Glomus Jugulare Tumors With Intracranial Extension

C. Gary Jackson, MD; David M. Kaylie, MD; George Coppit, MD; Edward K. Gardner, MD

Disclosures

Neurosurg Focus. 2004;17(2) 

In This Article

Clinical Material and Methods

Patient Population

Between January 1, 1971, and December 31, 2003, 228 patients underwent surgery for glomus tumors at our institution. The mean age was 33 years and the age range was 12 to 58 years. The male/female ratio was 2.3:1. One hundred ninety-two patients had glomus jugulare tumors, 33 had glomus vagale lesions with skull base involvement, and three had carotid body tumors with skull base involvement.

Diagnostic Methods

Clinical findings alert the clinician to the possibility of a lateral skull base lesion with involvement of the ear. Symptoms usually include pulsatile tinnitus and hearing loss. Conductive hearing loss is the result of mechanical obstruction of the ossicular mechanism by tumor, whereas sensorineural hearing loss is a consequence of labyrinthine involvement.[5] A vascular tumor is often seen in the inferior aspect of the middle ear. A glomus tympanicum tumor will sometimes have tumor margins that are visible for 360°, whereas the inferior border of a glomus jugulare tumor will not be visible.[4] Lower cranial nerve palsies can occur with tumor involvement of the pars nervosa.[5] "Idiopathic" vocal cord palsy or paralysis is an ominous sign indicating vagus nerve involvement. With the advancements in MR imaging, this diagnosis should be considered obsolete. A complete cranial nerve examination will elucidate the extent of pars nervosa involvement.

The goals of surgical planning are to determine the size, extent, and type of tumor (glomus tympanicum or jugulare), presence of associated lesions, and status of major blood vessels. Preoperative MR imaging is used to determine the type and extent of tumor. It can be used to determine intracranial extension accurately in 95 to 98% of cases,[6] and it provides information about the tumor's relation to the carotid region. A CT scan provides superior detail of bone involvement around the jugular bulb, carotid canal, and inner ear.[5] The axial and coronal neuroimages will reveal bone erosion of the jugular foramen and inner ear. Imaging of only the temporal bone is insufficient. Synchronous lesions are seen in 10% of patients with glomus tumors and 50% of patients with hereditary paragangliomas.[2] Therefore, MR imaging of the neck is mandatory. Angiography is performed in all patients the day before surgery. This provides information about patency of the major vessels and the tumor's relationship to these vessels. It also allows for preoperative embolization of the tumor. Embolization should be performed within 72 hours of surgery, and preferably within 24 hours.[4]

Paragangliomas have the potential for secreting catecholamines and neuropeptides.[2] Approximately 1 to 3% of all paragangliomas are secretors and are considered functional tumors.[4] The evaluation of a patient with a glomus tumor should specifically seek symptoms indicative of catecholamine production, such as palpitations, excessive sweating, and headaches. All patients should be screened with blood tests for elevated catecholamine metabolites. Patients who have "functioning" tumors need to receive both alpha and beta blockers preoperatively.[2] Paragangliomas have been associated with other neoplasms such as pheochromocytoma, thyroid neoplasms, parathyroid adenomas, and multiple endocrine neoplasm syndromes;[4] these need to be ruled out.

Surgical Approach

Surgical approaches to the cranial base are quite complex, requiring the expertise of practitioners from several disciplines,[7] including neurosurgeons, neurootological surgeons, and head and neck reconstructive surgeons. The various approaches have been described in great detail elsewhere (Fig. 3).[3] The basic surgical principle of wide exposure is particularly important for tumors with intracranial extension. The exposure afforded by the previously described bone dissection is extensive and will provide access to margins of the entire tumor and all vital vascular, neural, and intracranial structures (Fig. 4). Extension of the dissection for greater access to the posterior fossa is easily accomplished. The dissection can easily be enlarged to expose posterior or middle cranial fossae.

Figure 3.

Individualized surgical approaches require a coordinated multispecialty effort using combinations of various routes.

Figure 4.

A complete mastoidectomy has been performed with an extended facial recess. The mastoid tip is removed and vital neck anatomy is exposed and controlled.

The surgery proceeds in an orderly sequence, with attention paid initially to identification of the CA proximally in the neck and distally in the temporal bone. Proximal and distal control of major vessels is a cardinal principle of vascular surgery and holds true for glomus tumor surgery. The level of distal control is dictated by the extent of the tumor, which may necessitate dissection of the tympanic, petrous, or cavernous portion of the artery. It is critical to have 180° exposure of the CA to allow for instrumentation in the event of loss of integrity or resection of the artery.[3]

Facial nerve management options for tumors with intracranial extension require some degree of facial nerve mobilization (Fig. 5).[4] It is not possible to expose the jugular bulb adequately without mobilizing the facial nerve. A short mobilization extends from the external genu of the facial nerve to the parotid, and patients generally have excellent long-term facial function thereafter.[4] Larger tumors require a long mobilization from the internal genu laterally. Transient facial paralysis will occur, but long-term outcome is generally very good, resulting in House—Brackmann Grades II to IV.[4] Resection of the facial nerve is rarely necessary, but is unavoidable if the nerve is infiltrated by the tumor and dissection is not possible. Preoperative facial paralysis invariably is caused by tumor infiltration into the facial nerve. Exposure of the petrous CA and infratemporal fossa requires anterior—inferior dislocation of the mandible. This can only be safely done with mobilization of the facial nerve.[3]

Figure 5.

Long mobilization of the facial nerve is seen here. Tumor dissection from the internal CA can now proceed. The internal jugular vein is ligated and the lateral venous sinus is intraluminally packed.

Lower cranial nerve preservation is facilitated at this point by identification of the nerves in the neck. They can be dissected from the neck, where they are uninvolved with tumor, into the pars nervosa, and intracranially if necessary. This technique provides maximum safety and nerve preservation. The intracranial extension component of the tumor is then removed. When there is more extensive intracranial involvement, a larger posterior cranial fossa exposure may be necessary. This is easily accomplished; the prior bone dissection has afforded easy access for a posterior fossa craniotomy. Removal of tumor from the posterior fossa is rarely difficult because the tumor has been largely devascularized by this point in the surgery (Figs. 6 and 7).[6]

Figure 6.

The devascularized tumor is resected along with posterior fossa dura, leaving a medium-sized defect.

Figure 7.

The cerebellum is exposed in this medium-sized defect.

Reconstruction of Defects

Dural defects are the consequence of resection of tumors with intracranial extension. Because of this, prevention of CSF leaks is a particular challenge. Dural defect reconstruction is size-dependent and the complexity of the reconstruction should be tailored to the size of the defect.[5] Basic principles of defect reconstruction include exclusive use of vascularized tissue supported by tissue bulk to resist CSF pressure and to support the dural reconstruction. Lumbar drainage is uniformly used to decompress the CSF space.[4]

Successful defect reconstruction is dependent on the careful preservation and mobilization of tissues. The initial incisions are designed to provide the necessary surgical exposure, but equally important, they are designed to allow for reconstruction and closure (Fig. 8).[6] The workhorse of reconstructive flaps is the superficial temporalis fascia flap. Its design begins with the initial skin incision described by Netterville and Civantos (Figs. 9 and 10).[10] It is based on the anatomical description of the blood supply to this tissue by Abu-Hassan, et al.[1] Supportive tissue is necessary to provide bulk for cosmetic purposes as well as supporting dural reconstruction and internal CA coverage. Free abdominal fat works well. The sternocleidomastoid muscle flap is closed over the reconstruction to hold the fat packing firmly in place with pressure on the dural defect. This closure is used regardless of the presence or absence of the external auditory canal (Fig. 11). Lumbar drain age is used for 5 to 7 days to allow for adequate tissue healing.[6]

Figure 8.

The large C-shaped incision is outlined superior enough to prevent foreshortening of the superficial temporalis fascia flap. The incision is now modified to the smaller C-shaped incision.

Figure 9.

The superficial temporalis fascia flap has great size potential. This flap is supplied by the superficial temporal artery. The smaller deep temporalis fascia is supplied by the middle temporal artery.

Figure 10.

The flap is isolated down to a 1-cm pedicle surrounding the superficial temporal artery and vein. The length of this flap easily allows it to cover the dural defect.

Figure 11.

The sternocleidomastoid muscle facial flap is closed over the free fat graft to the deep temporal fascia as well as the temporalis muscle. This forms a tight closure and firmly holds the fat in place with pressure on the dural defect.

Small defects are usually seen when the labyrinth is left intact[7] and the intracranial extension of tumor involves the pars nervosa (Fig. 12).[3] This size defect is amenable to re construction with the vascularized superficial temporalis fascia flap, placement of abdominal fat, and primary wound closure.[6] Medium-sized defects result from more extensive temporal bone dissection and larger dural resections (Fig. 13). Local tissue may not be available in these cases because of previous surgeries or radiation. In these instances, larger myocutaneous flaps like the trapezius or the latissimus dorsi flaps are used.[10] Lumbar drains are always used postoperatively. Large defects are rare, and the special needs that arise from such defects are individually addressed. Prior surgery, extensive CA exposure, or prior radiation can all result in large dural defects. Micro vascular free flaps can be used when local tissue is not available and the defect is very large. The rectus abdominis flap is suitable because it provides vascularized tissue and bulk.[6,10]

Figure 12.

The small dural defect seen here is based on the pars nervosa.

Figure 13.

A medium-sized defect is seen here with exposed cerebellum and brainstem.

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....