Le Fort III Osteotomy With External Distraction
Gökhan Tunçbilek
DEFINITION
The Le Fort III osteotomy corrects midface retrusion for patients with syndromic craniosynostosis and after the sequelae of Le Fort III fractures.
Gillies performed the first Le Fort III advancement in a patient with Crouzon syndrome.1
The first attempts of combining the Le Fort III procedure with distraction osteogenesis were in the mid-1990s and have become an effective, reliable technique for managing patients with midface hypoplasia.3,4
Midface retrusion may cause significant functional, morphological, and psychological impairment in patients with syndromic craniosynostosis.
All the parts of the face and forehead are affected, leading to breathing difficulties and ocular and occlusal problems, all of which impair the life of the patient.
Anterior movement of the facial skeleton addresses all of these problems.
Combining Le Fort III osteotomies with gradual distraction overcomes soft tissue resistance and produces skeletal corrections greater than 10 mm, which is the upper limit for conventional osteotomies with rigid fixation alone.5
ANATOMY
The midface consists of a maxilla-ethmoidonasal complex located between the two zygomas. This complex is suspended from the middle portion of the frontal bone anteriorly and the anterior cranial fossa posteriorly. The midface region is bounded above by a transverse line connecting the zygomaticofrontal sutures, passes through the frontomaxillary and frontonasal sutures, and is defined inferiorly by the occlusal plane of the maxillary teeth. Posteriorly the region is limited by the sphenoethmoidal junction and includes the free margins of the pterygoid plates inferiorly.
FIG 1 • A-E. Osteotomy lines of traditional Le Fort III osteotomy.
The skull and the facial skeleton have a fixed relationship. The facial skeleton is connected to the pterygoid process through the intermediate palatine bones and to the body of the sphenoid through the septonasal strut.
It is fixed laterally by the zygomatic arch and suspended from the frontal bone by the processes of the zygomatic bones and of the maxilla (FIG 2).
The facial region is subject to the vertical strains of mastication and therefore arranges its osseous trabeculae vertically and horizontally in areas of strength (pillars), which are separated by zones of weakness.
The facial complex is weakened by the presence of two kinds of cavities—air cavities (sinuses) and receptor cavities (orbits)—and sutures.
The sinuses are accessories to the nasal fossa, whose extent determines the degree of facial skeletal pneumatization; the receptor orbits house the peripheral receptors of vision.
PATHOGENESIS
Midface retrusion is a major finding of syndromic craniosynostosis, caused primarily by autosomal-dominant FGFR mutations and MSX2 and TWIST 1 mutations.
Most infants born with syndromic craniosynostosis present with bilateral coronal suture synostosis and a variable degree of midface retrusion.
 FIG 1 (Continued) |
PATIENT HISTORY AND PHYSICAL FINDINGS
A family history or a resemblance of the child to a relative suggests an inherited trait.
Pregnancy and birth histories are helpful with patient management.
Lethargy, vomiting, and difficulty seeing or following objects may be clues to underlying neurological disorders.
Seizure activity and developmental delays indicate abnormal brain function.
Malar flatness and midface retrusion is a common constituent of syndromic craniosynostosis and secondary to growth restriction of the cranial base.
Midface recession and concave profile can be severe, resulting in obstruction of nasopharyngeal airflow and respiratory distress (FIG 3).
An evaluation of the extremities is essential in patients with syndromic craniosynostosis. Syndactyly is a major component of Apert syndrome. Abnormalities of the thumbs and toes are elements of Pfeiffer and Carpenter syndromes.
IMAGING
Computed tomography (CT) is useful to determine evidence of sutural fusion, signs of increased intracranial pressure, and indications of pathologic neuroanatomy.
Three-dimensional (3D) CT scan provides a clear image of the bony anatomy and deformities of the craniofacial skeleton (FIG 4A) and can be combined with plain films for surgical planning (FIG 4B).
MRI is necessary only if further detail of the brain is required or if a Chiari malformation exists.
Structural anomalies of the central nervous system should be evaluated by a pediatric neurosurgeon.
 FIG 2 • Separation of the facial skeleton from the skull and skull base at the Le Fort III level. |
 FIG 3 • A,B. Malar flatness and exophthalmos in a patient with Pfeiffer syndrome. C. The cranium has a trigonocephalic shape, and thumb printing can be seen on the lateral x-ray. The close positioning of the posterior pharyngeal wall to soft palate can lead to airway compromise. |
SURGICAL MANAGEMENT
Preoperative Planning
Patients undergoing Le Fort III distraction require a multidisciplinary team, including a plastic and craniofacial surgeon, ophthalmologist, otolaryngologist, and orthodontist.
The craniofacial surgeon and the orthodontist play important roles in the surgical planning and in managing the pre- and postintervention occlusion and appearance.6
The treatment strategy of a child with syndromic craniosynostosis includes a series of operations separated over time responding to the growth and development of the craniofacial skeleton.
This phased treatment plan is based on the differential growth patterns of the cranial vault, the midface, and the mandible. Institutional preferences and functional requirements may change the timing of these staged operations.
Midface advancement using Le Fort III distraction is generally performed between 7 and 10 years of age.
The degree of airway obstruction and exposure of the globes may accelerate timing of surgery to the midface.
Approach
Advancement of the midface can be performed with a conventional Le Fort III osteotomy and rigid fixation or by using Le Fort III osteotomy with distraction.
Le Fort III distraction has several advantages over the traditional technique.
The soft tissue envelope limits mechanical advancement of the midface with the traditional procedure.
Resistance of soft tissue is generally manageable for advancements of less than 10 mm.5
FIG 4 • A. 3D CT view of a patient with Apert syndrome. Bilateral coronal suture synostosis (note the ridging of the coronal sutures) and a large anterior fontanelle are common. B. Severe midface retrusion and class III malocclusion of a patient with Crouzon syndrome.
Elimination of soft tissue resistance using distraction leads to lower relapse rates than conventional midface advancement techniques.7
Conventional Le Fort III osteotomy often requires repeat surgery at completion of facial skeletal growth. Le Fort III overdistraction can compensate for future growth, avoiding the need for repeat surgery.8
Le Fort III distraction eliminates the need for bone graft, thereby decreasing length of the procedure and eliminates donor-site morbidity. There is also significant decrease in blood loss and postoperative pain after the operation and hospital stay is shorter.7
Le Fort III distraction can be performed with either internal or external devices.
Internal systems are semiburied, laterally placed devices, and may be tolerated better than external devices.
Internal systems limit control over the midfacial skeletal segments, especially in vertical and transverse vectors. Lack of control over the central midfacial structures tends to push the zygomas forward and create midline collapse and increased facial concavity.9
The author’s preferred technique is external distraction.Related posts:
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