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

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

Mandible - Angle and ramus, simple - ORIF

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Glossary

1 Principles top

Two points of fixation provide much more stability enlarge

Biomechanics

All biomechanical models developed to date have shown that two points of fixation (ie, two plates) provide much more stability than a single one. Therefore, when more stability is deemed necessary the addition of a second plate provides more stable fixation.


Special considerations

Following special considerations may need to be taken into account:

Click on any subject for further detail.

2 Choice of implant top

The factor to determine whether a 4- or 6-hole miniplate should be used is the condition of the labial plate of bone. If the bone where the third molar is/was very thin and/or the third molar is positioned laterally within the alveolus, a 6-hole plate may be needed to span the area of the third molar where screws may not be possible to safely and securely placed. In such instances, it is not necessary to use six screws, and a hole can be left empty in the area where the third molar is positioned. It is only necessary to place two secure screws on each side of the fracture.

Some surgeons prefer to use a thicker plate for the lower position (below the mandibular nerve) such as a medium or large profile 2.0 locking plate with bicortical screw for additional stability in specific clinical situations.


The surgeon must choose whether to use a 4- or 6-hole miniplate along the oblique ridge in the angle region enlarge

Superior border plate

The surgeon must choose whether to use a 4- or 6-hole miniplate along the oblique ridge in the angle region. Very often a 4-hole titanium miniplate can be adapted quite nicely to this area. However, if a third molar is present or recently extracted, the bone in this area may be absent. The surgeon may choose to use a longer 6-hole plate to span the defect. Obviously, there may be empty screw holes over the region where bone is missing.

The surgeon has several options when choosing a plate for this region. The minimum size would be a mandible miniplate 2.0. However, some surgeons prefer a more rigid plate such as the locking plate 2.0 which comes in incremental profiles. The small profile and medium profile plates are applicable to the oblique ridge.


Choice of implant enlarge

Lower plate

The profile and type of the inferior border plate can range from a conventional miniplate to locking plates of incremental size.

The following varieties will yield sufficient stability:

  • 4- or 6-hole mandibular plate 2.0 with or without center space
  • 4- or 6-hole locking small profile plate 2.0
  • 4- or 6-hole locking medium profile plate 2.0
  • 4- or 6-hole locking large profile plate 2.0

3 Reduction top

Fixation of the occlusion enlarge

Open reduction and stable internal fixation in the dentate patient begins with fixation of the occlusion. Prior to placing the patient into MMF, the fracture should be exposed and any extractions determined necessary be performed. The bones should also be reduced prior to placing the patient into occlusion and securing the MMF.

Click here for further details on methods for applying MMF.

4 Plate adaption top

Twist the plate approximately 90° enlarge

Twist the plate approximately 90° to facilitate adaptation to the superior border of mandible in the angle region.


Twist the plate approximately 90° enlarge

Twist the plate approximately 90° to facilitate adaptation to the superior border of mandible in the angle region.

5 Fixation of superior border plate top

Apply the screw just posterior to the fracture first enlarge

Application of first screw

Apply the screw just posterior to the fracture first. Use a 1.5 mm drill to make a mono cortical hole.


Apply the screw just posterior to the fracture first enlarge

Insert a 6 mm screw but tighten loosely, allowing the anterior portion of the plate to be rotated upwards or downwards as necessary to better adapt it to the bone.


Drill the hole just anterior to the fracture. enlarge

Placement of second screw

Drag the plate anteriorly with a point of a periosteal elevator and move it up or down until it is seating flush with the buccal cortex. Drill the hole just anterior to the fracture.


Insert the second screw and tighten it enlarge

Insert the second screw and tighten it as well as the first screw.


Insert and tighten the screw enlarge

Placement of third screw

Drill a hole through the most anterior plate hole. Insert and tighten the screw.


The last screw will be placed after the lower border miniplate has been applied enlarge

Note that the posterior hole is not accessible for screw placement. Therefore, the last screw will be placed after the lower border miniplate has been applied by opening the mouth and instrumentation underneath the maxillary dentition.

Note that the inferior borders are not well aligned. The addition of a second plate is thought necessary.

6 Fixation of lower border plate top

The first hole is drilled 4-5 mm posterior to the fracture line enlarge

Fixation of lower border plate - Drilling first screw hole

Using transbuccal trocar instrumentation the first hole is drilled 4-5 mm posterior to the fracture line and 3-4 mm above the inferior border.

Click here for a detailed description of the use of the transbuccal system.


The first hole is drilled 4-5 mm posterior to the fracture line enlarge

The hole can be drilled monocortically or bicortically if it is certain that the inferior alveolar canal is located above this area.


Overbend a 4-hole malleable miniplate and insert it into the surgical site enlarge

Pearl: plate placement
Once the first hole has been drilled, overbend a 4-hole malleable miniplate and insert it into the surgical site. To facilitate locating the hole in the bone, use a stylette inside the trocar to drag the second-to-last hole in the plate into position and to locate the first drill hole. The trocar is then pushed to hold the plate to the bone and the stylette is withdrawn.


The screw is then immediately inserted and tightened enlarge

The screw is then immediately inserted and tightened while ensuring that the anterior portion of the plate is positioned properly above the inferior border.


Drill the hole through the plate hole located just in front of the fracture enlarge

Placement of second screw

Drill the hole through the plate hole located just in front of the fracture. The plate should be pulled anteriorly during this maneuver to help close the fracture gap. The drill should be placed anteriorly within the hole of the plate to produce slight compression of the fracture when tightening the screw.


Once the hole has been drilled, the screw is placed and tightened fully enlarge

Once the hole has been drilled, the screw is placed and tightened fully.

Note that the inferior borders are now aligned.


Drill the hole through the plate hole located just in front of the fracture enlarge

Additional screw placement

The holes on the terminal ends of the plate are then drilled and the screws are inserted.

7 Completion of osteosynthesis top

Fine tuning of superior border plate enlarge

Fine tuning of superior border plate

If the most superior/posterior part of the upper plate is not well adapted to the underlying bone, one may very readily do so by …


Once the hole has been drilled, the screw is placed and tightened fully enlarge

… placing one beak of a wire twister lateral to the ramus and the other against the plate. By squeezing the wire twister, the plate is pressed to the bone-in this case because of the malleability of the grade II titanium miniplate used.


Once the hole has been drilled, the screw is placed and tightened fully enlarge

Placement of final screw

If it is not possible to drill and place the most posterior screw because of inadequate access, ...


Once the hole has been drilled, the screw is placed and tightened fully enlarge

... the mandible can be opened at this point and instrumentation can proceed from underneath the maxillary dentition.


Check the occlusion for accuracy before proceeding with closure enlarge

Final check

One should then release the MMF and check the occlusion for accuracy before proceeding with closure.


Completed osteosynthesis enlarge

Completed osteosynthesis

X-ray shows the completed osteosynthesis.


Completed osteosynthesis enlarge

X-ray shows the completed osteosynthesis.

v1.0 2008-12-01