Advances in the Treatment of Syndromic Midface Hypoplasia Using Monobloc and Facial Bipartition Distraction Osteogenesis

Crouzon Syndrome Spanning Three Generations: Advances in the Treatment of Syndromic Midface Deficiency

Background

Crouzon syndrome is an autosomal dominant genetic disorder characterized by craniosynostosis, midface retrusion, and exophthalmos. Over the past century, the treatment of craniofacial disorders like Crouzon syndrome has evolved significantly.

Methods

An institutional review board-approved retrospective study was conducted to ascertain the treatment of three individuals with Crouzon syndrome from one family, complemented with a series of literature searches to examine the evolution of craniofacial surgical history.

Results

Dr. David Williams Cheever developed the Le Fort I level to correct malocclusion, maxillomandibular malformations, and midface hypoplasia. Later, Dr. Paul Tessier introduced the Le Fort II and III osteotomies to treat syndromic midface hypoplasia. In 1978, Dr. Fernando Ortiz-Monasterio and Dr. Antonio Fuente del Campo published the first series of monobloc osteotomies, allowing for simultaneous correction of supraorbital and midface malformations, although complicated by blood loss and high infection rates. In 1992, McCarthy et al introduced the concept of gradual distraction to the craniofacial skeleton. In 1995, Polley et al performed the first monobloc advancement using external distraction. Subsequently, in 1997, Polley and Figueroa introduced a rigid external distraction device with multiple vector control to manage severe cleft maxillary hypoplasia. The technique was further refined and applied to treat syndromic midface hypoplasia, reducing complication rates. Currently, either external or internal distraction approaches are used to safely treat this challenging group of patients.

Conclusion

The treatment of syndromic midface deficiency has significantly evolved over the past 50 years, as evidenced by this report of three generations of Crouzon syndrome.

Syndromic Synostosis: Frontofacial Surgery

Frontofacial surgery, encompassing the monobloc with or without facial bipartition and the box osteotomy, can treat the frontal bone and midface simultaneously, providing comprehensive improvement in facial balance. Complex pediatric patients with genetic syndromes and craniosynostosis are most optimized by an interdisciplinary team of surgeons, pediatricians, geneticists, speech pathologists, audiologists, dietitians, pediatric dentists, orthodontists, and psychosocial support staff to manage the myriad of challenges and complications throughout early childhood and beyond. Despite early treatment of the anterior and posterior cranial vault, these patients frequently have resultant frontal and/or midface hypoplasia and orbital abnormalities that are best managed with simultaneous surgical treatment.

Frontofacial Reconstruction Technique Modification with Preservation of Blood Supply to the Monobloc Segment

ABSTRACT

Craniosynostosis syndromes, including Apert Syndrome, Pfeiffer Syndrome, and Crouzon Syndrome, share similar phenotypes, including bicoronal craniosynostosis, midface hypoplasia, hypertelorism, and exorbitism. The standard surgical treatment for these craniofacial abnormalities is monobloc osteotomy with distraction osteogenesis. Complications of this technique include the failure of osteogenesis or resorption of the frontal bone. The authors propose an alternative surgical technique with a frontal arch in continuity with the midface segment to ensure vascularization to anterior and posterior borders of distraction. A case report of an 8-year-old female patient with Apert Syndrome is reported using our technique. Our frontal arch monobloc distraction procedure preserves blood supply to a cranial component of the monobloc segment site that becomes the anterior portion of distraction rather than with the traditional devascularized frontal bone flap. This technique modification should improve osteogenesis outcomes by preventing resorption or failure of bone formation.

Midface Morphology and Growth in Syndromic Craniosynostosis Patients Following Frontofacial Monobloc Distraction

BACKGROUND

Facial advancement represents the essence of the surgical treatment of syndromic craniosynostosis. Frontofacial monobloc distraction is an effective surgical approach to correct midface retrusion although someone consider it very hazardous procedure. The authors evaluated a group of patients who underwent frontofacial monobloc distraction with the aim to identify the advancement results performed in immature skeletal regarding the midface morphologic characteristics and its effects on growth.

METHODS

Sixteen patients who underwent frontofacial monobloc distraction with pre- and postsurgical computed tomography (CT) scans were evaluated and compared to a control group of 9 nonsyndromic children with CT scans at 1-year intervals during craniofacial growth. Three-dimensional measurements and superimposition of the CT scans were used to evaluate midface morphologic features and longitudinal changes during the craniofacial growth and following the advancement. Presurgical growth was evaluated in 4 patients and postsurgical growth was evaluated in 9 patients.

RESULTS

Syndromic maxillary width and length were reduced and the most obtuse facial angles showed a lack in forward projection of the central portion in these patients. Three-dimensional distances and images superimposition demonstrated the age did not influence the course of abnormal midface growth.

CONCLUSION

The syndromic midface is hypoplastic and the sagittal deficiency is associated to axial facial concavity. The advancement performed in mixed dentition stages allowed the normalization of facial position comparable to nonsyndromic group. However, the procedure was not able to change the abnormal midface architecture and craniofacial growth.

Anterior Skull Base and Pericranial Flap Ossification after Frontofacial Monobloc Advancement

BACKGROUND

Frontofacial monobloc advancement creates a communication between the anterior cranial fossa and nasal cavities. To tackle this issue, transorbital pericranial pedicled flaps are routinely performed in the authors' center. This study aimed to assess the postoperative ossification of the anterior skull base and pedicled flaps following frontofacial monobloc advancement, and to identify factors influencing this ossification.

METHODS

Measurements of the skull base only and of the ossified pedicled flaps together with the skull base were performed on computed tomographic scans at the nasofrontal and the nasoethmoid frontal junctions. The total thickness of the skull vault was measured and a qualitative defect score for the anterior skull base was computed.

RESULTS

Twenty-two patients who underwent frontofacial monobloc advancement at a median age of 3.1 years (range, 1.9 to 3.6 years) were included: 14 with Crouzon, five with Pfeiffer, and three with Apert syndrome. One year and 5 years after surgery, the distraction gap was completely ossified in the anterior skull base midline in all patients. Ossified pedicled flaps together with the skull base were thicker in patients than in controls at these two time points (p < 0.005 and p < 0.02). Patients with Pfeiffer syndrome had a significantly thicker skull base only and ossified pedicled flaps together with the skull base thicknesses (p = 0.01 and p = 0.03) and lower defect scores than patients with Crouzon or Apert syndrome (p = 0.03) 1 year postoperatively.

CONCLUSION

As ossification of the pedicled flaps and total reossification of the anterior skull base midline were observed in all patients, the authors indicate that performing pedicled flaps in frontofacial monobloc advancement surgery could promote the reossification of the anterior skull base.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.