Orthodontic and surgical treatment of facial asymmetry in a patient with unicoronal craniosynostosis

This case report presents the unique treatment of a patient with varying asymmetries at different levels within the face. The patient was a 17-year-old male with a diagnosis of right unilateral coronal synostosis. He had frontal and superior orbital retrusion on the fused side, and bossing of the contralateral side. The middle and lower portions of his face were rotated toward the nonfused side. This unique diagnosis presented particular challenges to surgical and orthodontic correction. The treatment approach, which included a combination of Le Fort I and II osteotomies, bilateral sagittal split osteotomy, and orthodontic treatment with 4 premolar extractions, enabled simultaneous correction of nasal, midfacial, lower facial, and dental asymmetries. The orthodontist and surgeon integrated their efforts to correct dentofacial asymmetry in all 3 planes of space. Facial esthetics and dental function were significantly improved with no appreciable relapse occurring over a 2-year retention period.

Highlights

  • The patient had right unilateral coronal synostosis with multiple complications.

  • The unique presentations included varying asymmetries at different levels within the face.

  • Treatment included Le Fort I and II and bilateral sagittal split osteotomies, and 4 premolar extractions.

  • Nasal, midfacial, lower facial, and dental asymmetries were corrected simultaneously.

  • Facial esthetics and dental function improved significantly.

Craniosynostosis is a congenital condition characterized by early fusion of 1 or more sutures of the calvarium. , These fusions subsequently affect growth and development of the craniofacial skeleton, resulting in abnormal skull shapes as well as forehead anomalies, midface retrusion, and malocclusion particularly in coronal synostosis and associated syndromic conditions. , In craniosynostosis syndromes such as Apert and Crouzon, compensatory growth produces a brachycephalic or turricephalic head shape as growth proceeds parallel to the fused suture. Serious physiological concerns can arise as a consequence of restricted calvarial growth, including dangerously elevated intracranial pressure, airway compromise, and globe exposure. In both Apert and Crouzon Syndromes, the maxilla is positioned posteriorly and is smaller in transverse and anterior-posterior dimensions, which frequently leads to a skeletal Class III malocclusion, complete lingual cross-bite, and impactions of erupting maxillary teeth. Delayed eruption of maxillary anterior teeth and a restricted nasal airway often produce an anterior open bite malocclusion. Definitive treatment of syndromic craniosynostosis is a multiple procedure process including fronto-orbital advancement during infancy, midface advancement during childhood, and concluding with orthognathic surgery.

Nonsyndromic unicoronal craniosynostosis is the second most common type of craniosynostosis overall, with a birth prevalence of 66 in 1 million. Unlike syndromic craniosynostosis, functional disturbances, such as elevated intracranial pressures, airway obstruction, and globe exposure, are rare events. The characteristic plagiocephalic skull shape of unicoronal synostosis is characterized by frontal and superior orbital retrusion on the fused side, whereas the nonfused side has bossing of the forehead. In addition to the forehead, facial abnormalities are manifested in such patients. The middle and lower portions of the face are rotated toward the nonfused side. The nasal root generally points in the direction of the fused suture; whereas, the nasal tip points in the direction of the unfused suture. In the uncorrected state, the face curves in C-shape and presents as a unique challenge in surgical correction of facial asymmetry because of the presence of varying asymmetry at different levels within the face. For example, a mild Class III jaw relationship and slight chin point deviation may be present in combination with significant nasal deviation and canting of the interpupillary plane.

A critical component in the correction of dentofacial asymmetry is the interplay between orthodontics and surgery. The following case presents an example of facial asymmetry treated through a combination of Le Fort I and II osteotomies with rotation and impaction, and 4 premolar extractions with orthodontic space closure.

Diagnosis and etiology

A 17 year 7 month old Hispanic male with a diagnosis of right unilateral coronal suture synostosis and nasomaxillary deviation to the left presented to the Craniofacial Orthodontic Clinic at the University of California, Los Angeles. The patient was also diagnosed with Autism spectrum disorder. Although the patient underwent a fronto-orbital advancement as an infant, the skull shape was severely asymmetrical with greater fullness on the left resulting in overall trapezoidal head shape ( Fig 1 ). From the frontal, his facial appearance was characterized by a C-shaped deformity with concavity bending toward the left side and greater fullness on the right. The left orbit was significantly lower than the right. The nasal tip and chin point were deviated to the left, with pogonion deviated 4 mm to the left of facial midline. His head tilted slightly to the right because of torticollis. On profile, his face was convex, with deficient chin projection and a significant resting interlabial gap. Both lips were protrusive with mentalis strain observed on closing, and maxillary excess on smiling.

Fig 1
Initial clinical presentation, frontal and lateral views of skull extracted from cone-beam computed tomographic at 17 years 7 months.

Cephalometric examination revealed that the anterior-posterior jaw relationship was Class II because of a retrognathic mandible, and a hyperdivergent vertical jaw relationship because of a posteriorly rotated mandible ( Fig 2 ). The frontal radiographic view illustrates significant asymmetry of the orbits, with nasal base, maxilla, and mandible all canted upward to the left ( Fig 1 ; cone-beam computed tomographic frontal view). Both occlusal planes were similarly canted upward to the left. The dental molar and canine relationships were end-on Class II on the left, and Class I on the right ( Fig 3 ). His dental relationship was bimaxillary protrusive, with significantly proclined maxillary and mandibular incisors and mild crowding. The overjet was 3 mm, and overbite was 4 mm. The maxillary midline was deviated 2 mm to the left of the facial midline, with the mandibular midline also deviated 4 mm to the left of facial midline.

Fig 2
( A ) Lateral cephalometric radiograph, ( B ) tracing and ( C ) panoramic radiograph at initial clinical presentation.

Fig 3
Dental casts at 17 years 7 months (initial clinical presentation).

Treatment objectives

The nasal base deviation, convex facial profile, and protrusive dental relationship were addressed through a combination of surgical and orthodontic treatment. The goals of this treatment were to (1) surgically align the nose and chin point with the facial midline and achieve symmetry of malar eminences, (2) align the mandibular midline with the maxilla and achieve a Class I molar and canine relationship, (3) reduce the facial convexity, improve the chin point projection and level the occlusal cant, and (4) improve the lip profile by retracting and uprighting the incisors into the extraction space of the 4 first premolars.

These goals required surgical correction in all 3 planes of space. For this objective, osteotomies were planned at 2 different levels in the facial skeleton ( Fig 4 ). A more superior Le Fort II osteotomy was planned for transverse rotation of the midface from left to right to correct asymmetry at the level of the nose and malar eminence. Separate Le Fort I and bilateral sagittal split osteotomies were planned to address the occlusal canting and facial convexity, with forward rotation of the occlusal plane and maxillary impaction to improve the chin projection. Excessive incisor proclination was addressed through extraction of all first premolars and retraction under moderate anchorage.

Fig 4
Osteotomies planned in the facial skeleton of the patient.

Treatment alternatives

Orthodontic treatment alone would not address the nasal, midline, and chin point asymmetry. Orthodontic treatment alternatives included extraction of the maxillary second premolars and mandibular first premolars. This approach would have resulted in an improved match in mesial-distal premolar size (the maxillary second premolars were relatively small), with increased retraction of the mandibular incisors, enabling greater advancement and forward rotation of the mandible. Maximum maxillary anchorage with temporary skeletal anchorage devices or high pull headgear would have also improved the degree of maxillary incisor retraction.

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Mar 9, 2020 | Posted by in Orthodontics | Comments Off on Orthodontic and surgical treatment of facial asymmetry in a patient with unicoronal craniosynostosis
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