Le Fort I osteotomy - Conventional

Le Fort I osteotomies in cleft patients can be more challenging than in non-cleft patients because of the anatomy, scar tissue from previous surgery and the amount of advancement sometimes required. Modifications to address these issues will be highlighted.

The maxillary vestibular approach is modified to improve the blood supply and to facilitate more radical mobilization.

A periosteal elevator is inserted between the nasal mucosa and the lateral wall of the nose on one side. A curved retractor is inserted behind the maxillary tuberosity. A further instrument is used to retract upwards the lip and mucoperiosteal flap, exposing the antero-lateral maxilla.

The cut starts at the piriform rim just below the inferior turbinate. It then traverses the anterior maxilla approximately 5 mm below the infraorbital foramen and crosses the maxillary buttress at which point the direction of the cut should be inferior.

The use of a high osteotomy on the lateral wall of the maxilla allows better midface projection in the cleft patient.

Pitfall: The direction of the cut posteriorly is important as it must not travel upwards. That could result in a posterior osteotomy fracture line that may either result in excessive bleeding or travel upwards into the orbit.

The osteotomy is completed anteriorly and laterally with fine osteotomes.

Posteriorly a fine gently curved osteotome is used with the curvature pointing downwards to complete the cut as far as the pterygomaxillary junction.

Pitfall: The direction of the cut posteriorly is important as it must not travel upwards. That could result in a posterior osteotomy fracture line that may either result in excessive bleeding or travel upwards into the orbit.

The lateral walls of the nose and the nasal crest of the maxilla in the midline are then divided with nasal osteotomes while protecting the nasal mucosa.

Special "guarded" osteotomes are used for this purpose to protect the nasal mucosa.

A curved pterygoid chisel is placed with the curvature pointing medially and inferiorly between the tuberosity and the pterygoid plates.

A mallet is used to drive the osteotome medially to complete the pterygomaxillary dysjunction. The position of the tip of the osteotome can be checked with a palpating finger.

Pitfall: An upward and posteriorly oriented osteotome will not reliably separate the maxilla from the pterygoid plates. It is also associated with increased risk of bleeding from the pterygoid plexus and internal maxillary artery.

The lower part of the maxilla is then mobilized initially by digitally pushing it downwards. The term downfracture was coined to describe this downward movement and the fracture of the posterior wall of the maxilla which has not been cut with either saws or chisels.

The remainder of the clefted nasal mucosa can now be visualized and sharply separated from the palatal mucosa to allow completion of the mobilization.

Pitfall: Incomplete osteotomies and excessive force during the downfracture are thought to have caused fracture of the posterior wall of the maxilla running up into the orbit and as a result causing blindness. Consequently excessive force during downfracture and incomplete osteotomies should be avoided.

If major resistance is encountered, the following action should be taken:

1. Re-examine all of the osteotomy cuts especially in the posterior pterygoid region
2. Ensure all of the cuts have been completed successfully and if not, complete them
3. At downfracture it is usually possible to visualize the maxillary sinuses through the cuts and across the sinus to see the posterior wall of the maxilla. The posterior wall can be gently osteotomized under that direct vision using a fine osteotome taking care not to cause major bleeding.

During downfracture it is possible to visualize both the lateral wall of the nose, the nasal septum and the posterior wall of the maxilla across the maxillary sinus. Where the bone cuts are incomplete it is possible to complete the maxillary osteotomy with fine osteotomes under direct vision.

It may be necessary to trim the lateral wall of the nose and the nasal septum with bone rongeurs.

Digital manipulation (twisting) of the down fractured maxilla is performed to continue the mobilization.

Once initial mobilization digitally has been accomplished, Rowe's maxillary disimpaction forceps or similar devices may be used and the mobilization of the maxilla is completed. This should only be performed after inserting a custom made cast steel palatal protection plate to avoid damaging the palate or accidently fracturing the maxilla.

The mobilization is carried out by downward circular movements and then twisting the maxilla on each side in turn. During this procedure it is necessary to ensure that the mucoperiosteal pedicle to the maxilla postero-laterally does not tear.

It is often necessary to break down posterior scar tissue in the region of the soft palate either digitally or very carefully with blunt end dissection scissors. If this is not done, that scar tissue will be a major factor for future relapse.

It is sometimes useful also to use Tessier mobilizers which are inserted behind the maxilla on each side in order to pull the maxilla forwards.

At this point the mobilized maxilla should be free and able to be advanced by the surgeon by his or her hand much more than is actually required.

With the maxilla displaced downwards, bony interferences on the lateral nasal wall and the anterior and posterior wall of the maxilla are removed. This can be done initially with rongeurs but usually bone has to be removed with a drill whilst carefully protecting the soft tissues. The greater palatine vessels may need to be sacrificed if they interfere with complete mobilization of the maxilla.

In order to prevent unfavourable pressure on the nose (widening of the alar base etc.) the piriform rims are rounded off and the anterior nasal spine reduced.

A preformed acrylic occlusal splint or wafer is then inserted and the maxilla advanced into its new preplanned position. The upper and lower teeth are fixed together across this preformed splint in the new occlusion with continuous orthodontic powerchain elastic.

The preplanned vertical position of the maxilla is then established against the fixed reference point of the screw in the glabella. When necessary, maxillary bone is removed with a drill until that vertical relationship is achieved passively. If the nasal septum or the inferior turbinates are preventing upward movement of the maxilla, they are reduced at this stage.

Before fixation, the maxilla is retracted downwards, and in so far as it is possible, any tears in the nasal mucosa are repaired with resorbable sutures.

The advanced maxilla is then fixed with four titanium strong L-shaped miniplates and screws at the four buttresses. This is an ideal situation for self-drilling screws.

At this point the mandibulo-maxillary fixation and the wafer are removed and the occlusion is checked.

A block of cortico-cancellous bone (ideally harvested from the anterior iliac crest medially, but other donor sites are possible), contoured and placed over the anterior maxillary wall on each side. This bone rests on the advanced maxilla between the miniplates on each side. The principal purpose of the bone graft is to improve the bony union between the advanced maxilla and the rest of the craniofacial skeleton, and thus minimize relapse.

The glabellar reference screw is removed.

If MMF screws or Temporary Anchoring Devices (TADs) are used intraoperatively, they are removed at the end of surgery if not further needed for elastic traction. If a final splint was used, it may be fixed to the orthodontic devices (brackets) of the upper jaw to assure the planned occlusion and to serve as guidance for the neuromuscular adaption during functional training for about 2 weeks postoperatively.

To reduce swelling, the application of ice-packs or cooling devices during the early post-operative phase is advice. Intravenous steroids should also be continued for a short period postoperatively for the same purpose.

Antibiotic prophylaxis is continued for 1-5 days depending on the nature, complexity, and duration of the surgical procedure.

Especially in two-jaw surgery, the airway control is of major importance. An individual decision has to be taken if the patient can be extubated or should remain intubated until it is clear that safe airway can be established.

Early post-operative x-rays are obtained to verify correct segment position. Additional postoperative imaging is performed as needed.

Regular follow up examinations to monitor healing and the postoperative occlusion are required. If an occlusal problem is present in the early postoperative phase, the surgeon must determine its etiology. If the malocclusion is secondary to surgical edema or muscle detachment/disorders, training elastics may be beneficial. The elastics are only used for guidance, because active motion of the mandible is desirable. Patients should be instructed how to place and remove the elastics using a hand mirror. If the malocclusion is secondary to a bone problem due to inadequate fragment positioning, displaced or failed hardware, or condylar displacement during surgery, elastic training will be of no benefit. The patient must be rescheduled for revision surgery.

At each appointment, the surgeon must evaluate the patient's ability to perform adequate oral hygiene and wound care and should provide additional instructions if necessary.

Postoperatively, patients will have to follow three basic instructions:

1. Diet
In orthognathic surgery the internal fixation devices usually do not allow for full functional load. A soft diet should be used up to 6 weeks, starting with liquids for the first 3-4 days. Elastics can be removed during eating.

2. Oral hygiene
Patients with intraoral wounds must be instructed in appropriate oral hygiene procedures. The presence of orthodontic appliances, the splint, and elastics makes this a more difficult task. A small soft toothbrush with toothpaste should be used.Any elastics are usually removed for oral hygiene procedures. Additionally, antiseptic rinses can be used in the early postoperative period. An oral irrigator (eg, Waterpik) is a very useful tool to help . If a Waterpik is used, care should be taken not to direct the jet stream directly over intraoral incisions to prevent wound dehiscence in the early postoperative phase.

3. Functional training/physiotherapy
The patient is instructed how to perform functional training (opening and excursive exercises) as soon as possible. The progress should be monitored by the surgeon. If available and needed, a physiotherapist can support the functional rehabilitation. An undisturbed mouth opening of minimum 35 mm interincisal jaw opening should be attained by 4 weeks postoperatively.

In case of undisturbed healing, the postoperative orthodontic treatment can usually start 2 to 6 weeks after surgery depending on the case.