Surgery for Glomus Tumors and Other Lesions of the Jugular Foramen

Chapter 46 Surgery for Glomus Tumors and Other Lesions of the Jugular Foramen



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The therapy for glomus tumors of the temporal bone is controversial. Because the clinical characteristics and growth rates of these tumors vary, the full gamut of management has been recommended from observation alone through radiation therapy and surgical management. Although there are isolated case reports of prolonged survival without treatment, these lesions can be quite deadly. The studies of Rosenwasser,1 Bickerstff and Howell,2 Steinberg and Holz,3 Brown,4 and Spector and colleagues5 have documented mortality rates of 5% to 13% for glomus jugulare tumors. This chapter outlines the diagnostic and preoperative evaluation, surgical techniques, and results and complications in the management of glomus tumors of the temporal bone. The application of these surgical techniques for other lesions of the jugular foramen is also reviewed.



PATIENT SELECTION


Temporal bone glomus tumors are neoplasms of the normal paraganglioma in the temporal bone that principally occur in the adventitia of the dome of the jugular bulb, but are also found in the submucosa of the cochlear promontory within the tympanic plexus. Numerous classification schemes have been proposed for these lesions, primarily by their origin (tympanic plexus versus jugular bulb) and the anatomic extent of lesion. The clinical surgical classification proposed by De La Cruz is particularly useful in planning the clinical management of patients with glomus tumors. The extent of the tumor is described by the involvement of structures of the temporal bone and skull base. A series of operations that correspond to the extent of the tumor is used (Table 46-1). Other classification schemes include the Fisch classification (Table 46-2) and the Glasscock-Jackson classification (Table 46-3).


TABLE 46-1 Modified De La Cruz Glomus Tumor Classification with Associated Surgical Approach



























Classification Surgical Approach
Tympanic Transcanal
Tympanomastoid Mastoid/extended facial recess
Jugular bulb Mastoid/neck (possible limited facial nerve rerouting)
Carotid artery Infratemporal fossa ± subtemporal
Transdural Infratemporal fossa/intracranial
Craniocervical Transcondylar
Vagale Cervical

Surgery for Glomus Tumors, Chapter 49 Brackman DE, Arriaga MA in Otologic Surgery, eds Brackmann DE, Shelton C, Arriaga MA WB Saunders, Philadelphia. p579-593


TABLE 46-2 Fisch Classification of Glomus Tumors


















Type A Tumors limited to middle ear cleft
Type B Tumors limited to tympanomastoid area with no infralabyrinthine compartment involvement
Type C1, C2, C3 Tumors involving infralabyrinthine compartment of temporal bone and extending into petrous apex
Type D1 Tumors with intracranial extension <2 cm in diameter
Type D2, D3 Tumors with intracranial extension >2 cm in diameter

Fisch U, Infratemporal Fossa Approach for Glomus Tumors of the Temporal Bone. nn Otol Rhinol LAryngol 91–474-479, 1982.


TABLE 46-3 Glasscock-Jackson Glomus Tumor Classification


































Type Physical Findings
GLOMUS TYMPANICUM
I Small mass limited to promontory
II Tumor completely filling middle ear space
III Tumor filling middle ear and extending into mastoid
IV Tumor filling middle ear, extending into mastoid or through tympanic membrane to fill external auditory canal; may also extend anterior to internal carotid artery
GLOMUS JUGULARE
I Small tumor involving jugulare bulb, middle ear, and mastoid
II Tumor extending under internal auditory canal; may have intracranial extension
III Tumor extending into petrous apex; may have intracranial extension
IV Tumor extending beyond petrous apex into clivus or infratemporal fossa; may have intracranial extension

Lateral Temporal Approach to the Skull Base, Chapter 8, Jackson G, Johnson GD, Poe DS in Surgery of the Skull Base, ed Jackson CG. New York, Churchill Livingston, 1991 p 141-196.









Jugular Foramen Schwannoma


Although schwannomas are the second most frequently occurring tumor of the jugular foramen, they still are extremely rare. They arise from the Schwann cells of CN IX, X, and XI. The most common cranial nerve to be affected is the vagus nerve.7,8 The clinical distinction between glomus vagale tumors and vagale schwannomas is that glomus vagale tumors develop vocal cord paralysis early in their course.9


Presentation of a jugular foramen schwannoma depends on the growth pattern. Kaye and colleagues10 categorized three different patterns: A, B, and C. Type A tumors occur primarily in the posterior fossa. Type A tumors with intracranial extension may manifest with CN IX, X, or XI palsies. Similar to most cerebellopontine angle tumors, hearing loss or imbalance or both may be the only significant presenting symptoms. Type B tumors remain confined to the skull base with extension often into the clivus. Type C tumors begin in the jugular foramen and extend inferiorly into the neck. Type B and C tumors manifest more frequently with lower cranial neuropathies than type A tumors.10


Radiologic assessment is performed with magnetic resonance imaging (MRI) and CT. MRI of the jugular foramen schwannoma shows a smooth contoured mass isodense on T1-weighted images, high signal intensity is usually noted on T2-weighted images, and significant enhancement occurs on T1-weighted gadolinium scans. CT is helpful in differentiating schwannoma from glomus jugulare tumors. Schwannomas tend to produce smooth erosion of the jugular foramen. Glomus tumors tend to show an irregular bone margin at the jugular foramen. The third most common lesions in this area are meningiomas of the jugular foramen. These lesions may be difficult to distinguish from schwannomas preoperatively. An enhancing dural tail on MRI is helpful. They also tend to infiltrate the bone around the jugular foramen, rather than smoothly enlarge it.



PREOPERATIVE EVALUATION


Thorough preoperative evaluation permits surgical planning for complete and safe tumor removal. Advances in imaging technology now permit accurate preoperative assessment of tumor involvement within the temporal bone. The following tests are routinely used in the evaluation of patients with glomus tumors of the temporal bone.





Magnetic Resonance Imaging


Because bone involvement by tumor is not clearly shown on MRI, this technique provides only adjunctive information regarding the extent of tumor involvement. If the diagnosis is in question, MRI combined with CT provides exquisite preoperative guidance in the differential diagnosis of petrous apex lesions.11 MRI can indicate occlusion of the jugular bulb and vein because the normal flow signals are altered. In intradural tumors, MRI can delineate more clearly the tumor-brain interface and the relationship of the lesion to the intradural structures. MRI must be interpreted cautiously because T1 images of glomus tumors may overestimate the degree of tumor involvement. Marrow-containing bone of the petrous apex is hyperintense and indistinguishable from enhancing tumor in the petrous apex. Magnetic resonance angiography and MR venography offer another diagnostic tool in evaluating glomus tumors. In their present form, however, MR angiography techniques cannot provide adequate imaging resolution to define feeding vessels to the tumor. CT angiography is another promising technology in evaluating vascular temporal bone lesions12; however, the role of these techniques in the preoperative assessment of glomus tumors has not been fully clarified.13,14




Brain Perfusion and Flow Studies


For tumors that abut the ICA, it is necessary to assess the adequacy of the cerebral cross-perfusion from the contralateral ICA. Cross-compression angiography, stump pressure measurements, and clinical evaluation during test occlusion of the involved carotid are basic guides to the risk of stroke in the event that the affected carotid artery must be sacrificed. Xenon blood flow and radioisotope studies offer much more precise quantification of the risk of stroke and the possible need for surgical replacement of the ICA.15 In certain cases with extensive invasion of the carotid artery and acceptable results on the perfusion studies of the contralateral artery, the involved carotid artery may be permanently occluded with a detachable balloon. We generally do not recommend carotid sacrifice. Despite excellent advances in diagnostic flow studies, an appreciable risk (about 5%) of stroke exists with carotid artery sacrifice even in cases with favorable functional and perfusion characteristics or test occlusion studies. If possible, repair or graft replacement of the carotid is recommended if the carotid is injured during tumor removal.



Embolization


Large glomus tumors may result in significant intraoperative blood loss. We have found that preoperative embolization of feeding vessels can significantly reduce such loss.16 The embolization is usually performed with polyvinyl alcohol (Ivalon) and is performed at the time of angiography 1 or 2 days before surgery. A longer interval between embolization and surgery may result in collateral blood flow to the tumor, which may paradoxically increase tumor perfusion and intraoperative blood loss.





SURGICAL APPROACHES


The following surgical techniques are used for removal of glomus tumors of the temporal bone. The specific approaches described correspond to the tumor classification system described earlier.



Transcanal Approach


The transcanal approach is used for small glomus tympanicum tumors that are limited to the mesotympanum. Because the entire circumference of the tumor is visible within the middle ear, preoperative imaging studies are unnecessary. If there is any doubt of the possibility of an aberrant ICA, however, preoperative CT scanning should be obtained to exclude this possibility. The tympanomeatal flap is modified with the inferior incision extending more anteriorly so that the inferior aspect of the tympanic membrane can be elevated. The tumor is identified on the promontory (Fig. 46-1).



The inferior tympanic branch of the ascending pharyngeal artery supplies the glomus tympanicum tumor. The vessel may be controlled with bipolar cautery or a small piece of absorbable knitted fabric (Surgicel) to occlude the bony canaliculus from which the vessel arises. It is crucial to avoid unipolar cautery on the tympanic promontory because this may severely injure the cochlea.


The tumor is removed with cup forceps. The brisk bleeding from the distal end of the artery anterior to the stapes (near the cochleariform process) is difficult to control directly; however, it usually clots readily. Small pledgets of Surgicel assist in hemostasis; the tympanomeatal flap is replaced, and the ear canal is packed. No specific dressing is necessary, and the patient is ready for hospital discharge the following day. Accurate preoperative assessment is crucial for success with the transcanal approach for glomus tympanicum tumors. If the entire circumference of the lesion is not visible through the meatus, the hypotympanotomy or mastoid–extended facial recess approach should be considered.


Tumors with limited hypotympanic extension without posterior involvement on CT scan may be removed by a modified transcanal (hypotympanic) approach.17

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Jun 14, 2016 | Posted by in OTOLARYNGOLOGY | Comments Off on Surgery for Glomus Tumors and Other Lesions of the Jugular Foramen

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