1 Principles topenlarge
Considerations related to dental occlusion render nasotracheal intubation necessary. If that is not feasible, primary submental/submandibular intubation should be considered. Depending on the patient’s general condition, a tracheostomy might also be considered.
The aim of successful reconstruction of midface fractures is reestablishing the midfacial vertical buttresses. These pillars can serve an even more important role in patients who lack dentition (partial or completely edentulous patients).
A principle in all Le Fort fractures is to reestablish the premorbid dental occlusion. Portions of the pterygoid plates and associated musculature are still attached to the posterior portion of the maxilla, so passive mobilization of the fracture can be difficult. Without passive mobilization, Class III tendency often occurs in the postoperative period. The reason for this is that when patients are placed into MMF during surgery, soft-tissue tension from the attached musculature distalizes the mandibular condyles in the glenoid fossae. When the MMF is removed, the condyles re-seat themselves into their normal position, bringing the mandibular dentition forward, creating a Class III malocclusion. In order to properly achieve a passive position of the maxilla, the maxilla requires strong mobilization forces using varied instrumentation: Rowe’s disimpaction forceps, “Stromeyer” hook, Tessier retromaxillary mobilizers, etc.
The goal is to achieve an anatomical correct repositioning by means of 3-D reconstruction. If available, dental cast, stereolithographic models, and/or premorbid photographs may be useful guides for treatment.
As a general principle, all facial fractures should be exposed and reduced before plating.
Le Fort I fractures with bilateral comminution display the highest degree of maxillary mobility of all Le Fort fracture types. They can occur with larger fracture fragments (that may be fixed to the plate), or with smaller comminution or defects where fracture fixation to the segments is not possible.
Establishing the correct facial height is crucial in this procedure. It is extremely rare that at least one point of bone contact across the Le Fort I level cannot be found to establish the appropriate vertical dimension. Occasionally a free bone fragment from within the Le Fort I gap can be used to provide the proper vertical dimension. A bone plate should be placed in the area where the proper vertical dimension can be determined. Other bone plates are then applied across the bone gaps which are then grafted.
Choice of implant
It is difficult to give absolute guidelines as to the strength of the plates that would be used at the bony interfaces for a Le Fort I fracture. The following however should be considered:
- A plate that is placed for the fixation of the fracture at the zygomaticomaxillary buttress is generally a larger plate because it is the point that will provide most stability to the Le Fort I fracture. The highest forces of mastication would be in this area. Depending on the fracture pattern an L-, T-, Y-plate or a straight plate may be used.
- Another plate can also be applied at the piriform rim.
There is considerable variation in different cases as to how unstable or comminuted the fractures may be. Furthermore, the majority of Le Fort I fractures are also associated with a multitude of other midface fractures. This has further impact on deciding the size and strength of the plate that must be used. Finally, in many cases of Le Fort I fracture with other panfacial trauma, many surgeons may choose to leave the patient in MMF for a period of time postoperatively. This has a further impact in deciding whether a larger or smaller plate is adequate.
Click here for a description of implant options.
2 Reduction topenlarge
First, arch bars are secured to the dentition. Click here for a detailed description of mandibulomaxillary fixation.
After exposure of the fracture segments through a maxillary vestibular approach, the fracture has to be mobilized to enable reduction and fixation.
In most cases Le Fort I fractures with bilateral comminution can easily be reduced manually. After reduction, comminuted fracture fragments need to be repositioned (in the case without defect, ie, with large fragments). If these fragmented pieces are too small they may be removed (defect cases).
Rowe disimpaction forceps
The Rowe disimpaction forces are side specific. They allow the application of great amounts of force to disimpact and reposition the maxilla and midface.
Note: Special attention has to be given to the patient individual fracture pattern so that the use of these instruments does not result in significant shearing at the skull base or orbit. Otherwise, severe complications such as blindness can occur.
Special attention has to be paid regarding the correct placement of the Rowe disimpaction forceps so that the upper anterior dentition is not harmed.
The maxillary fracture is completely mobilized and an attempt should be made to make the fragment as passive as possible. This may require an up-down and side-to-side movement of the forceps.
According to regional preferences and various schools of teaching, different bone hooks are used for fracture reduction.
- Reduction hook (Stromeyer hook)
The Stromeyer hook (Georg Friederich Louis Stromeyer, Hannover, Germany, 1804-1876) is very versatile for transoral reduction of Le Fort fractures.
In selected cases the Stromeyer hook can also be used for manipulating the Le Fort complex by hooking the tip of the instrument inside the piriform aperture and pulling downwards and anteriorly. This technique is called downfracture procedure in Le Fort osteotomies.
Placing the patient into MMF
After the fracture has been adequately mobilized, the patient is placed into MMF. Click here for a detailed description of various MMF techniques.
Note: In case of concomitant mandibular fractures, the integrity of the mandible should be restored as a first measure.
Reducing the maxilla
Ensuring that the condylar heads are properly articulating, the maxillomandibular complex is rotated superiorly until the point where the vertical facial height can be established.
3 Decision on whether to use bone graft top
After reduction it must be decided whether the comminuted fragments can be used for restoration of vertical buttresses. If not, bone grafting should be considered.
4 Fixation (without bone graft) topenlarge
Apply two L-plates to the lateral buttresses
Fix two plates which have been bent to conform to the shape of the lateral buttresses.
Contour the plates before applying them to the bone. The plate location must take into account the tooth roots and the location of the comminuted fracture fragments to be attached to plate.
Insert at least two screws on each side of the fracture line in each plate.
Apply two plates to the medial buttresses
Fix two plates to the medial buttresses.
Insert at least two screws on each side of the fracture in each plate.
Secure fracture fragments to the plate
After the plates are properly fixed, further screws can be inserted in order to fix fracture fragments to the plates.
Pearl: predrilling of comminuted fragments
Fixation of comminuted fragments to the plate is a demanding procedure. It can be facilitated by predrilling the bony fragment outside the operational field. Therefore:
- Mark (or remember) the plate hole position on the surface of the fragment
- Remove the bony fragment
- Drill a pilot hole into the bony fragment
- Reposition the bony fragment using a forceps
- Fix the fragment with a screw.
Note: self-retaining screw drivers can be a disadvantage when dealing with thin bony fragments. It is advised to use non-self-retaining screw drivers.
Note: Using a screw with small diameter and low pitch allows for better retention.
5 Fixation (with bone graft) topenlarge
Bone graft is used to fill the defect and the buttresses are restored by L-plates.
The lateral buttresses are plated first, followed by the medial buttresses. The lateral segment is repaired in the following order:
- Contour the plate to the buttress area.
- Insert the bone graft.
- Position the plate.
- Fix the bone graft to the plate while the surgeon or an assistant holds the graft in place.
- Fix the plate to the main fracture fragments (at least two screws in each fragment).
Apply the second lateral buttress plate in the same manner.
The medial plates are then applied. Therefore, the bone graft is fixed to the plate while an assistant holds the bone graft with a forceps. Once the plate is fixed to the bone graft, the plate is fixed to each fracture fragment with at least two screws.
Shaping the bone graft
If the bone graft is prominent, trimming with a diamond burr may be necessary. This is particularly important along the piriform aperture in order not to impinge on the nasal soft tissues.
6 Check of occlusion topenlarge
After internal fixation has been completed, MMF is released and the occlusion checked.
If an open bite and/or Class III tendency occurs when checking the occlusion, one or both mandibular condyles were malposed in posterior and/or inferior direction. In such cases, it is necessary to remove the bone plates, reapply MMF, and passively reposition the maxillomandibular complex again, assuring the condyles are properly seated. Bone plates are again applied and the occlusion verified.
The reason for a malocclusion may be the fact that the condylar heads were not positioned correctly in their respective glenoid fossae when securing MMF (as illustrated).
Illustration shows the subsequent malocclusion.