10 The Role of Endovascular Surgery in the Management of Vascular Lesions of the Head and Neck
The role of endovascular therapy in the management of vascular lesions (VLs) of the head and neck has expanded over the last 30 years to a very safe, reliable, reproducible, and sophisticated level. In this chapter, we review the indications and various techniques of embolization and sclerotherapy, which are minimally invasive image-guided techniques that can reach very distal parts of the vascular tree or can be placed directly into the nidus or center and core of the lesion.
The diagnosis of a VL is usually made based on clinical history and physical examination. Cross-section noninvasive imaging such as computed tomography (CT) and magnetic resonance imaging (MRI) is very helpful for assessment of the extent of the disease, associated lesions, or multifocality of involvement. MRI is the most useful single imaging modality in the investigation of vascular malformations. 1 The combination of multiplanar spin-echo imaging and flow-sensitive sequences permits characterization of the nature and extent of most lesions. CT scanning is less helpful in defining flow characteristics and the extent of vascular malformations, but it is useful in demonstrating the nature and extent of bony involvement and the presence of phleboliths, which are pathognomonic of venous malformations (VMs). 2 Ultrasound, including Doppler techniques, is a modality for determining tissue and flow characteristics in superficial lesions but is suboptimal in demonstrating the extent of lesions. Ultrasonography is useful for needle-guided techniques at the time of treatment. Plain radiographs are useful in selected patients, mainly to document bony changes. For example, a simple panorex radiograph may suffice to follow the bony changes in dental VLs. Angiography is reserved for patients for whom a decision has been made to intervene and is generally performed at the same time as the embolization or sclerotherapy. Exceptionally, angiography may be necessary to confirm the diagnosis and to demonstrate the extent of the soft tissue capillary or arteriovenous malformations or fistulae. The advent of three-dimensional rotational angiography is expanding our ability to study intraosseous VLs.
Treatment of VLs is challenging and requires the skills of an interdisciplinary team. Management of these lesions is best achieved by a specialist who understands the various clinical expressions of the problem, the natural history of the lesion, and the needs of the patient. Such a specialist diagnoses the lesion, establishes clinical and morphological objectives, and then introduces the problem to other specialists for management strategies. Over the last 30 years, the advancement of surgical techniques added by preoperative, intraoperative, or postoperative embolization or sclerotherapy has created a new group of specialists combining competence in endovascular, plastic, reconstructive head and neck, and maxillofacial surgery, and in our center this expansion has been extended to the pediatric population. 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10
In this chapter, we describe the multiple endovascular treatment options in the management of the various VLs of the head and neck region.
10.2 Management Strategies and Endovascular Treatment Goals
Most VLs are nonlethal. The primary goal of treatment is to restore and preserve function, stop and control bleeding, and improve or restore cosmesis. At our institution, all VLs are seen in an interdisciplinary fashion to discuss management options.
Partial treatment using a less risky and less invasive method may be more beneficial to the patient than aggressive curative treatment. VLs in children younger than 10 years may interfere with natural growth and maturation of the maxillomandibular frame, causing malocclusion of the mouth or modeling defects resulting from external pressure of the forming bones or sinuses. Early intervention can arrest or even reverse such changes, especially if treatment is performed before puberty and maturation of the bone formation process. The following are the main indications for early management of vascular malformations:
Dental arch and occlusal stabilization
Recurrent hemorrhagic complications
Mass effect (swallowing, compression)
Episodic swelling and airway compromise
The following questions should be answered to set up an appropriate treatment goal for a child with a VL:
What is the nature of the malformation?
What is the type, and the extent, of already existing damage?
What is the potential future development of the lesion?
Is it possible to arrest the progression of the disease and restore damaged function?
What is the possibility of newly developing treatments becoming available?
What are the psychosocial implications of the VL in the child during the years of formation and development of personality?
We discuss specific problems and treatment in each subcategory of VLs in the following sections.
10.2.1 Venous Malformations
The VMs are the most frequently seen vascular malformation. The lesions are typically nonpulsatile, soft, and compressible. They are easily emptied and distend with use of Valsalva maneuvers. Development of abnormal vessels in this syndrome is caused by a local uncoupling of endothelial smooth muscle cell signaling. 11 The skin temperature over the lesion is normal. When superficial, VMs are characterized by a bluish discoloration of the skin or mucosa. When they are located in deeper planes, there may be no discoloration, and coloration may fluctuate with changes of position or mastication when the VM involves the muscles of mastication.
Most of these lesions consist of spongy masses of sinusoidal spaces and have variable communications with adjacent veins. 12 , 13 They typically contain phleboliths, which are pathognomonic if present. 2
Characteristic MRI findings include focal or diffuse collections of high T2 signal that often contain identifiable spaces of variable size separated by septations. 14 Phleboliths may be evident as areas of signal void, which are most prominent on gradient echo images. Angiography is not necessary to make the diagnosis but typically shows either no filling of the malformation or delayed opacification or sinusoidal spaces with a “grapes”-like appearance, with or without dysplastic draining veins. 15 Direct percutaneous catheterization of the malformation with contrast injection shows the interconnecting sinusoidal spaces. Careful attention should be paid to the communication between the drainage and transcranial, orbital, or vertebral venous channels.
Direct injection of sclerosing agents, including 98% ethanol, bleomycin, sodium tetradecyl, or sodium morrhuate, results in thrombosis and gradual shrinkage of the malformation and is the preferred treatment. 12 , 16 , 17 , 18 , 19
The technique of sclerotherapy involves percutaneous catheterization of the malformation using a needle or Teflon-sheathed needle cannula. After confirming free blood return, contrast is injected, recording with serial angiographic imaging or under the live-subtraction mode to document the cannula position within the malformation and the presence or absence of venous outflow. In the presence of significant venous outflow, local compression over the venous outflow is applied during the injection of sclerosing agents. If there is drainage toward the intracranial venous system, where compression is not possible, liquid coils can be placed to block the undesired drainage. 20
The most common complication of ethanol sclerotherapy is skin or mucous necrosis and neuropathy. Skin blistering or full-thickness necrosis is likely to occur if the malformation involves the skin or mucosal surface. We monitor the neurophysiological characteristics of the facial nerve to decrease the incidence of nerve damage. Our agent of choice for endovascular microcatheter sclerotherapy has been sodium morrhuate. Side effects of the sodium morrhuate and sodium tetradecyl sulfate include skin necrosis, when these agents are injected close to the skin surface, as well as renal insufficiency secondary to hemoglobinuria resulting from localized rhabdomyolisis caused by the sclerotherapy. Total volume injected should not exceed 0.5 mg/kg for sodium morrhuate. We premedicate patients with intravenous infusions of sodium bicarbonate to alkalinize the urine and prevent renal insufficiency. Treatment of large malformations is usually staged to avoid complications related to the dose of the sclerosing agents.
In the case of recurrence after sclerotherapy, surgical resection should be considered if feasible. For extensive cervicofacial VMs, staged sclerotherapy, over time, can have a dramatic effect in reducing size and improving appearance.
Often VMs of the tongue and airway can often be successfully treated with sclerotherapy after tracheostomy, although laser photocoagulation has been proven effective. More recently, we have been using bleomycin as the sclerosing agent of choice for VMs in the mucosal, periorbital, and tongue regions ( Fig. 10.1 ).
Bleomycin is a glycopeptide antibiotic that is used as a chemotherapeutic agent. It acts by induction of DNA strand breaks and is believed to work as a sclerosing agent as well as at the molecular level of the malformation. Swelling seen after treatments with bleomycin is not as significant as with other sclerosing agents. In infants the authors limit the dose to 0.5 mg/kg, with a maximum of 15 mg per session, regardless of age. The most serious complication of bleomycin is pulmonary fibrosis, which appears dose related (cumulative dose of more than 250 mg). Other side effects include, but are not limited to, fever, hyperpigmentation at pressure sites, and alopecia. Results appear promising, even though we need to treat and follow up a larger number of patients. 21 , 24 , 25
In very young children, VMs may remodel the maxillofacial bones. Early intervention is indicated in such cases to reverse these changes. If there is a need for orthodontic work, it should be done after maximal control of the malformation but before the peripubertal years because remodeling the bones after that age will be more difficult ( Fig. 10.2 ).
More recently, we have excised VMs 24 to 36 hours after sclerotherapy in well-defined lesions, taking advantage of the thrombosed malformation and the surrounding edema, which facilitates developing a surgical plane of demarcation between the malformation and normal tissue (Waner and Berenstein unpublished data). Facial-nerve neurophysiological monitoring is used when clinically warranted.