Salivary glands Flashcards
According to Cinti 2021 in Vet Surg, was a ventral or lateral approach for sialoadenectomy associated with a higher rate of complications and recurrence?
Ventral approach associated with lower recurrence but higher rate of wound related complications.
Compare to Swieton 2022 in JAVMA which reported no difference in complications or recurrence (8% for lateral, 17% for ventral) between the lateral and ventral approaches. Hospitalization was shorter for the lateral approach. Age and pharyngeal mucocele were the only factors associated with the risk for complications.
According to Dorner 2021 in Vet Surg, which approach for zygomatic salivary gland removal resulted in the most complete excision with the lowest tissue trauma?
1) Zygomatic ostectomy
2) Dorsal nonostectomy approach
3) Ventral nonostectomy approach
Ventral approach
Compare to Viitanen 2022 in Vet Surg who describes an intraoral approach (faster than the lateral approach, with complete gland removal in 8/10 cadavers).
In a study by Bush 2023 in Vet Surg, what was the MST for dogs treated for salivary gland carcinoma? What was a negative prognostic indicator for survival?
MST 1886 days.
The presence of lymph node metastasis was a negative prognostic indicator (29% of dogs, MST 248 days).
In a study by Gordo 2020 in JSAP, what was used to aid in parotidectomy and potentially helped to reduce the incidence of facial nerve paralysis?
Methylene blue staining
In a study by Martinez 2024 in JSAP, what methods of surgical treatment for parotid duct ectasia were reported? What was the outcome?
Marsupialization of the parotid duct papilla, surgical exploration of the parotid duct, parotid duct marsupialization with surgical exploration of the duct, parotidectomy, and en block parotid duct resection.
All cases of parotid duct ectasia resolved.
The most common presenting clinical sign was a lateral swelling of the face.
In a study by Oetelaar 2022 in VRU, what were the CT characteristics of sialoceles?
Fluid attenuating, non-contrast enhancing contents with soft tissue attenuating contrast enhancing walls. Smooth external margins with frond-like protrusions sometimes seen from the internal margins. Sialoliths or osseous metaplasia observed in some instances.
In a study by Tan 2022 in VRU, what was the sensitivity of detecting surgically confirmed diseased salivary glands based on CT sialography (injection of iodinated contrast directly into a cannulated salivary gland duct)? How frequently was contrast leakage from the gland observed?
The sensitivity of CT sialography was 67%.
The frequency of contrast leakage was 55%, with 58% being intrasialocele.
In a study by Bobis-Villagra 2022 in JFMS, what were the most common clinical signs in cats with sialocele (3)? What were the two most common locations, and the most commonly affected gland? What was the recurrence rate?
Ptyalism, anorexia and dysphagia were the most common clinical signs.
The two most common locations were cervical and sublingual. The sublingual/mandibular gland complex was most commonly affected. The underlying etiology was unknown in most cases.
There were no recurrences reported with a variety of treatment techniques ranging from surgery, stab incision, needle drainage, ranula marsupialization, and parotid duct ligation.
What are the four major salivary glands?
Mandibular, zygomatic, parotid, sublingual.
What vital structures surround the parotid salivary gland?
Facial nerve, maxillary and temporal arteries, internal maxillary vein.
Where do the ducts of the salivary glands open into the oral cavity?
Parotid: level of the fourth premolar.
Zygomatic: caudolateral aspect of the last upper molar.
Sublingual: monostomatic portion empties at the sublingual caruncle, just caudal to the mandibular duct. The polystomatic portion (rostral to the lingual nerve) empties directly into the oral cavity.
Mandibular: sublingual caruncle.
What is the lymphatic drainage of the salivary glands:
Parotid: parotid and medial retropharyngeal.
Zygomatic, sublingual, mandibular: medial retropharyngeal.
What is the blood supply to the salivary glands?
Parotid: arterial = parotid artery (branch of external carotid), venous = superficial temporal and great auricular veins.
Zygomatic: arterial = branch of the infraorbital, venous = deep facial vein.
Mandibular: arterial = glandular branch of the facial artery, venous lingual vein.
Sublingual: arterial = glandular branch of the facial artery (monostomatic), sublingual branch of the lingual artery (polystomatic), venous = satellite veins.
Saliva is rich in which substances?
Bicarbonate and potassium.
Which nerves control saliva production?
The mandibular and facial via parasympathetic innervation.
Which gland is most commonly affected with sialodenosis?
The mandibular gland. Non painful, bilateral swelling of the glands.
What is the treatment for sialodenosis?
Phenobarbital, surgical removal does not resolve clinical signs.
How does sialadenitis differ from sialodenosis?
Glands are painful on palpation.
What is the proposed cause of sialadenitis?
Possible hyperstimulation of the vagus nerve (esophageal and GI disease is often identified concurrently), or limbic epilepsy (due to response to phenobarbital).
What is the treatment for sialadenitis?
Phenobarbital.
What are the four most common presentations of sialocele?
- Exophthalmus: zygomatic sialocele.
- Labored breathing: pharyngeal sialocele.
- Dysphagia: sublingual sialocele or ranula.
- Intermandibular swelling: cervical sialocele.
Which breed of dog is predisposed to pharyngeal sialocele?
Male poodles
What is the treatment for pharyngeal sialocele?
Stab incision and drainage if in acute respiratory distress. Marsupialization should be performed. Removal of the sublingual and mandibular glands (most common glands affected) recommended to prevent recurrence.
What is the surgical treatment for a sublingual sialocele?
Ranula drainage and marsupialization, sialoadenectomy of the sublingual and mandibular gland complex.
What stain can help to confirm the presence of saliva on smear cytology?
Periodic acid-Schiff (mucin specific stain).
What imaging techniques can be used to identify the glands associated with a cervical sialocele?
Sialography, CT, MRI. Alternatively exploratory surgery can be performed.
What is the rate of recurrence of sialocele after resection of the salivary glands?
5%
What are post-operative complications associated with sialoadenectomy?
Seroma, infection, recurrence, sublingual swelling, bleeding. Placement of a drain does not seem to decrease the risk of seroma formation.
Which duct are sialoliths most frequently associated with?
The parotid duct
What are the potential stone compositions of sialoliths?
Calcium, oxalate, phosphate, magnesium, carbonate, ammonium.
What is the most common clinical sign associated with a parotid sialolith?
Swelling on the lateral face that may regress and then reoccur.
What are some surgical treatment options for sialolith?
Surgical removal of the duct/gland, direct excision of the sialolith via the oral papilla, ligation of the duct, duct resection and anastomosis, primary repair of the affected duct, marsupialization of the duct into the oral cavity.
Which glands are most commonly affected by neoplastic disease?
Parotid and mandibular
What is the most common salivary gland neoplasia?
Adenocarcinoma or acinic carcinoma
What is the rate of regional and distant metastatic disease for salivary gland neoplasia?
Regional: cats = 39%, dogs = 17%.
Distant: cats = 16%, dogs = 8%
What is the MST for dogs with salivary gland neoplasia?
Varied, 74-550 days.
Prognosis is correlated with stage of disease.
During ventral mandibular/sublingual sialoadenectomy, which muscle is the mandibular and monostomatic sublingual glands tunnelled under?
The digastricus
During ventral mandibular/sublingual sialoadenectomy, which muscle can be excised to improve exposure to the rostral glandular tissue and lingual nerve?
Mylohyoideus
During ventral mandibular/sublingual sialoadenectomy should dissection be continued rostral to the lingual nerve?
In instances of ranula dissection should continue cranially. For pharyngeal and cervical sialoceles dissection to the level of the lingual nerve is usually adequate.
For lateral mandibular/sublingual sialoadenectomy what venous landmark can be used to identify the expected location of the glandular complex?
Bifurcation of the linguofacial and maxillary veins.
What structure needs to be removed for zygomatic sialoadenectomy?
The rostrolateral portion of the zygomatic arch. The aponeurosis of the masseter muscle is reflected ventrally and the orbital fascia is reflected dorsally.
What is a common complication of parotid sialoadenectomy?
Facial nerve paralysis.
In cases of lateral facial swelling care should be taken to also dissect the accessory parotid gland just dorsal to the parotid duct.
