An innovative method of facilitating ranula excision with methylene blue injection.

Ranulas are pseudocysts of the floor of the mouth that develop as a result of mucus extravasation into the surrounding sublingual soft tissues secondary to sublingual gland trauma or salivary duct obstruction. Oral ranulas are localized superior to the mylohyoid muscle, whereas cervical (plunging) ranulas extend into the neck along fascial planes. Patients with oral ranulas often complain of a painful swelling of the floor of the mouth that may interfere with respiration, mastication, speech, and swallowing. Patients with cervical ranulas usually present with an enlarging neck mass that is often otherwise asymptomatic.

Surgical management is preferred for most ranulas. Marsupialization, which preserves the sublingual gland and adjacent tissue, is still practiced despite reported recurrence rates as high as 61 to 89%. (1) The treatment of choice for most ranulas is complete excision of the ranula and the associated sublingual gland. Complications associated with surgical excision are not uncommon; they include recurrence, tongue paresthesias, damage to Wharton's duct, wound dehiscence, bleeding, hematoma, and postoperative infection. (2)

We have developed an innovative technique of intraranula injection with methylene blue that facilitates pseudocyst localization and complete surgical removal while decreasing the risk of the aforementioned complications. With the patient under general anesthesia, the tongue is retracted to expose the floor of the mouth and the ranula (figure, A). The ranula is injected with 0.1 to 0.2 ml of methylene blue via a 30-gauge needle. The needle is inserted through the contralateral surface of the tongue and introduced into the pseudocyst from the lingual side. This prevents the ranula from rupturing and prevents the methylene blue from leaking out of the injection site. The methylene blue permeates through the mucus of the ranula and effectively demarcates the ranula from the surrounding normal tissue (figure, B).

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Once the extent of the ranula has been localized with methylene blue, a #15 blade is used to incise the mucosa around the periphery of the lesion. The ranula is meticulously dissected circumferentially around the demarcated pseudocyst, and the sublingual gland is transected and removed along with the ranula. Loupe magnification (x2.5) can improve visualization during dissection, but it is often unnecessary because the methylene blue stains only the pseudocyst. As a result, the underlying structures, such as Wharton's duct and the lingual nerve, can be preserved (figure, C). In the event of a ranula rupture, the methylene blue effectively stains the interior of the pseudocyst cavity, and complete excision can be easily accomplished by excising all of the stained tissue (figure, D). The surgeon then performs primary closure of the wound with absorbable sutures.

Complete excision of the pseudocyst and associated sublingual gland is the treatment of choice for most ranulas. Ranula injection with methylene blue facilitates pseudocyst localization, aids in complete surgical removal, decreases unnecessary dissection, and preserves uninvolved tissue while decreasing the risk of complications.

References

(1.) Crysdale WS, Mendelsohn JD, Conley S. Ranulas-mucoceles of the oral cavity: Experience in 26 children. Laryngoscope 1988;98: 296-8.

(2.) Zhao YF, Jia J, Jia Y. Complications associated with surgical management of ranulas. J Oral Maxillofac Surg 2005;63:51-4.

C. Spencer Cochran, MD; Constance Q. Zhou, BS; Robert J. DeFatta, MD, PhD; Robert T. Adelson, MD

From the Department of Otolaryngology-Head and Neck Surgery, University of Texas Southwestern Medical Center at Dallas (Dr. Cochran, Ms. Zhou, and Dr. DeFatta), and the Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology, University of Miami School of Medicine (Dr. Adelson).