Gland excision in submandibular sialolithiasis : A case report

271 ISSN Online 0719-2479 ©2014 Official publication of the Facultad de Odontología, Universidad de Concepción www.joralres.com INTRODUCTION. Sialoliths or salivary calculi are calcified structures. They are round or oval with a rough texture and usually of yellowish color1. Calculi consist of minerals like calcium phosphate and hydroxyapatite, in addition to magnesium, potassium and ammonia2. Calculi often cause obstruction of the salivary f low, causing pain, inf lammation and recurrent infections, a condition known as sialolithiasis3. Sialolithiasis affects 60 million people a year4, two men for every woman, and is most prevalent in adults2. The submandibular gland is more susceptible to sialolithiasis (60%)5, due to its anatomy and physiology, since saliva is alkaline and has a higher concentration of calcium, phosphate and mucin, which may cause the appearance of foreign bodies in the walls of excretory ducts, contributing to the development of salivary stones6. The etiology of this disease is still unknown2; however Harrison proposed that the inf lammatory edema causes partial duct obstruction, resulting in the stagnation of secretory material rich in calcium that forms a calcified core, which eventually will become a sialolith7. Its growth rate has been estimated at 1 millimeter per year8. One of the most common indications for submandibular sialoadenectomy is sialolithiasis9. Kukuckova recommended this procedure routinely to prevent future glandular infection10. The aim of this paper is to report a case of a 34-yearold female patient diagnosed with intraparenchymal sialolithiasis treated surgically.


INTRODUCTION.
Sialoliths or salivary calculi are calcified structures. They are round or oval with a rough texture and usually of yellowish color 1 . Calculi consist of minerals like calcium phosphate and hydroxyapatite, in addition to magnesium, potassium and ammonia 2 . Calculi often cause obstruction of the salivary f low, causing pain, inf lammation and recurrent infections, a condition known as sialolithiasis 3 . Sialolithiasis affects 60 million people a year 4 , two men for every woman, and is most prevalent in adults 2 .
The submandibular gland is more susceptible to sialolithiasis (60%) 5 , due to its anatomy and physiology, since saliva is alkaline and has a higher concentration of calcium, phosphate and mucin, which may cause the appearance of foreign bodies in the walls of excretory ducts, contributing to the development of salivary stones 6 .
The etiology of this disease is still unknown 2 ; however Harrison proposed that the inflammatory edema causes partial duct obstruction, resulting in the stagnation of secretory material rich in calcium that forms a calcified core, which eventually will become a sialolith 7 . Its growth rate has been estimated at 1 millimeter per year 8 .
One of the most common indications for submandibular sialoadenectomy is sialolithiasis 9 . Kukuckova recommended this procedure routinely to prevent future glandular infection 10 .
The aim of this paper is to report a case of a 34-yearold female patient diagnosed with intraparenchymal sialolithiasis treated surgically.

CASE REPORT.
Female patient, 34 years old, who attended a private practice in the city of Monterrey, Nuevo Leon, Mexico, after she noticed a swelling in the right submandibular region, that had been increasing in size during the past 18 months. Six months ago she began to feel pain when chewing. Then the woman detected the swelling in submandibular region, which she described as a "ball that grows" during meals. The patient was referred to a maxi- llofacial surgeon for evaluation.
The patient's medical history showed no pathological clinical data relevant to the current condition, except for tobacco smoking for little over three years, so she was classified as ASA I 11 .
The extraoral physical examination showed an increased volume in the right submandibular region. The swelling was firm, mobile on palpation and pressure upon it caused pain ( Figure 1). Intraorally, it was possible to visualize the swelling by palpating the lesion extraorally. The patient has had a recent blood count and blood chemistry with normal serum parameters.
Due to the location of the lesion, symptoms and the absence of previous clinical pathological data, it was suspected that the patient was affected by a submandibular sialolith, so a computed tomography (CT) was requested to confirm the presumptive diagnosis.
At the second appointment, the patient brought her CT. It showed a hyperdense area of approximately 1000 Hounsfield Units within the parenchyma of the right submandibular gland, and an increase in the density of adipose tissue surrounding the gland, indicating a chronic inflammatory process ( Figure 2). The removal of the calcification, along with the removal of the salivary gland was scheduled. The patient was given preoperative indications before hospitalization.
At the third appointment, the surgical procedure under general anesthesia, with endotracheal intubation, was performed. Using a Risdon submandibular approach, Robbins IB region was exposed and platysma muscle was dissected to observe the submandibular gland. The gland was firm to palpation, and by blunt dissection strong fascia adhesions the gland had with adjacent soft tissue were disinserted. Once mobile to palpation, the gland was turned to locate its salivary duct, which was ligated before performing salivary gland excision (Figure 3). The flap was repositioned and sutured in layers. The patient was instructed not to smoke for four weeks and was prescribed ketorolac 10mg every 6 hours for 5 days, and amoxicillin 500mg every 8 hours for 7 days.  Subsequently, histopathological examination was performed using hematoxylin and eosin. A specimen formed by epithelial cells with cylindrical metaplasia and mucussecreting cells was observed. Calcified concentric mate-At the end of the first postoperative week, the patient reported slight discomfort in the area of surgery; however a significant decrease in volume was observed. After three months, no lesion to the facial nerve was confirmed by asking the patient to make a lip protrusion gesture (Figure 4).

DISCUSSION.
The diagnosis of submandibular sialolithiasis requires an accurate clinical examination by means of X-rays; however, not all sialoliths can be detected radiographically. Many do not show signs and predictable symptoms. CT is currently the preferred diagnostic method because it has demonstrated superior accuracy to detect small stones, in comparison to ultrasound, X-rays 12 and magnetic resonance 13,14 .
Some authors have reported that submandibular sialolithiasis causes a reduction of the salivary flow 15 , while others as Gaetti et al. state that salivary flow is increased due to glandular enlargement 6,16 . In the present case, despite that a sialometry was not performed to check if there was a reduction of the salivary flow, no clinical or symptomatic evidence of changes or alterations occurred in the flow.
In this case it was decided to perform a complete removal of the lesion and of the salivary gland; however, there are other alternatives such as laser technique, which allows the removal of the calculi without glandular excision. The removal of the gland is performed to prevent infection and the development of tumors 17 . Yilmaz et al. report that when submandibular sialolithiasis becomes symptomatic, producing pain when chewing or inflammation, the calculi and the gland must be removed to relieve these symptoms 18 .
Small sialoliths require no invasive techniques and the sialolith may be removed stimulating the salivary gland by localized massage, by mechanical sialogogues such as chewing gum or wax, or chemical sialogogues such as citric acid. However, these techniques are only limited to small sialoliths; large ones should be removed by surgical excision 1 .  rial within a stroma of well-vascularized dense fibrous connective tissue was also observed. Mixed ancini with serous predominance were observed. They showed diffuse chronic inflammatory infiltrate, confirming the diagnosis of submandibular sialolithiasis.
In conclusion, in this case, the patient diagnosed with submandibular sialolithiasis underwent a surgery to remove the pathological lesion and the submandibular gland. No adverse effects were reported during the three months of postoperative follow-up. It is important to be updated about the different diagnostic methods and treatments to deal with submandibular sialolithiasis, in order to avoid complications such as recurrent infections and glandular neoplasia.

ACKNOWLEDGEMENTS.
The authors acknowledge Dr. Juan Manuel Solís Soto for his advice during the writing of this paper.