Parotidectomy for the treatment of parotid sialocoele in 14 dogs

Abstract

OBJECTIVES To describe the presentation, diagnosis, cause, complications and outcome in 14 dogs that presented with a parotid sialocoele and that were treated by complete parotidectomy. MATERIAL AND METHODS Multi‐institutional retrospective study. RESULTS Each dog presented with a non‐painful, fluctuant, soft tissue mass over the lateral aspect of the face in the region of the parotid salivary gland. Diagnosis was made by sialoradiography (3/14), CT (3/14), ultrasound (11/14) and MRI (2/14). The cause of the sialocoele could be determined in 8 of 14 patients and included: foreign body (2/14), sialolithiasis (1/14), neoplasia (3/14), salivary gland lipomatosis (1/14) and trauma (1/14). Treatment incurred one anaesthetic complication (regurgitation) and seven postoperative surgical complications [self‐limiting seroma formation (2/14), haemorrhage (1/14), wound dehiscence (1/14), abscessation 7 months postoperatively (1/14) and facial nerve paralysis (2/14)]. Sialocoele did not recur in any dog during a median follow‐up time of 14 months. CLINICAL SIGNIFICANCE Parotidectomy has been considered a technically challenging procedure but can have a good success rate with long‐term resolution of the clinical symptoms. Intra‐ and postoperative complications are reasonably common.

The use of methylene blue to assist with parotid sialadenectomy in dogs

“…They reported a moderate complication rate, as 35% of the cases developed a major complication: active bleeding from a branch of the caudal auricular artery (7%); wound breakdown requiring debridement and a flap to reconstruct the lip in a case that had been attacked by a badger (7%); abscess after retained drain material (7%); permanent facial nerve paralysis (14%). Seroma is a common complication reported after parotidectomy (Trumpatori et al 2007, Proot et al 2016. In our cases, the complication rate was lower than previously reported possibly due to straightforward dissection of local vessels and nerves facilitated by the use of methylene blue.…”

“…Recurrence of clinical signs was not reported for the nonneoplastic cases within a mean follow-up period of 14 months. Regarding the cases affected by neoplasms, one was euthanased 4 months after surgery due to distant metastases (but no gross evidence of local disease was reported), and the other case had (Spangler & Culbertson 1991, Jeffreys et al 1996, Tivers & Moore 2007, Trumpatori et al 2007, Proot et al 2016) and neoplasia (Carberry et al 1988, Spangler & Culbertson 1991, Hammer et al 2001, Proot et al 2016. Two of the above reported cases had a histopathological diagnosis of chronic sialoadenitis, but this was secondary to a branchial cyst.…”

“…Multiple surgical techniques have been described for the management of non-neoplastic inflammatory parotid disease (associated or not with lithiasis), such as parotidectomy (Trumpatori et al 2007, Guthrie & Hardie 2014, Proot et al 2016; opening of the duct for removal of the sialolith and primary closure or leaving it to heal by second intention (Tivers & Moore 2007); complete ligation of the duct (Harvey 1977, Goldsworthy et al 2013, Yoon et al 2017; resection of the affected part and anastomosis (Harvey 1977, Jeffreys et al 1996; primary repair of the affected duct in case of rupture (Harvey 1977, Jeffreys et al 1996 and marsupialization of the duct into the oral cavity (Ladlow & Gregory 2003).…”

“…The procedure should be reserved for lesions involving the parotid gland itself (Harvey 1977). The most comprehensive review published in veterinary literature is a multiinstitutional retrospective study that gathered 14 cases over a period of 7 years across six referral hospitals (Proot et al 2016). They reported a moderate complication rate, as 35% of the cases developed a major complication: active bleeding from a branch of the caudal auricular artery (7%); wound breakdown requiring debridement and a flap to reconstruct the lip in a case that had been attacked by a badger (7%); abscess after retained drain material (7%); permanent facial nerve paralysis (14%).…”

“…Due to the close association of the gland with the surrounding structures, parotidectomy is considered a challenging surgery (Ritter & Stanley 2018). The most commonly reported permanent complication after surgical resection of the parotid gland is facial nerve injury (14% in dogs), and the overall reported morbidity remains high (up to 35%), mainly including different degrees of facial nerve damage and wound complications (Bova et al 2004, Proot et al 2016. Methylene blue staining has been used to overcome the most common complication of facial nerve injury in people (Cheesman 1977).…”