AIRWAY COMPROMISE

The airway is the primary concern in an infant with a vascular malformation involving the head and neck. Signs and symptoms usually correlate with the extent of the lesion. Extrinsic compression on the airway by the vascular anomaly or intrinsic involvement of the hypopharynx or larynx can occur. Narrowing of the airway demands prompt recognition and treatment, because a marginal airway can rapidly obstruct from small changes resulting from viral infection or intralesional bleeding.

A prenatal diagnosis of vascular malformations by ultrasonography and/or MRI is becoming increasingly common. If prenatal imaging identifies the potential for airway compromise, ex utero intrapartum treatment (EXIT) with intubation or tracheostomy should be planned.

INITIAL EVALUATION

Patients with vascular malformations of the oral cavity and upper airway will often present with recurrent infections, swelling, and tenderness. In addition, involvement of the tongue may cause dysphagia, dysarthria, or airway obstruction. Mucosal lymphatic vesicles may cause bleeding, tenderness, and oozing, which may often worsen during upper respiratory tract infections or after trauma.

All patients presenting with a vascular malformation of the head and neck with possible airway involvement should undergo flexible fiberoptic nasopharyngolaryngoscopy to evaluate the involvement of the hypopharynx, supraglottis, and glottis. Examination findings should be integrated with radiologic evaluation to determine the complete extent of the lesion and its proximity to vital structures. In lymphatic malformations, ultrasonography will typically demonstrate multilocular cystic tissue without flow except in the septal areas; a CT scan reveals a low-attenuated lesion with enhancement of the channel walls after injection of contrast. An MRI with gadolinium is the single best radiologic technique for characterizing lymphatic malformations and typically shows cystic spaces and rim enhancement on T1-weighted images.

SURGICAL MANAGEMENT

Treatment goals for vascular malformations of the head and neck include providing a safe airway, reducing symptoms, correcting functional problems, and improving appearance. Because complete resection is rarely possible, treatment focuses on reducing symptoms while causing as little damage as possible to adjacent tissue.

Options for treatment include expectant management, surgical excision, sclerotherapy, and ra-diofrequency ablation (RFA).

CONSERVATIVE MANAGEMENT

SURGICAL EXCISION

Resection is the only way to potentially “cure” a vascular malformation. The surgeon must consider possible involvement of neural and vascular structures. Limiting blood loss and preservation of vital structures are of paramount importance in these cases.

Open Resection

A number of issues should be considered when planning surgical resection of a vascular malformation. First, the timing of surgery is important, as is the mode of dissection, whether by sharp dissection, electrocautery, or laser. Second, it is important to consider whether it is best to attempt complete resection in a single procedure or whether staged resection is indicated. Dividing vascular malformations into subtypes is also often useful for surgical planning. Those lesions located below the level of the mylohyoid muscle in general may be safely resected within the first year of life. In this case sharp dissection is frequently the modality of choice, and they can often be resected during one procedure. Malformations above the level of the mylohyoid muscle are frequently poorly defined, and the planes between the malformation itself and the normal anatomy may be difficult to dissect. Complete surgical resection in these circumstances can be quite a challenge. The use of loupes or operating microscope is helpful, and a nerve stimulator is imperative, because normal anatomy is frequently disrupted. We recommend that surgery be performed before 5 years of age if possible. Factors such as expected blood loss, duration of the procedure, and extent of dissection may help to determine whether multiple procedures are needed.

Lingual excision should be avoided except in rare cases of solitary lesions of the anterior tongue. Transoral resection of the tongue base or floor of the mouth should be avoided because of the high likelihood of postoperative dysphagia and/or aspiration. We have found that RFA is a safe and effective treatment modality for many patients with lymphatic malformations of the oral cavity.

Endoscopic and Laser Surgery

In sites in which disease is not readily resectable by open, sharp dissection, such as lesions of the larynx, oropharynx, and oral cavity, endoscopic techniques can be used. Retraction sutures or suspension laryngoscopy may be necessary for exposure. Binocular microscopic visualization is essential to provide depth perception. Palpation of the lesion with a probe or spatula provides the haptic feedback necessary to fully appreciate the extent of the lesion. Endoscopic management will rarely allow a complete resection but can be particularly effective for debulking obstructive lesions in the upper airway.

The carbon dioxide or neodymium-doped yttrium aluminum garnet (Nd:YAG) laser can be used to perform resection or debulking. Energy from laser light can be used to coagulate, vaporize, or cut malformed tissue. The pulsed-dye laser has been used to shrink vascular lesions that contain blood. The intralesional bare fiber laser technique has been used for deep vascular lesions with a potassium titanyl phosphate (KTP), argon, or Nd:YAG laser attached to a fiberoptic wand. This approach may be helpful in conjunction with conventional surface laser therapy for lingual lesions with both deep and superficial components. Nd:YAG and carbon dioxide lasers seem most appropriate for vesicular oozing or surface bleeding that accompanies infection or minor trauma.

Numerous sclerosing agents have been used for the treatment of venous and macrocystic lymphatic malformations, including bleomycin sulfate, ethanol, tetracycline, dextrose, interferon alfa-2a, fibrin sealant, and OK-432. OK-432 is a lyophilized mixture of group A streptococci and Streptococcus pyogenes. It produces an inflammatory reaction, followed by gradual regression of the lesion. OK-432 is thought to leave minimal perilesional fibrosis, making subsequent resection less hazardous. OK-432 is more effective for macrocystic than for microcystic lesions; the efficacy rates are 86% versus 66%, respectively. In patients with microcystic lesions or those in whom the use of OK-432 has failed to produce an impressive result, surgical resection should be considered.

Absolute ethanol is also used for macrocysts and mucosal vesicles but must be injected with care near the hypoglossal and lingual nerves when used in the tongue. Doxycycline is another effective sclerosing agent; it does not cause neural toxicity or stain the teeth.

Embolization

Fluoroscopically guided embolization with coils or glue is used to control recurrent lingual bleeding that can be traced to specific vessels in the oral floor, usually from an arteriovenous malformation. Bleeding from a lymphatic malformation is from vesicular eruptions on the lingual surface. Lingual arterial embolization can shrink a tongue with a lymphatic malformation.

Radiofrequency Ablation

RFA, or coblation, is a relatively new technology that is used in various areas of otolaryngology. Because of its mechanism of low-temperature tissue destruction, thermal injuries to surrounding tissues are limited, and therefore patients may have a better course of recovery. Two modes of RFA have been described. The high-frequency mode is used for destruction of deep tissue, resulting in a reduction in size from secondary fibrosis without affecting the mucosal surface. In low-frequency mode, energy is transmitted by way of a conduction medium in small volumes for the removal of a thin, superficial layer, with minimal thermal injury to nearby tissue. For selective patients with lesions that are localized and superficial, we have observed excellent results with RFA in terms of postoperative recovery, complication rate, and clinical outcome.

Patient selection is critical when considering RFA treatment. Patients are typically treated with systemic antibiotics for acute infection and optimization of oral hygiene with mouth rinse and frequent dental care before and after the procedure. Treatment is performed with the patient under general anesthesia with oral or nasal intubation. Intraoperative antibiotics and corticosteroids (0.5 mg/kg of dexamethasone) are administered. Tissue is removed in layers from superficial to deep in broad strokes with continuous saline solution irrigation. After surgery, patients do not typically have significant pain issues and tolerate feeding almost immediately.

The complication rate is very low and includes postoperative hemorrhage, leading to acute swelling and airway obstruction. Given the possibility of airway swelling and obstruction, however, we recommend that every patient who undergoes RFA treatment of the oral cavity be observed in the hospital during the immediate postoperative period.

For patients with more extensive microcystic lymphatic malformations of the oral cavity, radiofrequency ablation is not the ideal primary treatment modality of choice. The characteristic feature of RFA—low-temperature tissue destruction with limited injury to surrounding tissue also serves as a limitation for lesions that are deep and involve underlying muscle. For lesions involving deeper structures, multimodal treatments, including surgical excision and/or sclerotherapy, may be necessary.

EX UTERQ INTRAPARTUM TREATMENT AIRWAY MANAGEMENT