The soft-tissue resiliency of the cheek is the key for shifting the transbuccal cannula to the intended screw insertion site. As a principle the cannula is best movable if it is inserted at the maximal transverse extension of the wound cavity. Movements are limited approaching the borders of the cavity being reduced along concentric lines around the soft-tissue channel. The dissection cavity along the lateral surface of the mandible is reduced in its transverse spacing towards the posterior border of the ramus and towards the mental foramen.
Be aware that if the cannula is inserted in the vicinity of the mental foramen, the neurovascular bundle can easily be stretched or damaged by brisk movements of the transbuccal handle. Usually, the zone next to the neurovascular mental bundle is preferably reached transorally.
In case of placing several screws at a time, eg, for application of a longer osteosynthesis plate, it may be advantageous to use several transbuccal channels. This provides a perpendicular insertion of the drill bit and screw driver.
To use the full space of the dissection cavity the retractor should be mounted at a short distance to the tip of the cannula.