The surgical management of Treacher Collins syndrome

Bite Force, Masticatory Performance, and Nutritional Status of Adult Individuals With Treacher Collins Syndrome

OBJECTIVE

To characterize the stomatognathic system of individuals with Treacher Collins syndrome (TCS) by assessing bite force (BF) and masticatory performance (MP) and to evaluate the nutritional status (NS) of this population through anthropometric measurements.

DESIGN

Cross-sectional study.

SETTING

A public tertiary care hospital.

PATIENTS

Forty-one individuals were divided into 2 groups: (1) Control (CON): 20 control adults with class I skeletal pattern and (2) TCS: 21 adults with TCS.

INTERVENTIONS

BF measurement was assessed using a gnathodynamometer (IDDK Kratos). MP assessment was done using Image J-NIH software, by calculating the particles size of food submitted to standard chewing cycles ). NS was assessed based on body mass index (BMI).

MAIN OUTCOME MEASURES

Based on the craniofacial dysmorphology, it is our hypothesis that this population present a dysfunctional masticatory system, which can negatively impact NS.

RESULTS

Means BF values for the TCS were significantly reduced when compared with the CON group and corresponded to 170.9  ±  109.4N and 431.6  ±  134.1N (right molar [RM]) and 171.2  ±  93.9N and 427.4  ±  147.8N (left molar [LM]), respectively (P < .05). Although no significant differences were observed, the mean particle size of the TCS was greater when compared with the CON group and corresponded to 1.58  ±  1.93 mm2 and 0.66  ±  0.52 mm2, respectively. Although statistically similar mean values of BMIs were observed on both groups (CON  =  23.4  ±  4.7/TCS  =  23.4  ±  6.1), underweight and overweight individuals were found in 48% of the individuals with TCS and in 15% of the CON group participants.

CONCLUSION

Individuals with TCS showed a significant BF reduction, but no differences were observed in MP and NS when compared with the control individuals.

Hospitalizations from Birth to 28 Years in a Population Cohort of Individuals Born with Five Rare Craniofacial Anomalies in Western Australia

OBJECTIVE

To describe trends, age-specific patterns, and factors influencing hospitalizations for 5 rare craniofacial anomalies (CFAs).

METHODS

Data on livebirths (1983-2010; n = 721 019) including rare CFA (craniofacial microsomia, mandibulofacial dysostosis, Pierre Robin sequence, Van der Woude syndrome, and frontonasal dysplasia), episodes of death, and demographic and perinatal factors were identified from the Western Australian Register of Developmental Anomalies, Death Registrations and Midwives Notification System. Information on incident craniofacial and noncraniofacial related admissions, length of hospital stay, and intensive care and emergency-related admissions were identified using principal diagnosis and procedural codes were extracted from the Hospital Morbidity Data Collection and linked to other data sources. Associations of hospitalizations by age groups as well as demographic and perinatal factors were expressed as incidence rate ratio (IRR).

RESULTS

The incident hospitalizations were 3 times as high for rare CFA (IRR 3.22-3.72) throughout childhood into adolescence than those without. Children with rare CFA had 3-4 times as many potentially preventable hospitalizations until 18 years of age than those without. Specifically, respiratory infections (IRR 2.13-2.35), ear infections (IRR 7.92-26.28), and oral health-related conditions contributed for most noncraniofacial admissions until the adolescence period. A greater incidence of noncraniofacial related hospitalizations was observed among Indigenous children, births with intrauterine growth restrictions, and families with high socioeconomic disadvantage.

CONCLUSIONS

Throughout childhood, individuals with rare CFA had greater hospital service use, specifically for potentially preventable conditions, than those without. These population-level findings can inform new preventive strategies and early disease management targeted toward reducing preventable hospitalizations.

Description of Total Population Hospital Admissions for Treacher Collins Syndrome in Australia

OBJECTIVE

To describe patterns and demographic characteristics of total-population hospital admissions with a diagnosis of Treacher Collins syndrome (TCS) in Australia.

DATA SOURCE

Population summary data for inpatient hospitals admissions (public and private) with a principal diagnosis of TCS (ICD10-AM-Q87.04) were obtained from the Australian Institute of Health and Welfare National Hospital Morbidity Database for a 11-year period (2002-2013).

MAIN OUTCOME MEASURES

The primary outcome was hospital separation rate (HSR), calculated by dividing the number of hospital separations by estimated resident population per year. Trends in HSR s adjusted for age and sex were investigated by negative binomial regression presented as annual percent change and the association of rates with age and sex was expressed as incidence rate ratio.

RESULTS

In 244 admissions identified, we observed an increase of 4.55% (95% confidence interval [CI] -1.78, 11.29) in HSR's over the 11-year period. Rates were higher during infancy (1.87 [95% CI 1.42, 2.42]), declining markedly with increasing age. The average length of hospital stay was 6.09 days (95% CI 5.78, 6.40) per episode, but longer for females and infants.

CONCLUSIONS

Findings indicate an increase in hospitalization rates, especially among infants and females which potentially relates to early airway intervention procedures possibly influenced by sex specific-disease severity and phenotypic variability of TCS. Awareness of the TCS phenotype and improved access to genetic testing may support more personalized and efficient care. Total-population administrative data offers a potential to better understand the health burden of rare craniofacial diseases.

Treacher Collins Mandibular Distraction

Treacher Collins syndrome (TCS) is a genetic disorder that presents with a variety of craniofacial deformities. One classic feature of TCS is a steep, counterclockwise rotation of the occlusal plane, and microretrognathia with bony deficiencies in both the body and ramus of the mandible. This morphology commonly necessitates reconstruction by the craniofacial surgeon. This article discusses strategies and considerations for surgically correcting the mandibular deformity associated with TCS using mandibular distraction osteogenesis and other related techniques. The proper implementation of these techniques can yield excellent results that greatly improve quality of life in this challenging patient population.

Long-term treatment outcomes from a patient's perspective with Treacher Collins syndrome

The management of patients with Treacher Collins Syndrome (TCS) is complex and involves many different specialists within multidisciplinary teams (MDT). The treatment pathway extends from birth well into adulthood and is associated with a heavy burden of care. Due to the extensive nature of the interaction with these patients, MDT members have opportunities to provide enhanced patient-centred care and support.This case report provides an overview of the current knowledge of the aetiology of TCS, the management of these patients and provides a unique perspective from one of the coauthors who has TCS and reports on his treatment experiences and long-term treatment outcomes. By having a better understanding of the impact of TCS and treatment provided, MDT members can not only provide improved clinical treatment but also offer improved patient experiences for those with craniofacial anomalies in particular an increased awareness of the psychosocial challenges they endure.

Treacher Collins syndrome: Orthodontic treatment with mandibular distraction osteogenesis and orthognathic surgery

Interdisciplinary treatment for patients with Treacher Collins syndrome is challenging because of the rarity of the condition and the wide variety of phenotypic expression. A 23-year-old male was diagnosed with Treacher Collins syndrome with a history of severe obstructive sleep apnea. He presented with a Pruzansky-Kaban classification grade I mandible, skeletal type II pattern with a hyperdivergent mandibular plane, severe convex profile, and Class II malocclusion with a missing mandibular incisor. Improvement of facial esthetics was achieved by a combination of orthodontics, mandibular distraction osteogenesis, and 2-jaw maxillomandibular advancement surgery. Presurgical orthodontic treatment involved permanent tooth extraction to relieve severe crowding, and Class III mechanics were employed to increase overjet. Correction of mandibular hypoplasia by increasing ramal height and the mandibular length was done by intraoral mandibular distraction osteogenesis. Counterclockwise rotation of the mandibular plane angle and a Class III occlusion with negative overjet were achieved after mandibular distraction osteogenesis. A postdistraction posterior open bite was maintained with a biteplane during the consolidation period. Subsequently, 2-jaw orthognathic surgery was performed. LeFort I osteotomy was done for maxillary advancement to correct an anterior crossbite, eliminate canting, and reestablish occlusal contact at the mandibular occlusal plane. Bilateral sagittal split ramus osteotomy was done to correct the residual mandibular deviation. A genioplasty was also performed to improve chin projection. Postoperatively, the oropharyngeal airway was enlarged. The patient's facial profile and obstructive sleep apnea problem were improved as a result of advancement and counterclockwise rotation of the maxillomandibular complex.

Imaging of the Fetal Zygomatic Bone: A Key Role in Prenatal Diagnosis of First Branchial Arch Syndrome

OBJECTIVES

First arch syndromes are congenital defects caused by failure of neural crest cells to migrate into the first branchial arch. First arch syndrome is classified into 2 main clinical manifestations: Treacher Collins syndrome, characterized by bilateral underdevelopment of the zygomatic bones; and Pierre Robin sequence. The aim of this study was to describe the feasibility of visualization of the fetal zygomatic bone and assess its application in cases referred for features suggestive of first arch syndrome.

METHODS

A prospective cohort study was conducted. The feasibility of visualization of the zygomatic bone was performed in 50 sequential fetuses with a normal anatomic scan between 12 and 24 weeks' gestation using 3-dimensional sonography. Following this, cases referred for targeted scans for suspected first branchial arch syndrome were assessed for the presence or absence of the zygomatic bones.

RESULTS

Visualization of the fetal zygomatic bone was feasible in all low-risk cases. Cases referred for targeted scans included 11 isolated cases of micrognathia or retrognathia, 3 cases of microtia, and 3 cases of auricular or facial vestiges. Within this group, the zygomatic bones were visualized in all but 2 cases. No associated extrafacial malformations were detected; therefore, this phenotype was consistent with Treacher Collins syndrome.

CONCLUSIONS

Prenatal imaging of the zygomatic bones offers a clinically based sonographic approach to cases referred for features suggestive of first arch syndrome and enables differentiation between the 2 main clinical manifestations: Treacher Collins syndrome and Pierre Robin sequence.

Mutation analysis of TCOF1 gene in Chinese Treacher Collins syndrome patients

Background

Treacher Collins syndrome (TCS) is a rare autosomal dominant or recessive disorder, that involves unique bilateral craniofacial malformations. The phenotypes of TCS are extremely diverse. Interventional surgery can improve hearing loss and facial deformity in TCS patients.

Method

We recruited seven TCS families. Variant screening in probands was performed by targeted next‐generation sequencing (NGS). The variants identified were confirmed by Sanger sequencing. The pathogenicity of all the mutations was evaluated using the guidelines of the American College of Medical Genetics and Genomics (ACMG) and InterVar software.

Results

Three frameshift variants, two nonsense variants, one missense variant, and one splicing variant of TCOF1 were identified in the seven TCS probands. Five variants including c.1393C > T, c.4111 + 5G>C, c.1142delC, c.2285_2286delCT, and c.1719delG had not been previously reported. Furthermore, we report the c.149A > G variant for the first time in a Chinese TCS patient. We provided prenatal diagnosis for family 4. Proband 7 chose interventional surgery.

Conclusion

We identified five novel variants in TCOF1 in Chinese patients with TCS, which expands the mutation spectrum of TCOF1 in TCS. Bone conduction hearing rehabilitation can improve hearing for TCS patients and prenatal diagnosis can provide fertility guidance for TCS families.

[Progress of diagnosis and treatment of upper respiratory obstruction in patients with Treacher Collins syndrome]

Objective

To summarize the progress of diagnosis and treatment of upper respiratory obstruction in patients with Treacher Collins syndrome (TCS).

Methods

The domestic and abroad literature about the diagnosis and treatment of upper respiratory obstruction in patients with TCS was extensively reviewed and analyzed.

Results

TCS is an autosomal-dominant craniofacial developmental syndrome. It is often accompanied by midface and/or mandibular hypoplasia, soft tissue hypertrophy, and other respiratory tissue developmental abnormalities, which can lead to different degrees of upper respiratory obstruction symptoms. Respiratory obstruction in patients with TCS is affected by many factors, and the obstructive degree are different. Early detection of the causes and obstructive sites and adopted targeted treatments can relieve the symptoms of respiratory obstruction and avoid severe complications.

Conclusion

Due to the low incidence of TCS, there is still a lack of high-quality research evidence to guide clinical treatment. Large-scale and prospective clinical studies are needed to provide new ideas for the treatment and prevention of upper respiratory obstruction.

Three-Dimensional Upper Airway Assessment in Treacher Collins Syndrome

Objectives:

The purpose of this investigation was to assess the pharyngeal dimensions and the craniofacial morphology of individuals with Treacher Collins syndrome (TCS) when compared to vertical skeletal class II individuals. It is our hypothesis that the upper airways of individuals with TCS are reduced in view of the skeletal pattern and the maxillomandibular dysmorphologies.

Materials and Methods:

Cone-beam computed tomography scans of 26 individuals had the pharyngeal volume (V) and minimal cross-sectional area (mCSA) evaluated. Study group (TCS) was formed by 13 scans of patients with TCS (7 males and 6 females; 20.2 ± 4.7 years). Control group (CG) assembled 13 scans of nonaffected individuals with the same type of skeletal pattern (2 males and 11 females; 26.6 ± 5.4 years). Cephalometric data of maxillomandibular position, maxillomandibular dimensions, and growth pattern were assessed. Statistical analysis ( P ≤ .05) included Student t test and Pearson correlation coefficient.

Results:

Although reduced, pharyngeal V and mCSA of TCS were not statistically different from the CG. On both groups, mCSA was mostly at the oropharyngeal level. Individuals with TCS presented retrognathic chin, reduced maxillomandibular dimensions, and increased clockwise rotation of the palatal plane. Maxillary and mandibular lengths were correlated with pharyngeal V and mCSA.

Conclusions:

The pharyngeal dimensions of individuals with TCS are impacted by the micrognathia and retrognathia. In association with the skeletal pattern, the reduction of the airways, although not statistically significant, may explain the increased prevalence of airways disorder in this syndrome.

[Pathogenic genes and clinical therapeutic strategies for Treacher Collins syndrome]

Treacher Collins syndrome is a congenital craniofacial malformation with autosomal dominant inheritance as the main genetic pattern. In this condition, the biosynthesis of ribosomes in neural crest cells and neuroepithelial cells is blocked and the number of neural crest cells that migrate to the craniofacial region decreases, causing first and second branchial arch dysplasia. Definite causative genes include treacle ribosome biogenesis factor 1 (tcof1), RNA polymerase Ⅰ and Ⅲ subunit C (polr1c), and RNA polymerase Ⅰ and Ⅲ subunit D (polr1d). This paper provides a review of research of three major patho-genic genes, pathogenesis, phenotypic research, prevention, and treatment of the syndrome.

TCOF1 pathogenic variants identified by Whole-exome sequencing in Chinese Treacher Collins syndrome families and hearing rehabilitation effect

Background

Treacher Collins syndrome (TCS, OMIM 154500) is an autosomal disorder of craniofacial development with an incidence rate of 1/50,000 live births. Although TCOF1, POLR1D, and POLR1C, have been identified as the pathogenic genes for about 90% TCS patients, the pathogenic variants of about 8–11% cases remain unknown. The object of this study is to describe the molecular basis of 14 clinically diagnosed TCS patients from four families using Whole-exome sequencing (WES) followed by Sanger sequencing confirmation, and to analyze the effect of bone conduction hearing rehabilitation in TCS patients with bilateral conductive hearing loss.

Results

Four previously unreported heterozygous pathogenic variants (c.3047-2A > G, c.2478 + 5G > A, c.489delC, c.648delC) were identified in the TCOF1 gene, one in each of the four families. Sanger sequencing in family members confirmed co-segregation of the identified TCOF1 variants with the phenotype. The mean pure-tone threshold improvements measured 3 months after hearing intervention were 28.8 dB for soft-band BAHA, 36.6 ± 2.0 dB for Ponto implantation, and 27.5 dB SPL for Bonebridge implantation. The mean speech discrimination improvements measured 3 months after hearing intervention in a sound field with a presentation level of 65 dB SPL were 44%, 51.25 ± 5.06, and 58%, respectively. All six patients undergoing hearing rehabilitation in this study got a satisfied hearing improvement.

Conclusions

WES combined with Sanger sequencing enables the molecular diagnosis of TCS and may detect other unknown causative genes. Bone conduction hearing rehabilitation may be an optimal option for TCS patients with bilateral conductive hearing loss.

What Surgical Education the Speciality Offers? Perception of Role of Oral and Maxillofacial Surgery by 1200 Healthcare Professionals, Students and the General Public in Hyderabad, India

Aim

To investigate the perception of Oral and maxillofacial surgery by healthcare professionals, students and general public.

Materials and Methods

A questionnaire form was created that listed ten clinical situations, and given by hand to 1200 individuals, divided into six groups: group 1, medical professionals; group 2, Specialties of dentistry; group 3, general dentists; group 4, medical students; group 5, dental students; and group 6, general public, each comprising 200 individuals. Respondents were asked to indicate who they would expect to treat them if they had one of the specified conditions listed in the questionnaire. We present the results and current awareness levels of this simple questionnaire. The present study addresses the common issue raised by many authors, 'What surgical education the speciality offers?' especially to medical professionals, medical students and general public to enhance an appropriate referral.

Results

Most of the respondents in groups 2, 3 and 5 agreed that specific conditions listed in the questionnaire were within the domain of oral and maxillofacial surgery, but such response was not seen in groups 1, 4 and 6 (p < 0.001). An overall awareness level of oral and maxillofacial surgery was found to be 50.2%.

Conclusion

The onus of creating and improving the awareness and perception of our specialty lies on oral and maxillofacial surgeon. Unified efforts at individual as well as global level will help achieve this goal.

Orthognathic Surgery: A Review of Articles Published in 2014-2015

OBJECTIVES

We did a retrospective study and reviewed some of the orthognathic surgery related papers that were published between January 2014 and December 2015 in a leading International Maxillofacial Surgery Journal. It was conducted to ascertain the trends of articles being published.

METHOD

A total of around 57 articles were reviewed, of which most of the full length articles were on post operative outcomes and obstructive sleep apnoea.

RESULTS

Bulk of the studies were retrospective, and less interest was shown onto experimental researches.

CONCLUSION

A thorough review and analysis thus gives an impression that there is a high requirement of well designed clinical studies.

Mandibulofacial dysostosis Bauru type: Refining the phenotype

Mandibulofacial dysostosis (MFD) Bauru type (OMIM 604830) is a rare genetic condition characterized mainly by malar hypoplasia, orofacial cleft, and micrognathia. Here, we describe the clinical and radiographic sings of 13 individuals (12 female and 1 male) from eight unrelated kindreds with MFD Bauru type, including four previously reported cases, treated at the Hospital for Rehabilitation of Craniofacial Anomalies. The clinical phenotype was characterized by severe underdevelopment of mandible, midface hypoplasia, orofacial cleft, bitemporal narrowing, mild upper eyelid down slanting, high nasal bridge, thick and everted lower lip, minor ears abnormalities, and hearing loss. Radiographic aspects included downslanting of zygomatic arch, maxillary hypoplasia, microretrognathia, hypoplastic mandibular condyles, and ectopic external auditory canal. Recurrence was observed in two of eight families and the affected distribution pattern was compatible with autosomal dominant inheritance in one and autosomal recessive in another, indicating possible genetic heterogeneity for this condition. Clinical and radiographic findings in this report contribute to the delineation of this rare MFD.

[Autologous fat grafting in children]

Lipofilling or fat grafting transfer is defined as a technique of filling soft tissue by autologous fat grafting. The basic principle of lipofilling is based on a harvest of adipose tissue, followed by a reinjection after treatment. Lipofilling main objective is a volume defect filling, but also improving cutaneous trophicity. Lipofilling specificities among children is mainly based on these indications. Complications of autologous fat grafting among children are the same as those in adults: we distinguish short-term complications (intraoperative and perioperative) and the medium and long-term complications. The harvesting of fat tissue is the main limiting factor of the technique, due to low percentage of body fat of children. Indications of lipofilling among children may be specific or similar to those in adults. There are two types of indications: cosmetic, in which the aim of lipofilling is correcting a defect density, acquired (iatrogenic, post-traumatic scar) or malformation (otomandibular dysplasia, craniosynostosis, Parry Romberg syndrom, Poland syndrom, pectus excavatum…). The aim of functional indications is correcting a velar insufficiency or lagophthalmos. In the paediatric sector, lipofilling has become an alternative to the conventional techniques, by its reliability, safety, reproducibility, and good results.

Combined soft and skeletal tissue modelling of normal and dysmorphic midface postnatal development

BACKGROUND

Midface hypoplasia as exemplified by Treacher Collins Syndrome (TCS) can impair appearance and function. Reconstruction involves multiple invasive surgeries with variable long-term outcomes. This study aims to describe normal and dysmorphic midface postnatal development through combined modelling of skeletal and soft tissues and to develop a surgical evaluation tool.

MATERIALS AND METHODS

Midface skeletal and soft tissue surfaces were extracted from computed tomography scans of 52 control and 14 TCS children, then analysed using dense surface modelling. The model was used to describe midface growth, morphology, and asymmetry, then evaluate postoperative outcomes.

RESULTS

Parameters responsible for the greatest variation in midface size and shape showed differences between TCS and controls with close alignment between skeletal and soft tissue models. TCS children exhibited midface dysmorphology and hypoplasia when compared with controls. Asymmetry was also significantly higher in TCS midfaces. Combined modelling was used to evaluate the impact of surgery in one TCS individual who showed normalisation immediately after surgery but reversion towards TCS dysmorphology after 1 year.

CONCLUSION

This is the first quantitative analysis of postnatal midface development using combined modelling of skeletal and soft tissues. We also provide an approach for evaluation of surgical outcomes, laying the foundations for future development of a preoperative planning tool.

Treacher Collins Syndrome: A Systematic Review of Evidence-Based Treatment and Recommendations

BACKGROUND

No reviews or guidelines are available on evidence-based treatment for the multidisciplinary approach in Treacher Collins syndrome. The authors' aim is to provide an evidence-based review of multidisciplinary treatment of Treacher Collins syndrome based on levels of evidence and supported with graded recommendations.

METHODS

A systematic search was performed by means of the PubMed, Web-of-Science, Embase, and Cochrane Central databases (1985 to January of 2014). Included were clinical studies (with five or more Treacher Collins syndrome patients) related to therapy, diagnosis, or risk of concomitant diseases. Level of evidence of the selected articles was rated according to the American Society of Plastic Surgeons evidence-based clinical practice guidelines. After two panelists had reviewed each abstract separately, a consensus method was used to solve any disagreements concerning article inclusion.

RESULTS

Of the 2433 identified articles, 63 studies (Level of Evidence II through V) were included. Conclusions and recommendations were extracted consecutively for the following items: upper airway; ear, hearing, and speech; the eye, eyelashes, and lacrimal system; growth, feeding, and swallowing; the nose; psychosocial factors; and craniofacial reconstruction.

CONCLUSIONS

In this systematic review, current evidence for the multidisciplinary treatment of Treacher Collins syndrome is provided, recommendations for treatment are made, and a proposed algorithm for treatment is presented. Although some topics are well supported, others, especially ocular, nasal, speech, feeding, and swallowing problems, lack sufficient evidence. In addition, craniofacial surgical reconstruction lacks a sufficient level of evidence to provide a sound basis for a full treatment protocol. Despite the rarity of the syndrome, more research is needed to compare outcomes of several surgical treatments, especially in orbitozygomatic/maxillary regions.

The neural crest: a versatile organ system

The neural crest is the name given to the strip of cells at the junction between neural and epidermal ectoderm in neurula-stage vertebrate embryos, which is later brought to the dorsal neural tube as the neural folds elevate. The neural crest is a heterogeneous and multipotent progenitor cell population whose cells undergo EMT then extensively and accurately migrate throughout the embryo. Neural crest cells contribute to nearly every organ system in the body, with derivatives of neuronal, glial, neuroendocrine, pigment, and also mesodermal lineages. This breadth of developmental capacity has led to the neural crest being termed the fourth germ layer. The neural crest has occupied a prominent place in developmental biology, due to its exaggerated migratory morphogenesis and its remarkably wide developmental potential. As such, neural crest cells have become an attractive model for developmental biologists for studying these processes. Problems in neural crest development cause a number of human syndromes and birth defects known collectively as neurocristopathies; these include Treacher Collins syndrome, Hirschsprung disease, and 22q11.2 deletion syndromes. Tumors in the neural crest lineage are also of clinical importance, including the aggressive melanoma and neuroblastoma types. These clinical aspects have drawn attention to the selection or creation of neural crest progenitor cells, particularly of human origin, for studying pathologies of the neural crest at the cellular level, and also for possible cell therapeutics. The versatility of the neural crest lends itself to interlinked research, spanning basic developmental biology, birth defect research, oncology, and stem/progenitor cell biology and therapy.