Surgical Diseases of the Salivary Glands Flashcards
What is saiva composed of? (3)
-Water,
- Enzymes (such as lysozyme)
- Antibodies.
What is the main stimuli for saliva?
Presence of food in the mouth (tactile) and taste; the sight and of food can also cause salivation.
What are the functions of saliva? (4)
Lubrication of food to assist in swallowing
Oral hygiene (washing food from between teeth)
Antimicrobial activity
Buffering weak acids and bases
Does the saliva contribute to digestion of carbohydrate via the enzyme salivary amylase?
This is incorrect. Saliva in cats and dogs contains little amylase and contributes minimally to the digestion of carbohydrates in these species.
What are the two types of salivary glands?
Major and minor
Major salivary glands:
A) How are they organised?
B) Where are the located?
C) How do they discharge saliva into the mouth?
A) Pairs
B) Away from the oral cavity
C) Salivary ducts
Major salivary gland:
A) Size?
B) Amounts of saliva produced?
A) Larger
B) Large quantities
Are minor or major salivary glands more likely to be affected by disease?
Major
Parotid gland:
A) Superficial or deep?
B) Shape?
C) Where does it overlie?
A) Superficial
B) V
C) The lateral part of the vertical ear canal
What muscles lie over the Parotid gland? (2)
A thin muscle (parotidoauricularis muscle)
Platysma muscle
What muscle and joint lie cranially to the parotid gland? (1,1)
Masseter muscle
Temporomandibular joint
What muscles lie caudal to the parotid gland? (2)
Sternomastoideus and Cleidocervicalis muscles
What runs deep to the parotid gland?
A) Artery (3)
B) Vein (1)
C) Nerve (1)
A) Superficial temporal, External carotid, Maxillary
B) Superficial temporal
C) Facial nerve
What is the difference in anatomy between cats and dogs in regards to the parotid gland and maxillary vein?
In dogs the maxillary vein passes ventral to the parotid gland, in cats this vein passes through the parotid gland.
What covers the parotid gland and blends with surrounding structures?
A thin capsule
The parotid duct forms from several smaller ducts at which aspect of the parotid gland?
Rostral
How does the parotid duct run in relation to the masseter muscle?
Runs over the ventral third of the masseter muscle
When does the parotid duct become more mobile?
It is firmly attached to Masseter muscle until it become more mobile as it continues forwards dorsal to the buccinator muscle
Where does the parotid duct open?
At the parotid papilla above the caudal end of the upper 4th premolar tooth (carnassial tooth).
Why is complete parotid gland removal a challenge?
The proximity of the vessels and nerves, and their close association with the parotid capsule
The mandibular gland shares a common connective tissue capsule with part of which gland?
Sublingual Salivary gland
Where is the mandibular palpable?
Caudal to the angle of the mandible
What veins does the mandibular salivary gland lie between? (2)
Superficial maxillary
Liguofacial
What do the superficial maxillary and linguofacial form in cats?
Jugular veins
Where does the mandibular duct leave the mandibular gland?
Deep rostroventral aspect
Where does the mandibular duct open?
The sublingual caruncle at the base of the frenulum of the tongue.
Mandibular duct:
A) Runs medial to?
B) Muscle between where it runs? (2)
C) Subsequent muscle that lies medially?
A) Horizontal ramus of mandible
B) mylohyoid muscle (ventrolaterally) and the styloglossus muscle
C) Genioglossus muscle
How common is it for the mandibular gland to be affected by disease?
Rare
What is the removal of the mandibular gland commonly removed with?
sublingual gland (because of their close association)
What are the 2 parts of the sublingual gland?
- a monostomatic part
- a polystomatic part
Where does the monostomatic part of the sublingual salivary gland drain to? Via?
The oral cavity via single duct
Where does the polystomatic part of the sublingual salivary gland drain? via?
Into the oral cavity by several small short ducts.
Which is the largest and most caudal part of the sublingual gland?
Monostomatic portion
The sublingual gland caudal aspect is in contact with the rostral part of the mandibular salivary gland and it tapers rostrally to a ?shape.
triangular
External to the capsule the sublingual salivary gland continues rostrally in close association with the?
mandibular duct.
The monostomatic portion of the sublingual gland is packed into loose clusters of salivary tissue deep to what muscles (2)?
digastricus
mylohyoideus.
Sublingual tissue caudal to the lingual nerve empties into the A) and is considered to be part of the B) salivary gland.
A) sublingual duct
B) monostomatic
The polystomatic part of the sublingual salivary gland consists of small clusters of glandular tissue rostral to which nerve?
Lingual
The polystomatic drains where?
directly into the oral cavity.
The major sublingual salivary duct passes forwards alongside the mandibular duct and drains saliva into A) at B) C) where?
A) Oral cavity
B) Sublingual caruncle
C) Caudal to mandibular duct
Where is the zygomatic salivary gland located in relation to the eye?
Ventral and rostrolateral
Where is the zygomatic salivary gland in relation to the zygomatic arch?
Medial to rostral end
Difference in the anatomy of the zygomatic salivary gland/maxillary nerve in cats vs dogs?
In dogs the zygomatic gland is lateral to the maxillary nerve; in cats it is ventral.
Where does the major zygomatic duct open?
Into the oral cavity at the caudolateral aspect of the last maxillary molar tooth about 1cm caudal to the parotid papilla.
Where do the minor zygomatic ducts open?
Caudal to Major zygomatic opening and are seen as several red spots behind the opening of the major zygomatic duct.
Zygomatic salivary gland:
Major vs minor ducts?
Major - 1
Minor - several
What is the surgery like for the zygomatic duct?
Relatively inaccessible
Do cats and dogs have the same major salivary glands?
Dogs have 4 pairs of major salivary glands. Cats have 5 pairs of major salivary glands. The additional glands in cats are the molar glands which are smaller than the other major glands.
The molar glands are sandwiched between the orbicularis oris muscle and the mucous membrane of the lower lip at the angle of the mouth. The molar glands open by short ducts into the neighbouring buccal vestibule. The molar glands are rarely affected by disease.
Name the minor salivary glands(4)
Lingua
Buccal
Labia
Palatine
Where do minor salivary glands discharge?
Directly into the mouth
What disease of salivary glands require surgery? (3)
Sialoceles (also called salivary mucoceles),
Sialoliths
Neoplasia.
How do salivary gland diseases present?
With a swelling/mass in the region of the salivary gland.
Salivary gland plain radiography:
A) What can be seen with sialolith?
B) What can be seen with FB?
A) Rarely, small radio-opaque sialoliths
B) Air possibly, unless bone/mineral opacity
What is sialography?
Sialography is described in veterinary radiology and surgery textbooks. It involves cannulation of the salivary ducts via their oral papilla and injection of iodine based radiographic contact agent. Cannulation of the ducts is difficult, the process is time consuming and the process rarely localises the lesion or alters treatment so it is not recommended as routine.
How useful is ultrasound in salivary glands?
Ultrasonography is a very useful means of assessing a mass or swelling because it will differentiate fluid from tissue.
The amount of information obtained on ultrasound examination is highly dependent on the operator and is affected by the machine and probe available. A skilled ultrasonographer may be able to identify local lymphadenomegaly and even distension of the major salivary ducts and sialoliths but this is beyond the capabilities of most of us!
If an abscess, migrating foreign body or neoplasia is suspected to be the underlying cause of the swelling what imaging modalities are preferred?
CT or MRI
A diagnosis of a sialocele is usually straightforward and is made by …?
aspiration of viscous pale yellow fluid from a fluctuant non-painful fluid swelling at a typical site.
Named underlying causes of sialoceles? (4)
- Trauma
- FB
- Sialolith
- Neoplasia
Most common complex involved in sialocele?
The sublingual gland/duct complex is most frequently involved.
Which salivary gland:
AFFECTED GLAND/ORIGIN:
– Rostral sublingual glands or duct
CLINICAL SIGNS:
– Fluid filled swelling alongside/under tongue, occasionally tongue may be deviated away from the sialocele causing difficulty in prehension, eating and or swallowing. The sialocele may be traumatised by the teeth releasing blood stained saliva.
Sublingual (ranula)
Which salivary gland:
AFFECTED GLAND/ORIGIN:
– Sublingual salivary gland and duct complex
CLINICAL SIGNS:
– Acute onset swelling in the intermandibular or cranioventral cervical area.
Cervical
Which salivary gland:
CLINICAL SIGNS:
– Exophthalmos, protrusion of the 3rd eyelid, painless orbital swelling.
– Occasionally may see ventral deviation/mass effect of oral mucosa in region of last maxillary molar tooth mucosa on oral examination.
Zygomatic
Which salivary gland:
AFFECTED GLAND/ORIGIN:
– Sublingual and mandibular salivary gland and duct complex
CLINICAL SIGNS:
– Dyspnoea, stertor, stridor due to swelling in caudodorsal or lateral pharynx just rostral to the epiglottis. Can result in upper airway obstruction.
– Occasionally may also cause coughing.
Pharyngeal
Which salivary glands must be accessed under sedation? (3)
Pharyngeal
Sublingual
Zygomatic if not confident
Which sialocele is directly accessible (3)
- Cervical
- Pharyngeal
- Sublingual
What properties of fluid is supportive of sialocele?
The viscous “stringy” nature of the fluid is typical of saliva and is strongly supportive of a sialocele.
What test confirms the presence of mucin in fluid to confirm +ve sialocele?
positive staining with periodic acid Schiff
How likely is it that needle/surgical drainage is going to work?
as sole treatment are not recommended because the sialocele will recur as saliva continues to leak away from the affected duct or gland, drainage may result in introduction of infection and inflammation and scarring of local tissues may complicate later surgery.
What is the surgical treatment of a cervical sialocele?
Removal of the monostomatic sublingual salivary gland and duct AND removal of the mandibular salivary gland and duct
If the cervical sialocele appears midline of caudal inter mandibular area (rather than lateral). How can the side be identified?
nce the dog has been anaesthetised for surgery, the patient should be turned into dorsal recumbency and placed “square” and non-rotated. This will usually result in the mucocele lateralising to the side of the damaged salivary gland/duct complex and identify the side for surgery.
If there is a bilateral sialocele - can these be removed in the same surgery?
In these cases the mandibular and sublingual salivary glands are removed on one side first with a second surgery to remove the contralateral salivary glands at a later date if the first surgery is not curative. Alternatively surgery can be performed bilaterally under one anaesthetic.
What are the 2 approaches to mandibular and sublingual salivary glands and ducts?
Lateral and ventral
Difference between cervical and pharyngeal sialocele?
In a pharyngeal sialocele the saliva accumulates underneath the pharyngeal mucosa whilst in a cervical sialocele the saliva accumulates in the submandibular/cranial cervical region.
What is one of the main concerns regarding the lateral technique for removal of the mandibular and sublingual salivary glands?
It incompletely removes the more rostrally located sublingual salivary tissue. If the rostral salivary tissue is the site of saliva leakage, then recurrence would therefore be more likely because of incomplete removal of the sublingual salivary tissue when using the lateral technique.
What is the recurrence of cervical sialocele after lateral approach?
5%
Which approach is best in the case of a recurring cervical sialocele?
Ventral
How are sublingual sialoceles treated?
Marsupialisation
If a sublingual sialocele recurs; how should this be treated?
mandibular and sublingual salivary glands should be removed using the ventral approach.
What to do If sublingual and cervical mucoceles are present?
Then marsupialisation of the sublingual sialocele is inadequate and the mandibular and sublingual gands should be removed as for treatment of a cervical sialocoele.
Define marsupialisation
is creating a continuation between the oral mucosa and the sialocele cavity.
How to perform marsupialisation?
Make a large oval incision through the oral mucosa extending the length and width of the sialocele. Excessive tissue can be “trimmed” and submitted for histopathology. Suture the remaining oral mucosa to the lining of the sialocele using 1.5 metric monofilament absorbable suture material in a simple interrupted or continuous pattern.
Following marsupialisaton; what should happen with excised tissue?
Send for histopath
Pharyngeal sialoceles can occur on their own or with which other?
ipsilateral cervical sialoceles
Dogs with pharyngeal mucoceles can present with airway obstruction in respiratory distress. Do you know why?
Saliva accumulates in the pharyngeal tissues and the pharyngeal mucosa bulges into the oro/laryngopharynx causing airway obstruction.
Pharyngeal sialocele - The patient should be anaesthetised by a rapid intravenous induction technique and a rapid assessment of the oro and laryngopharynx should be made to see if an endotracheal tube can be placed. What if the tube cannot be placed?
Incision should be made in the bulging pharyngeal mucosa and the saliva should be removed with suction to prevent it draining into the larynx and trachea.
How is the zygomatic arch initially approached?
Make a horizontal incision through the skin and subcutaneous tissue over the dorsal aspect of the zygomatic arch.
Cut along zygomatic arch
What muscles are reflected on the approach to the zygomatic sialocele?
Reflect the aponeurosis of the masseter muscle off the ventral aspect of the zygomatic arch and reflect the orbital fascia dorsally to expose the zygomatic arch.
Following muscle resection on the approach to the zygomatic, what are the next steps to approach?
- Remove a portion of the rostral zygomatic arch either by making two vertical cuts with a saw or by removing a segment of bone using rongeurs.
-Gently reflect the orbital fat to locate the zygomatic gland on the medial aspect of the zygomatic arch ventrolateral to the eye. - Remove saliva via suction
What artery must be ligated when removing the zygomatic salivary?
Malar a.
Following zygomatic salivary removal, what is the orbital fascia sutured to?
Masseter m.
Which diagnostic imaging techniques is preferable to investigate/diagnose sialolithiasis?
CT
Downside of sialography
This technique is difficult and time consuming to perform because cannulation of the salivary papilla is challenging. The technique rarely gives sufficient additional information to justify its use.
What does the treatment of sialoceles depend on? (4)
The location of the sialolith
The ease of gland/duct removal
The degree of duct dilation or suspected fibrosis
The potential for recurrence.
Possible options to resolve sialolith? (3)
- Removal of the affected gland/duct complex (suitable for sialoliths affecting the mandibular/sublingual gland/duct complex)
- Marsupialisation of the duct into the oral cavity
- Ligation of the salivary duct (with expected atrophy of the gland).
How to repair when the sialolith is located near the oral papilla an incision can be made into the duct over the sialolith?
Granulation
Salivary gland neoplasia - origin and malignancy?
Epitelial origin and malignant
Which salivary glands are most likely to be affected by neoplasia? (2)
Mandibular
Parotid
How many salivary neoplasias have metastasised at time of presentation?
20-40% (5-15% with distant mets)
Clinical signs of salivary gland neoplasia (4)
- Unilateral nonpainful swelling on the side of the face or near the base of the ear
- Halitosis,
- Dysphagia (caused by the primary tumour or metastases to local lymph nodes)
- Exophthalmos (if the zygomatic gland is affected).
What diagnostics should be performed when investigating salivary gland neoplasia? (3)
- FNA/biopsy
- LN
- Thorax imaging
What is the treatment for salivary neoplasia
Surgery should be aggressive and involves removal of the salivary gland/mass and any lymph nodes that are positive for metastatic disease. followed by chemo/radio
What is the aim of surgery with salivary gland neoplasia?
Cytoreduction
Why is he parotid gland a challenge to remove?
- Diffuse nature of the parotid gland, its thin capsule attaching it to local structures
- Very close association to a number of arteries, veins and nerves.
What is the prognosis of salivary neoplasia?
A cure of salivary gland neoplasia is highly unlikely; prognosis is correlated with the stage of the disease.
How can mandibular salivary gland neoplasia be approached surgically?
Lateral
