Executive Editor: Marcelo Figari, Gregorio Sánchez Aniceto General Editor: Daniel Buchbinder

Authors: Ricardo Cienfuegos, Carl-Peter Cornelius, Edward Ellis III, George Kushner

Mandible

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Glossary

Intraoral approach to symphysis
Intraoral approach enlarge

Principles

Vestibular incisions
The intraoral approach is the usual access for simple fractures of the body, symphysis, and angular regions.
The approach can be extended posteriorly (dashed line) for better access to the body, angle and ramus regions.

Restricted access and contamination
In complex fractures including comminuted, edentulous, and avulsive fractures requiring the placement of load-bearing reconstruction plates, a transfacial approach may provide better access.
Oral contamination is not a contraindication for an intraoral incision.


Keep the incision superior to the mental nerve in the body region enlarge

Neurovascular structures
The mental nerve is a branch of the fifth cranial nerve (trigeminal nerve). This nerve provides sensation to the anterior mandibular vestibule, lip and chin.
When the incision is extended posterior to the canine teeth, the mental nerve can be damaged. Keep the incision superior to the mental nerve in the body region.
Particularly in the extended intraoral approach, care must be taken to protect the mental nerve in the anterior body region.


The incision is made through the mucosa in the vestibule enlarge

Intraoral incision

Mucosal incision
Unless contraindicated, infiltrate the area with a local anesthetic containing a vasoconstrictor.
Make an incision through the mucosa in the vestibule. Between the canines the incision is made 10–15 mm away from the attached gingiva in a curvilinear fashion. Posterior to the canine the incision is only 5 mm away from the attached gingiva, staying superior to the mental nerve.


The image shows the carrying of the incision through the mucosal layer enlarge

Surgical flap dissection
Carry the incision through the mucosal layer in the anterior region out in the lip away from vestibular fold. Dissect a mucosal flap that retracts or is lifted (as shown) to expose the surface of the mentalis muscle. The branches of the mental nerve are located just underneath the mucosal flap and must be respected.

Mentalis muscle dissection
The mentalis muscle is incised near the alveolar bone ridge thus creating a stepwise approach which protects the mental nerve. Later, during wound closure the mentalis muscle should be properly reattached.


This image shows a elevated mucoperiosteal flap enlarge

Fracture site exposure
Elevate a mucoperiosteal flap to expose the fracture.


Extend the approach laterally and posteriorly enlarge

Extension of approach

Lateral/posterior vestibular incision
The approach can be extended laterally and posteriorly to provide access to the body, angle and ramus regions of the mandible.
Right-angled retractors are helpful in this approach.


Dissect the mental nerve enlarge

Dissection of the mental nerve
In the extended intraoral approach, care must be taken to protect the trunk of the mental nerve which exits in the anterior body region.

Keep the incision superior to the mental nerve trunk.


Free the mental nerve enlarge

Pearl: freeing of the mental nerve (skeletonization)
Freeing of the mental nerve allows for better soft-tissue retraction.

Tissue scissors are used to spread parallel to the nerve. Scalpels could be used but at the risk of injuring the nerve.


Mental foramen and mental nerve exposed enlarge

Mental foramen and mental nerve are exposed.


Spreading scissors parallel to nerve to remove soft-tissue envelope enlarge

By spreading scissors parallel to nerve the soft-tissue envelope is removed.


Skeletonization of the mental nerve. enlarge

This image shows the skeletonization of the mental nerve.


Minimizing mental nerve retraction enlarge

Combination with the transbuccal technique

To place posterior screws minimizing mental nerve retraction, the transbuccal trocar may assist the surgeon and keep the screws perpendicular to the plate.

Click here for a detailed description of the transbuccal technique.


Closing the incision enlarge

Wound closure

After thoroughly irrigating the wound and checking for hemostasis the incision is closed. Anteriorly, the mentalis muscle is reapproximated to prevent drooping of the chin tissues. The mucosa is closed with interrupted or running resorbable sutures.


Elastic pressure dressing enlarge

An elastic pressure dressing on the chin region helps support the soft tissues and prevent hematoma formation.

v1.0 2008-12-01