Mandibulectomy and Maxillectomy Flashcards
Why is cautery and laser therapy advised to be used sparingly?
Incisions with diathermy or laser can increase the risk of wound dehiscence
Where cautery is required, can you think of a way to limit damage to the surrounding tissues and vasculature?
If electrocautery is required, it is best applied with bipolar forceps (avoiding monopolar cautery) to limit the effect on surrounding tissues and decrease vascular damage.
What are the different types of Mandibulectomies and maxillectomies? (5)
unilateral
bilateral
rostral
lateral/segmental,
caudal.
What recumbency is most commonly used for surgery?
Lateral
What positioning is very useful for resections of the rostral and lateral aspects of the Maxilla?
Dorsal recumb
Dorsal recumbency allows good access to what parts of mandible?
Caudal
What approach is used for For caudal Maxillectomies?
A combined intraoral and dorsolateral approach
Which recumbency, with the head elevated and the maxilla suspended between intravenous poles secured to the ceiling can be useful for mandibulectomies?
Sternal
What is cut during a mandibulectomy for a tumour removal?
soft tissues (laterally and medially), and the bone is cut on both sides of the tumour without touching the actual tumour
Define rim excision mandibulectomy
partial segmental excision leaving the ventral border of the mandible intact.
Define A total or unilateral mandibulectomy
complete excision of one of the mandibles. In some literature this is less accurately referred to as “hemi-mandibulectomy”.
Define A bilateral rostral mandibulectomy
The rostral parts of both mandibles are removed after an osteotomy between the second and third premolars. If necessary, the osteotomy can be performed as far caudally as between the fourth premolars and first molars.
Define In a unilateral rostral mandibulectomy,
only the part of the bone that carries the three incisors, canine, and first and second premolars is removed. This is indicated for a small tumour not crossing the mandibular symphysis.
Define a caudal mandibulectomy,
the ramus of the mandible (including the condylar and coronoid processes) is removed.
Define segmental mandibulectomy,
a full thickness part of the midsection of the mandible is excised.
What is a rim excision?
The excision of only the dorsal two thirds of the mandible, leaving the mandibular canal and the ventral cortex intact
When is a rim incision indicated? (2)
- wide excision of small and minimally invasive tumours on the alveolar margin;
- marginal excision of benign lesions, such as a small benign odontogenic tumours.
Steps for a rim excision.
1.After mucoperiosteal incision, the soft tissues are subperiosteally elevated (ventrally) away from the planned ostectomy site.
2. At the level of the attached gingiva, the soft tissue incision must be narrower than the bony incision to be able to cover the bone tension-free with gingiva on completion of the procedure.
3. The ostectomy is performed in an interdental space. A surgical handpiece combined with an osteotomy burr or an oscillating saw or a TPLO saw are the instruments of choice.
4.The bone margins may have to be smoothed.
5. The attached gingiva and alveolar mucosa are sutured over the bony defect.
Rim excision:
At the level of the attached gingiva, the soft tissue incision must be ??? than the bony incision to be able to cover the bone tension-free with gingiva on completion of the procedure.
narrower
Rim excision - where is the ostectomy performed?
Interdental space
What must happen to bone margins in a rim excision?
Smoothed.
What is excised with a unilateral rostral mandibulectomy?
incisors, canine, first and second premolars in the dog.
Why is An osteotomy between the canine tooth and the first premolar or between the first and second premolar teeth
not indicated?
because this would transect the alveolus and root of the canine tooth.
Why is a unilateral rostral mandibulectomy rarely indicated for oncology?
10mm surgical margin; proximity of mandibular symphysis
What is ligated in unilateral rostral mandibulectomy?
All labial and lingual blood vessels.
What should be avoided in a unilateral rostral mandibulectomy if sx allowed?
Sublingual caruncle
Where is an osteotomy performed in unilateral rostral mandibulectomy?
between the second and third premolar teeth is performed using an oral surgery handpiece or saw.
What commonly happens during osteotomy to inferior alveolar artery during unilateral rostral mandibulectomy?
prone to retracting into the mandibular canal; if this occurs, a haemostatic agent can be packed into the mandibular canal.
What falp is created during unilateral rostral mandibulectomy?
A labial mucosal-submucosal flap is created by dissecting from the mandibulectomy site toward the lip margin between the submucosa and the skin.
How is a unilateral rostral mandibulectomy sutured?
The free edge of the flap is sutured to the attached gingiva at the symphysis with single interrupted sutures.
Where is the mandible amputated for Bilateral Rostral Mandibulectomy?
Both mandibles are amputated between the second and third premolars,
How far caudally can we go with a Bilateral Rostral Mandibulectomy?
PM 4 - M1
If the Bilateral Rostral Mandibulectomy is taken far caudally; what must happen post op?
Learn how to feed; hand feed at start
If the Bilateral Rostral Mandibulectomy is taken far caudally; what ducts are ligated?
sublingual and mandibular salivary ducts
Midline tumours extending facially; how is it closed for Bilateral Rostral Mandibulectomy?
A single wedge of skin is excised on the facial aspect; this should preferably be done as part of the originally plannedincision but can also be performed after the ostectomy.
What is the possible surgical compliated of a Segmental Mandibulectomy?
Malocclusion (because of drifting) i
When can a Segmental Mandibulectomy be performed?
relatively small tumours that are believed not to have infiltrated rostrally or caudally into the mandibular canal, or caudally into the ramus of the mandible.
How can Caudal Mandibulectomy be approached? (3)
- A skin incision and osteotomy of the zygomatic arch
- Dorsal
- Ventral
Where does dissection start for Total Unilateral Mandibulectomy?
Rostrally
During a Total Unilateral Mandibulectomy, when in the op should the symphysis be split - early or late?
Early
How is the ramus dissected in a Total Unilateral Mandibulectomy?
subperiosteally elevating the muscles of mastication on the lateral and medial aspect, provided that the predetermined surgical margins allow this.
During a Total Unilateral Mandibulectomy, what should be ligated early on in mandibular foramen?
Inferior alveolar blood vessels
During a total unilateral mandibulectomy, why is it important to remain close to the bone?
avoid inadvertently damaging he maxillary artery or one of its main branches, which lie in close proximity.
During a total unilateral mandibulectomy, how is lip commisure closed?
three-layer closure is performed, consisting of mucosa, muscularis, and skin.
Why might a commissurorrhaphy be performed rostrally?
to prevent protrusion of the tongue.
A variation on the total Unilateral Mandibulectomy procedure for tumours that are located not as far caudally, is to perform the osteotomy at the level of the..?
the rostral edge of the masseter muscle, thereby leaving most of the ramus behind.
Name the procedure:
The mandibular canal and ventral cortex remain intact.
Rim excision
Name the procedure:
An osteotomy is performed between second and third premolars.
Unilateral rostral mandibulectomy
Name the procedure:
If necessary, can be performed as far caudally as between the fourth premolar and first molar.
Bilateral rostral mandibulectomy
Name the procedure:
Indicated for small tumours without rostral or caudal infiltration into the mandibular canal, or caudal infiltration into the ramus.
Segmental mandibulectomy
Name the procedure:
Traditionally involves skin incision and osteotomy of the zygomatic arch but can also be approached intra-orally or ventrally.
Caudal mandibulectomy
Name the procedure:
Most appropriate surgical option for large and infiltrative tumours
Total unilateral mandibulectomy
What is always entered during a maxillectomy?
Nasal cavity
How can nasal cavity defects be closed during maxillectomy? (2)
Soft tissue flaps:
- vestibular mucosal-submucosal flaps
+/- without palatal mucoperiosteal flaps.
Define incisivectomy
(premaxillectomy) an excision confined to the rostral incisive bone,
Define total unilateral maxillectomy
Removing most of one maxillary bone (combined with the excision of all or parts of the incisive and palatine bones)
Define a unilateral rostral maxillectomy,
one side of the incisive bone and the most rostral part of the maxillary bone are removed.
Define A bilateral rostral maxillectomy
involves resection of the entire incisive bone with part of the maxillary bone. This procedure can be combined with a nasal planectomy.
Define central maxillectomy.
A partial maxillectomy involving the midportion of the maxilla
Define A caudal maxillectomy can be combined with an orbitectomy
which entails removal of portions of bones that comprise the orbit, including the maxilla, palatine, zygomatic, lacrimal, and frontal bones.
What bleeding should be anticipated in Incisivectomy?
Major palatine arteries
What nasal structure is exposed during Incisivectomy?
Ventrolateral nasal cartilages
How is the Incisivectomy closed?
- flaps; how?
Surgical closure is achieved by means of a vestibular pedicle flap, created by making two vertical releasing incisions from the corners of the defect into the alveolar and buccal mucosa. The flap is raised and advanced over the defect and sutured to the palatal mucosa.
What can happen to the nose following Incisivectomy?
Dip ventrally
When is a unilateral rostral maxillectomy indicated?
small tumours on the buccal aspect of the canine tooth
Where is the removal during a A bilateral rostral maxillectomy up to in dogs?
incisors, canines, and first and second premolars
Where is the removal during a A bilateral rostral maxillectomy up to in cats?
incisors, canines, and second premolar
What pattern can be followed when making a palatal incision for A bilateral rostral maxillectomy ?
Rugae pattern
What flap can be used for A bilateral rostral maxillectomy ?
vestibular mucosal-submucosal flap.
What shape closure for A bilateral rostral maxillectomy ?
T shaped
Which side should sutures be in deep layer closure of A bilateral rostral maxillectomy ??
Nasal
Other tahn simple interrupted for deep layer closure for A bilateral rostral maxillectomy, what is the alternative?
simple-interrupted sutures pre-placed through holes drilled through the bony hard palate.
Central, Caudal, and Total Unilateral Maxillectomy - which is performed last?
caudal
What approach is best for the resection of large caudal maxillary tumours?
combined extraoral-dorsal and intraoral approach
During caudal maxillectomy; what must be ligated before bony incsions?
Maxillary artery
What is described: Indicated for small tumours on the buccal aspect of the canine. More commonly performed as a bilateral procedure.?
Rostral maxillectomy
What is described: Rarely indicated given the need for 10 mm margins for most tumours.
Incisivectomy
What is described: It is important that the maxillary artery is ligated before any bony incisions are made.
Caudal maxillectomy
What chewing should be prevented post surgery
Hard toys and sticks
How often should surgery site be evaluated for tumour?
3-6mo
Success rate of Sx:
A) SCC
B) Fibrosarcoma
C) Osteosarcoma
A) Good
B) Fair
C) Fair
Success rate of Sc:
A) Odontogenic
B) Malignant melanoma
A) Excellent
B) Poor
What post op effects my happen after mandibulectomy because of damage or trauma to the salivary ducts?
Swelling + oedema of sublingual tissue
Haemorrhage is the main intraoperative complication, which typically occurs after the inadvertent transection of one of the main arteries (the inferior (A) artery during a mandibulectomy and the infraorbital, sphenopalatine, and major (B) arteries during a maxillectomy) before ligation.
A) Alveolar
B) Palatine
What ligation can be performed pre op if severe haemorrhage is anticipated?
bilateral temporary carotid artery ligation
Which surgery is wound dehiscence more commonly seen with?
Maxillectomy
