A sialocele is a subcutaneous cavity containing saliva, most often caused by facial trauma or iatrogenic complications. In subcondylar fractures, most surgeons are conscious of facial nerve injury; however, they usually pay little attention to the parotid duct injury. We report the case of a 41-year-old man with a sialocele, approximately 5×3 cm in size, which developed 1 week after subcondylar fracture reduction. The sialocele became progressively enlarged despite conservative management. Computed tomography showed a thin-walled cyst between the body and tail of the parotid gland. Fluid leakage outside the cyst was noted where the skin was thin. Sialography showed a cutting edge of the inferior interlobular major duct before forming the common major duct that seemed to be injured during the subcondylar fracture reduction process. We decided on prompt surgical treatment, and the sialocele was completely excised. A duct from the parotid tail, secreting salivary secretion into the cyst, was ligated. Botulinum toxin was administrated to block the salivary secretion and preventing recurrence. Treatment was successful. In addition, we found that parotid major ducts are enveloped by the deep lobe and extensive dissection during the subcondylar fracture reduction may cause parotid major duct injury.
The transparotid approach provides direct access to mandibular ramus and condylar fractures. In subcondylar fractures, complete exposure of the fracture site requires extended dissection to the sigmoid notch. Most surgeons are very conscious of the facial nerve injury when approaching through the parotid gland to the fracture areas. However, they usually pay little attention to the parotid duct or branch injury even though the duct injury may lead to a sialocele or sialo-cutaneous fistula. We experienced a case of intractable parotid sialocele that occurred after reduction-fixation of a mandibular subcondylar fracture via the retromandibular transparotid approach. It was successfully treated with a combination of complete excision and botulinum toxin injection. We also discuss the surgical anatomy of the parotid duct with respect to the major tributaries and their relationship to sialocele formation.
A 41-year-old man presented for mandibular subcondylar fracture which was reconstructed with direct open reduction and internal fixation of the condyle via the retromandibular transparotid approach. Two weeks after the surgery, he revisited our outpatient office with a chief concern of swelling approximately 5×3 cm in size under the surgical incision wound on the left retromandibular area for the past 1 week (
A 4 mL of aspiration was performed and serosanguinous fluid was observed. Triamcinolone (0.2 mL×40 mg/mL) and bleomycin (0.2 mL×1 mg/mL) were administered. Pressure dressing was applied. However, the 2 weeks of treatment was not effective. After 2 weeks, the sialocele size did not decrease and the skin overlying the sialocele was thinning. A 5 mL of aspiration was performed again and the serosanguinous fluid had become turbid. This fluid analysis showed no bacterial growth and high amylase levels (17,250 units/L). Triamcinolone and bleomycin were administered again, and pressure dressing was applied continuously.
We conducted computed tomography and sialogram for the further evaluation. Computed tomography revealed a well-defined thin-walled cyst (32×22×21 mm) below the earlobe and retromandibular area between the body and tail of the parotid gland (
The patient underwent surgery through the previous incision line. The sialocele was located beneath the skin and encapsulated with thin capsule that was the part of protruded parotid fascia. Dissection was conducted to parotid fascia layer. The parotid gland was dissected along the sialocele wall that was located between the parotid body and tail area (
The parotid gland is located below and in front of each ear canal and above the inferior border of mandible. Each gland lies posterolateral to the mandibular ramus and masseter muscle and anterolateral to the mastoid process of temporal bone [
Sialocele is a rare complication characterized by subcutaneous cavity containing parotid saliva. It is caused by trauma, neoplastic process, or surgery to parotid gland lesion [
For the subcondylar fractures, preauricular approach is too high to access below the sigmoid notch regions [
Our patient had a subcondylar fracture extending to the sigmoid notch region. The subcondylar fracture was located between the buccal and zygomatic nerve. The inferior branch of the parotid duct ran along the posterior portion of the mandible. Extensive dissection of buccal and zygomatic nerve and periosteal elevation between the nerves were required for visualization of the subcondylar fracture site including its sigmoid notch region. During these dissection process, the inferior branch of parotid duct in the deep lobe might have been exposed. We thought the exposed duct might have been damaged or transected as the parotid gland parenchyma was dissected. Another reason for parotid duct injury might be for the intensive traction force applied for the drilling process and plate fixation, especially for the sigmoid notch or the anterior portion of the fracture site. The sialogram revealed the transected inferior branch of the parotid duct which was the area where dissection and traction force were applied. Previous report described that the parotid fascia could be damaged during the subcondylar fracture surgery, and the inadequate closure of the parotid fascia might have an effect on the formation of sialocele [
It was reported that patients with sialoceles or sialo-cutaneous fistulas were treated using botulinum toxin injections [
No potential conflict of interest relevant to this article was reported.
The patients provided written informed consent for the publication and the use of their images.
Retromandibular swelling approximately 5×3 cm in size (arrow) and fluctuation developed weeks after subcondylar fracture reduction.
Radiographic findings of the sialocele. (A) Computed tomography shows a well-defined thin-walled sialocele (asterisk) between the body and tail of the left parotid gland. (B) Sialogram of the left parotid gland through the Stensen’s duct orifice showed no accumulation of contrast media in the sialocele. The arrow indicates the cutting end of inferior interlobular duct. (C) Sialogram by percutaneous contrast media injection shows the sialocele (asterisk) which was located at the tail of the parotid gland.
Anatomical relationship and correction of a sialocele. (A) Anatomical relationship of subcondylar fracture to the parotid gland, intralobular ducts and sialocele. Severed intralobular duct in the parotid gland tail located in the path from the retromandibular incision line (red line) to the fracture site. (B) Surgical correction. Complete excision of the sialocele and proximal duct ligation state was performed, followed by botulinum toxin injection (dotted circle).
Clinical photograph at 7-month follow-up.