Vascular anomalies encompass a huge range of pediatric conditions and are broadly classified as vascular malformations or hemangiomas. They are defined by their individual morphology and growth rate and are in rare cases part of a global syndrome. Hemangiomas are largely treated medically, surgery is reserved for lesions resistant to medical therapy or those causing a significant functional deficit. Vascular malformations may be treated with sclerotherapy or surgery depending on size, anatomical site, and morphology. While both medical and surgical therapy has its advantages, the risk of damage to surrounding neuromuscular structures with each individual case should be weighed up. In experienced hands, resection of lesions in low risk areas can offer removal of the disease, improved cosmesis, restoration of function, and minimal risk to surrounding neurovasular structures.
16 Surgery for Lymphatic Vascular Malformations
Vascular anomalies encompass a wide range of pediatric head and neck lesions. They are commonly classified according to the Mulliken and Glowacki classification system, which divides them into two broad categories, vascular malformations and hemangiomas (▶ Table 16.1). The former are classified according to the morphology of the dominant vasculature and the flow rate. Slow flow lesions include capillary, lymphatic, and venous malformations. These are commonly mixed, i.e., venolymphatic malformations. Fast flow lesions include arterial and arteriovenous malformations. Unlike hemangiomas, vascular malformations are characterized by normal growth and normal turnover of endothelial cells. They grow commensurately with the child. Hemangiomas, often known as “birthmarks” are flat or absent at birth. They exhibit three stages of development, a period of rapid endothelial proliferation shortly after birth, followed by regression, and eventually complete involution. In this chapter we aim to describe the surgical approach and preoperative considerations to lymphatic disease of the head and neck and give the reader an overview of this complex and challenging disease process.
Infantile hemangiomas are the most common and present shortly after birth as red or bluish macules. They grow rapidly from 6 weeks of age and their proliferative phase is between 6 and 12 months followed by regression. The rate of involution is approximately 10% per year. Complete involution can occur but may also leave stigmata such as redundant skin, fibro-fatty tissue, or telangiectasia. The treatment of hemangiomas is dependent on the site and size of the lesion. For example, a skin lesion may cause anything from a minor cosmetic defect to a compressive or restrictive effect on the eye, ear, or airways. Large hemangiomas may lead to congestive cardiac failure and subglottic hemangiomas present as worsening stridor and increasing respiratory compromise. Congenital hemangiomas are less common and are present and fully formed at birth. They either undergo rapid involution within 12 to 18 months or no involution.
The treatment of hemangiomas has therefore always been based on the functional impact. Prior to 2008, treatment of these lesions involved the use of high-dose corticosteroids or lasers or surgery. Propranolol is now used for the majority of lesions as it was accidently discovered to cause involution of hemangiomas. Whilst most children do not experience side effects, patients are monitored for bronchospasm, hypoglycemia, bradycardia, and hypotension. If the lesion is sensitive to propranolol, involution occurs fairly quickly and the duration of treatment is dependent on the size and site of the lesion. Small subsets of hemangiomas that are resistant to propranolol or causing a significant functional defect require laser, endoscopic, or open excision alongside corticosteroid treatment.
16.3 Vascular Malformations
Lymphatic malformations, often known as cystic hygromas, consist of several dilated lymphatic channels lined by a single layer of epithelium and have an incidence of 1 in 5000 at birth. They form a collection of thin-walled cysts that vary in size and architecture. Macrocystic disease, where the malformation compromises one or a few very large cysts, may invade large spaces, causing compression and displacement of surrounding structures such as the pharynx, airway, or esophagus (▶ Fig. 16.1 and ▶ Fig. 16.2). Microcystic disease is formed of multiple tiny cysts clustered together, which, in the head and neck region, can invade other structures, (e.g., parotid gland). Lymphatic malformations may also be categorized as mixed lesions such as venous-lymphatic malformations.
Lymphatic malformation may present at birth or may become apparent during childhood as a result of minor trauma, inflammation, or infection. Large malformations may be evident on prenatal scans (▶ Fig. 16.3) and if preventing normal delivery may require an EXIT procedure (ex utero intrapartum treatment) to secure the airway. Commonly lymphatic malformations involve levels II–IV in the neck but may extend superiorly to the floor of the mouth and tongue or infiltrate the larynx affecting the voice and airway. Lesions involving the tongue may lead to tongue protrusion (▶ Fig. 16.4). This, in turn, causes ulceration and bleeding and interferes with feeding and speech.
Venous malformations appear as a soft bluish compressible swelling commonly in the skin and subcutaneous tissue, sometimes infiltrating skeletal muscle. They grow with the child and often have a rapid enlargement during trauma and puberty. Surgical excision can be challenging with a high risk of massive hemorrhage. Capillary malformations, colloquially known as “port-wine stain,” are abnormally dilated capillaries in the superficial dermis. Present from birth, the color deepens in adulthood and may be associated with Sturge–Weber syndrome. Surgery for such lesions mostly involved the use of the pulsed-dye laser to achieve lightening of the lesion and rarely surgical excision with skin grating has been undertaken.