may present with cerebellar signs, retrotympanic mass, and hearing loss, as well as lower cranial nerve palsies (45). Etiologies of JFS are summarized in Table 3.

PATHOGENESIS

Mass effect on neural contents of the jugular foramen from various neoplastic, vascular, infectious, and inflammatory processes is the main pathophysiologic mechanism of this syndrome. Trauma and direct injury to the nerves in the foramen is another etiology.

ANATOMY OF THE JUGULAR FORAMEN

The jugular foramen is limited anterolaterally by the temporal bone and posteromedially by the occipital bone. Anterior to the foramen lies the carotid artery, with the facial nerve coursing laterally. The foramen is divided by a fibrous or bony ridge connecting the jugular spine of the temporal bone to the jugular process of the occipital bone, to form the pars nervosa and the pars vascularis. Contrary to the suggestion of the names, the two segments each contain both vascular and nervous structures. Cranial nerves X and XI along with the jugular bulb usually occupy the pars vascularis, while cranial nerve IX and the inferior petrosal sinus traverse the pars nervosa. There are two openings in the dura medial to the sinus. These superior and inferior openings transmit cranial nerve IX and nerves X and XI, respectively. Exiting the skull base, nerve XI is posterior and nerve IX is anterior, with the vagus medial to the two in their caudad

TABLE 3 Etiologies of Jugular Foramen Syndrome

Neoplastic Benign

Glomus jugulare tumor Schwannoma/neurilemmoma Meningioma Malignant Metastatic

From head and neck primary tumors Kidney (39) Prostate (41) Skin (38) Primary

Lymphoma (46)

Myxoid chondrosarcoma (47)

Chondroid chordoma (48)

Malignant glomus tumors, schwannomas, and meningiomas Infectious

Neuroinflammatory disorders—varicella zoster (49) Parapharyngeal abscess (50) Vascular

Thrombosis/thrombophlebitis of the intraforaminal sigmoid sinus/jugular vein (36) Carotid dissection (51) Traumatic

Skull base fracture (52) Penetrating trauma (53,54)

extension. The vascular anatomy is variable but the inferior petrosal sinus usually enters the medial jugular bulb after passing medial to the internal carotid (44). The anatomical and functional innervation of cranial nerves IX-XI is outlined in Table 4.

CLINICAL MANIFESTATIONS

Hoarseness and dysphagia with aspiration are the cardinal manifestations of JFS. It has traditionally been thought that lesions involving the superior and recurrent laryngeal nerve lead to a lateral or cadaveric position of the paralyzed cord and associated breathy dysphonia. It has been reported, however, that site of nerve injury has no statistically significant relationship to vocal cord position (45).

The combination of vocal cord and superior pharyngeal muscle paralysis along with decreased sensation of the pharynx makes these patients prone to aspiration pneumonia.

Paralysis of the soft palate and superior constrictor muscles may lead to velo-pharyngeal insufficiency.

Decreased taste sensation of the ipsilateral tongue and weakness of the ipsilateral trapezius and sternocleidomastoid muscles may be reported.

Other manifestations such as PT and/or hearing loss are common in patients with glomus tumors.

DIAGNOSIS

A detailed history and a high index of suspicion are of paramount importance in making the diagnosis of JFS. Symptoms such as breathy voice, dysphagia, and aspiration should alert the astute physician to this syndrome. Subtle taste changes and neck and shoulder

TABLE 4 Anatomical and Functional Description of Cranial Nerves IX, X, and XI

IX (Glossopharyngeal)

X (Vagus)

XI (Spinal accessory)

Efferent

Efferent

Efferent

Special

Special

Cranial root

Stylopharyngeus

Voluntary muscles of pharynx

Some fibers are

and larynx, palatoglossus,

accessory to vagus

palatopharyngus, levator veli

in innervation of

palatini, salpingopharyngeus,

pharynx and larynx

and constrictors

and run primarily with the tenth nerve

General

General

Spinal root

Parasympathetics to smooth

Parasympathetics to pharynx,

Trapezius and sterno-

muscle and glands of

larynx, and thoracoabdominal

cleidomastoid

pharynx, larynx, and some

viscera

muscles

thoracoabdominal viscera

Afferent

Afferent

Not afferent

Visceral

Visceral

Carotid sinus and body

Baroreceptors, receptors from aortic arch, chemoreceptors from aortic body, sensory from larynx, esophagus, trachea and abdomino-thoracic viscera

Somatic sensory

Somatic sensory

External ear, medial surface

Skin of posterior auricle and

of tympanic membrane,

external auditory canal, parts

upper pharynx, and

of lateral tympanic

posterior third of tongue

membrane, and pharynx

Special sensory

Special sensory

Taste posterior third of

Taste to epiglottic area

tongue

weakness may also be noted. A history of unilateral hearing loss or PT may be associated with glomus tumors or other tumors that extend to the middle/inner ear.

Otoscopy may reveal a retrotympanic mass. Figure 3 depicts the otoscopic findings of a patient with a glomus jugulare tumor. Inspection of the oropharynx may reveal weakness of the ipsilateral soft palate with uvular deviation away from the lesion (curtain sign).

Examination of the upper aerodigestive tract is best accomplished with a fiberoptic nasopharyngoscope. Typically, there is ipsilateral hypesthesia of the pharynx as detected by lack of gag reflex, and the vocal fold may be immobilized. More directed examination of the supraglottis and lower pharynx can be done with flexible endoscopic evaluation of swallowing with sensory testing (55).

Laboratory testing should be individualized according to manifestations and clinical findings. For glomus jugulare tumors, serum should be screened for levels of epinephrine, norepinephrine, dopamine, and serotonin. Twenty-four-hour urinalysis should also be performed to assess for the presence of elevated metabolites of these substances, such as vanillylmandelic acid (VMA) and 5-hydroxyindole-acetic acid (5 HIAA) (43). Glomus tympanicum tumors do not require routine screening for these substances; however, these tests should be obtained if endocrine symptoms are present.

Audiological testing should be obtained in cases with hearing loss, PT, or retro-tympanic mass.

Imaging studies constitute the cornerstone of evaluation of these patients. Paragangliomas, meningiomas, schwannomas, and metastatic lesions have different

FIGURE 3 Otoscopio view of a glomus jugulare tumor.

radiographical characteristics. MRI and computed tomography (CT) are complementary to each other and are often used together to determine the nature and extent of the pathology under investigation. CT is superior to MRI for evaluating bone destruction; MRI is more useful for detection of dural invasion and intracranial extension (56-58).

For patients with a retrotympanic mass and/or PT, CT angiography (CTA) of the head is the preferable initial imaging study at our institution. This study can differentiate between a glomus tympanicum and a glomus jugulare tumor. It is also diagnostic of an ectopic carotid artery or a high jugular bulb. Figure 4 depicts a CTA of a patient with a glomus jugulare tumor. Since the upper neck is included in head CTA, a coexisting carotid body tumor can be detectable in patients with glomus tumors. For glomus jugulare cases, a head MRI should follow the CTA to better determine the size of the lesion and any possible intracranial extension. Carotid angiography is indicated only for prospective surgical cases to evaluate the collateral circulation of the brain (arterial and venous) in anticipation of possible vessel ligation and/or preoperative tumor embolization (59).

Bone scanning or positron emission tomography (PET) scanning is recommended if JFS occurs in a patient with a known or suspected history of malignancy.

Imaging characteristics of common jugular foramen tumors are depicted in Table 5.

TREATMENT

Treatment must be directed toward the primary etiology. An exhaustive discussion of treating the various etiologies of this syndrome is beyond the scope of this chapter, but modalities of choice for the most common causes will be addressed.

The three most common primary jugular foramen lesions, glomus jugulare, schwannoma, and meningioma, have traditionally been treated surgically through the lateral skull base approach (44,62). In an area so anatomically intricate, complete surgical resection can be difficult, and the risk of injury to cranial nerves VII-IX, as well as vascular and inner ear structures, can be considerable. However, recent advances in surgical techniques have allowed for thorough resection with acceptable morbidity. Another option for treatment is fractionated or Gamma knife radiation therapy (44,63). A recently published meta-analysis of surgery versus radiosurgery revealed that both are safe and efficacious

TABLE 5 Imaging Characteristics of Jugular Foramen Tumors

Glomus jugulare Schwannoma

Computed tomography

Magnetic resonance

Angio

Irregular shape Homogeneous Moth-eaten bony rim of destruction (20) Enhances with contrast

Smooth margin and smooth erosion of bone Less homogeneous than glomus Mild contrast enhancement

Small flow voids with "salt and pepper" appearance (61). Isointense with brain on T1 High T2 signal High contrast enhancement

Smooth contour Flow voids absent Low T1 signal similar to brainstem High T2 signal Marked contrast enhancement

Intense contrast stain Vascular pedicle (46)

Not vascular

Meningioma

Lym phoma/metastases

Osseous erosion with hyperostotic, sclerotic bone High contrast enhancement dural tails (60)

Irregular lobulated borders Dural tails (60) Flow voids absent Low T1 signal similar to brainstem Variable T2 signal (44) Highest contrast enhancement

Not vascular

Evaluation of venous drainage may determine need for sigmoid sinus occlusion prior to removal

Osteolytic destruction with poorly demarcated borders (46)

Signal characteristics similar to schwannoma

Not typically useful

FIGURE 4 Computed tomography angiogram of patient with glomus jugulare (arrow).

modalities of treatment. Morbidity and recurrences were infrequent in both groups; however, the incidence of late recurrences (after 10-20 years) in the radiosurgery group is unknown (64). Gamma knife treatment has also been shown to be useful for meningiomas (63).

Since schwannomas and glomus jugulare tumors are typically benign and slow-growing lesions, observation should be considered in selected cases, particularly in older individuals and patients in poor general health.

Metastatic processes, of course, must be approached according to the specific pathology involved. In most cases, this will involve chemotherapy with or without radiotherapy.

In cases with uncompensated vocal cord paralysis, medialization should be considered. This can be accomplished by type I thyroplasty, vocal cord injection, or arytenoid adduction procedure. Vocal cord injection can be accomplished with micronized alloderm, calcium hydroxyapatite, and fat, among other substances. Vocal cord injection and type I thyroplasty are efficacious for medialization of the anterior vocal cord. If posterior medialization is also necessary, arytenoid adduction procedure is useful in conjunction with an anterior medializa-tion procedure. Injection with gelfoam or collagen is the procedure of choice if recovery of function is expected.

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