Mandibular Lengthening by Distraction for Airway Obstruction in Treacher-Collins Syndrome: The Long-Term Results

Microtia and Related Facial Anomalies

Infants may be born with external ear deformities or malformations that can present a diagnostic clue to an affiliated syndrome while also presenting the possibility of surgical intervention. Microtia is a malformation of the ear that is associated with other craniofacial or systemic anomalies in 50% of cases. Surgical correction of microtia and associated facial anomalies is complex and must be integrated thoughtfully into the overall care plan for children with complex medical needs. Familiarity with types of ear and facial anomalies and their association with more global concerns can allow perinatal practitioners to better serve their patients.

Decannulation and Airway Outcomes With Maxillomandibular Distraction in Treacher Collins and Nager Syndrome

BACKGROUND

Treacher Collins syndrome is a rare disorder (1/50,000 live births) with features that include hypoplastic orbitozygomatic complex with downward slanting eyes, and maxillary/mandibular retrusion. Obstructive sleep apnea and tracheostomy-dependence are common. This study presents the outcomes of skeletal distraction on avoidance of tracheostomy and decannulation in this patient population.

METHODS

The authors reviewed charts of all patients with Treacher Collins syndrome who underwent craniofacial reconstruction from 2003 to 2016. Primary outcome measures included decannulation of tracheostomy dependent patients and avoidance of tracheostomy. Secondary outcome measures included cephalometric parameters, polysomnography scores, and airway exposure scores on direct laryngoscopy.

RESULTS

Twenty-five patients underwent mandibular and maxillary advancement to resolve upper airway obstruction. Mandibular distraction was performed in 24 of 25 patients, and maxillary distraction in 14 of 25 patients. Maxillary distraction was combined with mandibular distraction in 13 of 17 to accomplish greater advancement and counter-clockwise rotation of the entire maxillary-mandibular complex. Six of 7 patients, 85.7%, avoided a tracheostomy and 39% (7 of 18) were decannulated. Cephalometric changes in sella-nasion-A point, sella-nasion-B , occlusal plane angle, and posterior airway space were equivalent between the groups who were able to clear their obstruction and those who were not.

CONCLUSIONS

Treacher Collins is a very challenging disease in which to resolve airway obstruction. Thus, thorough evaluation of the entire airway for all levels of obstruction is critical to successful outcomes. Future collaborative efforts between multiple institutions can help to increase our understanding and effective management of this rare disease.

The ontogeny of Robin sequence

The triad of micrognathia, glossoptosis, and concomitant airway obstruction defined as "Robin sequence" (RS) is caused by oropharyngeal developmental events constrained by a reduced stomadeal space. This sequence of abnormal embryonic development also results in an anatomical configuration that might predispose the fetus to a cleft palate. RS is heterogeneous and many different etiologies have been described including syndromic, RS-plus, and isolated forms. For an optimal diagnosis, subsequent treatment and prognosis, a thorough understanding of the embryology and pathogenesis is necessary. This manuscript provides an update about our current understanding of the development of the mandible, tongue, and palate and possible mechanisms involved in the development of RS. Additionally, we provide the reader with an up-to-date summary of the different etiologies of this phenotype and link this to the embryologic, developmental, and genetic mechanisms.

The effectiveness of mandibular distraction in improving airway obstruction in the pediatric population

BACKGROUND

Distraction osteogenesis is an effective technique for elongating the deficient mandible. The authors specifically evaluated its effectiveness in the treatment of airway obstruction in pediatric patients with mandibular hypoplasia.

METHOD

A comprehensive literature review of the National Library of Medicine (PubMed) database was performed. English-language studies involving isolated distraction of the pediatric mandible (younger than 18 years) with descriptive reporting of airway changes were included. Extracted data included demographics, initial diagnosis, distractor type, distraction protocol, predistraction and postdistraction airway status, and complications.

RESULTS

Seventy-four articles met the inclusion criteria, resulting in 711 patients with craniofacial abnormalities who underwent mandibular distraction osteogenesis. Mean age at the time of distraction was 18.1 months. The most common diagnoses were isolated Pierre Robin sequence (52.9 percent), syndromic Pierre Robin sequence (7 percent), and Treacher Collins syndrome (6.8 percent). Mandibular distraction osteogenesis successfully treated airway obstruction in 89.3 percent of cases. Success was defined as either decannulation of tracheostomy, avoidance of tracheostomy or continuous positive airway pressure, or alleviation or significant improvement of obstructive sleep apnea symptoms. One hundred seventy-one (84.2 percent) of the 203 tracheostomy-dependent patients were successfully decannulated. Among the 181 patients with obstructive sleep apnea, mandibular distraction osteogenesis successfully allowed for either complete resolution or significant improvement of symptoms in 95.6 percent. A 23.8 percent overall complication rate was noted. The mean follow-up time was 28.7 months.

CONCLUSION

In addition to its positive effect on facial appearance, mandibular distraction osteogenesis is an effective procedure for the treatment of airway obstruction associated with congenital craniofacial defects involving mandibular hypoplasia in appropriately selected patients.

Treacher Collins syndrome: clinical implications for the paediatrician--a new mutation in a severely affected newborn and comparison with three further patients with the same mutation, and review of the literature

Treacher Collins syndrome (TCS) is the most common and well-known mandibulofacial dysostosis caused by mutations in at least three genes involved in pre-rRNA transcription, the TCOF1, POLR1D and POLR1C genes. We present a severely affected male individual with TCS with a heterozygous de novo frameshift mutation within the TCOF1 gene (c.790_791delAG,p.Ser264GlnfsX7) and compare the clinical findings with three previously unpublished, milder affected individuals from two families with the same mutation. We elucidate typical clinical features of TCS and its clinical implications for the paediatrician and mandibulofacial surgeon, especially in severely affected individuals and give a short review of the literature.

CONCLUSION

The clinical data of these three families illustrate that the phenotype associated with this specific mutation has a wide intra- and interfamilial variability, which confirms that variable expressivity in carriers of TCOF1 mutations is not a simple consequence of the mutation but might be modified by the combination of genetic, environmental and stochastic factors. Being such a highly complex disease treatment of individuals with TCS should be tailored to the specific needs of each individual, preferably by a multidisciplinary team consisting of paediatricians, craniofacial surgeons and geneticists.

Orthognathic surgery for secondary cleft and craniofacial deformities

Orthognathic surgery is a critical component of surgical management of craniofacial deformities such as cleft lip and palate, craniofacial dysostoses, and mandibulofacial dysostoses. These operations can correct discrepancy in jaw relationship and malocclusion, relieve airway obstruction, correct facial asymmetry, optimize facial aesthetics, improve speech articulation, improve ability to masticate, and enhance psychological development and social interaction. Oral and maxillofacial surgeons who treat these deformities should be part of a craniofacial team to provide interdisciplinary care for patients. Distraction osteogenesis is a useful technique in the management of severe craniofacial deformities but does not replace conventional orthognathic surgery, which is safe and predictable. Recent advances in three-dimensional imaging and planning tools have made it possible to plan surgery more accurately and predictably.

Obstructive sleep apnoea in Treacher Collins syndrome: prevalence, severity and cause

This cohort study in 35 patients (13 children) evaluates the prevalence, severity and anatomical cause of obstructive sleep apnoea syndrome (OSAS) in patients with Treacher Collins syndrome. Ambulatory polysomnography was performed cross-sectionally to determine OSAS prevalence and severity. All upper airway related surgical interventions were evaluated retrospectively. In 11 patients, sleep endoscopy, and flexible and rigid endoscopy were applied to determine the level of anatomical obstruction of the upper airway. The overall prevalence of OSAS in Treacher Collins patients was 46% (54% in children; 41% in adults). Thirty-eight upper airway related surgical interventions were performed in 17 patients. Examination of the upper airway revealed various anatomical levels of obstruction, from the nasal septum to the trachea. Most significant obstruction was found at the level of the oro/hypopharynx. OSAS in Treacher Collins patients is an important problem so all patients should be screened for OSAS by polysomnography. Endoscopy of the upper airways was helpful in determining the level of obstruction. Surgical treatment at one level will not resolve OSAS in most patients because OSAS in Treacher Collins has a multilevel origin. Non-invasive ventilation (continuous positive airway pressure or bilevel positive airway pressure) or tracheotomy should be considered as a treatment modality.

Pediatric Craniofacial Surgery: A Review for the Multidisciplinary Team

Pediatric craniofacial surgery is a specialty that grew dramatically in the 20th century and continues to evolve today. Out of the efforts to correct facial deformities encountered during World War II, the techniques of modern craniofacial surgery developed. An analysis of the relevant literature allowed the authors to explore this historical progression.

Current advances in technology, tissue engineering, and molecular biology have further refined pediatric craniofacial surgery. The development of distraction osteogenesis and the progressive study of craniosynostosis provide remarkable examples of this momentum. The growing study of genetics, biotechnology, the influence of growth factors, and stem cell research provide additional avenues of innovation for the future. The following article is intended to reveal a greater understanding of pediatric craniofacial surgery by examining the past, present, and possible future direction. It is intended both for the surgeon, as well as for the nonsurgical individual specialists vital to the multidisciplinary craniofacial team.

Cephalometric evaluation of the craniofacial complex in patients treated with an intraoral distraction osteogenesis device: a long-term study

INTRODUCTION

Distraction osteogenesis has gained popularity because of the hypothesized concurrent soft-tissue expansion, which is believed to reduce postoperative relapse. Although many articles describe the immediate success of mandibular distraction, little research has been done on its long-term stability. Our goal was to examine the long-term craniofacial changes after distraction.

METHODS

Four hemifacial microsomic patients treated with unilateral mandibular distraction were recalled. Changes in maxillary width and height, occlusal height, ramus height, mandibular length, and chin position were quantified by using the posteroanterior and 45 degrees lateral oblique cephalographs. Predistraction and postdistraction measurements were taken over a 5-year period. The data were analyzed by using paired t tests and ANOVA.

RESULTS

Maxillary height, ramus height, mandibular length, and chin point deviation all experienced moderate improvement after distraction. Although the growth patterns between the control side and the treated side were comparable until 2 years after removal of the device, the normal side outgrew the affected side thereafter until 5 years after distraction.

CONCLUSIONS

Because of the greater inherent growth potential of the unaffected side, more overcorrection than originally believed is needed to offset the persistent asymmetry in growing hemifacial microsomia patients who undergo unilateral distraction osteogenesis.

Meta-analysis of mandibular distraction osteogenesis: clinical applications and functional outcomes

BACKGROUND

Mandibular distraction osteogenesis has been used effectively to treat syndromic craniofacial deformities. In recent years, its scope of application has widened to include treatment of airway obstruction in adults and children and nonsyndromic class II mandibular hypoplasia. So far, there has been no evidence-based review of mandibular distraction osteogenesis for mandibular lengthening.

METHODS

Two rounds of searches were performed by two independent assessors. The first-round PubMed search used the keywords "mandible" and "distraction osteogenesis." In the second-round search, the reference lists of the articles were retrieved. For both rounds, abstracts and then full articles were reviewed and selected on the basis of a set of inclusion and exclusion criteria.

RESULTS

The 178 retrieved articles yielded 1185 mandibular distraction osteogenesis patients: 539 received unilateral mandibular distraction osteogenesis and 646 received bilateral mandibular distraction osteogenesis. Mandibular distraction osteogenesis was reported to improve facial asymmetry and retrognathia (50.1 percent), correct the slanted lip commissure (24.7 percent), and improve or level the mandibular occlusal plane (11.1 percent) in unilateral asymmetry cases, whereas bilateral mandibular distraction osteogenesis was shown to be effective in preventing tracheostomies for 91.3 percent of neonates or infants with respiratory distress, and in relieving symptoms of obstructive sleep apnea for 97.0 percent of children and 100 percent of adult patients.

CONCLUSIONS

Mandibular distraction osteogenesis is effective in treating craniofacial deformities, but further clinical trials are required to assess the long-term stability and to compare the treatment with conventional treatment methods, especially in cases of obstructive sleep apnea or class II mandibular hypoplasia.

Mandibular distraction osteogenesis in a skeletal Class II patient with obstructive sleep apnea

We report the orthodontic treatment of a 31-year-old man with severe skeletal Class II malocclusion and documented obstructive sleep apnea (OSA). He had a retrognathic profile with an overbite of 4 mm and an overjet of 14 mm. Mandibular distraction osteogenesis was performed to lengthen the small, retruded mandible by 18 mm and improve the symptoms of OSA. Orthodontic treatment after the mandibular distraction osteogenesis procedure lasted 3 years 1 month. An acceptable occlusion was obtained, and the patient's OSA was significantly alleviated. Although the patient was satisfied with the treatment, condylar resorption was observed. The relevance of condylar resorption with reference to a comprehensive evaluation of the treatment outcome is discussed.

A Soft-Tissue Approach to Midfacial Hypoplasia Associated With Treacher Collins Syndrome

INTRODUCTION

Treacher Collins syndrome is an autosomal dominant mandibulofacial dysostosis with characteristic hard- and soft-tissue facial abnormalities. These include ocular malformations, ear malformations, and hypoplasia of the facial skeleton, especially of the malar bones and mandible. Traditionally, surgical correction of the facial abnormalities has focused on skeletal reconstruction to restore facial form and symmetry. In this report, we describe the use of customized parascapular free flaps, after standard reconstructive surgeries, for the correction of defects of facial contour in Treacher Collins patients. In most cases, bony reconstruction of the zygoma or periorbita is not required.

METHODS

From June 1995 to December 2003, 8 patients with Treacher Collins syndrome underwent microsurgical correction of facial contour using 16 free flaps. In all patients, staged parascapular free flaps were used for reconstruction. The microvascular technique involved a 2-team approach with simultaneous ipsilateral parascapular flap harvest and facial pocket dissection. The flaps were contoured, revascularized (14 superficial temporal vessels, 2 facial vessels), and inset. No vein grafts were used. The patients were followed for a minimum of 1 year, and postoperative evaluation included medical photography, visual assessment, and evaluation by the patient and family.

RESULTS

Seven patients had previous facial skeleton correction using craniofacial techniques. The age at operation ranged from 4-19 years. Sixteen parascapular free flaps were used in the 8 patients. Postoperative complications were limited to 1 hematoma. There were no partial or total flap losses. All of the patients had improved facial contour and symmetry. Overlying skin tone and color similarly improved.

CONCLUSION

After traditional skeletal reconstruction for the complex craniofacial defects of Treacher Collins syndrome, deficiencies in facial contour and symmetry usually persist. Customized soft-tissue free flaps can be employed to differentially resurface these defects and achieve optimal esthetic results in these challenging patients.

An unusual complication of mandibular distraction

BACKGROUND

The authors present an unusual complication of mandibular distraction in a child with the curious condition of multiple pterygium syndrome is presented.

CASE REPORT

The patient was a Caucasian male with severe pterygia in his neck. As a result of his limited mouth opening and restricted upper airway leading to obstruction, he underwent lengthening of his mandible by distraction, which significantly improved his breathing. During his follow-up, it was observed that an unusually elongated permanent molar was present in an abnormal position.

CONCLUSION

This case highlights the need to carefully plan the sites for osteotomy and the potential for damage to the developing permanent dentition in young children.