Minimal Access Le Fort III Osteotomy for Midface Hypolasia



Minimal Access Le Fort III Osteotomy for Midface Hypolasia


Scott J. Rapp

Christopher B. Gordon





DEFINITION



  • Midface hypoplasia can lead to significant aesthetic and functional airway compromise.


  • Le Fort III distraction osteogenesis is a useful surgical approach to address hypoplasia and facial dysmorphism at skeletal maturity or when severity of symptoms warrants earlier intervention.


  • A Le Fort III approach involves osteotomies to the floor/lateral/medial wall of orbit, nasal bones, zygomaticofrontal suture, pterygoid plates of sphenoid, ethmoid, zygomatic arch, and posterior wall of maxillary sinus.


ANATOMY



  • Midface hypoplasia (FIG 1) is characterized by:



    • Facial disharmony


    • Malar deficiency and concavity to profile


    • Exorbitism, lack of globe protection


    • Class III occlusion


    • Posterior airway space (PAS) narrowing


    • Dental crowding


PATHOGENESIS



  • Events leading to severe craniofacial skeletal dysplasia are likely multifactorial but are believed to be associated with abnormalities in neural crest cell development and migration.1


  • Most are associated with genetic syndromes, but occasionally they may be sporadic.2


  • Midface sutures such as the spheno-occipital suture may prematurely fuse leading to growth disturbances.3






    FIG 1 • Midface hypoplasia can have profound effects on projection (A), occlusion and airway (B), and eye protection (C).


  • Genes associated with midface hypoplasia are the fibroblast growth factor receptor genes (FGFR2, FGFR3), twist-related protein gene (TWIST), and treacle ribosome biogenesis factor 1 gene (TCOF1).1


  • Midface hypoplasia is often observed with concomitant craniosynostosis, most often with bicoronal synostosis seen in syndromic patients:



    • Apert (FGFR2)


    • Crouzon (FGFR2)


    • Saethre-Chotzen (TWIST)


    • Meunke (FGFR3)


  • Other syndromes leading to maxillary hypoplasia include Treacher Collins syndrome and craniofacial microsomia (hemifacial microsomia, Goldenhar syndrome).


  • Neurologic dysfunction may be present including:



    • Hydrocephalus/ventriculomegaly


    • Gyral abnormalities


    • Hypoplastic/heterotopic white and gray matter


    • Corpus callosal agenesis


    • Kleeblattschadel/megalocephaly


NATURAL HISTORY



  • Surgical approaches to the midface in syndromic patients were first reported by Gilles in the 1950s and then advanced through Paul Tessier’s work in the 1960s.4


  • Midface osteotomies have been historically performed at skeletal maturity to prevent undergrowth or reduce relapse rates.


  • However, distraction techniques provide greater bony movements and more structural stability at an earlier age to address life-threatening airway compromise and ocular exposure.



PATIENT HISTORY AND PHYSICAL FINDINGS



  • Clinical exam findings may include



    • Midface retrusion


    • Craniosynostosis


    • Exorbitism/shallow orbit


    • Keratitis/corneal ulcers


    • Lagophthalmos/scleral show


    • Orbital hypertelorism


    • Class III occlusion


    • Anterior open bite


    • Narrow arch/dental crowding


IMAGING



  • Cephalometric consideration for PAS (FIG 2A)


  • Nasopharynx


  • Pterygomaxillare (pm) to posterior pharyngeal wall (upaw)


  • Oropharynx


  • Tip of uvula (U) to posterior pharyngeal wall (mpaw)


  • Hypopharynx


  • Tongue base (V) to posterior pharyngeal wall (lpaw)


  • Plain film/CT exam findings (FIG 2B)


  • Shallow orbits


  • Hypertelorism


  • Exotropia


  • Bicoronal synostosis—brachycephaly


  • Choanal stenosis/atresia




DIFFERENTIAL DIAGNOSIS



  • Syndromes that may require Le Fort III advancement


  • Crouzon


  • Apert


  • Pfeiffer


  • Treacher Collins


  • Nager






    FIG 2 • Imaging (A) demonstrates posterior airway space narrowing that can be measured through cephalometrics (B) to determine distance required during distraction.


  • Meunke


  • Saethre-Chotzen


  • Carpenter


NONOPERATIVE MANAGEMENT



  • Severe midface hypoplasia observed in syndromic newborn may require early nonsurgical management.


  • Airway compromise may be managed with:



    • Prone positioning


    • Positive pressure ventilation or assistance


    • Mandibular distraction for concomitant tongue-based obstruction


    • Globe protection


    • Taping


    • Eye lubrication


SURGICAL MANAGEMENT



  • A multidisciplinary team is required for optimal surgical intervention, including:



    • Plastic surgery/oral surgery


    • Orthodontics


    • Genetics


    • Dentistry


    • Ophthalmology


    • Speech pathology


    • Otolaryngology and audiology


    • Social work and psychology


Preoperative Planning

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Nov 24, 2019 | Posted by in Craniofacial surgery | Comments Off on Minimal Access Le Fort III Osteotomy for Midface Hypolasia

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