Authors of section

Authors

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

Executive Editors

Marcelo Figari, Gregorio Sánchez Aniceto

General Editor

Daniel Buchbinder

Open all credits

ORIF, miniplate fixation to the oblique ridge

1. Principles

Champy’s ideal line of osteosynthesis

For angle fractures the ideal line of osteosynthesis is located along the external oblique ridge (A). If it is not possible to plate this area, a miniplate located along the lateral surface of the mandible can also be used (B).

Be prepared to change the fixation plan to using two miniplates in case of reduction at the basal region or if the stability is not sufficient.

Biomechanics of the mandible.

For angle fractures the ideal line of osteosynthesis is located along the external oblique ridge

Special considerations

Teaching videos

Application of a miniplate to the oblique ridge

Application of a locking plate to the oblique ridge

2. Approach

For this procedure the intraoral approach to the angle is normally used.

revision orif

3. Choice of implant

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.

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

4. Reduction

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 deemed necessary 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.

the fracture should be exposed and any extractions deemed necessary performed

5. Plate adaption

Twist the plate approximately 90° to facilitate adaptation to the superior border of mandible in the angle region. Pretwisted mandible plates 2.0 are available at 70°.

Twist the plate approximately 90°

Apply the plate to the bone spanning the fracture. Note that the two posterior holes of the plate are located medial to the external oblique ridge and the two anterior holes are placed along the lateral cortex.

Apply the plate to the bone spanning the fracture

6. Fixation

Application of first screw

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

Application of first screw

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

Application of first screw

Placement of second screw

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

Drill the hole just anterior to the fracture

Insert the second screw and tighten it loosely like the first screw.

Insert the second screw

Placement of third screw

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

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

Placement of final screw

In some cases the most posterior hole of the plate is accessible for drilling and screw placement.

Drilling and placing the screw into the most posterior hole of the plate

If it is not possible to drill and place the most posterior screw because of inadequate access, the mandible can be opened at this point and instrumentation can proceed from underneath the maxillary dentition.

Drilling and placing the screw into the most posterior hole of the plate

The last screw is inserted.

The last screw is inserted

Final check

Release the MMF and check the occlusion for accuracy before proceeding with closure.

Completed osteosynthesis

X-ray shows the completed osteosynthesis.
Note that the patient is not in MMF in the postoperative phase.

The arch bars are left in place for around two weeks and are only removed if no postoperative complications arise.

The completed osteosynthesis

Alternative: plate on the lateral surface of the angle

Illustration shows the alternative position of a single plate on the angle.

If it is decided that placement of a bone plate along the external oblique ridge is not possible and instead will be placed on the lateral surface of the bone, a stronger, thicker miniplate is required. In such cases, one should use a miniplate made of grade IV titanium, and one should consider using a thicker plate or one with a broader centerspan, because when a plate is placed on the lateral surface, the plate will be stressed in torsion rather than tension. The plate must be much stronger in such instances. For this technique, transbuccal trocar instrumentation will be necessary to place all screws.

Alternative position of a single plate on the angle

7. Aftercare following ORIF of mandibular symphysis, body, angle and ramus fractures

If arch bars or MMF screws are used intraoperatively, they are usually removed at the conclusion of surgery if proper fracture reduction and fixation have been achieved. Arch bars may be maintained postoperatively if functional therapy is required or if required as part of the fixation.

Postoperative x-rays are taken within the first days after surgery. In an uneventful course, follow-up x-rays are taken after 4–6 weeks.

The patient is examined approximately 1 week postoperatively and periodically thereafter to assess the stability of the occlusion and to check for infection of the surgical wound. During each visit, the surgeon must evaluate the patients ability to perform adequate oral hygiene and wound care, and provide additional instructions if necessary.

Adequate dental care is required in most patients having suffered a mandibular fracture.

If a malocclusion is detected, the surgeon must ascertain its etiology (with appropriate imaging technique). If the malocclusion is secondary to surgical edema or muscle splinting, training elastics may be beneficial. The lightest elastics as possible are used for guidance, because active motion of the mandible is desirable. Patients should be shown how to place and remove the elastics using a hand mirror.

If the malocclusion is secondary to a bony problem due to inadequate reduction or hardware failure or displacement, elastic training will be of no benefit. The patient must return to the operating room for revision surgery.

Follow-up appointments are at the discretion of the surgeon, and depend on the stability of the occlusion on the first visit. If a malocclusion is noted and treatable with training elastics, weekly appointments are recommended.

Postoperatively, patients will have to follow three basic instructions:

1. Diet
Depending upon the stability of the internal fixation, the diet can vary between liquid and semi-liquid to “as tolerated”, at the discretion of the surgeon. Any elastics are removed during eating.

2. Oral hygiene
Patients having only extraoral approaches are not compromised in their routine oral hygiene measures and should continue with their daily schedule.
Patients with intraoral wounds must be instructed in appropriate oral hygiene procedures. The presence of the arch-bars and any elastics makes this a more difficult procedure than normal. A soft toothbrush (dipping in warm water makes it softer) should be used to clean the surfaces of the teeth and arch-bars. Any elastics are removed for oral hygiene procedures. Chlorhexidine oral rinses should be prescribed and used at least three times each day to help sanitize the mouth. For larger debris, a 1:1 mixture of hydrogen peroxide/chlorhexidine can be used. The bubbling action of the hydrogen peroxide helps remove debris. A Waterpik® is a very useful tool to help remove debris from the wires. If a Waterpik is used, care should be taken not to direct the jet stream directly over intraoral incisions as this may lead to wound dehiscence.

3. Physiotherapy
Physiotherapy can be prescribed at the first visit and opening and excursive exercises begun as soon as possible. Goals should be set, and, typically, 40 mm of maximum interincisal jaw opening should be attained by 4 weeks postoperatively. If the patient cannot fully open his mouth, additional passive physical therapy may be required such as Therabite or tongue-blade training.