Ok-432 ( Picibanil ) In the Treatment of Ranulas

appearance of the ‘tail sign’ is vital for distinguishing plunging ranulas. However, these images are insufficient to differentiate between cystic hygroma, second branchial cleft cyst, or dermoid cysts [4]. USG can be used preoperatively to determine the characteristics of pediatric ranulas, and are a radiation-free and a rather inexpensive modality [2]. Plunging ranula diagnosis is complicated due to the absence of clinical features apart from a swelling in the neck. In this case, FNAC is useful for diagnosis. Amylase and Mucin are positive in the yellow aspirate in the ranula, whereas lymphatic malformations often contain cholesterol crystals and lymphoid and endothelial cells in watery aspirates [5].


Introduction Ranula
Ranula, derived from the Latin word 'rana' meaning, describes the blue, translucent swelling at the base of the mouth resembling the abdomen of a frog.Ranulas are pseudocysts formed by salivary extravasation from the sublingual and minor salivary glands [1].The cystic wall contains no epithelial tissue, but rather granulation, connective-or fibrous-type tissue.
Ranulas can be divided into simple (intraoral) or plunging (cervical) types.Simple ranulas are limited to the base of the mouth and gradually show painless growth.On the contrary, plunging ranulas are localized under the mylohyoid muscle, grow towards the parapharyngeal area of the neck, and form a cystic swelling [2].The ranulas seen most often in the second decade of life are of the simple type in women, while plunging ranulas are more common in males.Oral ranulas tend to be more common on the left side while plunging ranulas are more common on the right side [3].
The diagnosis of a ranula can be made primarily on clinical exam, as well as by ultrasonography (USG), computed tomography (CT), magnetic resonance imaging (MRI) and fine needle aspiration cytology (FNAC), which is primarily used for the diagnosis of the plunging ranula type [1].CT and MRI are the most-used diagnostic modalities.On CT examination, the by Kinoshita et al. [10,11].Fukase et al. in 2003 published a case series consisting of 23 oral and 11 plunging ranulas [12].
In patients who will undergo OK-432 treatment, a history of penicillin allergy should be elucidated as the OK-432 formulation contains benzyl penicillin.It may even be appropriate to perform a skin allergy test [20].The application is performed as described by Ogita et al. with 0.1 mg of OK-432 (defined as 1 Klinische Einheit (KE) unit) mixed with 10 ml of saline after the lesional volume is calculated [8].Under USG guidance, the ranula content, often described as a yellowish mucoid fluid, is aspired as much as possible.Then the OK-432 mixture is added to the cyst in the same volume as the aspirated liquid.This procedure is often performed without the need for local anesthetic [16].Syringes used are between 18-27 gauge and depend on the location of the cystic lesion as well as the clinical situation of the patient [11,17].It is not always clear how much OK-432 mixture should be given; however, the general practice is between 0.1−0.5 KE [16].This amount varies according to the experience and preference of the physician.
Previously, patients were hospitalized for the application of OK-432 in the treatment of ranulas, but this practice was deemed unnecessary.Only those at risk of airway obstruction should be hospitalized [21].Post-sclerotherapy follow-up also varies according to the clinician's preference.However, follow-up on days 2, 7, 14, and 28 are generally considered suitable.USG and CT are often used for monitoring.Sclerotherapy can be performed again 4-6 weeks after the initial application [12].Although the number of applications can vary, most patients require between 1-5, with greater than 5 applications rarely needed [17].
The outcomes following ranula treatment with OK-432 vary considerably among studies.Rho et al. [13] reported a complete reduction rate of 33%, whereas Fukase et al. reported this rate to be above 90% [12].In children, this rate is 70% in simple ranulas but over 90% in the plunging ranula type [18,19].Surprisingly, in ranulas with parapharyngeal extension, the treatment success rate is outstanding.Ohta et al. reported adequate treatment in all five of their patients [22].
OK-432 is an uncomplicated treatment with few complications.The most common complaints in ranula treatment are local pain, swelling, redness, and mild fever; these symptoms often resolve within a few days.Fukase et al. reported the rate of occurrence of these complications as 53% and stated that fever was correlated with OK-432 dose [12].Apart from these, odynophagia, injection outside the cyst, and penicillin allergy are other important complications.Abscess and scar development have not been reported; therefore, there is no need for preventative antibiotic therapy.It is also known that the surgery after sclerotherapy is not more complex [16].
The use of OK-432 in the treatment of ranula has many advantages, including 1) ease of application, 2) cosmetic appearance, 3) cost of treatment, 4) alternative surgical options if treatment failure occurs, 5) few complications, 6) no requirement for hospitalization, and 7) no need for general anesthesia.
The disadvantages of sclerotherapy include 1) difficulty in obtaining the sclerotherapeutic agent in some countries, 2) the need for frequent applications, 3) the need for periodic monitoring, and 4) that it cannot be applied to patients with a penicillin allergy.
Considering these advantages and disadvantages, using OK-432 as the first line in the treatment of simple, plunging, and parapharyngeal ranulas in all age groups is a logical choice.Further studies into the dosing of OK-432 are required.