When do ranulas require a cervical approach?

摘要

Ranulas are a diverse set of disorders that may be congenital or acquired, intraoral and/or cervical, true cysts and/or pseudocysts, and primary or recurrent. Whereas some ranulas are amenable to intraoral procedures, others appear refractory to a variety of surgical interventions. When do ranulas require a cervical approach? A ranula is a mucocele arising in the floor of the mouth, secondary to the obstruction of the salivary ducts of the sublingual glands. “Plunging” ranulas present as masses involving the submandibular triangle or other neck spaces, secondary to herniation of a portion of the sublingual gland through dehiscences in the mylohyoid muscle. The cervical component of a ranula is a pseudocyst lined by granulation or connective tissue that is without a true epithelial lining. Another hallmark feature of plunging ranulas is the lack of respect for tissue planes, often following the previous elevation of neck flaps or extending deeply into the soft tissues and fascial planes of the neck. Ranulas may result from any type of traumatic or iatrogenic injury to the sublingual gland or its ducts. Ranulas uniformly arise from the sublingual gland, which constitutively secretes saliva with high protein content. A ranula will increase in size when lymphatic drainage and clearance by macrophages recruited in the inflammatory response are insufficient to keep pace with the extravasation of mucous.1 Spontaneous regression has been reported, and some authors suggest deferring surgery until the lesion has been present for 6 months, particularly in recurrent cases where the diagnosis is clear.2 Fine needle aspiration (FNA) is routinely used by some authors for diagnosis of ranulas based on aspiration of mucous, presence of amylase in the fluid, and/or cytology consistent with inflammation.1-3 However, FNA under local anesthesia may not be well tolerated by children. Imaging is not uniformly necessary, but it may be useful to confirm diagnosis.4 With ultrasound, ranulas appear as hypoechoic cystic masses with internal echoes. For plunging ranulas, a dehiscence in the mylohyoid muscle is characteristically observed. For recurrent lesions or plunging ranulas, computed tomography or magnetic resonance imaging may be helpful to localize the lesion and exclude other etiologies. However, imaging may not always give a definitive diagnosis. For example, lesions such as dermoid cysts may also appear as well-circumscribed, low attenuation masses. Intraoral treatment options for ranulas include simple incision and drainage, marsupialization, excision of the ranula with or without excision of the sublingual gland, or excision of the sublingual gland with “evacuation” of a plunging ranula.1 External cervical approaches include needle aspiration of the cervical component, excision of the submandibular gland, excision of the pseudocyst, or external incision and drain placement, all of which may be combined with intraoral approaches. Use of OK-432, various lasers, and robotic surgery have also been reported. Many case series are small; and many reports combine pediatric and adult cases, intraoral and plunging ranulas, primary and recurrent cases, and a variety of surgical approaches, contributing to a lack of clarity in the literature. Very small, well-encapsulated lesions are amenable to simple intraoral excision. The consensus in the literature supports the excision of the sublingual gland for all other ranulas, with excision of any intraoral component of the ranula.1 For plunging ranulas, most authors agree that complete removal of the entire pseudocyst wall is unnecessary, as granulation tissue will resolve once the flow of mucous has stopped.2-4 However, 76% of the American Head and Neck Society members surveyed reported a preference for a cervical approach for the excision of plunging ranulas, most commonly with excision of the sublingual gland, an approach also utilized in nine of 10 of the authors' own cases.2 For plunging ranulas, there i