The Le Fort III advancement was first described in 1950 and has since become a key technique in the armamentarium of craniofacial surgeons. The application of distraction osteogenesis to the craniofacial skeleton has allowed for large movements to be performed safely in young patients. This technique is valuable for correcting exorbitism, airway obstruction owing to midface retrusion, and class III malocclusion. It can be performed with either an external distractor or internal distractors. Although serious complications have been reported, these occur rarely when performed by experienced providers.
Key points
- •
Le Fort III distraction is used to improve the airway and midface appearance at the level of the infraorbital rims.
- •
Device selection (external or internal) is critical for technical success and patient satisfaction.
- •
A multidisciplinary craniofacial team is critical for evaluating and treating patients with craniofacial anomalies.
- •
The surgeon-orthodontist relationship is important preoperatively and postoperatively to control and adjust the Le Fort III distraction vector.
Introduction
In 1950, Sir Harold Gillies published a Le Fort III pattern osteotomy. This procedure was performed in a 14-year-old patient to improve the appearance of her midface. She had midface retrusion, including the maxillary dental arch, infraorbital rims, and zygomas. After the osteotomies, advancement of the midface was performed and held in place with intermaxillary wiring. After 2 weeks, the intermaxillary wires were removed and the patient was transitioned to a metal cap splint that was attached to the teeth and secured to a plaster head cap. After 5 weeks, this device was removed. There is some disagreement regarding the success of the procedure, but in his original paper, Gillies himself stated the patient developed relapse of the advancement.
Paul Tessier is credited for designing the Le Fort III osteotomy technique used today, and demonstrating stability in midface advancement. The results of his initial 14 cases were first reported at the 1967 Fourth International Congress of Plastic and Reconstructive Surgery in Rome and he subsequently published his techniques in 1971. , Tessier modified Gillies’ approach by using a coronal incision and moving the medial orbital osteotomy from along the anterior lacrimal crest to behind the posterior lacrimal crest, preserving the medial canthus and lacrimal apparatus within the Le Fort III segment. In addition, bone grafts were used to maintain the advancement and a traction system was implemented to prevent relapse. ,
The concept of distraction osteogenesis was first developed in the 1950s by G. A. Ilizarov. Compressive forces were supposed to be applied on a patient who had developed hypertrophic nonunion. The compression device was turned in the wrong direction and applied distraction instead of compression forces. He subsequently observed findings on a radiograph of the site, which he believed was the result of osteogenesis.
The technique of distraction osteogenesis was first applied to the human craniofacial skeleton by Joseph McCarthy and colleagues and reported in 1992. This procedure was undertaken to lengthen the human mandible in a child with craniofacial microsomia. The possibility of applying distraction osteogenesis to the midface was suggested in laboratory work by Staffenberg and McCarthy presented at the International Society of Craniofacial Surgeons in Oaxaca, Mexico, in 1993, and published in 1995. , The first midface distraction performed on a human was subsequently performed in 1993 by Muhlbauer in Germany and presented in 1995. In 1996, Chin and Toth published a series of patients who underwent internal distraction, including 1 patient who underwent Le Fort III advancement.
Since the original Le Fort III distraction, surgeons and device manufacturers have continued to modify their devices and techniques. Both internal and external distractors have had multiple iterations in design, and some internal devices have been modified to include absorbable components. The first external distraction device was used on the midface in 1997 by Polley and Figueroa after performing a Le Fort I osteotomy. The use of the external distractor subsequently expanded for use in patients following Le Fort III osteotomies.
Indications
Indications for Le Fort III Advancement
The indications for a Le Fort III advancement include shallow orbits with exorbitism, airway obstruction owing to midface retrusion, and class III malocclusion. , Although absolute and relative indications have been published previously, it is notable that the severity of many indications are subject to interpretation and can be temporized by less invasive interventions. For example, a clear definition of severe exorbitism has not been codified and most cases of exorbitism can be temporized or conservatively managed by a tarsorrhaphy and eye lubrication. Sleep studies can quantify the severity of airway obstruction, but the sleep study values for which midface distraction is indicated have not been defined. Furthermore, continuous positive airway pressure and adenoidectomy can also be used as temporizing measures. If supraorbital retrusion is present with signs of increased intracranial pressure, monobloc advancement with or without distraction can be considered.
Conventional Versus Distraction Le Fort III Advancement
The indication for distraction osteogenesis versus traditional Le Fort III advancement with bone grafts is determined by the age of the patient and the degree of advancement required. A traditional Le Fort III advancement is ideal for patients who have completed facial growth and require smaller advancements (<10–12 mm). , Advantages include completion of surgery in a single operation, greater control of the final position of the midface, and better restoration of occlusion. In an adult patient, a Le Fort I osteotomy may be required at the time of the Le Fort III or as a second surgery, to restore functional occlusion. The midface should be positioned to correct exorbitism and restore convexity to the midface as the priority, rather than to optimize occlusion. The midface is most frequently advanced forward along the Frankfurt horizontal so the inferior orbital rim is properly positioned in regard to the globe (orbitale advanced to the cornea). The remaining malocclusion is corrected with a Le Fort I, which can be altered as needed in 3 dimensions without distorting the midface, orbits, or nose. The authors prefer to undertake this procedure as a combined operation with an occlusal wafer and class III elastics offering postoperative stability to the advancement. The disadvantages include longer operative times, need for bone graft, and increased blood loss compared with a midface distraction.
The growing face presents different priorities for care. Restoration of occlusion is not the surgical goal of surgery, because the patient will require further midface growth. Therefore, overcorrection of the anterior position of the maxilla and orbitale are the end points of distraction. The patient should be placed in an anterior crossbite with a moderate degree of enophthalmos. This degree of overcompensation is a matter of clinical judgment; however, it should be noted that maxillary growth is typically limited after pterygoid separation. Therefore, the older the patient is at the time of the procedure, the less likely it is that the patient will require a second distraction. Conversely, patients who undergo midface distraction at an early age (≤5 years of age) are more likely to require a second midface distraction before skeletal maturity and, therefore, a greater degree of overcompensation is required. Of course, patients who require an early midface surgery typically have a more severe expression of the condition; however, the limits of anterior facial growth after midface distraction should be kept in mind regarding the timing of surgery and the extent of midface advancement. Overcorrection can be difficult for the patient and family members because, although the distraction process will bring their facial appearance to normal, overcorrection will continue to advance the patient’s midface to an improved but perhaps also abnormal appearance. However, our experience indicates that overcorrection is very well-tolerated and accepted with appropriate preoperative consultation. We believe that early midface distraction is reserved for patients with severe anatomic airway obstruction who will require a tracheostomy or who are tracheostomy dependent. Patients should not have a significant secondary airway anomaly precluding successful airway restoration by midface distraction. Performing conventional Le Fort III advancement in a child is rarely, if ever, indicated. A large degree of midface advancement is more difficult using conventional techniques. Additionally, if a secondary Le Fort III is required, the retained rigid fixation hardware can complicate the procedure.
A Le Fort III distraction can advance the midface to a greater degree than a conventional Le Fort III advancement. , This procedure is ideal when performed in a growing child in whom an overcorrection of the advancement is required to compensate for future facial growth. A Le Fort III distraction can simplify any subsequent midface advancement, because there are no indwelling rigid internal fixation plates ; however, a repeat osteotomy of a previously distracted bony site may have other challenges. There may be areas of fibrous union or nonunion in specific sites of osteogenesis creating difficulty in bony separation or subsequent bone generation. When compared with the conventional Le Fort III advancement, a Le Fort III distraction has been shown to have shorter operative time, less blood loss, and a decreased length of hospital stay. It has also been reported to have lower costs than conventional Le Fort III advancements.
Age Considerations for Surgical Distraction
The age at which midface distraction should be performed is a topic of active debate. As stated elsewhere in this article, in patients with severe airway obstruction or exorbitism, early correction can be justified to correct these functional impairments. If the deformity is less severe, delaying surgical intervention until a later age (8–11 years) can provide benefits, such as limiting the possibility of requiring a repeat Le Fort III advancement owing to relapse or initial incomplete advancement. , Additionally, awaiting the eruption of the 6-year molars can decrease complications associated with the pterygomaxillary disjunction.
One concern about performing Le Fort III osteotomies in a growing child is the potential risk of midfacial growth impairment. Multiple studies have demonstrated that, after Le Fort III osteotomies in patients with craniofacial dysostoses, there is continued vertical growth with minimal anterior growth of the midface. , However, patients with craniofacial dysostosis have been shown to exhibit impaired forward growth of the maxilla, even without an operation. , Therefore, it is not entirely known how much of the impairment of midfacial growth seen after Le Fort III osteotomies is due to the underlying pathology versus the surgery itself. There are no known studies evaluating the effect on midfacial growth of Le Fort III osteotomies in patients without craniofacial pathology. Considering what is known about the phases of pediatric midface growth and the lack of anterior growth maxillary growth after distraction, parents and surgeons should be aware of the increased risk of recurrence of the facial dysmorphology as the child grows and the potential need for repeat midface surgery before facial maturity in children who undergo midface distraction before the age of 7 years.
There are additional considerations when considering early distraction. Children younger than 3 years of age tend to have thinner skulls, leading to the potential for poor retention of the calvarial pins with the use of external distractors. Furthermore, performing midface distraction on patients younger than 3 years of age can be difficult owing to poor patient cooperation. For these reasons, when early Le Fort III is indicated, internal distraction osteogenesis devices may be favored.
If elective midface distraction is being considered in an adolescent patient with no immediate need for intervention (eg, corneal exposure, airway obstruction), one should consider delaying the procedure until skeletal maturity. This practice prevents the need to estimate the degree of advancement required. When performed at skeletal maturity, the Le Fort III segment can be brought into its ideal position. Delaying surgery until skeletal maturity should be weighed against the psychological benefits obtained from performing the surgery earlier. This information should be included in discussion of timing with the patient and family.
Preoperative workup and planning
Physical Examination
One should evaluate the periorbital region to assess the degree of exorbitism, the position of the supraorbital and infraorbital rims, the degree of scleral show, and the amount of lower eyelid support. Extraocular motility should be assessed, and a baseline ophthalmologist evaluation is recommended. Patients with syndromic craniosynostosis should already be followed routinely by an ophthalmologist. The mouth should be evaluated, assessing the occlusion, degree of maxillary arch constriction, degree of dental compensation, dental crowding, condition of the teeth, and orientation of the occlusal plane. The condition of the teeth is critical if an external distraction device is used because they serve as an anchor for the device. The skull should be palpated to assess for any cranial defects.
Dental and Orthodontic Assessments
The patient should be evaluated by a dentist and orthodontist before the operation to assess the condition of the teeth. They should be evaluated for dental decay and treated accordingly.
If an external distractor is chosen for the operation, the patient should undergo fabrication of a dental splint. The considerations for choosing an external versus internal distractor are included elsewhere in this article.
Ophthalmology Assessment
Referral to an ophthalmologist is critical for diagnosing the presence of papilledema, strabismus, anisometropia, astigmatism, and ametropia. In particular, the ophthalmologist should be asked to evaluate for evidence of corneal exposure.
Respiratory Evaluation
Patients with craniofacial dysostosis commonly have airway obstructions at the level of the nasopharynx. One must be aware of other potential areas of obstruction, because this can occur at multiple levels in syndromic patients. For example, patients with Pfeiffer syndrome more commonly have tracheal stenosis and bronchial abnormalities, making a midface advancement only partially effective for improving the patient’s airway. Therefore, the workup should include nasoendoscopy and a sleep study for at-risk patients. Nasoendoscopy will identify a second location of anatomic airway obstruction that can preclude successful restoration of airflow by midface distraction. This assessment is recommended for patients with Pfeiffer syndrome. A sleep study will quantify the severity of airway obstruction and identify the presence of central sleep apnea. This type of assessment with provide an objective assessment of airflow and can be useful in determining the indication and timing of midface advancement. Patients with a Chiari malformation may exhibit a degree of central sleep apnea that will not improve with midface advancement. If a sleep study is obtained preoperatively, a postoperative evaluation should also be performed to assess for changes in airflow.
General Health and Specialist Evaluation
The general health of the patient should be considered before the operation. These considerations include having had regular visits with the child’s pediatrician or specialists for optimization of medical problems including cardiac, neurologic, genetic, ophthalmologic, and respiratory anomalies.
Photographs
Standardized medical photography is useful for the planning, documentation, and assessment of results. Standard photographs should include frontal, three-quarters, profile, submental vertex, bird’s eye, occlusal, and oculomotor photographs. If 3-dimensional photography is available, it should be considered.
Imaging
A computed tomography (CT) scan is helpful for operative planning, especially when previous surgery has been performed. The scan is useful for evaluating the morphology of the facial skeleton, the quality and quantity of bone, and the dimensions of the airway and orbits. If the procedure is a repeat advancement, CT imaging is critical for determining the quality of bone and for confirming the presence and location of any existing hardware. The quality of bone can help determine the appropriate placement of the distraction devices and may impact the decision to use external versus internal devices. A critical absence of bone from resorption after prior procedures may indicate bone grafting before or after advancement. It is also important to rule out nasofrontal and nasopharyngeal encephaloceles.
Cephalograms can be obtained preoperatively and subsequently repeated postoperatively to determine the degree of translation and rotation of the Le Fort III segment during device activation. On occasion, the patient’s age or behavioral factors may make reliable cephalograms impossible, whereas CT scans may be performed with anesthesia.
Panoramic radiographs are useful for evaluating the patient’s dentition and are generally not needed for preoperative evaluation. This information is readily available on CT images.
Choice of External Versus Internal Distraction
No single device is ideal in every situation, and each has its own advantages. Internal distractors are rapidly applied, less visibly conspicuous, and have less of a psychological impact on the patient and family. The devices are lower profile and, therefore, have a decreased risk for accidental trauma. Being inconspicuous and less vulnerable to trauma make them ideal for patients who would otherwise be unlikely to tolerate an external distractor (those patients with attention deficit hyperactivity disorder, behavioral challenges, and gait disturbance). Because the internal devices are activated posteriorly, it is easy for 1 parent to hold the child facing them on their lap while the other parent activates the devices. Some practitioners perceive that the primary disadvantage of internal distractors is that, once placed, these devices are limited to a single vector for distraction. One should keep in mind that the single vector for advancement of the midface is along the Frankfurt horizontal, although 1 side may be advanced further than the other if that is indeed indicated. The occlusal correction is addressed by the Le Fort I at a later date. These internal devices have been used effectively in patients as young as 3 years and even younger in patients who undergo very early monobloc distraction. Rotation of the Le Fort III segment can occur during the distraction, resulting in more movement of the zygomaticomaxillary complex than at the level of the occlusal plane. If manipulation of the device is required or if malfunction occurs, the device needs to be surgically adjusted under anesthesia, although this tends to occur more frequently with external devices. If the patient has thin bone, the device is at a greater risk for dislodgement and distraction failure. The internal devices are very well-tolerated once distraction is completed and the activation arms are removed. Removal of the devices may be more difficult if there is significant growth of bone over the plates. Removal of the devices is done through the lower part of the coronal scars on an outpatient basis.
External devices have the advantage of being more stable than internal distractors owing to the broad points of fixation to the craniofacial skeleton. If the distraction vector needs to be adjusted, the adjustment can be performed postoperatively in a cooperative patient without surgical intervention. , Removal of the external device is relatively simple and can be performed without surgical exposure. If the patient has poor or absent dentition, the application of a dental splint may not be possible, but distraction can still be performed with the use of skeletal anchors or osseointegrated implants. A disadvantage of the external devices is that they are large and physically imposing. This factor can impact the patient and family psychologically. Because the device is larger, it is also at a greater risk of accidental trauma and dislodgement. There have also been reports of accidental and gradual intracranial pin migration. This risk is greater in young children (<3 years of age) in whom the cranial bone may still be thin and in patients with complex craniosynostosis in whom previous cranial surgery has rendered the skull thin. Some surgeons have advocated for the placement of a titanium mesh if thin areas of bone are encountered on CT scan or at the time of surgery. If transcutaneous wires attached to fixation screws are used, this practice has the potential to result in unsightly scarring.
Virtual Surgical Planning and Image-Guided Systems
Virtual surgical planning has been reported and can be helpful for visualizing the planned movements. However, the benefit of these systems in the background of the added costs are still pending. Image-guided systems have also been used in an attempt to more safely perform the Le Fort III osteotomies, claiming particular benefit for the nasofrontal and pterygomaxillary osteotomies, which are commonly performed in a blind fashion and can result in significant morbidity with incorrect trajectories. , Although these systems can be of potential use for the novice surgeon, these systems should not be required in experienced hands.
Operative techniques
Preoperative Setup
The patient is intubated with an orotracheal tube and the globes are protected using corneal shields with or without lid sutures to prevent corneal injury during the operation. Because corneal shields alone may be easily dislodged during the surgery, the surgeon must constantly reassess the ocular protection during the surgery. Packed red blood cells should be available and in the room. Tranexamic acid may be used to help decrease blood loss. A low blood pressure should be maintained during pterygomaxillary disjunction and the nasofrontal separation.
Exposure for Osteotomies
A coronal incision is designed and infiltrated with weight-based local anesthetic with epinephrine. Frequently, the scar from prior cranial vault surgery is reopened and may be revised later upon closure. The scalp flap is elevated anteriorly in the subperiosteal plane to the orbits. The lateral orbital rim and anterior aspect of the zygomatic arch is exposed. When conventional Le Fort III is performed, the majority of the arch is exposed. Subperiosteal degloving of the orbits is completed.
The lateral orbital exposure should include identification of the lateral aspect of the inferior orbital fissure. In syndromic patients with severe midface retrusion, this structure may be quite narrow. The inferior orbital fissure marks the boundary between the skull base and the facial skeleton at the lateral orbit. Medial orbital dissection must allow for the identification of the posterior lacrimal crest and the anterior ethmoid artery. Again, in syndromic patients, the distance between these important landmarks is diminished and the anterior ethmoid should be preserved carefully. The anterior ethmoid artery marks the junction of the skull base and the facial skeleton in the medial orbit.
The anterior aspect of the temporalis muscle is dissected from the posterior aspect of the lateral orbital rim and the anterior zygomatic arch. The pterygomaxillary suture is exposed by inserting a periosteal elevator behind the zygomatic body and dissecting inferiorly along the lateral wall of the lateral maxilla until the pterygomaxillary suture is reached. It is important to maintain a subperiosteal plan to prevent injury to the internal maxillary artery during ostetomy. In cases where there is severe midface retrusion, making complete pterygomaxillary separation from above challenging, a Kawamoto osteotome can be used to complete a transoral osteotomy typically performed during a Le Fort I.
Exposure for Internal Distraction
If an internal distractor is used, the anterior footplate is positioned at the junction between the arch and the lateral orbital rim. The temporal muscle is taken down and split vertically above the helix of the ear to allow the temporal (skull base) footplate to be secured.
Osteotomies
Detailed descriptions of all osteotomies performed in the Le Fort III procedure and many cardinal craniofacial procedures are available through a freely accessibly surgical simulator CIVApro. This can be accessed through the website, www.myface.org/civa or through the smartphone app (CIVApro) available for the iPhone and Android.
Internal Distractor Placement
If internal distractors are used, they are placed through the coronal incision. Multiple internal distractor designs have been used for Le Fort III distraction, with the primary difference being the lateral projection, size, and location of the footplates. The anterior footplate is commonly placed at the junction of the zygoma and lateral orbital rim. , The posterior footplate can be attached to the temporal bone immediately above the root of the helix, which is typically thicker bone. , This placement allows the two to be placed parallel to each other and the Frankfurt horizontal ( Fig. 1 ). The temporalis muscle may be draped over the distractor or split so the distractor can lie along the deep temporal fascia ( Fig. 2 ).
