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

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ORIF, one plate and arch bar

1. Principles

Biomechanics of the symphysis

The mandibular symphysis undergoes rotational forces (twisting) during function. Therefore, fixation strategies must take this into account. When using anything less stable than a reconstruction plate, two points of fixation should be applied.

In general, the further apart the points of fixation, the more stable the construct. For symphysis fractures, when one plate is applied along with a stable arch bar, the plate should be placed as close as possible to the inferior border of the mandible.

This technique requires a stable arch bar be placed across the fracture line. For those cases where there is a tooth missing in the line of fracture or the teeth are loose, an arch bar is not recommended to provide the second point of fixation. Thus, a second point of fixation on the bone must be provided.

Plate is placed as close as possible to the inferior border of the mandible.

Special considerations

2. Approach

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

orif one plate and arch bar

3. Reduction

Drilling monocortical holes

It is necessary to pre-drill two monocortical holes below the apices of the teeth on either side of the fracture to help when placing the reduction forceps.

Manipulate the mandible fragments until anatomic reduction is achieved, apply the reduction forceps and then place patient into occlusion and secure it with MMF.

Some surgeons prefer to place the patient into occlusion and apply MMF before using the reduction forceps.

How to predrill two monocortical holes below the apices of the teeth

Clamp application

The clamp has to be placed perpendicular to the line of fracture to prevent fracture displacement when tightening the reduction clamp.

The clamp has to be placed perpendicular to the line of fracture

4. Fixation

Choice of implant

An ideal choice is a large, thick and wide plate type such as the large profile locking plate 2.0, dynamic compression plates (DCP) or universal fracture plates (UFP).

For further details on compression plate application, click here.

Details on emergency screws can be found here.

The minimum size for the plate at the lower border of the mandible is a mandible plate 2.0 or a small profile locking plate 2.0.

For more information on mandibular plate types, click here.

Shows the different plate types.

Plate contouring

Contour the plate using bending pliers.

Contouring a 4-hole plate by using bending pliers.

Plate positioning

Position the plate in the desired location. Because miniplate fixation is adaptation osteosynthesis and does not compress the fracture, the plate can be placed in a direction other than perpendicular to the fracture line.
Because miniplates do not compress the fracture, the fracture must be perfectly reduced prior to application of plates because the plates will not facilitate better reduction as might a compression technique do.

Plate is positioned to the desired location.

Drill first screw hole

Use a 1.5 mm drill bit with 6 mm stop to drill monocortically through the plate hole next to the fracture.

Usage of a 1.5 mm drill bit with 6 mm stop

Insert screw

Insert a 2.0 mm screw, 6 mm in length. Do not fully tighten it until the final reduction and plate position are confirmed.

Screws placed from opposite sides

Insert second screw

Insert a second screw on the other side of the fracture in the same way.
Tighten both screws.

Insertion of a second screw on the other side of the fracture.

Additional screw placement

Fill the remaining plate holes with screws.

Completed osteosynthesis.

Alternative: 6-hole locking plate 2.0

Illustration showing the final osteosynthesis using a 6-hole locking plate 2.0.
Screws inserted bicortically could provide additional stability when using a medium or large profile 2.0 locking plate.

Final osteosynthesis using a 6-hole locking plate 2.0

Confirmation of reduction

Confirm adequate reduction. There must be no gap at the lingual aspect. Such a gap would lead to occlusal disturbance and mandibular widening.
MMF may be released and the occlusion checked.
The arch bar must be maintained for 5-6 weeks to provide a second point of fixation.

5. Case example

Simple symphyseal fracture

Example of a simple symphyseal fracture.

Example of a simple symphyseal fracture.

Exposure of fracture

Note that a stable arch bar has been applied.

A stable arch bar has been applied

Completed osteosynthesis

Clinical photographs shows the completed osteosynthesis.

Completed osteosynthesis

X-ray of the completed osteosynthesis

X-ray shows the completed osteosynthesis

X-ray of the completed osteosynthesis.

6. 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.