Paragangliomas

Paragangliomas are slow-growing tumors that originate from the neural crest of the autonomic nervous system and can be hereditary in 7% to 9% of cases.¹³ Locations in the head and neck include the carotid body (35%), glomus vagale (11%), tympanic and/or jugular regions (almost 50%; jugulotympanic if the tumor is larger and melds together over the two regions), and other locations (6%) including the orbit, nasal cavity, and the rare laryngeal case, 90% of which are supraglottic.¹⁴ The malignant potential of paragangliomas is generally low at around 4%,¹⁵ but it can be up to 10% to 18% for the vagal, carotid, and laryngeal types.³

Recommended therapy for paragangliomas is complete surgical excision. Given the high vascularity of these tumors, the role of endovascular management by preoperative angiogram and embolization can be significant. If a paraganglioma is suspected, a diagnostic superselective angiogram should precede any biopsy attempt, lest the attempt lead to arterial rupture. The angiogram should include bilateral exploration,¹⁶ since multicentric paragangliomas occur in up to 80% of familial cases and 10% to 20% of nonfamilial,¹⁷ and bilateral carotid body tumors occur in 5% of sporadic and 33% to 38% of familial lesions.¹³ In addition, diagnostic angiography may demonstrate occult lesions not previously demonstrated on computed tomography (CT) or magnetic resonance imaging (MRI).¹⁶ Diagnostic evaluation demonstrates the blood supply and flow dynamics of the tumor. The venous supply can be mapped, allowing the surgeon to preserve the venous drainage, limiting blood loss.

The role of embolization in paraganglioma management depends on the extent of the tumor and the anatomy of its feeding branches.3,16,17 In jugular or jugulotympanic paragangliomas with more complicated vasculature involvement, preoperative embolization has become a definite part of surgical management and can significantly reduce intraoperative blood loss.^17,18 In most tympanic and laryngeal cases, preoperative embolization is unnecessary.^17,19 Transarterial or direct puncture embolization as an alternative to radiotherapy could be considered as the primary therapy for paragangliomas that are unresectable or where resection would be debilitating.^1,20–22,63

As for the management of carotid body and vagal paragangliomas, most recommend preoperative embolization, but the role of preoperative embolization is still a matter of debate, especially it seems for carotid body tumors.14,17,23 Carotid body tumors are potentially the most challenging to resect. This tumor originates in the bifurcation of the common carotid artery (CCA), where it commonly involves the internal carotid artery (ICA) and receives feeding vessels from external carotid branches and muscular branches of the ICA.²⁴ When small, hemostasis can be controlled during resection through careful preoperative and intraoperative consideration of the ascending pharyngeal artery (Fig. 94-1).^14,13,11

Finally, if resection of the paraganglioma may require sacrifice of the carotid artery, particularly in the case of large jugulotympanic tumors and larger carotid body tumors, another necessary preoperative endovascular intervention is BTO of the ICA.²⁴

Juvenile Nasal Angiofibromas

JNAs are benign, submucosal, unencapsulated, vascular tumors that are most commonly diagnosed in adolescent males between 14 and 25 years old, but can present at any age. The tumor is locally destructive and tends to erode bone as it spreads.²⁴ Patients usually present with unilateral nasal obstruction or epistaxis. The majority originate in the sphenopalatine foramen and progress to the pterygopalatine fossa, infratemporal fossa, sphenoid sinus, and/or other locations within the head/neck.^25,26 Though benign, the risk of bleeding and/or further intracranial extension can be life threatening.²⁷ Surgical resection is considered one of the best treatment options, in which preoperative embolization plays a significant role to prevent excessive intraoperative blood loss.²⁸

Determining the extent of intracranial involvement is crucial to treatment planning for these lesions, as is determining the vascular supply, which may include ipsi- and contralateral, internal and external carotid artery (ECA) systems.²⁹ Pretherapeutic planning often involves endoscopic biopsy, CT scan, MRI, and diagnostic angiography (Fig. 94-2). In cases where diagnostic angiography shows risk of surgical injury to or potential involvement of the ICA, BTO of the ICA should be used to determine adequacy of collateral blood flow. Because profuse intraoperative bleeding is a hallmark of JNA surgery, preoperative embolization of feeding vessels from the external carotid system is consistently recommended in the ear, nose, and throat literature, although some authors rely on intraoperative ligation of feeding vessels.^25,29,30,31 Decreased blood loss, surgical time and morbidity have been demonstrated with either approach. This consideration is crucial because the relatively lower intravascular blood volume of children limits their tolerance for blood loss. Direct embolization with Onyx has been performed as part of endoscopic resection as well.³²

Congenital Vascular Malformations

Congenital vascular malformations are primarily treated with percutaneous therapy, where direct puncture of these lesions allows instillation of sclerosing agents. In some cases, however, endovascular techniques can assist in therapy (Fig. 94-3).

Congenital vascular malformations are categorized as either low- or high-flow lesions. The low-flow group includes telangiectasias, lymphangiomas, and hemangiomas. Although sclerotherapy is the dominant therapy for this group,12,33 when hemangiomas present as superficial fungating hemorrhagic lesions large enough to sequester platelets or obstruct vision or vital structures, polyvinyl alcohol (PVA) embolization may be used conservatively.^3,34 To prevent disfigurement or facial nerve injury when hemangiomas present in the face, surgical excision is usually performed but requires complete resection to minimize the high rate of recurrence. Preoperative embolization assists resection by shrinking the tumor and also helps preserve cosmetic appearance following surgery.^1,35,36

The high-flow group, in addition to JNAs, includes arteriovenous fistulas (AVFs)/aneurysms and arteriovenous malformations (AVMs). Kohout et al.’s study (1998), the largest analysis of patients with head/neck AVMs, showed the most success with those lesions treated by a combination of super-selective embolization and aggressive surgical resection.37,38 Although embolization and surgery lead to a much higher curative rate for head/neck AVMs, the complication rate has been reported as almost double that of ethanol sclerotherapy.³⁹ Thus, Jeong emphasized that ethanol sclerotherapy should be considered the primary treatment modality, followed by a combination of embolization and surgery if repeated sclerotherapy fails.³⁹

Most head/neck malignancies are relatively hypovascular and do not require preoperative embolization for surgical resection,⁴² but involvement of the carotid artery by head and neck carcinoma can hinder safe tumor resection. In these cases, preoperative BTO followed by preoperative carotid artery occlusion can greatly reduce neurologic morbidity and assist in planning for resection of tumor involving the carotid artery.

Candidates for surgery with preoperative embolization include those whose carotid arteries are invaded by the less radiosensitive carcinomas (e.g., adenocarcinoma, adenoid cystic carcinoma, melanoma) or any residual or recurrent head/neck carcinomas including squamous cell.⁴³ Usually such a patient will present with a fixed neck mass. Clinical presentation, however, has a highly inaccurate (32%-63%) rate of predicting carotid invasion. Circumferential carotid artery involvement of at least 270 degrees should be confirmed by MRI, CT, or ultrasound, which predicts arterial wall invasion with high sensitivity and specificity. In one series, arteriography only identified invasion in 1 of 12 patients^2,44,45 (Fig. 94-4).

Historically, carotid artery ligation can cause up to 45% neurologic morbidity rate and 31% to 41% reported mortality.² Stroke can occur either immediately from decreased blood flow or later from a postprocedural thrombus or embolic event.⁴³ Preoperative BTO with/without single-photon emission computed tomography (SPECT) imaging or induced hypotension can help identify those who would be less neurologically vulnerable to decreased blood flow. Patients whose preocclusion diagnostic evaluation indicates inadequate collateral flow may benefit from a bypass procedure during surgical ligation, though this approach adds morbidity and mortality. For those patients with demonstrated sufficient collateral flow allowing for carotid resection without reconstruction, preoperative coil embolization of the ICA can minimize surgical blood loss as well as minimize postprocedural thromboembolic complications. In particular, coil embolization of the preophthalmic petrous carotid artery with postembolization heparinization has been shown to help prevent distal embolization after surgical resection.⁴³ After allowing clot formation to stabilize, surgical ligation can follow 2 to 6 weeks later⁴² (Fig. 94-5).

Carotid Blowout Syndrome

Rupture of any branch in the extracranial carotid artery system, known as carotid blowout, can follow extravasation, pseudoaneurysm, or AVF from any number of causes and can lead to acute transoral or transcervical hemorrhage. Carotid blowout syndrome is a broader term that encompasses carotid blowout as well as the threat of it in cases where the carotid is injured or exposed.⁴⁶ Most commonly, the cause leading to carotid blowout is therapy for squamous cell carcinoma (Figs. 94-6 and 94-7). Radiation weakens the arterial wall and has been associated with a sevenfold increase in the risk of CBS. Other etiologies include other tumors, neck trauma, and functional endoscopic surgery for refractory epistaxis.⁴⁷ Historically, treatment of CBS with emergent surgical ligation alone led to a 60% neurologic complication rate and 40% overall mortality.^48,49 With advances in interventional endovascular therapies that include embolization, occlusion, and stenting, morbidity and mortality has been reduced substantially. Attempts should therefore be made to treat CBS endovascularly. A combination of anatomy, severity, and availability of interventional services determines the appropriate endovascular management of CBS. A helpful algorithm has been proposed by Cohen and Rad⁴⁷ (Fig. 94-8).

If CBS severity falls under the categories of threatened by pseudoaneurysm or neoplasm, or impending or acute, angiography and CT with contrast should be used to confirm the anatomy and the potential of sentinel hemorrhage.⁵⁰ If ICA or CCA involvement is demonstrated by angiography/CT, BTO is indicated to determine extent of collateral flow. If collateral flow is inadequate, stenting is indicated to achieve hemostasis until permanent occlusion with surgical extra-anatomic bypass (i.e., subclavian to carotid) can be performed. Covered stent technologies have advanced to a point where their use in such patients may also be beneficial.⁵¹ ICA/CCA involvement with adequate collateral flow as well as ECA involvement should be managed by distal and proximal occlusion using coils or detachable balloons (currently unavailable in the United States). If the tumor itself is the source of hemorrhage, as indicated by tumor blush on angiography/CT, the entire tumor bed should be embolized. This can be accomplished with PVA particles via superselective transarterial microcatheterization of all arterial supply to the tumor or by direct-puncture ethanol or cyanoacrylate as a last resort⁴⁸ (Table 94-1).

TABLE 94-1

Balloon Test Occlusion Decision Matrix*: Indications for Bypass from Temporary Balloon Occlusion: Institutional Protocol

Clinical	EEG	SPECT	Hypotension	Intervention
Pass	Pass	Pass	Pass	PO
Pass	Fail	Fail	Fail	PO + low-flow bypass (STA-MCA)
Fail	Fail	Fail	Fail	PO + high-flow bypass (venous/radial artery bypass)
Pass	Pass	Fail	Fail	PO + low-flow bypass (STA-MCA)

EEG, Electroencephalogram; PO, permanent occlusion; SPECT, single-photon emission computed tomography; STA-MCA, superficial temporal artery to middle cerebral artery.

^*The suggested testing matrix was devised from multiple components of balloon test occlusion and results of surgical management of the carotid artery during tumor resection.

From Parkinson RJ, Bendok BR, O’Shaughnessy BA, et al. Temporary and permanent occlusion of cervical and cerebral arteries. Neurosurg Clin N Am 2005;16:249–56.

Radplat/Intraarterial Chemotherapy

Surgery and radiotherapy are the primary treatments for head/neck cancer therapy. Yet surgical resection of areas of the larynx, pharynx, and/or tongue can severely diminish quality of life through limits on speech and swallowing.⁴ While radiotherapy alone may better preserve organ function, it does not always provide better rates of local control and survival.⁵² Chemotherapy is a promising treatment; studies of head/neck squamous cell carcinomas have shown that they may be highly responsive in a dose-related fashion to the drug cisplatin. Systemic delivery of cisplatin, however, can result in side effects like severe nephrotoxicity.

Selective intraarterial chemotherapy may decrease the risk and severity of these systemic effects while permitting high-dose cisplatin delivery directly to the tumor bed by taking advantage of the angiographer’s ability to selectively catheterize distal external carotid branches. Intraarterial chemotherapy is often administered in conjunction with radiotherapy, as seen in the most well-known of the intraarterial head/neck regimens, RADPLAT, reported by Robbins et al.53–55 RADPLAT (radiotherapy and concomitant intraarterial cisplatin) also combines intraarterial chemotherapy with an intravenous systemic infusion of the competitive cisplatin antagonist, sodium thiosulfate, to further protect the rest of the body from cisplatin’s systemic toxic effects.⁵⁶ In this manner, RADPLAT allows for delivery of high doses of cisplatin to head/neck tumors while limiting systemic exposure. Other applications of intraarterial chemotherapy under investigation include its preoperative use to improve the quality of head/neck tumor resection (neo-RADPLAT), its role in palliative therapy,⁵⁷ and its use as a potential prognostic indicator that can guide further management of disease. Patients who completely respond to intraarterial chemoradiation may have a significantly higher overall survival rate than those who have a lesser response.^57,58 Several authors have subsequently reported success with selective intraarterial chemotherapy using direct superficial temporal artery access.^59–62

Carotid Blowout Syndrome

An increasing number of CBS cases are recurrent CBS. In contralateral recurrent cases, if the carotid originally affected by CBS has already been occluded or ligated, contralateral occlusion or ligation is an unavailable option.⁴⁸ Endovascular occlusion is also contraindicated in any patient where the contralateral carotid artery is already occluded by atherosclerosis, and in patients who have proven CBS bleeding of the ICA/CCA systems but fail BTO. In cases where occlusion is contraindicated, a self-expandable stent should be placed.^47,51 If using a stent-graft (i.e., covered stent), placement in an uninfected, unexposed area is strongly recommended. Favorable sites are often unavailable in impending or acute CBS. A near certainty of subsequent infection and a high risk of occlusion or re-hemorrhage persists when stenting in unfavorable locations^51,64,65 (see Fig. 94-8).

Radplat/Intraarterial Chemotherapy

Related posts:

Aortic Stent-Grafts Use of Skull Views in Visualization of Cerebral Vascular Anatomy Stents Alimentary Tract Vasculature Periradicular Therapy Radioembolization for Hepatocellular Carcinoma

Stay updated, free articles. Join our Telegram channel

Join