Ranulas and Plunging Ranulas Treatment & Management

Sclerotherapy, most often with OK-432 or bleomycin, has become more commonly reported in the scientific literature. ^{[9, 10]}  OK-432 contains a particular strain of group A Streptococcus pyogenes that presumably works through local inflammatory responses and may require multiple injections. Effectiveness, with reduction or elimination of the lesion, has been demonstrated in over 90% of patients in some sclerotherapy trials, and both intraoral and plunging ranulas have been successfully treated. ^{[9, 11]}  Studies have reported that nearly half of all patients experienced local pain and fever, which resolved over a few days. OK-432 sclerotherapy may be considered as a first-line treatment option in experienced centers.

Congenital ranulas

Some have advocated that all patients with submandibular duct obstruction leading to ranula formation need early marsupialization and ductoplasty to prevent complications such as sialoadenitis.

Evidence exists that imperforate ducts may spontaneously resolve if rupture takes place during feeding. Therefore, observation for spontaneous resolution of congenital ranulas is reasonable. If airway obstruction or feeding problems arise, surgery is indicated. ^[12]

Ranulas

Marsupialization

Simple marsupialization is the oldest and most widely reported treatment for ranulas. It involves unroofing the cyst and tacking the edges of the cyst to adjacent tissue. Failure rates range from 61-89%, with cysts recurring anywhere from 6 weeks to 12 months later. Inferior compression on the cyst from the tongue leads to premature closure of the opened cyst. This increases the risk of the cyst recurring. Packing the cyst cavity with gauze for 7-10 days improves the success rate. ^[13] In one report, 11 of 12 patients had resolution of their ranula with marsupialization and subsequent packing of the cavity.

In a prospective study, Woo et al reported that micromarsupialization is an effective initial treatment for oral ranulas, with resolution of the ranulas occurring in all 20 of the trial’s patients. The ranulas recurred in five patients, with two patients again showing recurrence 6 months after revision, prompting resection of the ranula and sublingual gland. ^[14]

Placement of suture or Seton ^[15]

With micro-marsupialization, a silk suture or Seton can be placed through the surface of the ranula under local anesthesia. This is left in place a minimum of 7 days while an epithelial tract forms to allow for mucus drainage between the surface and the underlying salivary glandular tissue. Morbidity is minimal to nonexistent, and recurrence or treatment failure is the primary complication. This can also be performed in the office.

Carbon dioxide laser ^[16]

The carbon dioxide laser has been used with limited patients with good success to remove the cyst and scar the gland enough to decrease risk for recurrence. A tissue biopsy is recommended first to confirm the diagnosis of ranula.

Radiation therapy ^[17]

In the rare patient who cannot tolerate surgery, radiation therapy is a viable alternative. Low doses, from 20-25 grays (Gy), are effective. Xerostomia can be avoided with low-dose therapy and shielding of the contralateral parotid gland. The risk of radiation-induced malignancy is real but small.

Sublingual gland excision

The criterion standard for treatment of ranulas is excision of the sublingual gland. This removes the source of the mucus and thus significantly decreases the risk for recurrence. ^[18] A review of 580 patients with ranulas and plunging ranulas found that recurrence rates varied greatly depending on the surgical method chosen. Marsupialization, excision of the ranula alone, and excision of the sublingual gland combined with the ranula resulted in recurrence rates of 66.67%, 57.69%, and 1.20% respectively. ^[19]

Plunging ranulas

Transoral approach

This provides better access for complete removal of the sublingual gland. If ectopic sublingual gland is present on the cervical surface of the mylohyoid, this may be missed without exploring the undersurface of the muscle. Some surgeons advocate simply draining the cervical portion of the ranula and excising the gland transorally. Complete excision of the cyst is not necessary if the gland itself is excised. A biopsy of the cyst wall is recommended for tissue confirmation.

Yang and Hong reported in a prospective study that an intraoral surgical approach can safely and effectively be used to remove plunging ranulas. During the median 14-month follow-up period, none of the study’s 23 patients experienced a recurrence. ^[20]

Transcervical approach

Complete removal of the sublingual gland is difficult with this approach, requiring division of the mylohyoid muscle and dissection up to the floor of the mouth. Some surgeons recommend a transoral excision of the gland with drainage of the cyst first. If that is unsuccessful, complete excision of the cyst via a transcervical approach is indicated. A transcervical approach is also indicated for ranulas located exclusively in the neck.

Some authors advocate the injection of methylene blue into the ranula at the start of the procedure to improve the preservation of vital surrounding structures. Care must be taken in injecting the dye to avoid extravasation into surrounding tissue. ^[21]

Dilation and cannulation of the sublingual caruncle and submandibular duct (Wharton duct) with lacrimal probes is useful, when achievable, to accentuate the ductal course and prevent injury. The plane of dissection medially is of particular interest because of the lingual nerve and submandibular duct. Of note, the lingual nerve crosses the submandibular duct twice, coursing lateral to and under the duct before rising into the tongue medial to it.

Note the preoperative, intraoperative, and postoperative images below.

Ranulas

Risks include paraesthesia of the lingual nerve (up to 25% in some studies), injury to the Wharton duct with the possibility of obstructive sialadenitis, and ductal laceration leading to salivary leakage. In a study of 571 patients who underwent 606 procedures for ranulas, the most common complications included recurrence of the ranula (5.78%), lingual nerve injury resulting in sensory deficit of the tongue (4.89%), and damage to Wharton's duct (1.82%). ^[22] Other complications included hematoma, infection, and dehiscence of the wound, all of which were uncommon. The tongue numbness generally resolves over the course of six months.

Plunging ranulas

Risk for paresis and paralysis of the marginal mandibular nerve is increased because the nerve often lies just on the surface of the cyst. Drainage of the cyst following identification of the nerve can often reduce risk for postoperative complications.

A literature review by Chung et al assessing different treatment approaches to ranulas formed from salivary extravasation found intraoral resection of the sublingual gland to be an effective means of oral ranula cure. Although cure rates obtained through micromarsupialization and its modification were comparable to those associated with sublingual gland resection, the results showed moderate inconsistency. With regard to plunging ranulas, the cure rates for the intraoral and transcervical surgical approaches did not significantly differ, but the rates for both techniques were superior to that for OK-432 sclerotherapy. The investigators found fewer complications associated with the intraoral approach to sublingual gland resection than with transcervical surgery. ^[23]

The overall risk for recurrence when the sublingual gland is not excised has been reported to be in excess of 50%. This rate drops to as low as 2% if the gland is excised. Because the risk to adjacent structures is higher for gland-excising procedures, a trial of less-invasive procedures is advocated by some. Smaller cysts (< 1.5 cm) are usually more superficial in nature and may respond more readily to marsupialization. Larger cysts are more closely associated with the gland and usually require gland excision in association with cyst removal.

Obtaining a specimen for pathology is essential, not only for histologic confirmation but also because the presence of squamous cell carcinoma arising in the cyst wall of a ranula ^[24] and papillary cystadenocarcinoma of the sublingual gland presenting as a ranula have been reported. ^[25]