Ch 87 Oral cavity Flashcards
Label 1-10 on the attached diagram
1 - Vestibule
2 - Canine
3 - Hard Palate
4 - Soft Palate
5- Tongue
6 - Sublingual Caruncle
7 - Palaoglossal arch
8 - Palatine Tonsil
9 - Frenulum
10 - Philtrum
Define oropharynx, oral cavity proper and oral vestibule
Oropharynx - Space ventral to the soft palate bound caudally by the pharyngeal wall
Oral cavity proper - Space between the lower and upper dental arcades
Oral vestibule - Real and potential space lateral to the teeth and inside the cheeks
Label the arteries and their associated branches which supply the lips and cheeks
facial artery supplying the lower lip and cheek infraorbital artery supplying the upper lip and cheek
What nerve supply motor function and sensation to the cheeks?
Motor function - Facial Nerve (CNVII)
Sensation - Trigeminal Nerve (CNV)
where do the salivavy gland ducts exit?
- mandibular and sublingual ducts course under the mucosal folds and open at the caruncle
- oral vestibule > Parotid and zymogatic
tongue
- root of the tongue consists of a set of three paired extrinsic muscles: the styloglossus, hyoglossus, and genioglossus
- under control of the hypoglossal nerves.
- tongue is covered with a thick mucous membrane consisting of cornified squamous epithelium
- Branches of the trigeminal, facial, and glossopharyngeal nerves play a role in taste, pain, heat, and sensation
- the right and left lingual arteries (branch of external carotid a.) anastomose throughout parenchyma of the tongue muscle
List the three extrinsic muscles of the tongue and its associated function
Styloglossus - Draws the tongue caudally
Hyoglossus - Retracts and depresses the tongue
Genioglossus - Depress and protrude the tongue
All innervated by the hypoglossal nerve
List the fibre units which make up the intrinsic muscles of the tongue
Superficial longitudinal
Deep longitudinal
Transverse
Perpendicular
All innervated by the hypoglossal nerve
What is the lyssa?
A tube-like structure of muscle, fat and somtimes cartilage encased in a dense sheath of connective tissue that lies on the median plane on the ventral tongue.
Its function is unclear but one theory is that is acts as a stretch receptor for the tongue
List the paired muscles of the soft palate
Palatine
Tensor and Levator Veli Palatini
Pterygopharyngeal
Palatopharyngeal (Make up the palatopharyngeal arches)
What nerve supply the muscle of the soft palate?
CN IX and X
(vagus and glossopharyngeal)
List all the tonsils which dogs and cats possess
Paired palatine tonsils
Lingual tonsil (base of tongue, not grossly appreciable)
Pharyngeal tonsil (on roof of nasopharynx)
Cats also have paired paraepiglottic tonsils (craniolateral to base of epiglottis, macroscopocally visible in some)
List the three stages (and associated sub stages) of deglutition
(1) Oropharyngeal (oral, pharyngeal, pharyngoesophageal)
(2) Oesophageal
(3) Gastroesophageal
Describe the three subphases of the oropharyngeal phase of deglutition
- Oral - Formation of a food bolus by compression of food between tongue and palate and then propelling towards pharynx. This is the only stage that is completely voluntary (CN V, VII, XII)
- Pharyngeal stage - Tongue and pharyngeal constrictor muscles transport food, epiglottis covers the glottis and soft palate presses against nasopharyngeal wall (Swallowing center, CN IX, X)
- Pharyngoesophageal - Passage of food through cricopharyngeal sphincter and into the oesophagus (CN IX, X)
Which LNs drain the oral cavity?
Parotid
Mandibular
Medial retropharyngeal
These all subsequently drain into the superficial cervical
Lymph vessels of the head and neck can cross midline, so nodes on both sides of the head and neck should be evaluated, even when the lesion is unilateral
palpation is an insensitive and nonspecific method of evaluating for metastasis and enlargement is nonspecific for metastasis. Computed tomography (CT) is more sensitive in the detection of retropharyngeal lymph node enlargement
What solutions can be used for surgical prep of the oral mucosa?
Povidone Iodine
0.2% chlorhexidine gluconate
Why cant spring-loaded gags be used in cats?
Causes compression of the maxillary arteries resulting in neuro deficits, including blindness
Disorders of the Lips and Cheeks
What is tight lip syndrome and in what breed is it seen?
What are the treatment options?
The rostral edge of the lip tissue is pulled over the mandibular dental arcade resulting in trauma to the lip tissue during mastication and in some cases inhibiting normal mandibular growth and tooth eruption.
This condition has only seen seen in Shar-Peis.
Treatment options: Incising lip mucosa at gingival margin, excising a segment of skin on chin to pull lip ventrally, or deepening the rostral and lateral vestibule
congenital
- Primary cleft palate
- tight lip syndrome
- Congenital redundancy and eversion of the lower lip
What is the procedure in the picture called? What condition is it used to treat?
Antidrool Chelioplasty
Used to treat congenital redundancy and eversion of the lower lip.
Alternative treatment - Redundant fold resected with full-thickeness wedge resection
trauma - avulsion
- Small avulsions will heal quickly by second intention, provided adequate tissue lavage and debridement have been performed.
- Gingival tissue has a comparatively lower suture pull-out strength > suture around intact incisor teeth or small holes are drilled through the mandible
What are the most common forms of neoplasia of the lips and cheeks in dogs and cats?
Dogs - Melanomas and SCC
Cats - (Rare) SCC, MCT and FSA
metastatic rates for oral malignant melanoma? non-tonsil SCC? cats oral SCC?
- oral malignant melanomas - 12.9% to 59%
- oral nontonsillar SCC 0% to 37.5%
- oral SCC in cats 31%
Excisional techniques
- proper tissue-handling techniques
- ## Full-thickness labial advancement flap
What is the MST of dogs with well differentiated melanomas treated with surgical excision?
34 months
tongue
What is ankyloglossia?
What breed is it reported in?
What is the treatment
Ankyloglossia is a condition where the frenulum is abnormally short and thickened, restricting movement of the tongue.
It is seen in Anatolian Shepherd Dogs
Treatment in frenuloplasty - surgical resection of the tissue band
What is Feline Oral Pain Syndrome (FOPS)?
What breed is it reported in?
What is the treatment?
FOPS is a syndrome of exaggerated licking and chewing movements with pawing at the mouth. Oral self-mutilation, often lateralised to one side of the mouth, can result.
Most common in Burmese cats
Most cats respond to antiepileptic drugs
suspect condition of neuropathic (trigeminal?) pain and allodynia
trauma
- Burns and chemical injuries may not reach full necrotic potential for several weeks, so definitive repair of these lesions may need to be delayed.
- Most clean lacerations can be closed primarily using aseptic technique and gentle tissue handling.
What are the most common lingual tumours in dogs and cats?
Dogs - Malignant melanoma and SCC
(Mast cell tumor, hemangiosarcoma, granular cell tumor, chondrosarcoma, squamous papilloma, plasmacytoma, fibrosarcoma, and ectopic thyroid carcinoma)
Cats - SCC > 61%, most commonly on ventral aspect close to frenulum
(Fibrosarcoma, fibromatous epulis, and lymphosarcoma, hyperplastic/eosinphilic lesions)
dx
- Melanomas are often darkly pigmented; however, up to 33% of all malignant melanomas in the mouth are amelanotic
- Staging ideally consists of cross-sectional imaging of the head, neck, and thorax for suspected neoplastic lesions and sampling of regional lymph nodes.
- Because only 54% of dogs with regional lymph node metastasis have mandibular lymph node involvement, sampling the medial retropharyngeal and parotid lymph nodes will provide a more accurate staging assessment.
What is the recommended surgical margin for neoplastic lingual lesions?
2cm
List the different types of glossectomy and define each
Wedge glossectomy - Acceptable for small malignant tumour or benign masses requiring less aggressive excision
Partial glossectomy - Amputation of all or part of the apex of the tongue, rostral to the frenulum
Subtotal glossectomy - Removal of the entire apex and a portion of the genioglossus, geniohyoid or both, caudal to the frenulum
Near total glossectomy - Removal of >75% of the tongue
Total glossectomy - Amputation or removal of the entire tongue
List some methods of achieveing adequate haemostasis during glossectomy
Using electrosurgery
Laser excision
Preplacement of mattress sutures outside of surgical margins prior to excision
What crystal are deposited with calcinosis circumscripta?
What are some causes of this disorder?
What percentage of cases are seen in the tongue?
Calcium hydroxyapatite and calcium phosphate crystals
Causes:
- Dystrophic (Repetitive injury)
- Abnormal Ca and phosphate metabolism secondary to renal failure
- Idiopathic
23% of cases are seen in the tongue (2nd most common)
What are some DDx which can closely resemble lingual neoplasia?
Chronic periodontal disease causing hyperplastic gingiva
Eosinophilic granuloma
Plasmacytic stomatitis
List reported risk factors of development of oral SCC in cats
Diets consisting mainly of canned food
Eating canned tuna on a regular basis
Flea collars (5x higher risk compared to those who dont wear flea collars)
Live with a smoker (not statistically significant)
What % of dogs with oral neoplasia with LN mets, have involvement of the mandibular LNs?
Only 54%
- Should also sample the medial retropharyngeal and parotid LNs
What is the reported rate of development of mets after surgery in dogs with lingual melanoma and SCC?
Melanoma - 11-71 % (MST 241d)
SCC - 6-43% (MST 216d)
What are the different MSTs reported for lingual melanoma or SCC excised when under 2cm and compared to over 2cm in size?
What is the reported rate of recurrence after glossectomy?
MST of masses over 2cm 207d
MST of masses under 2cm 818d
Recurrence 28% at a median of 127d
What is the prognosis for cats with oral SCC?
Poor - MST 44-203 days
glossectomy in dogs and cats
- Long-term effects of glossectomy in dogs are surprisingly few and mild in nature.
- resection of up to 50% of the tongue in dogs is well tolerated
- may need assistance, such as hand feeding, providing a deep water bucket or soaking kibble with water
Information on short- and long-term consequences of tongue resection in cats is scarce
- greater unwillingness or inability to adapt to a change in oral structure
- o-tube
List some examples of structural abnormalities which can result in dysphagia
Congenital palate defects
Ankyloglossia
Macroglossia
Microglossia
Tight lip syndrome
List some examples of causes of functional dysphagis
Idiopathic (most common) (GOLPP)
Peripheral neuropathies
Myaesthenia Gravis
Brainstem lesions and other intracranial abnormalities
What are the three broad categories of causes of dysphagia?
Space-occupying mass
Structural congenital abnormalities
Functional abnormalities
What are the most common pharyngoesophageal dysphagias in the dog?
Cricopharyngeal asynchrony
Cricopharyngeal achalasia
Penetrating Injuries to the Pharynx
- CS: dysphagia, drooling, depression, oral pain, pain on flexion of the neck, subcutaneous emphysema, blood in the saliva, and pain on opening of the mouth
- Plain radiographs for initial diagnostic workup + EUS
- Extraluminal gas between fascial planes in the cervical region > can dissect along fascial planes, causing pneumomediastinum or pneumothorax, and make localization difficult
- chronic cases: CT or MRI very useful
Sx
- rigid endoscopy
- acute: transoral pharyngeal examination, debridement, and lavage
- ventral midline approach (avoid recurrent laryngeal nerves)
- C&S
- drainage
Common sites of pharyngeal penetration
- esophagus,
- lateral and dorsal pharyngeal walls
- sublingual region
Tonsils
What is primary tonsillitis?
Inflammation of the tonsils in dogs <1yo causing persistent cough, gagging, dysphagia, depression, pyrexia and anorexia. Tonsils may be bright red, friable and may or may not be enlarged. Treatment consists of antibiotics and analgesics. If recurrent, can consider tonsillectomy
List some cause of tonsillar eversion or enlargement
Primary tonsillitis
Chronic BOAS
Cleft palate
Periodontal disease
Neoplasia
What is the MST of tonsillar SCC with surgical excision in dogs and cats?
feline tonsillar neoplasia is rare
Dogs - 2 months. High rate of early metastasis (73%) and high recurrence rate/incomplete excision
Cats - 2-14 weeks
Tonsillectomy followed by radiation therapy in dogs resulted in MST of 110d
Chemotherapy +/- tonsillectomy or chemotherapy with radiation therapy +/- tonsillectomy had a MST of 212 and 355d respectively
Tonsillectomy
- indicated for diagnosis and treatment of neoplasia, tonsillitis or brachycephalic syndrome
- transection and hemostasis can be achieved simultaneously with an electrosurgical unit set on a low level or with a laser or vessel sealing device.
- complications are rare and include hemorrhage, pharyngeal swelling secondary to tissue trauma, and postoperative aspiration of blood or fluid.
Preoperative computed tomography,
surgical treatment and long-term
outcomes of dogs with abscesses on
migrating vegetal foreign bodies and
oropharyngeal stick injuries: 39 cases
(2010-2021)
Manzoni 2023
retrospective study
foreign body was identified on CT in 11 of 39 (30%) cases and later confirmed at surgery
in 10 cases.
28 of 39 cases, a vegetal foreign body was not identified on CT, but in seven it was found at surgery (25%)
Resolution of clinical signs was achieved in 11 of 11 cases when a vegetal foreign body was identified on CT and in 26 of 28 cases without a foreign body identified
Two cases of recurrence were observed in animals in which no foreign body was detected. (5%)
resolution of clinical signs after a single surgical procedure in 95% of the cases
Although CT sensitivity in detecting VFB was moderate,
it allowed for precise visualisation of the extent and localisation
of the abscesses
consider use of intra-op ultrasound
Endoscopic treatment of acute oropharyngeal stick injuries in dogs:
46 cases (2010-2020)
Kilduff-Taylor 2023
Retrospective analysis
injury tracts were explored using 0° and 30° forward-oblique, 2.7 mm diameter, 18 cm length rigid endoscopes
38 (95.0%) had no major long-term complications. The remaining two dogs developed cervical abscessation after endoscopy, one of which resolved after repeat endoscopy and the other resolved after open surgery.
Histologic evaluation of mandibular and medial
retropharyngeal lymph nodes during staging of oral
malignant melanoma and squamous cell carcinoma in dogs
Grimes 2019
Retrospective multi-institutional study.
ANIMALS
27 dogs with OMM and 21 dogs with OSCC.
Prevalence of lymph node metastasis OMM (10/27 [37%]) and OSCC (6/21 [29%]).
Distant
metastasis was identified in 11 (41%) dogs with OMM
The MRLN was affected in 13 of 16 dogs with lymph node metastasis
Metastasis contralateral to the primary tumor in 4 of 17 dogs that underwent contralateral
lymph node removal.
bilateral lymphadenectomy of the MLN and MRLN lymphocentra is recommended for such dogs
It is also possible that the presence or absence of lymph node metastasis may be a poor predictor of distant metastasis
because metastatic patterns are subject to interindividual variation and are seldom straightforward
Mickelson 2020 – canine tonsillar neoplasia and tonsillar metastasis
VCO
- primary neoplasms: SCC 55%, lymphoma 17%, melanoma 12%
- 92% of neoplasms malignant- metastasis: 9% of tonsillar neoplasia
25/41 melanoma, 10/41 carcinoma, 2/41 hemangiosarcoma
1/41 fibrosarcoma, malignant histiocytosis, basal cell tumour and sarcoma - tonsillar melanoma: 28/53 primary, 25/53 metastatic from distant primary
- 9/53 concurrent LN metastasis
- indirect contrast lymphangiography → no lymphatics draining to palatine tonsil
- likely hematogenous spread to tonsils
- metastasis: 9% of tonsillar neoplasia
