The ontogeny of Robin sequence

Impact of upper airway obstruction management in Robin Sequence on need for myringotomy tubes

OBJECTIVE

Investigate an association between upper airway obstruction (UAO) management in Robin Sequence (RS) and need for bilateral myringotomy and tubes (BMT).

METHODS

Retrospective chart review of RS patients treated at a tertiary free-standing pediatric hospital from 1995 to 2020 was performed. Patients were grouped based on airway management: conservative, tracheostomy, tongue-lip adhesion (TLA), and mandibular distraction osteogenesis (MDO). Demographic data, cleft palate (CP) association, numbers of BMT and ear infections, and audiogram data including tympanograms were collected. One-way ANOVA and Chi-square/Fisher's exact tests were used to compare continuous and categorical data, respectively. Multivariable regression analysis was used to compare BMT rates between treatment groups.

RESULTS

One hundred forty-eight patients were included, 70.3 % of which had CP. Most patients (67.6 %) had at least one BMT; 29.1 % required two or more BMT. The rate of BMT was higher in patients with CP compared to those with intact palates (p = 0.003; 95 % CI 1.30-3.57) and those treated with tracheostomy (p = 0.043; 95 % CI 1.01, 2.27). Surgically managed patients were more likely to have hearing loss (67.5 % vs. 35.3 %, p = 0.017) and ear infections (42.1 % vs. 20.0 %, p = 0.014) pre-compared to post-procedure for airway management.

CONCLUSION

Most RS patients require at least 1 set of BMT. Those with CP and/or treated with tracheostomy had a higher likelihood of needing BMT. Rate of hearing loss and ear infection was higher in surgically managed RS patients. Patients with RS and overt CP require a statistically higher number of BMTs compared to those with either submucous cleft palate or intact palate.

Minimally-invasive airway management and early cleft palate repair in infants born with Robin sequence

The objective of this study was to report outcomes of early cleft palate repair in infants born with Robin sequence (RS). A retrospective case series in a tertiary referral paediatric hospital was carried out, examining a consecutive series of 69 infants born with RS and cleft palate. A minimally invasive approach was taken to upper airway obstruction, with liberal nasopharyngeal airway (NPA) and non-invasive ventilation (NIV) use, guided by sleep studies. The palate was repaired between 6 and 9 months with a modified Malek technique. The most frequently used airway adjunct (59.4% of patients) was an NPA and the median duration of use was 5.6 months. All patients underwent a modified Malek cleft palate repair at a median of 7 months of age. Overnight oximetry demonstrated higher mean oxygen saturation (SpO2) across the group from initial neonatal admission to discharge (median 96.5% (interquartile range [IQR] 95-98%) vs 97.45% (IQR 96.5-98%) (P = 0.2, N = 34). Of those with a cardiorespiratory polysomnogram, the obstructive apnoea-hypopnea index (OAHI) was significantly lower postoperatively (5.9 vs 2.8, P = 0.028). This study supports the use of non-surgical airway strategies and early cleft palate repair in infants born with RS and cleft palate.

Spectrum of Disease in Hospitalized Newborns with Congenital Micrognathia: A Cohort of 3,236 Infants at North American Tertiary-Care Intensive Care Units

OBJECTIVE

To describe the spectrum of disease and burden of care in infants with congenital micrognathia from a multicenter cohort hospitalized at tertiary care centers.

STUDY DESIGN

The Children's Hospitals Neonatal Database was queried from 2010 through 2020 for infants diagnosed with micrognathia. Demographics, presence of genetic syndromes, and cleft status were summarized. Outcomes included death, length of hospitalization, neonatal surgery, and feeding and respiratory support at discharge.

RESULTS

Analysis included 3,236 infants with congenital micrognathia. Cleft palate was identified in 1266 (39.1%). A genetic syndrome associated with micrognathia was diagnosed during the neonatal hospitalization in 256 (7.9%). Median (IQR) length of hospitalization was 35 (16, 63) days. Death during the hospitalization (n = 228, 6.8%) was associated with absence of cleft palate (4.4%, P < .001) and maternal Black race (11.6%, P < .001). During the neonatal hospitalization, 1289 (39.7%) underwent surgery to correct airway obstruction and 1059 (32.7%) underwent gastrostomy tube placement. At the time of discharge, 1035 (40.3%) were exclusively feeding orally. There was significant variability between centers related to length of stay and presence of a feeding tube at discharge (P < .001 for both).

CONCLUSIONS

Infants hospitalized with congenital micrognathia have a significant burden of disease, commonly receive surgical intervention, and most often require tube feedings at hospital discharge. We identified disparities based on race and among centers. Development of evidence-based guidelines could improve neonatal care.

Tongue and Mandibular Disorders of the Pediatric Patient

Robin sequence, macroglossia, and ankyloglossia are disorders affecting the tongue and mandible in the pediatric population. Each of these can have a significant impact on breathing, feeding, speech, dentition, and craniofacial growth. This review discusses the interdependent and coordinated development of both the tongue and mandible, the functional impacts of these disorders, and appropriate management strategies.

Unusual phenotypes in patients with a pathogenic germline variant in DICER1

Pathogenic germline DICER1 variants are associated with pleuropulmonary blastoma, multinodular goiter, embryonal rhabdomyosarcoma and other tumour types, while mosaic missense DICER1 variants in the RNase IIIb domain are linked to cause GLOW (global developmental delay, lung cysts, overgrowth, and Wilms' tumor) syndrome. Here, we report four families with germline DICER1 pathogenic variants in which one member in each family had a more complex phenotype, including skeletal findings, facial dysmorphism and developmental abnormalities. The developmental features occur with a variable expressivity and incomplete penetrance as also described for the neoplastic and dysplastic lesions associated with DICER1 variants. Whole exome sequencing (WES) was performed on all four cases and revealed no further pathogenic or likely pathogenic dominant, homozygous or compound heterozygous variants in three of them. Notably, a frameshift variant in ARID1B was detected in one patient explaining part of her phenotype. This series of patients shows that pathogenic DICER1 variants may be associated with a broader phenotypic spectrum than initially assumed, including predisposition to different tumours, skeletal findings, dysmorphism and developmental abnormalities, but genetic work up in syndromic patients should be comprehensive in order not to miss additional underlying /modifying causes.

Associated anomalies in Pierre Robin sequence

Pierre Robin sequence (PRS) is frequently co-occurring with other non-PRS congenital anomalies. The types and the prevalence of anomalies co-occurring with PRS vary in the reported studies. The aims of this report was to study the types and the prevalence of the anomalies co-occurring with PRS in a well-studied population northeastern France. The types and the prevalence of anomalies co-occurring in cases with PRS were ascertained in all terminations of pregnancy, stillbirths and live births in 387,067 births occurring consecutively during the period 1979-2007 in the area covered by our registry of congenital anomalies which is population-based, 89 cases of PRS were registered during the study period with a prevalence of 2.29 per 10,000 births, 69.7% of the cases had associated non-PRS anomalies. Chromosomal abnormalities were present in 10 (11.2%) cases including three 22 q11.2 deletion. Non-chromosomal recognizable conditions were diagnosed in 27 cases (30.3%) including 10 Stickler syndrome, 8 Treacher Collins syndrome, 3 cases with short stature and 6 other syndromes. Multiple congenital anomalies (MCA) were present in 25 cases (28.1%). The most frequent MCA were in the ear, face and neck (35 out of 98 anomalies, 35.7%), cardiovascular (18 anomalies, 18.4%), musculoskeletal (11 anomalies, 11.2%), central nervous (7 anomalies, 7.1%), urinary (6 anomalies, 6.1%), and eye (6 anomalies, 6.1%) system. The high prevalence of associated anomalies justifies a thorough screening for other congenital anomalies in cases with PRS.

Structural elements promote architectural stripe formation and facilitate ultra-long-range gene regulation at a human disease locus

Enhancer clusters overlapping disease-associated mutations in Pierre Robin sequence (PRS) patients regulate SOX9 expression at genomic distances over 1.25 Mb. We applied optical reconstruction of chromatin architecture (ORCA) imaging to trace 3D locus topology during PRS-enhancer activation. We observed pronounced changes in locus topology between cell types. Subsequent analysis of single-chromatin fiber traces revealed that these ensemble-average differences arise through changes in the frequency of commonly sampled topologies. We further identified two CTCF-bound elements, internal to the SOX9 topologically associating domain, which promote stripe formation, are positioned near the domain's 3D geometric center, and bridge enhancer-promoter contacts in a series of chromatin loops. Ablation of these elements results in diminished SOX9 expression and altered domain-wide contacts. Polymer models with uniform loading across the domain and frequent cohesin collisions recapitulate this multi-loop, centrally clustered geometry. Together, we provide mechanistic insights into architectural stripe formation and gene regulation over ultra-long genomic ranges.

Mandibular morphology and distraction osteogenesis vectors in patients with Robin sequence

The aims of this cohort study were to compare the mandibular morphology between patients with Robin sequence (RS) and controls, and to examine the effects of mandibular distraction osteogenesis (MDO) using different vectors. Measurements of the mandibles of 80 patients with RS and 46 controls aged< 90 days were made using computed tomography. The data were compared among isolated RS patients (n = 58), syndromic RS patients (n = 22), and controls. Patients with RS exhibited significantly shorter ramus and body lengths and larger symphyseal angles than controls (all P < 0.001). Patients with isolated RS had shorter body lengths (P < 0.001), while syndromic patients had shorter ramus and body lengths (both P < 0.001) than controls. Seventy RS patients underwent MDO. Pre-MDO (n = 37) and post-MDO (n = 29) mandibular measurements were compared between patients undergoing MDO with a vertical vector and those undergoing MDO with a horizontal vector. Polysomnography data from part of the cohort highlighted the effectiveness of both vectors. MDO with a horizontal vector conferred 11% and 36% increases in ramus and body length, respectively, while these increases were 34% and 27.5%, respectively, with a vertical vector. MDO with a vertical vector was effective in lengthening ramus and body components and should be considered in the presence of ramus hypoplasia.

Long-term speech outcome in patients with Robin sequence after cleft palate repair and tongue-lip adhesion: A 21-year retrospective analysis

The purpose of this study was to assess the effect of tongue-lip adhesion (TLA) on the long-term speech and articulation outcomes of patients with Robin sequence (RS) after cleft palate repair. Outcomes were compared to those in patients with RS who required positioning alone and to patients with isolated cleft palate (ICP). All consecutive patients with RS (with or without TLA) versus isolated cleft palate (ICP) who underwent cleft palate repair were retrospectively reviewed. Speech and articulation included all assessments between the age of 3-6 years. Secondary speech operations, velopharyngeal insufficiency (VPI), hypernasality, and articulation errors by cleft-type characteristics (CTC), including 4 categories (passive), non-oral, anterior-oral, and posterior-oral. A total of 41 RS patients and 61 ICP patients underwent repair with sufficient follow-up. Of them, 23 patients underwent a TLA at median age of 12 days. Rates of hypernasality (p = 0.004), secondary speech operations (p = 0.004), and posterior oral CTC (p = 0.042) were higher in RS compared to ICP. Isolated RS had speech outcomes similar to those of ICP; however, syndromic RS patients needed more secondary speech operations compared to isolated RS (p = 0.043). TLA-RS patients did not demonstrate differences in speech outcomes or any CTCs (all p > 0.05) compared to non-TLA-RS patients, except for the anterior oral CTC (74% TLA-RS vs 28% non-TLA-RS, p = 0.005). Within the limitations of the study, it seem that TLA does not affect long-term velopharyngeal function in patients with RS. However, TLA-RS patients demonstrated higher rates of anterior-oral CTC, which might be related to a different positioning of the tongue after TLA. Every effort should be taken to treat patients with RS conservatively instead of with TLA because of this demonstrated a negative effect on one type of articulation error. However, if conservative therapy fails, a TLA is still a valuable adjunct in the treatment of RS, and cleft speech pathologists who treat such patients should be more aware of this phenomenon in order to improve long-term articulation outcomes.

Can Dynamic Magnetic Resonance Images Improve Prenatal Diagnosis of Robin Sequence

BACKGROUND

Robin sequence (RS) is a triad of micrognathia, glossoptosis, and airway obstruction. Prenatal diagnosis of RS improves delivery planning and postnatal care, but the process for prenatal diagnosis has not been refined. The purpose of this study was to determine if dynamic cine magnetic resonance imaging (MRI) can improve the reliability of prenatal diagnosis for RS compared to current static imaging techniques.

MATERIALS AND METHODS

This is a retrospective cross-sectional study including fetuses with prenatal MRIs obtained in a single center from January 2014 to November 2019. Fetuses were included if they: 1) had a prenatal MRI with cine dynamic sequences of adequate quality, 2) were live born, and 3) had postnatal craniofacial evaluation to confirm RS. Patients without postnatal confirmation of their prenatal findings were excluded. The primary predictor variable was imaging type (cine or static MRI). Outcome variables were tongue and airway measurements: 1) tongue height, 2) length and width, 3) tongue shape index, 4) observation of tongue touching the posterior pharyngeal wall, and 5) measurement of oropharyngeal space. All measurements were made independently on the cine images and on static MRI sequences for the same cohort of subjects by a pediatric radiologist. Data were analyzed using paired samples t tests and Fisher exact tests, and significance was set as P < .05.

RESULTS

A total of 11 patients with RS were included in the study. The smallest airway space consistently demonstrated complete collapse on the cine series compared to partial collapse on static images (0 mm vs 1.7 ± 1.4 mm, P = .002). No other imaging variable was statistically significantly different between techniques.

CONCLUSIONS

Cine imaging sequences on prenatal MRI were superior to static images in discerning complete collapse of the smallest airway space, an important marker of RS. This suggests a possible benefit to adding dynamic MRI evaluation for prenatal diagnosis of this condition.

Fetal Micro and Macroglossia: Defining Normal Fetal Tongue Size

OBJECTIVES

Abnormal fetal tongue size is a phenotypic feature of various syndromes including Beckwith-Wiedemann, Pierre-Robin, oromandibular limb hypoplasia, chromosomal aberrations, etc. Current data regarding normal fetal tongue size are limited. Hence, micro/macroglossia are subjectively determined. The aim of the study was to construct a contemporary fetal tongue nomogram and to assess its clinical contribution.

METHODS

A prospective cross-sectional study was performed in well dated, low risk, singleton pregnancies. Fetal tongues were measured by 5 trained sonographers. Highest quality images were selected. Intra- and interobserver variability was assessed. Tongue length, width, area, and circumference 1st to 99th centiles were calculated for each gestational week. Based on the normal tongue size charts, we created a Tongue Centile Calculator.

RESULTS

Over 18 months, 664 tongue measurements were performed. A cubic polynomial regression model best described the correlation between tongue size and gestational age. The correlation coefficient (r² ) was 0.934, 0.932, 0.925, and 0.953 for tongue length, width, area, and circumference, respectively (P < .001). Intra- and interobserver variability had high interclass correlation coefficients (>0.9). Using the new charts, we were able to identify 2 cases of macroglossia, subsequently diagnosed with Beckwith-Wiedemann, and 4 cases of microglossia, 3 associated with Pierre-Robin sequence, and 1 associated with persistent buccopharyngeal membrane.

CONCLUSIONS

We present novel fetal tongue size charts from 13 to 40 weeks of gestation. Clinical application of these nomograms may be beneficial in the prenatal diagnosis of syndromes or malformations associated with abnormal fetal tongue size.

Disrupted tenogenesis in masseter as a potential cause of micrognathia

Micrognathia is a severe craniofacial deformity affecting appearance and survival. Previous studies revealed that multiple factors involved in the osteogenesis of mandibular bone have contributed to micrognathia, but concerned little on factors other than osteogenesis. In the current study, we found that ectopic activation of Fgf8 by Osr2-cre in the presumptive mesenchyme for masseter tendon in mice led to micrognathia, masseter regression, and the disrupted patterning and differentiation of masseter tendon. Since Myf5-cre;Rosa26R-Fgf8 mice exhibited the normal masseter and mandibular bone, the possibility that the micrognathia and masseter regression resulted directly from the over-expressed Fgf8 was excluded. Further investigation disclosed that a series of chondrogenic markers were ectopically activated in the developing Osr2-cre;Rosa26R-Fgf8 masseter tendon, while the mechanical sensing in the masseter and mandibular bone was obviously reduced. Thus, it suggested that the micrognathia in Osr2-cre;Rosa26R-Fgf8 mice resulted secondarily from the reduced mechanical force transmitted to mandibular bone. Consistently, when tenogenic or myogenic components were deleted from the developing mandibles, both the micrognathia and masseter degeneration took place with the decreased mechanical sensing in mandibular bone, which verified that the loss of mechanical force transmitted by masseter tendon could result in micrognathia. Furthermore, it appeared that the micrognathia resulting from the disrupted tenogenesis was attributed to the impaired osteogenic specification, instead of the differentiation in the periosteal progenitors. Our findings disclose a novel mechanism for mandibular morphogenesis, and shed light on the prevention and treatment for micrognathia.

A parent's view on the care of their baby with Robin sequence

A Robin sequence parent presents the view that Robin sequence healthcare providers are engaging in practices which may be outdated, excessively invasive, and unnecessarily detrimental to quality of life, and proposes possible areas of research to improve patient outcomes.

Developmental outcome of children with Robin sequence: How does the question arise?

Robin sequence (RS) is a heterogeneous congenital condition characterized by retrognathia, glossoptosis, upper airway obstruction, and very often, posterior U-shape cleft palate. Half the children with RS have an underlying syndrome, either identified (syndromic RS) or not (RS+). Long-term intellectual developmental outcome first depends on the underlying diagnosis and is often poor in syndromic cases. On the contrary, the rare studies that analysed the long-term developmental outcome of children with isolated RS who received effective treatment of their respiratory and feeding difficulties early in life, showed intellectual and academic results close to or within the normal range. Speech outcome in RS is often delayed with phonation disorders. Speech difficulties depend on intellectual level, hearing and velar function after palate repair. It affects most children with RS and deserves active monitoring and care.

Genetics of craniofacial malformations

The field of craniofacial malformations is comprehensive and does not allow to discuss all craniofacial malformations which have been described as single entities. Many of the syndromes with craniofacial malformations are ultrarare. In this review we have chosen craniofacial malformation syndromes which are of relevance for the pediatrician, especially neonatologist: different types of craniosynostoses, oculo-auriculo-vertebral spectrum, Pierre Robin sequence and Treacher Collins syndrome. These syndromes will be described in detail. Diagnostic and therapeutic options will be discussed.

Advantages and disadvantages of mandibular distraction in Robin sequence

Robin sequence (RS) is diagnosed in infants born with micrognathia, glossoptosis and varying degrees of upper airway obstruction (UAO). Due to the variable levels of hypoxia, severe breathing and feeding problems can occur. Treatment is determined by clinical severity, ranging from conservative interventions for mild cases to surgical interventions for severe cases. Mandibular distraction osteogenesis (MDO) is a surgical technique that gradually lengthens the mandible after an osteotomy by using an internal or external distraction device, directly correcting the micrognathia. This review will focus on advantages and disadvantages of mandibular distraction in infants with RS.

Next Generation Sequencing and Cytogenetic Based Evaluation of Indian Pierre Robin Sequence Families Reveals CNV Regions of Modest Effect and a Novel LOXL3 Mutation

BACKGROUND

Pierre Robin Sequence (PRS) affects approximately 1 per 8500 to 14000 new-borns worldwide. Although the clinical entity is well defined, the pathogenesis of PRS is debated. The present study aims to understand the contribution of genomic imbalances and genetic variants in patients clinically diagnosed of PRS.

METHODOLOGY

A total of 7 independent patients with nonsyndromic PRS thoroughly evaluated by a medical geneticist at a tertiary care hospital, were included in the study. Blood samples were collected from these patients and their family members. Array CGH was performed on all 7 patients and their respective family members for detection of underlying cytogenetic defects. Whole exome sequencing (WES) was performed for 5 families to capture single nucleotide variants or small indels.

RESULTS

Cytogenetic analyses did not detect any previously reported gross chromosomal aberrations for PRS in the patient cohort. However, copy number variations (CNVs) of size <1 Mb were detected in patients which may have implications in PRS. The present study provided evidence for the occurrence of de novo deletions at 7p14.1 locus in PRS patients: further validating the candidate loci susceptibility in oral clefts. WES data identified LOXL3 as candidate gene, carrying novel deleterious variant, which is suggestive of the role of point mutations in the pathogenesis of PRS.

CONCLUSION

The present study offered considerable insight into the contribution of cytogenetic defects and novel point mutation in the etiology of nonsyndromic PRS. Studies comprising large number of cases are required to fully elucidate the genetic mechanisms underlying the PRS phenotype.

Quality of life and phonatory and morphological outcomes in cognitively unimpaired adolescents with Pierre Robin sequence: a cross-sectional study of 72 patients

Background

Pierre Robin sequence (PRS) is a heterogeneous condition involving retro(micro)gnathia, glossoptosis and upper airway obstruction, very often with posterior cleft palate. Patients with PRS, either isolated or associated with Stickler syndrome have good intellectual prognosis. Nevertheless, the quality of life in adolescence and the phonatory and morphological outcomes are rarely analysed. We assessed the phonatory and morphological outcomes of 72 cognitively unimpaired adolescents with PRS, studied their oral (COHIP-SF19), vocal (VHI-9i) and generic quality of life (QoL; KIDSCREEN-52), and searched for determinants of these outcomes.

Results

Two-thirds of our adolescents retained low or moderate phonation difficulties, but risk factors were not identified. For 14%, morphological results were considered disharmonious, with no link to neonatal retrognathia severity. Only one vs two-stage surgery seemed to affect final aesthetic results. The oral QoL of these adolescents was comparable to that of control patients and was significantly better than that of children with other craniofacial malformations (COHIP-SF19 = 17.5, 15.4 and 25.7, respectively). The oral QoL of the adolescents with non-isolated PRS was significantly worse (COHIP-SF19 = 24.2) than that of control patients and close to that of children with other craniofacial malformations. The vocal QoL of the adolescents (mean [SD] VHI-9i = 7.5 [5.4]) was better than that of patients with other voice pathologies and better when phonation was good. The generic QoL of the adolescents was satisfactory but slightly lower than that of controls, especially in dimensions concerning physical well-being, relationships and autonomy. QoL results were lower for adolescents with non-isolated than isolated PRS. Only non-isolated PRS and low oral QoL affected generic QoL.

Conclusion

Morphological or phonatory impairments remain non-rare in adolescents with PRS but do not seem to be directly responsible for altered QoL. These adolescents, especially those with non-isolated PRS, show self-confidence and social-relation fragility. We must focus on long-term functional and psychological results for PRS patients and improve therapy protocols and follow-up, notably those affecting the oral aspects of the disease.

Three-dimensional comparison of mandibular morphology in young people with Treacher Collins syndrome and Pierre Robin sequence

INTRODUCTION

Treacher Collins syndrome (TCS) and nonsyndromic Pierre Robin sequence (PRS) share mandibular deficiency as a similar clinical finding. This study aimed to compare the mandibular size and morphology of subjects with TCS and PRS.

METHODS

Group TCS was composed of 17 subjects (7 male, 10 female) with a mean age of 11.5 years (standard deviation, 4.4) from a single center. Group PRS was composed of 17 subjects paired by age and sex with group TCS. Preorthodontic cone-beam computed tomography examinations of all patients were evaluated using Mimics Innovation Suite 17.0 (Materialise, Leuven, Belgium). Nine 3-dimensional measurements were performed in segmented 3D images of the mandible. Intragroup comparisons were performed using paired t tests. Intergroup comparisons were performed using analysis of variance and Tukey tests. The significance level considered was 5%.

RESULTS

TCS showed a significant dimensional difference between less and more affected sides for ramus, condyles, and mandibular body. The mandibular dimensions in PRS were more symmetrical. Group TCS presented a smaller mandibular effective length and mandibular body length compared with PRS. The condyle width and height and the ramus width were also decreased in TCS. The gonial angle was greater in TCS compared with the PRS group.

CONCLUSIONS

Young subjects with TCS presented a smaller, more vertical, and more asymmetrical mandible compared with nonsyndromic PRS.

A Comparison of Weight Gain Following Mandibular Distraction Osteogenesis and Tongue-Lip Adhesion in the Treatment of Robin Sequence

ABSTRACT

Obstructive respiratory stress and feeding difficulties in infants with Robin sequence (RS) may result in poor weight gain or loss. Following failure of conservative treatment, surgical options include mandibular distraction osteogenesis (MDO) and tongue-lip adhesion (TLA). Whilst both techniques have demonstrated to improve airway patency and feeding behavior, an advantage of either in restoring weight growth remains unknown. This study aimed to improve procedural selection by examining weight gain following MDO and TLA. A retrospective chart review was performed for 17 RS patients that had undergone MDO and 25 that had received TLA. The mean body weight in both groups was below the 50th population percentile at birth and fell further in the period before surgery. A mixed model analysis demonstrated that postoperative weight gain depended on the progression of time and preoperative weight. Conversely, biological sex, congenital comorbidities, method of feeding, the respective cleft team, and the type of surgery did not significantly influence the evolution of postoperative body weight. In conclusion, both MDO and TLA were able to restore weight growth in infants affected by RS, though a clear superiority of either technique could not be established.

Cleft palate morphology, genetic etiology, and risk of mortality in infants with Robin sequence

Robin sequence (RS) has many genetic and nongenetic causes, including isolated Robin sequence (iRS), Stickler syndrome (SS), and other syndromes (SyndRS). The purpose of this study was to determine if the presence and type of cleft palate varies between etiologic groups. A secondary endpoint was to determine the relationship of etiologic group, cleft type, and mortality. Retrospective chart review of patients with RS at two high-volume craniofacial centers. 295 patients with RS identified. CP was identified in 97% with iRS, 95% with SS, and 70% of those with SyndRS (p < .0001). U-shaped CP was seen in 86% of iRS, 82% with SS, but only 27% with SyndRS (p < .0001). At one institution, 12 children (6%) with RS died, all from the SyndRS group (p < .0001). All died due to medical comorbidities related to their syndrome. Only 25% of children who died had a U-shaped CP. The most common palatal morphology among those who died was an intact palate. U-shaped CP was most strongly associated with iRS and SS, and with a lower risk of mortality. RS with submucous CP, cleft lip and palate or intact palate was strongly suggestive of an underlying genetic syndrome and higher risk of mortality.

Predictors of Respiratory Dysfunction at Diagnosis of Robin Sequence

OBJECTIVES/HYPOTHESIS

Robin sequence (RS) consists of associated micrognathia, glossoptosis, and respiratory dysfunction, with or without cleft palate. Studies on how different patient characteristics impact the severity of respiratory dysfunction are scarce and contradictory; this study investigates how different features affect respiratory obstruction severity at diagnosis of RS in controlled analysis.

STUDY DESIGN

Retrospective cohort study that enrolled 71 RS patients under 90 days old who received care in our institution from 2009 to 2020.

METHODS

The primary outcome, respiratory dysfunction, was categorized into four severity groups and analyzed using a multinomial logistic regression model that considered age, sex, mandible length, cleft palate, syndromic diagnosis, other airway anomalies, and degree of glossoptosis.

RESULTS

Mandible length, syndromic diagnosis, and Yellon grade 3 glossoptosis were related to poorer respiratory outcomes (need for respiratory support). In univariate analysis, for each additional 1 mm of mandible length at diagnosis, a mean reduction of 28% in the risk of needing respiratory support was observed (OR = 0.72; 0.58-0.89); syndromic diagnosis and grade 3 glossoptosis also raised the risk (OR = 6.50; 1.59-26.51 and OR = 12.75; 1.03-157.14, respectively). In multivariate analysis, only mandible length significantly maintained its effects (OR = 0.73; 0.56-0.96), a 27% reduction.

CONCLUSIONS

Mandible length was an independent predictor for more severe respiratory dysfunction in RS patients, with larger mandibles showing protective effects. Syndromic diagnosis and Yellon grade 3 glossoptosis are also likely to be associated with poorer respiratory outcomes, although this was not demonstrated in multivariate analysis.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Objective measurements for upper airway obstruction in infants with Robin sequence: what are we measuring? A systematic review

STUDY OBJECTIVES

Identifying optimal treatment for infants with Robin sequence (RS) is challenging due to substantial variability in the presentation of upper airway obstruction (UAO) in this population. Objective assessments of UAO and treatments are not standardized. A systematic review of objective measures of UAO was conducted as step towards evidence based clinical decision making for RS.

METHODS

A literature search was performed in Pubmed and Embase databases (1990-2020) following PRISMA-guidelines. Articles reporting on RS and UAO-treatment were included if the following objective measures were studied: oximetry, polysomnography and blood gas. Quality was appraised by methodological index for non-randomized studies (MINORS, range:0-24).

RESULTS

A total of 91 articles met inclusion criteria. Mean MINORS-score was 7.1 (range:3-14). Polysomnography was most frequently used (76%) followed by oximetry (20%) and blood gas (11%). Sleep position of the infant was reported in 35% of studies, with supine position most frequently, and monitoring time in 42%, including overnight recordings in more than half. Of 71 studies that evaluated UAO-interventions, the majority used polysomnography (90%), of which 61% did not specify the polysomnography technique. Reported polysomnography metrics included oxygen saturation (61%), apnea-hypopnea index (52%), carbon dioxide levels (31%), obstructive-apnea-hypopnea index (27%), and oxygen-desaturation-index (16%). Only 42 studies reported indications for UAO-intervention, with oximetry and polysomnography thresholds used equally (both 40%). In total, 34 distinct indications for treatment were identified.

CONCLUSIONS

This systematic review demonstrates a lack of standardization, interpretation and reporting of assessment and treatment indications for UAO in RS. An international, multidisciplinary consensus protocol is needed to guide clinicians on optimal UAO assessment in RS.

Long-term Speech Outcomes of Cleft Palate Repair in Robin Sequence versus Isolated Cleft Palate

Supplemental Digital Content is available in the text.

Whether treatment of cleft palate (CP) associated with Robin sequence (RS) should attain outcomes similar to those of isolated cleft palate (ICP) remains unknown. This study compares treatment and outcomes in both conditions and delineates predictors of long-term outcome.

Rigid Video Laryngoscopy for Intubation in Severe Pierre Robin Sequence: A Retrospective Review

OBJECTIVES/HYPOTHESIS

The anatomy of children with severe Pierre Robin sequence can present a challenge for direct laryngoscopy and intubation. Advanced techniques including flexible fiberoptic laryngoscopic intubation have been described but require highly specialized skill and equipment. Rigid video laryngoscopy is more accessible but has not been described in this population.

STUDY DESIGN

Retrospective cohort study.

METHODS

A retrospective review was completed at a tertiary care center of all children between January 2016 and March 2020 with Pierre Robin sequence who underwent a mandibular distraction osteogenesis procedure. Intubation events were collected, and a descriptive analysis was performed. A univariate logistic regression model was applied to direct laryngoscopy and flexible fiberoptic laryngoscopy with rigid video laryngoscopy as a reference.

RESULTS

Twenty-five patients were identified with a total of 56 endotracheal events. All patients were successfully intubated. Direct laryngoscopy was successful at first intubation attempt in 47.3% (9/19) of events. Six direct laryngoscopy events required switching to another device. Rigid video laryngoscopy was successful at first intubation attempt in 80.5% (29/36) of events. Two cases required switching to another device. Flexible fiberoptic laryngoscopy was found successful at first intubation attempt in 88.9% (8/9) of events. Direct laryngoscopy was 4 times more likely to fail first intubation attempt when compared to rigid video laryngoscopy (P < .05). There was no significant difference between rigid video laryngoscopy and flexible fiberoptic laryngoscopy for intubation.

CONCLUSIONS

For children with Pierre Robin sequence rigid video laryngoscopy should be considered as a first attempt intubation device both in the operating room and for emergent situations.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:1647-1651, 2021.

Phenotypes, Developmental Basis, and Genetics of Pierre Robin Complex

The phenotype currently accepted as Pierre Robin syndrome/sequence/anomalad/complex (PR) is characterized by mandibular dysmorphology, glossoptosis, respiratory obstruction, and in some cases, cleft palate. A causative sequence of developmental events is hypothesized for PR, but few clear causal relationships between discovered genetic variants, dysregulated gene expression, precise cellular processes, pathogenesis, and PR-associated anomalies are documented. This review presents the current understanding of PR phenotypes, the proposed pathogenetic processes underlying them, select genes associated with PR, and available animal models that could be used to better understand the genetic basis and phenotypic variation of PR.

Anterior Tongue Microglossia: Impact on Face Development

Microglossia is an extremely rare developmental condition that might impact the patient's respiratory, feeding and speech functions, in addition to other intraoral structures. Embryologically, the tongue has 2 origins, which when affected, will determine whether the patient has microglossia or aglossia. A multidisciplinary team should adopt an organized approach based on confirmation by direct laryngoscopy, determination whether associated airway anomalies, mandibular deformities are present; followed by assessment of the ventilatory and feeding status. The involvement of multiple factors, the presence of several anatomical anomalies and the growth exerted by patients, confer microglossia a rather dynamic clinical entity. Two cases of microglossia depicting these features are presented along with review of the literature and a management algorithm.

Clinical and genetic characterization of patients with Pierre Robin sequence and spinal disease: review of the literature and novel terminal 10q deletion

INTRODUCTION

The Pierre-Robin sequence (PRS) is a pattern of congenital facial abnormalities comprising micrognathia, glossoptosis, and airway obstruction. Associated spinal pathologies have rarely been reported with PRS.

METHODS

We explore the molecular genetic basis of this association through a systematic review of spinal disease in patients with PRS. We also present an illustrative case of a PRS patient with tethered cord in the setting of chromosome 10q terminal deletion.

RESULTS

Our systematic literature review of spinal disease in patients with PRS revealed several patterns in the underlying genetic syndromes causing these conditions to co-occur. These principles are illustrated in the case of a 6-month-old female with PRS and a 14.34-Mb terminal deletion of chromosome 10q, who was found to have a sacral dimple during a routine outpatient checkup. Magnetic resonance imaging of the spine revealed a lumbar syrinx associated with tethered spinal cord. Surgical de-tethering was undertaken, with subsequent improvement in motor function and decrease in the size of the syrinx. The deletion of chromosome 10q in our patient had not previously been described in association with tethered cord or PRS.

CONCLUSION

Spinal pathologies are understudied contributors to disease burden in patients with PRS. The range of predisposing syndromes and mutations in patients with both PRS and spinal disorders remains poorly characterized but may be more defined than previously conceived. Clinical screening is most critical during neonatal and adolescent developmental periods with continued neurological assessment. This study emphasizes the need for early genetic testing and counseling in this patient population, in parallel with research efforts to develop molecular classifications to guide clinical management.

Can Robin Sequence Be Predicted From Prenatal Ultrasonography?

PURPOSE

Prenatal diagnosis of Robin sequence (RS) could promote safe delivery and improve perinatal care. The purpose of this study was to evaluate the correlation between prenatal ultrasonography (US) and magnetic resonance imaging (MRI) studies for assessing micrognathia to determine if US alone can be used to reliably screen for RS.

MATERIALS AND METHODS

This was a retrospective case-control study of fetuses evaluated in the Advanced Fetal Care Center at Boston Children's Hospital from 2002 to 2017. To be included, 1) prenatal MRI and US must have been performed during the same visit, 2) the infant must have been live-born, and 3) the diagnosis must have been confirmed postnatally. Patients with images of inadequate quality for analysis were excluded. Patients were divided into 4 groups based on postnatal diagnosis: 1) RS (micrognathia, glossoptosis, and airway obstruction) (RS group), 2) micrognathia without RS (micrognathia group), 3) cleft lip and palate (CLP) without micrognathia (CLP group), and 4) gestational age-matched controls with normal craniofacial morphology (control group). The inferior facial angle (IFA) was measured using both imaging modalities and compared. Receiver operating characteristic curves were applied to identify a threshold for the diagnosis of RS from US. The sensitivity, specificity, positive predictive value, negative predictive value, and odds ratio were calculated.

RESULTS

A total of 94 patients were included (mean gestational age at imaging, 24.9 ± 5.2 weeks), with 25 in the RS group (26.6%), 29 in the micrognathia group (30.9%), 23 in the CLP group (24.5%), and 17 in the control group (18.1%). The IFA was significantly smaller in the RS group than in all other groups on both US and MRI (P < .001). A moderate correlation was found between IFA measurements on US and MRI (intraclass correlation coefficient, 0.729). An IFA threshold on US of 45.5° maximized sensitivity (84%) and specificity (81%) for the diagnosis of RS.

CONCLUSIONS

We suggest incorporating the IFA into routine prenatal US and referring patients for confirmatory MRI when the US IFA is lower than 45.5°.

Pierre Robin Sequence: Incidence of Speech-Correcting Surgeries and Fistula Formation

Objective:

Children with Pierre Robin sequence (PRS) and cleft palate have a high rate of velopharyngeal insufficiency (VPI) following primary palatoplasty. Our purpose was to determine the long-term incidence of speech-correcting surgeries (SCSs) and fistula rates in PRS after primary palatoplasty and the influence of possible causal factors.

Design:

A retrospective single-center, observational chart review study.

Participants:

After exclusion, the study cohort comprised 78 nonsyndromic PRS children (48 females) born between 1990 and 2009 and treated at the Cleft Palate and Craniofacial Center of Helsinki University Hospital, Finland. Causal factors included gender, surgeon, age at primary palatoplasty, surgical technique, airway obstruction in infancy, and cleft severity. We analyzed the outcome at age 8 years and at data retrieval, with a median follow-up of 14 years (range: 8-27 years).

Results:

Thirty-four (43.6%) children received SCS by age 8 years, and of the 19 (24.4%) postoperative fistulas, 6 (7.7%) underwent closure. At data retrieval, 37 (47.4%) children had undergone SCS and 8 (10.3%) had a fistula closure. Median age at SCS was 6 years. The results showed no significant association for gender, surgeon, age at primary palatoplasty, surgical technique, cleft severity, or airway obstruction in infancy regarding incidence of SCS, fistulas, or repaired fistulas.

Conclusion:

Pierre Robin sequence in children is associated with a high incidence of SCS and fistula formation, which necessitates accurate clinical follow-up and observation of speech development. The development of VPI in PRS is complex and most likely involving multiple factors.

The use of three-dimensional reconstructions of CT scans to evaluate anomalies of hyoid bone in Pierre Robin sequence: A retrospective study

AIM

The aim of the study was to investigate hyoid bone anomalies in patients with Pierre Robin sequence (PRS) compared to the control group, using computed tomography (CT) examination and three-dimensional reconstruction of the hyoid bone and mandible.

METHODS

A retrospective study was performed of patients between birth and 12 months old with isolated PRS (i-PRS) and syndromic PRS (ni-PRS), who had undergone CT examination, and whose results were compared to the control group of the same age. DICOM data was processed to highlight bone tissue. The mandible and hyoid bones were the main targets of the three-dimensional reconstruction. The study outcomes were the analysis of hyoid bone ossification, volume, and position (distance between hyoid and mandibular symphysis). Univariate and multivariate statistical analyses were performed with α=0.05 as level of significance.

RESULTS

The study sample included 29 i-PRS and 21 ni-PRS patients, while 43 infants in the control group. Hyoid ossification was present in 26/50 (52%) PRS patients (14 i-PRS; 12 ni-PRS) but in 31/43 controls (72%). Statistical analysis showed that absence of hyoid ossification was significantly associated with the diagnosis of PRS (P<0.05). Only ni-PRS patients showed a significant reduction of the distance between hyoid and mandible compared to the control group (P<0.001). Hyoid volume was significantly lower only in the ni-PRS group than in controls (P<0.001).

CONCLUSION

I-PRS and ni-PRS patients differ both etiologically and clinically. Ni-PRS patients confirmed their worst clinical condition than i-PRS with severe anomalies of hyoid development, helping for their ontogeny classification.