Mandibulectomy and maxillectomy Flashcards
(48 cards)
According to Goldschmidt 2020 in Vet Surg, what biometric skull measurements were associated with increased tension and decreased nasal aperture following nasal planectomy reconstruction?
Wider facial features and thicker lips, as well as philtrum design and placement
Specifically: width of the nasal planum (>3 cm), width of the caudal maxilla
(>6.2 cm), lip thickness (>0.5 cm), width of the labial flap (>2.9 cm), length of the incision created to make the cosmetic “philtrum” (longer incisions >2.8 cm), and philtrum placement (more dorsal placement).
In a study by Sharma 2021 in Vet Surg, what was the prognosis for juvenile dogs undergoing mandibulectomy or maxillectomy for oral squamous cell carcinoma?
Excellent - these patients can be treated effectively with surgery alone. All dogs were alive at follow up (median follow-up 1556 days).
In a study by Carroll 2020 in JAVMA, what size of oral melanoma was able to accurately predict the presence of lymphatic invasion on histologic grading?
> 24.5mm (100 specificity). Less than 6.5mm able to rule out lymphatic invasion (100 sensitivity).
In a study by Cray 2021 in JAVMA, what was the overall complication rate for dogs undergoing maxillectomy or mandibulectomy? What factors were associated with an increased risk of dehiscence or oral fistula formation?
The overall complication rate was 37% (longer surgical time was associated with an increased risk for complications).
Maxillectomies and preoperative chemotherapy or radiation had an increased risk for dehiscence or oral fistula formation.
Do peripheral odontogenic fibromas invade the bone?
No, can appear macroscopically invasive but there is no underlying bone involvement.
In a study by Lee 2021 in VRU, what were 5 features of oral tumour malignancy based on CT?
Large size, heterogenous contrast uptake, bone lysis, tooth loss, ipsilateral lymphadenopathy. However, benign tumours could also cause these changes (particularly acanthomatous ameloblastoma and therefore biopsy is still required to definitively differentiate).
In a study by Menghini 2023 in VRU, CT 3D volumetric analysis was used to identify nodal metastasis in cases of canine oral melanoma, what was the positive predictive value of mandibular lymphocenter volume?
57%
In a study by Shilo-Benjamini 2022 in JFMS, which of the maxillary block techniques shown was associated with best spread of infusate and potential maxillary anesthesia?
The infraorbital canal and maxillary foramen techniques both resulted in adequate distribution of infusate.
These techniques were suggested over traditional maxillary block techniques to avoid penetration of the globe.
In a study by Zaccone 2022 in JVIM, what were 4 risk factors identified for development of oral squamous cell carcinoma in cats?
Rural environment, outdoor access, environmental tobacco smoke, and petfood containing chemical additives.
What is the MST for canine oral melanoma based on stage?
Stage 1: 424 to 874 days (tumor < 2 cm, negative lymph nodes)
Stage 2: 246 to 818 days (tumor 2 to 4 cm, negative lymph nodes)
Stage 3: 173 to 495 days (tumor >4 cm or positive lymph nodes).
What are the major muscles of mastication?
Digastricus, masseter, pterygoideus, temporalis.
What is the major arterial supply to the mandible?
Inferior alveolar artery, a branch of the maxillary artery.
What is the major nervous innervation to the mandible?
The mandibular nerve, a branch of the trigeminal nerve. After entering the mandibular canal it becomes the inferior alveolar nerve, becoming the mental nerves as it exists the mental foramina rostrally.
What is the major arterial supply to the maxilla?
Major palatine artery and infraorbital, both branches of the maxillary artery. The infraorbital artery exits the mandible laterally through the infraorbital foramen at the level of the carnassial tooth.
What is the major nervous innervation to the maxilla?
The maxillary nerve becomes the infraorbital nerve that enters the infraorbital canal.
What are the most common oral tumours of dogs, in descending frequency?
What is the metastatic rate (either regional or distant) for these tumours?
Malignant melanoma (metastatic rate 81%), SCC (20%), fibrosarcoma (35%), osteosarcoma, acanthomatous ameloblastoma.
Is survival time of oral osteosarcoma typically better or worse than for appendicular osteosarcoma?
Better
What is the normal signalment for common oral tumours of the dog?
Melanoma: older, small breed dogs.
SCC: older, large breed dogs.
Fibrosarcoma: middle to older large breed dogs, particularly Golden retrievers and labradors.
Osteosarcoma: medium and large breed dogs.
What is the most common location for oral fibrosarcoma in the dog?
Gingiva near the maxillary carnassial tooth.
Where do acanthomatous ameloblastomas typically occur?
Rostral portion of the mouth. Locally aggressive and should be treated by maxillectomy/mandibulectomy.
What are peripheral odontogenic fibromas (POF)?
Previously called fibromatous and ossifying epulides. Slow growing, firm lesions that occur in the premaxillary region. Cured by tooth extraction and excision of a small margin of surrounding alveolar bone.
What is focal fibrous hyperplasia (FFH)?
A benign reactive lesion of the oral cavity that is thought to result from irritation caused by dental plaque and calculus.
What percentage of oral tumours display bone lysis?
60-80%
What are the optimum modalities for assessing bone margins for oral tumours?
CT or MRI (radiography underestimates the extent to bone destruction).
