Glomus tympanicum and glomus jugulare tumors

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PARAGANGLIOMAS OF THE HEAD AND NECK

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GLOMUS TYMPANICUM AND GLOMUS JUGULARE TUMORS C. Gary Jackson, MD, FACS

Advances in antibiotic therapy, radiology, and microsurgery have expanded the limits of otologic surgery, and have improved surgical control and rehabilitation after resection of neoplastic lesions of the ear and temporal bone. Most temporal bone lesions are benign. Progression can be so slow that ongoing neurologic deficits may undergo simultaneous compensation and go unnoticed by the patient. Once they extend beyond the confines of this privileged site, these lesions ultimately cause temporal bone and neurologic consequences related primarily to the phonopharyngeal capacity of adjacent anatomy. Paraganglioma is the most commonly diagnosed neurotologic neoplasm after acoustic neuroma. Occurring more commonly in caucasians,38 Paragangliomas have been reported in all the female to male ratio is 5:1.24,38 age groups but most frequently occur in the fifth and sixth decades of life. They are usually solitary. A hereditary tendency with an autosomaldominant mode of inheritance has been identified.43,53 For familial tumors, the incidence of multiple paragangliomas is 25% to 50%.5,43'53 Generally, the incidence of multiple lesions is 10%. The ideal management of most paragangliomas is complete surgical excision. Because of technical advances, issues of resectability have given way to issues of functional outcome and postsurgical quality of life. Effective reconstruction of sizable defects and rehabilitation of cranial nerve deficits, now routine, diminish the most common argument against surgery in the management of these tumors: the perceived risk of longterm functional disability. As an alternative, radiation therapy is proposed as a low-morbidity conservation strategy. The semantic dialogue discriminating between disease cure and disease control emerges. From The Otology Group, Nashville, Tennessee

OTOLARYNGOLOGIC CLINICS OF NORTH AMERICA VOLUME 34 NUMBER 5 * OCTOBER 2001

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This article reviews the surgical strategy for craniocervical parag a n g l i ~ m a s Intracranial .~~ extension, defect reconstruction, and cranial nerve rehabilitation are addressed." HISTORICAL PERSPECTIVE Surgery for paragangliomas and acoustic neuromas provides a focal point around which modern neurotologic skull base surgery has evolved over the past 50 years. Surgical adaptation and new challengesconsistently have been spurred on by diagnostic advances, which have enabled surgeons to better define extent of disease. A brief review of the principal events that led to current treatment options is appropriate. In 1945, R o s e n ~ a s s e rresected ~~ a middle ear lesion that he associated with Guild'sz4original description of glomus tympanicum. In 1949, L ~ n d g r e nattempted ~~ jugular bulb resection. As late as 1950, however, operations were limited to exploration of these tumors because of the extraordinary morbidity and mortality rates associated with Gastpar" advocated total tumor removal and sacrifice of cranial nerve VII and the labyrinth. In 1952, Capps5 considered facial nerve mobilization and elaborated on basic principles for dealing with the jugular bulb. 27,49, 71 Radiation Suboccipital and alternative routes were unsuc~essful.~~~ therapy became the preferred treatment.69 Polytomography,retrograde jugulography, and conventionaland subtraction angiography enhanced tumor delineation and diagnosis and prompted new developments. In 1964, Shapiro and Neues71 proposed complete resection of the paraganglioma by rerouting cranial nerve VII and widely exposing neck anatomy. Gejrot,19 in 1965, declared cure was possible only by jugular bulb resection, and advocated elaborate imaging detail and total isolation of the jugular venous system during surgery. Conservation surgery and the extended facial recess first was proposed by House in 1969.28Hearing and the external auditory canal could be preserved. In the 1970s, sporadic reports of complete successful tumor resection began to appear.I7,zo, 27, 76 Gardner et all7advocated surgery combined with radiotherapy. Fisch,14 in 1977, proposed the infratemporal fossa exposure for disease that extended beyond temporal bone confines. The internal carotid artery, clivus, and parasella; regions were no longer off limits.15,22,47 In 1980 and 1982, respectively, Kinney50 and Fisch13 addressed the problem of intracranial extension. Staging usually was recommended. Jackson et a141described a single-stage strategy for lesions extending intracranially. Later, they established guidelines for defect reconstruction and prevention of cerebrospinalfluid Emphasis on conservation surgery and functional outcome continued to mount.',35,39,40 Jackson and Netterville further emphasized reconstruction, cranial nerve rehabilitation, and hearing c o n s e r ~ a t i o n .Data ~ , ~ from ~ large series document the successful use of surgery.'6,44,60

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TUMOR CLASSIFICATION Accurate tumor classification is essential for tumor surgery planning and reporting standards. first ~ proposed an anatomic Alford and Guilford,' in the early 1 9 6 0 ~ classification. Systems in current use were developed by FischI4 and Oldring and Fis~h,5~ who proposed A, B, C, and D classifications, as follows: Type A: Tumors limited to the middle ear cleft Type B: Tumors limited to the tympanomastoid area Type C: Tumors involving the infralabyrinthine Type D1: Tumors with an intracranial extension less than 2 cm in diameter Type D2: Tumors with an intracranial extension larger than 2 cm in diameter The Glasscock-JacksonZ,37 system retained the basic tympanicumjugular dichotomy, expanding it according to tumor extent. In this scheme, intracranial extension is expressed as a superscript (e.g., a paraganglioma type IV2.0is a type IV lesion with 2 cm of intracranial extension). The classification for glomus tympanicum is as follows: Type I: Small mass limited to the promontary Type 11: Tumor completely filling middle ear space Type 111: Tumor filling middle ear and extending into mastoid process Type IV Tumor filling middle ear, extending into mastoid or through tympanic membrane to fill external auditory canal; may extend anterior to internal carotid artery The following is the classification for glomus jugulare: Type I: Small tumor involving jugular bulb, middle ear, and mastoid process Type 11: Tumor extending under internal auditory canal; may have intracranial extension Type 111: Tumor extending into petrous apex; may have intracranial extension Type IV Tumor extending beyond petrous apex into clivus or infratemporal fossa; may have intracranial extension

TUMOR BIOLOGY The term glornus is a misnomer because these tumors originate from special neural crest elements, the paraganglion cells, which, with autonomic ganglion cells, form the ~ a r a g a n g l i a . *The ~ , ~paraganglia ~ are part of the neuroendocrine system usually associated with the sympathetic gan63 glia, and consist of the adrenal medulla and extra-adrenal ~araganglia.~~, Paragangliomas may arise from adrenal and extra-adrenal sites and are classified accordingly.

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The distribution of craniocervicalparagangliomas is along the arteries and cranial nerves of the ontogeneticgill arches. They are derived from the branchiomeric system, and may be jugulotympanic, intercarotid, coronary, orbital, aorticopulmonary, pulmonary, coronary, or laryngeal. The vagal paraganglia are considered separate.*,63 Temporal bone glomus bodies are ovoid, lobulated structures vascularized by the inferior tympanic branch of the ascending pharyngeal artery. They average three per side and are in association with Jacob~on’s~,*~ and Arnold’s nerves. Vagal paraganglia occupy the epineurium of the nerve.= The ultrastructural appearance of paragangliomas mimics that of the paraganglia.62The chief cells are filled with cytoplasmic granules containing catecholamines.Light and dark chief cells can be identified. BIOCHEMISTRY

The chief cells of the paraganglia are one of 40 types classified in the DNES, and can produce neuropeptides and catecholamines. The neuropeptides can serve as neurohormones, neurotransmitters, hormones, and para hormone^.^^,^',^^ The biochemical behaviors of these tumors is variable, depending on the substance elaborated. Catecholamine elaboration, dopamine secretion, carcinoid syndrome, and paraneoplastic anemia have been reported.: Symptomatic tumor secretion is functional or secretory. Approximately 1% to 3%of paragangliomas are functional. The presence of immunoreactive peptides can be used to diagnostic advantage. Iodine-labeled type 3 octreotide, a somatostatin analogue, is used in octreotide ~ c a n n i n g . ~The 5 , ~ tendency toward malignancy is implied through immunohistochemical analysis of the ratio of chief cells to sustentacular cells and marker reactivity in sustentacular cell^.^^,^ Pheochromocytoma, thyroid and visceral neoplasms, parathyroid adenoma, and multiple endocrine neoplasia syndromes are associated with paraganglioma~.4~,~~, 79 Additional tumors can be ipsilateral or contralatera1 in various permutations in any of the branchiomeric paraganglionic stations. The most common association is glomus jugulare and carotid body t~~mors.4,41.43,52,77 Paragangliomas rarely exhibit malignant degeneration. The first study of a paraganglioma metastatic to the liver was reported in 1948.5’ Approximately 30 cases have been reported since then. The incidence of malignancy varies between 1%and 12%; 4% is the most commonly quoted Regional or distant metastases can be diagnosed only by incidence.’, the appearance of paraganglioma in sites not known as paraganglial locations. The diagnosis cannot be made histologically. The regional lymph nodes, skeleton, lung, and liver are common metastatic sites.30Splenic metastases are rare. Vagal paraganglioma malignancy rates are higher, at 19%.’,11,80 Symptoms, clinical course, cranial nerve deficits, and morbidity 11,43780

*References3,12,26,55,57,62,67,68, and 74.

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and mortality rates are higher in malignant tumors. Prolonged survival with active disease, however, is possible.',

DIAGNOSIS

Clinical The most common physical sign in paraganglioma diagnosis is a vascular middle ear mass. A mesotympanic mass is characteristic, but may be absent. The differential diagnosis of such a mass is globally small. A high jugular bulb is usually visually differentiable; it is posterior and more blue. A facial nerve neuroma can appear less vascular, and often is confined to the upper quadrants. Critically, an aberrant internal carotid artery must be differentiated from paraganglioma; it is often anterior in the mesotympanum. Primary neoplasms of the middle ear, meningioma, and AN are often not separable. Brown's sign is an uncommon physical finding (10%-30%). Superior mesotympanic paragangliomas occur rarely. The most common presenting symptom is pulsatile tinnitus (80%)followed by hearing loss (60%). Invasion of the labyrinth determines the degree of sensorineural hearing loss. TM erosion and bleeding are late symptoms. Lower cranial nerve dysfunction is common with paragangliomas and includes dysphagia, hoarseness, aspiration, tongue paralysis, shoulder drop, and voice weakness. Facial nerve paralysis signals advanced disease, and is an indication of poor facial nerve prognosis. Symptoms of functioning tumors must be sought. Otoscopy can be misleading. The mesotympanic mass, the margins of which are visible at 360", can be identified as a glomus tympanicum tumor. The same mass, the margins of which cannot be identified, must be assumed to be a glomus jugulare tumor until proved otherwise. Myringotomy and biopsy are to be avoided. Hemorrhage and the ensuing brisk bleeding can be controlled only by transcanal packing, which risks structural damage to the ear. If tissue is required for diagnosis, a postauricular, transmastoid approach, in which all vital anatomy is identified and bleeding can be safely controlled, is advisable.

Tests and Imaging

To formulate an effective treatment plan, the following diagnostic objectives must be met: Determining tumor size, extent, type (e.g., glomus tympanicum versus glomus jugulare tumor) Assessing for associated lesions Evaluating for neuroendocrine secretion Determining intracranial extension Assessing large vessels and collateral circulation

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The CT scan with thin-section temporal bone detail is the best test to differentiate glomus tympanicum tumors from glomus jugulare tumors and to assess the extent of the tumor relative to the vital anatomy of the temporal bone. CT scanning is performed in axial and coronal planes. An intact jugular bulb defines a glomus tympanicum tumor. In the series by Forest et a1,'6 in 100 glomus tympanicum tumor lesions, secretory or associated lesions were identified in all but one. Once a glomus tympanicum tumor is identified, no further studies are performed unless there are signs or symptoms of neuroendocrine behavior or there is a familial pattern. Figures 1 and 2 are CT scans of a tympanic paraganglioma and jugular paraganglioma, respectively. If a jugular paraganglioma is present, intracranial extension and the relation of the tumor to the regional neurovascular anatomy are assessed best by MR imaging. MR imaging is performed on the head and neck to assess multicentricity. Figures 3 and 4 are MR images of a jugular paraganglioma. Bilateral carotid angiography is performed to evaluate the relationship of the tumor to the internal carotid artery, and is done immediately preoperatively so that embolization can be accomplished simultaneously (Figs. 5 and 6 ) .The value of angiography also is used to determine tumor blood s~pply.4~ The value of embolization has been well documented,5'. 66, 78 and embolization should precede surgery by no longer than 72 hours. The author believes that 24 hours is the ideal time.

Figure 1. On this axial CT scan, the jugular bulb is uninvolved by the right tympanicum tumor.

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Figure 2. The right GJ lesion approaches the IAC and is destructive within the TB.

Figure 3. The GJ tumor surrounds the ICA on this MR image.

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Figure 4. MR imaging defines ICE.

Figure 5. GJ angiography prior to embolization.

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Figure 6. Successful ernbolization of the GJ lesion in Figure 5 is identified.

If catecholamine screen is elevated significantly (all are one to two times normal), pheochromocytoma must be differentiated. An exhaustive search for lesions below the clavicle is not routine because they rarely occur. MANAGEMENT Treatment Planning

Treatment for paraganglioma is palliative or curative. Observation and radiation therapy are palliative. Surgery is curative. A treatment plan is individualized based on diagnostic survey outcome, patient age and health, and tumor type. Observation is selected when, in the natural course of the patient’s projected lifespan, the paraganglioma is not expected to cause excessive morbidity or mortality. A patient’s with a paraganglioma does not mandate treatment. The paraganglioma is imaged annually to assess its individual biologic behavior. For the symptomatic patient or for the patient in whom the paragangliomal biology is too aggressive for surgery, radiation therapy is recommended. If synchronous lesions are present, the most life-threatening lesion is operated on first. The postsurgical neurological outcome then determines future management. Bilateral paragangliomas are challenging.

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After one is operated on and the patient emerges neurologically intact, the residual lesion is operated on no earlier than 6 months postoperatively. Neurological sequelae from the first operation may mandate palliation. Phonopharyngeal denervation and deafferentation bilaterally are to be avoided. Surgery is curative for all others. Radiation Therapy

The best primary treatment for paraganglioma is debated among surgeons and radiation therapists. Cummings et a18articulated the position on radiation therapy: ”. . .the relief of symptoms and the failure of the tumor to grow during the remainder of the patient’s lifetime is a practical measure of successful treatment.” The suggestion that irradiated paragangliomas consist of benign inert cellular debris is i n a c c ~ r a t e . ~ , ~ ’ ~ ~ , ~ ~ Jackson et al” reviewed 157 studies that addressed radiation therapy for paraganglioma.Although growth was arrested in several patients, a high incidence of hearing loss, CNS damage, osteoradionecrosis, and radiation-induced malignancy occurred.They concluded that the real risks of radiation therapy are long-term, ongoing, and undetermined. Stereotactic radiation therapy preliminarily has been proposed for the treatment of primary or recurrent paragangli~mas.~~ Surgery speaks to disease cure; radiation therapy to disease control; and coexistence with a biologically altered tumor. In most cases, surgical outcome is predictable and finite. Latency is a state of inconclusion for radiation therapy. Data regarding the best paraganglioma treatment by radiation therapy or surgery do not exist. Radiation therapy should not represent primary treatment for glomus tympanicum tumor, because the risks of surgery are low. Surgical Fundamentals

Paraganglioma growth is multidirectional and occurs as the tumor spreads from its point of origin along tracts of least resistance, predominantly the air cell system of the temporal bone. Vascular lumina, neurovascular foramina, and the eustachian tube provide routes of extratemporal extensionintracranially,into the infratemporal fossa or along the skull base. Bone erosion is by ischemic necrosis. Routes of extension are highlighted in Figure 7. This variable tumor extent mandates a system of surgical, multidisciplinary approaches that can create an operation to match the patient’s disease, not vice versa (Fig. 8). The approach must provide the following: Access to all tumor margins Access to intracranial extension Exposure for control of major vessels and cranial nerves (Text continued on page 952)

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Figure 7. From the hypotympanum, routes of tumor extension are quite variable.

Figure 8. Like the surgical team, the surgical approach must be individualized and totipotential.

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The facial nerve and internal carotid artery are critical landmarks in the successful execution of paraganglioma surgery. The Facial Nerve

In the lateral base of skull surgery, the facial nerve is an anatomic impediment to exposure of the tumor and the internal carotid artery. Its intrinsic blood supply allows its mobilization over long distances?* The intrinsic blood supply is derived from its extrinsic sources, which supply cranial nerve VII. It courses in and along the nerve so that relocation from isolated extrinsic sources is not neurologically disruptive. Tumor size and the consequent demands for internal carotid artery control determine what must be done with cranial nerve VII. Options include simple exposure, short mobilization, long mobilization, or segmental resection. Short mobilization from the external genu laterally is consistent with high-grade facial nerve function. For larger tumors, long mobilization from its internal genu is required. Transient facial paralysis usually results. Long-term outcome is generally satisfactory (grades 11-IV). Segmental resection rarely is indicated, but uniformly is heralded by preoperative facial nerve paralysis. When previous facial nerve function is within normal limits, facial nerve dissection from the paraganglioma is always advisable and usually successful.Preoperative paralysis is an ominous facial nerve sign. Reanimation is usually possible by end-to-end anastomosis or by interposition graft. Intraoperative facial nerve monitoring aids facial nerve preservation and postsurgical outcome. Internal Carotid Artery

Proximal and distal control of major vessels is fundamental to all vascular surgery, and is an inherent principle in paraganglioma surgery. Proximal control is achieved in the neck, whereas distal control is dictated by tumor size. Neurotologic skull base surgery must be able to access the tympanic, petrous, precavernous, and intracranial internal carotid arteries. The condition of the internal carotid artery or its level of involvement by paraganglioma cannot always be ascertained accurately before surgery. Guidelines for internal carotid artery sacrifice remain uncertain.70Preoperative or intraoperative internal carotid artery occlusion is reserved for only the most extraordinarycircumstances.In all cases in which the internal carotid artery is sacrificed, circulation is reconstituted with interposition grafting or extracranial bypass. Internal carotid artery spasm occurs in response to the longitudinal stretch of vascular musculature and can be catastrophic. If it occurs, manipulation should cease, and the problem should be managed topically or by injection of the arterial wall with appropriate medications. In refractory cases, manual dilation or surgical resection of the spasmodic segment with reconstitution by graft must be considered promptly.”

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Surgical Techniques Glomus Tympanicum Tumors

All type I glomus tympanicum tumors, the margins of which can be seen circumferentially,can be exposed and removed by transcanal tympanotomy ~ t r a t e g i e s . ~ ~ When any margin is indistinct on otoscopy (i.e., types 11-IV), a postauricular, transmastoid approach, using the extended facial recess or the infratympanic extended facial recess approaches should be ~ s e d . ~ ~ , ~ Only through these exposures can the relationship of the glomus tympanicum tumor to the internal carotid artery, ossicular chain, TM, labyrinth, facial nerve, and jugular bulb be assessed accurately (Figs. 9 and 10). Once the glomus tympanicum tumor margins are assessed fully and the tumor is mobile, it can be removed. Usually pedicled on the tympanic branch of the ascending pharyngeal artery, once cauterized, blood loss is minimal and the tumor can be removed. Bipolar electrocautery can be used to shrink and mobilize the tumor in the middle ear. Recently, defocused lasers have been used to accomplish the same If the ossicular mechanism or the TM is involved, resection deficits can be repaired by traditional tympanoplastic techniques. A canal wall down strategy rarely is indicated but when exposure dictates, it is promptly executed. Attachment and involvement of the jugular bulb necessitates abortion of the procedure and the patient’s return for a larger procedure. Bipolar electrocautery, Surgicel or Gelfoam (topical local hemostats) can control residual bleeding in the tumor bed. Facial nerve neural integrity monitoring is used during all cases. The operation lasts 1to 2 hours, and the patient is discharged the same day.

Figure 9. The postauricularextended facial recess approach.

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Figure 10. The infratympanicextended facial recess approach.

Glomus Jugulare Tumor Types I and II

For tumors confined to the infralabyrinthine chamber, involving only the tympanic segment of the internal carotid artery, a hearing conservation approach can be used (i.e., the external auditory canal and the middle ear structures are conserved). The incision should allow access to the temporal bone and neck. The carotid arteries; internal jugular vein; and cranial nerves IX,X, XI, and XI1 are isolated and controlled. The extratemporal facial nerve is identified. The internal carotid artery is exposed and secured with vascular loops. The internal jugular vein is ligated, and the lateral venous sinus is occluded. Complete mastoidectomy is performed with removal of the mastoid tip. An extended facial recess exposure is made through removal of the inferior temporal bone and skeletonization of the inferior-anterior external auditory canal, which is preserved. This step allows access to the mesotympanum and exposure of the tympanic internal carotid artery to the level of the eustachian tube. The facial nerve undergoes short mobilization. Proximal control of the lateral venous sinus is achieved by intraluminal packing with oxidized cellulose absorbable hemostat (e.g., Surgicel).The tumor is dissected from the internal carotid artery and is mobilized from the infralabyrinthine space. Opening the jugular bulb to remove the intraluminal tumor causes bleeding from the inferior petrosal sinus. This bleeding is controlled by packing. Delicate dissection of the glomus jugulare tumor from the contents of the pars nervosa and hypoglossal canal is critical to preserve the lower cranial nerves (Figs. 11to 13). (Text continued on page 956)

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Figure 11. GJ tumor incision. The vertical dissection is executed only for temporoparietal fascia.

Figure 12. Distal control of ICA in small tumors can be achieved allowing for hearing conservation.

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Figure 13. The EAC is skeletonized, the FN mobilized (short), and the ICA fully controlled.

Glomus Jugulare Tumor Types 111 and IV When the tumor extends beyond the temporal bone into the infratemporal fossa or when control of the petrous internal carotid artery is needed, a modified or extended infratemporal fossa approach is necessary. These approaches provide access to the deep recesses of the temporal bone, infratemporal fossa, clivus, nasopharynx, and cavernous sinus. The posterior, middle, and anterior cranial fossae can be accessed expediently if intracranial extension exists. Complete conductive hearing loss is conceded. The same incision used for types I and I1 glomus jugulare tumors is executed, but the external auditory canal is transected and oversewn. The external auditory canal, TM, and middle ear contents lateral to the stapes are resected. Access to the petrous internal carotid artery and infratemporal fossa necessitates anterior and inferior dislocation of the mandible by dividing its anteromedial ligaments. The facial nerve undergoes long mobilization. Current technical modifications preserve the periosteal tissue of the stylomastoid foramen and soft tissue surrounding the facial nerve during translocation. Mandibular retraction or segmental resection may be necessary to gain wider exposure. Access may be extended farther when the anterosuperior

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extension of the tumor is extreme. When the zygoma and the temporomandibular joints are resected together, the temporalis muscle is reflected inferiorly, the mandible is dislocated anteroinferiorly, and the infratemporal fossa can be accessed widely. The eustachian tube is resected, and the contents of the foramen spinosum are sacrificed as the internal carotid artery is exposed and mobilized from the pterygoid region to its precavernous segment. Access to the middle cranial fossa, nasopharynx, foramen rotundum, clivus, posterior cranial fossa, and cavernous sinus is possible. Tumor resection proceeds as previously described (Figs. 14 to 17).

lntracranial Extension The spread of the tumor through the dura into the subarachnoid space is intracranial extension. All paragangliomas push the dura ahead of it, but may not violate this barrier. A historical criterion of unresectability, the current trend is to consider the tumor and its intracranial extension a single lesion. Its resection at a single stage and single unit, in an oncologi41, 48, 50, 65 The spread of the tumor, cally sound procedure, is preferred.21,36, through dura, into the posterior cranial fossa is direct or along cranial nerve routes by way of the pars nervosa (Fig. 18). Single-stage resection is complicated because of cerebrospinal fluid defect reconstruction. Unlike the unidimensional problem of cerebrospinal fluid management for acoustic neuroma, the challenge of neurotologic

Figure 14. The EAC is transected and oversewn.

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Figure 15. Anteroinferior mandibular dislocation and long facial nerve mobilization provides petrous ICA control and safe high GJ dissectiori.

Figure 16. The zygoma, temporal muscle, and mandible are reflected as a unit to unveil the infratemporal fossa.

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Figure 17. With minimal MCF exposure, ICA is accessible to its precavernous segment and IFTF exposure is luxurious.

Figure 18. PCF, transdural ICE.

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skull base surgery is more complex. In neurotologic skull base surgery, the following obstacles exist: More complex bone and soft-tissue defects Local tissues may not be available for defect reconstruction Cerebrospinal fluid pressures exacerbated by venous occlusion Regional tissue effects of radiotherapy and external carotid artery sacrifice All cases have internal carotid artery exposure To manage intracranial extension at a single stage successfully, this challenge must be met by various reconstruction strategies, ranging from the simple to the multidisciplinarily complex. Exposure for access to the posterior cranial fossa, anterior cranial fossa, or middle cranial fossa is usually expedient (Figs. 17 to 19). The operative sequence is as follows: The section of paraganglioma from internal carotid artery to the infratemporal fossa Debulk paraganglioma from temporal bone down to dura Resect intracranial extension Defect reconstruction Defect Reconstruction

Defect reconstruction is size dependent. Extreme solutions are reserved for only extreme problems. Simple, small defects may require complicated reconstructions because of covariates (e.g., a small defect may require a complicated strategy because of a precondition of radiotherapy or

Figure 19. Access to ICE in these exposures, particularly with the LVS taken, is expedient.

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external carotid artery devitalization of regional tissues). The following basic principles for defect reconstruction, however, are observed uniformly: Defect reconstruction is done exclusively with vascularized tissue Tissue bulk is added to reinforce the dural reconstruction and to resist cerebrospinal fluid pressure Cerebrospinal fluid decompression by lumbar drain In any case, from the skin incision through deeper tissue planes, careful and responsible tissue manipulation and mobilization are executed with the ultimate objective of a cerebrospinal fluid tight closure.31,43,45,46 The incision should allow access to the superficial vascularized temporoparietal fascia based on the superficialtemporal artery. A vital sternocleidomastoid musculofascial flap is created and mobilized to facilitate closure, which is watertight with or without the external auditory canal present (Fig. 20).

Figure 20. A-C,

Intelligent development of the watertight flap closure after tumor resection.

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Small defects, perhaps after paraganglioma removal and a limited defect at the pars nervosa, are reconstructed by careful harvesting and mobilization of the vascularized temporal parietal fascia into the defect. Even when the external auditory canal is present and the middle ear and ET are open, this flap is luxurious enough to exclude this area from the defect (Fig. 21). A free abdominal fat graft and meticulous wound closure exhibited in Figure 20 support the flap. A lumbar drain decompresses cerebrospinal fluid for approximately 5 days. When defects are larger, complicated by previous radiation or devitalized regionalized tissue, or when the case may be a revision, great bulk and more reliable vascularization frequently are required. The internal carotid artery also must be covered. Anterior flaps are not preferred because most patients are wome In this population, the lower trapezius flap or, in more extreme circumstan es, a free flap is used. The author prefers the work-horse rectus abdominis (Figs. 22 and 23). A lumbar drain also is applied in both strategies.

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Cranial Nerve Rehabilitation

In the treatment of advanced lesions, existing or new cranial nerve loss is part of neurotologic skull base surgery. Cranial nerves IV through XI1 and the sympathetic trunk are particularly vulnerable. Loss in the elderly or loss in aggregate prompts phonopharyngeal morbidity by interdicting the complex integration of the lower cranial nerves’ control of swallowing and phonation. Before rehabilitationstrategies and during the gastrostomy and tracheotomy periods, postsurgical rehabilitation was prolonged and inadequately complete.

Figure 21. A and 6, Based on the superficial temporal artery, the temporoparietalfascia flap is utilitarian in the TB.

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Figure 22. A and B, The lower trapezius flap for moderate dural defect reconstruction.

Rehabilitation strategies outlined by Netterville et a15* and The Otology Groupzzhave shortened in-patient care, time to first deglutition, and recovery time dramatically. Speech and voice are improved, oral intake is facilitated, and outcome horizons are elevated. The morbid aftermath of neurotologic skull base surgery is minimized by the following: Silastic medialization of the vocal cord In the first postoperative week, Gelfoam injection is used In approximately 3 months, vocal cord medialization is planned Arytenoid adduction is optional Primary phonosurgery no longer is performed Unilateral palatal adhesion When velopharyngeal insufficiency is a problem, the soft palate is sutured to the posterior pharyngeal wall unilaterally

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Figure 23. A and B, The preferred rectus abdominus free flap should be oversized to allow for shrinkage.

Nasal competency in speech and deglutition is restored Hypernasality is eliminated Sleep apnea is not a problem Facial nerve support is compulsive Eye care Gold lid weights Shoulder rehabilitation is successful

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RESULTS Glomus Tympanicum The charts of 95 patients with a diagnosis of glomus tympanicum tumors seen by The Otology Group from May 25,1972, to July 3,1998, were reviewed.34Of these 95 patients, a diagnosis other than glomus tympanicum tumor was made in 15patients; the study population was 80. Followup ranged from 1 to 244 months; the average was 55 months. Twenty-two patients were followed for more than 5 years; 14 patients were followed for more than 10 years. Six patients were lost to follow-up. The average age was 53 years of age (range: 29-76 years of age). The female to male ratio was 10.4:l. The average symptom duration before diagnosis was 28 months. The most common presenting symptom was pulsatile tinnitus (73%),followed by hearing loss (49%), and aural fullness (39%).A middle ear mass was seen in 100%. Brown’s sign was present in 8.8%.Glasscock-Jackson classificationwas type I in 34%, type I1 in 52%, type I11 in 3%,and type IV in 11%. Urine catecholamines, MR imaging, MR angiography, angiography, and all other studies were negative except for one patient with a significant family history. No associated lesions were identified. A mastoid approach was performed in 89%; canal wall down approach was performed in 16%. Transcanal approach constituted 11%.There were two recurrences at 3 and 14 years postoperatively; one may have been a second tumor identified at the geniculate ganglion. There were four subtotal resections. Surgical control was 92.5%. There was one major complication: a cerebrovascular accident after internal carotid artery dissection of a glomus tympanicum tumor caused hemiparesis, which resolved to cane mobility. There was one facial nerve paralysis that, when decompressed, completely recovered.

Glomus Jugulare and Skull Base Vagal Paragangliomas Patient charts for neurotologic skull base surgery at The Otology Group from January 1970 to January 1998 were reviewed (N = 279).29One hundred eighty-two neurotologic skull base surgery procedures were performed in 176 patients for skull base paragangliomas: 152 for glomus jugulare tumors; 27 for GV; and 3 for carotid body tumors with skull base extension. The average patient age was 41 years old (range: 9-78 years of age). Average follow-up was 4.5 years, The female to male ratio was 2.59:1.127-49 ranging from 1to 279 months or 23.25 years. Glomus jugulare tumor classification was: class I, 21.4%; class 11,20.6%;class 111, 34.9%; class IV, 23%. Twenty-six (26%)tumors remained unclassified because they occurred before the development of the classification system. Preoperative evaluation yielded elevated catecholamines in 9.7%; multicentric lesions in 9%; previous surgery in 42%, and previous radiotherapy in 5.5%.Six (3.3%)patients had malignant tumors. Subtotal resection occurred in 18 patients (9.9%), mostly elderly patients who had internal carotid artery or cranial nerve preservation. Of

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these patients, 28%currently have no evidence of recurrent disease; 22% are alive with disease, whereas 50%have not been followed-up. There were nine recurrences (5.5%).Time to recurrence averaged 98 months (8.17 years; range: 25-273 months; median of 70 months [5.83years]).Seventy-eightpercent were identified in the first 10 years. Five patients5 underwent resection; two are being observed. One was treated with radiotherapy, whereas one was not followed-up. All nine recurrences were glomus jugulare tumors. The female to male ratio was 8:l. Twentytwo percent had previous surgery; no patient had previous radiotherapy. Preoperative cranial nerve deficits were present in 46% (cranial nerve VII, 18%;VIII, 13%;IX, 21%; X, 30%; XI, 17%;XII, 24%; any cranial nerve, 46%).Preoperative cranial nerve deficits were associated with a significantly (P < 0.01) higher incidence of intracranial extension. Preoperative deficits of cranial nerves IX, X, XI, and XI1 were associated with intracranial extension in 68%,63%,63%,and 56%,respectively. Aggregate lower cranial nerve resection is shown in Table 1. New cranial nerve deficits occurred for cranial nerve IX in 57%,X in 40%,XI in 62%,and XI1 in 54%of cases that involved the pars nervosa. New cranial nerve VII deficits occurred in 4.4%;all reanimated at operation. With intracranial extension, 67%resulted in resection of cranial nerves IX through XII. When preoperative cranial nerve deficits were present, pars nervosa was involved and the cranial nerve was resected in 61% ( P < 0.01). Without preoperative cranial nerve deficit or intracranial extension present, only 11% required cranial nerve resection. The pars nervosa was involved, and cranial nerves were resected in 100% of class IV lesions; 54% of class I11 lesions, 15%of class I1 lesions, and 0% of class I lesions. One or more new cranial nerve deficits occurred in 59% of all patients. New cranial nerve deficits of cranial nerves VII, IX, X, XI, and XI1 occurred in 4.4%,39%,25%,26%,and 21 %, respectively. Complete removal of the glomus jugulare tumor was possible without any cranial nerve resection in 31 %. Cranial nerve IX was sacrificed for internal carotid artery exposure in 19%. Preoperative

Table 1. AGGREGATE LOWER CRANIAL NERVE RESECTION Cranial Nerve 9,10,11,12 9,10,11 9,10,12 9,lO 9,12 9 10,11,12 10,11 10,12 10

12 None

Glomus Jugulare N (%)

Glomus Vagale N (Yo)

52 (34) 7 (4.6) 1 (0.6) 4 (2.6) l(0.6) 29 (19) 2 (1.3) l(0.6) 1 (0.6) 5 (3.2) 2 (1.3) 47 (31)

11 (41) l(3.7) l(3.7) l(3.7)

Carotid Body Tumor N (%)

2 (67) l(3.7) l(3.7) l(3.7) 10 (37) 1 (33)

Total N (%) 63 (35) 8 (4.4) 2 (1.1) 5 (2.7) l(0.5) 31 (17) 3 (1.6) 2 (1.1) l(0.5) 15 (8.2) 2 (1.1) 48 (26)

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paralysis of cranial nerve VII resulted in facial nerve resection segmentally in 100%. Intracranial extension was present in 36%of cases. Cerebrospinal fluid was encountered as an outcome of surgery or as a result of intracranial extension in 116 patients (64%).Before 1987, cerebrospinal fluid leakage occurred in 28%.After 1987,when the current defect reconstruction scheme was initiated, cerebrospinal fluid leak incidence was 4.5% ( P < 0.01). Of the three cerebrospinalfluid leaks, two were rhinorrhea, and there was one collection of cerebrospinal fluid in the neck after drainage of an abscess. The mortality rate was 2.7% (5 out of 182).Three53deaths were related to internal carotid artery resection, whereas two patients died of pulmonary emboli. These two pulmonary emboli were related to preoperative cr and blockades for tumor catecholamine secretion. Surgical tumor control (cure; control here is not equivalent to coexistence with tumor) was achieved in 85%.Complete tumor elimination, when attempted, was achieved in 95%. Because paragangliomas exhibit slow growth, recurrences may occur after many years; follow-up should be lifelong. Postoperative imaging of the head and neck is recommended at 1,3, and 5 years postoperatively and every 5 years thereafter. SUMMARY

Surgical resection of neurotologic skull base tumors using modern techniques is effective, safe, and predictable. The quality of postsurgical survival is extraordinary considering the acute magnitude of the process and its local impact on the patient as a whole.

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