Micrognathia and Oropharyngeal Space in Patients With Robin Sequence: Prenatal MRI Measurements

MicroNAPS: A Novel Classification for Infants with Micrognathia, Robin Sequence, and Tongue-based Airway Obstruction

Background

Robin sequence (RS) describes a heterogeneous population with micrognathia, glossoptosis, and upper airway obstruction (UAO). Workup, treatment, outcomes assessment, and research inclusion are widely variable. Despite several classifications and algorithms, none is broadly endorsed. The objective of this investigation was to develop and trial a novel classification system designed to enhance clinical communication, treatment planning, prognostication, and research.

Methods

This is a retrospective cross-sectional study. A classification system was developed with five elements: micrognathia, nutrition, airway, palate, syndrome/comorbidities (MicroNAPS). Definitions and a framework for "stage" assignment (R0-R4) were constructed. Stage "tongue-based airway obstruction" (TBAO) was defined for infants with glossoptosis and UAO without micrognathia. MicroNAPS was applied to 100 infants with at least 1-year follow-up. Clinical course, treatment, airway, and feeding characteristics were assessed. Descriptive and analytic statistics were calculated and a P value less than 0.05 was considered significant.

Results

Of the 100 infants, 53 were male. Mean follow-up was 5.0 ± 3.6 years. R1 demonstrated feeding-predominant mild RS for which UAO was managed nonoperatively but gastrostomy tubes were prevalent. R2 was characterized by airway-predominant moderate RS, typically managed with mandibular distraction or tongue-lip adhesion, with few gastrostomy tubes and short lengths-of-stay. R3 denoted severe RS, with similar UAO treatment to R2, but with more surgical feeding tubes and longer admissions. R4 represented a complex phenotype with 33% tracheostomies, protracted hospitalizations, and delayed palatoplasty. R0 ("at risk") and TBAO groups displayed the most variability.

Conclusions

MicroNAPS is easy to use and associated with relevant disease characteristics. We propose its adoption in clinical and research settings.

Prenatal Diagnosis of Pierre Robin Sequence and Its Prognosis: A Retrospective Cohort Study

OBJECTIVE

 This study aimed to explore the efficiency of ultrasound (US) in prenatal diagnosis and prognosis of Pierre Robin sequence (PRS) of 18 cases.

STUDY DESIGN

 A total of 79,305 women admitted for prenatal US examinations were recruited from January 2017 to December 2020. Eighteen cases of PRS fetuses were selected form the cohort and 40 cases of isolated micrognathia were recruited randomly as control group. All the clinical and imaging results were retrospectively reviewed. General condition, US measurements, and prognosis of fetuses were compared between groups.

RESULTS

 Cleft palate, glossoptosis, and micrognathia were found in all 18 fetuses with PRS by prenatal US. Compared with the isolated micrognathia group, there were no significant differences in the PRS group in examination of maternal age, gestational weeks at assessment, and gender of fetuses, but significant lower measures in inferior facial angle, jaw index, and frontal nasal-mental angle (each p < 0.05). Twelve fetuses were defined to have other associated malformations. Ear malformations were the most common associated malformations with a prevalence of 44.4% (8/18). All of the18 cases were confirmed with PRS after delivery or autopsy. Two delivered infants were found bucking easily, one baby was spitting up frequently but growth showed normal.

CONCLUSION

 Prenatal detection of PRS with US examination is highly efficient. Even with the triad of malformations, isolated PRS had good outcomes following initial stabilization and management in the neonatal period. Prenatal detection of Pierre Robin syndrome with targeted US examination is efficient in discerning characteristics of this rare syndrome. Even with the triad of malformations, isolated PRS had good outcomes following initial stabilization and management in the neonatal period.

KEY POINTS

· Prenatal diagnosis of fetal PRS is of great clinical importance.. · Micrognathia has been identified as the primary feature of PRS.. · Posterior displacement of the tongue may cause acute neonatal respiratory distress.. · Even with triad malformation, isolated PRS seemed to have good 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.

Prenatal diagnosis of micrognathia: a systematic review

Purpose

This systematic review aimed to analyze the characteristics of different diagnostic techniques for micrognathia, summarize the consistent diagnostic criteria of each technique, and provide a simple and convenient prenatal diagnosis strategy for micrognathia.

Methods

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the search was undertaken in three international databases (PubMed, Scopus, and Web of Science). The three reviewers assessed all papers and extracted the following variables: author's name and year of publication, country, study design, number of participants, gestational age, equipment for prenatal examination, biometric parameters related to micrognathia, main results.

Results

A total of 25 articles included in the analysis. Nineteen articles described cross-sectional studies (76 percent), 4 (16 percent) were case-control studies, and 2 (8 percent) were cohort studies. Fifteen studies (60 percent) had a prospective design, 9 (36 percent) had a retrospective design, and one (4 percent) had both prospective and retrospective design. Thirty-two percent of the studies (n = 8) were performed in USA, and the remaining studies were performed in China (n = 4), Israel (n = 3), Netherlands (n = 3), UK (n = 1), France (n = 1), Italy (n = 1), Belgium(n = 1), Germany (n = 1), Spain (n = 1), and Austria (n = 1). The prenatal diagnosis of micrognathia can be performed as early as possible in the first trimester, while the second and third trimester of pregnancy were the main prenatal diagnosis period. The articles that were included in the qualitative synthesis describe 30 biometric parameters related to the mandible.

Conclusion

Of the 30 biometric parameters related to the mandible, 15 can obtain the simple and convenient diagnostic criteria or warning value for micrognathia. Based on these diagnostic criteria or warning value, clinicians can quickly make a preliminary judgment on facial deformities, to carry out cytologic examination to further clarify the diagnosis of micrognathia.

Epidemiology of Pierre-Robin sequence in Europe: A population-based EUROCAT study

BACKGROUND

Pierre Robin sequence (PRS) is a rare congenital anomaly. Respiratory disorders and feeding difficulties represent the main burden.

OBJECTIVE

The aim of this study was to investigate the epidemiology of PRS using a cohort of cases from EUROCAT, the European network of population-based registries of congenital anomalies.

METHODS

We analysed cases of PRS born in the period 1998-2017 collected by 29 population-based congenital anomaly registries in 17 different countries. We calculated prevalence estimates, prenatal detection rate, survival up to 1 week, and proportions of associated anomalies. The effect of maternal age was tested using a Poisson regression model.

RESULTS

Out of 11 669 155 surveyed births, a total of 1294 cases of PRS were identified. The estimate of the overall prevalence was 12.0 per 100 000 births (95% CI 9.9, 14.5). There was a total of 882 (68.2%) isolated cases, and the prevalence was 7.8 per 100 000 births (95% CI 6.7, 9.2). A total of 250 cases (19.3%) were associated with other structural congenital anomalies, 77 cases (6.0%) were associated with chromosomal anomalies and 77 (6.0%) with genetic syndromes. The prenatal detection rate in isolated cases was 12.0% (95% CI 9.8, 14.5) and increased to 16.0% (95% CI 12.7, 19.7) in the sub-period 2008-2017. The prevalence rate ratio of non-chromosomal cases with maternal age ≥35 was higher than in cases with maternal age <25 for total (PRR 1.26, 95% CI 1.05, 1.51) and isolated cases (PRR 1.33, 95% CI 1.00, 1.64). Survival of chromosomal cases (94.2%) and multiple anomaly cases (95.3%) were lower than survival of isolated cases (99.4%).

CONCLUSIONS

This epidemiological study using a large series of cases of PRS provides insights into the epidemiological profile of PRS in Europe. We observed an association with higher maternal age, but further investigations are needed to test potential risk factors for PRS.

Imaging of the fetal oral cavity, airway and neck

Magnetic resonance imaging has proved to be an extraordinarily useful adjunct modality in assessment of the fetal face, oral cavity, head and neck because of its soft-tissue contrast, utility for acquiring more precise planar imaging and the inherent advantage of contrast provided by fluid-filled structures, including the oropharyngeal cavity, nasal passages and vascular structures. In this review, the author presents an organized approach to assessing normal anatomical structures of the fetus. The author presents cystic and solid lesions as well as structural and developmental abnormalities and discusses potential concomitant abnormalities. Prenatal consultation, patient counseling and delivery considerations are included.

Modelling growth curves of the normal infant's mandible: 3D measurements using computed tomography

Objectives

Data on normal mandibular development in the infant is lacking though essential to understand normal growth patterns and to discriminate abnormal growth. The aim of this study was to provide normal linear measurements of the mandible using computed tomography performed in infants from 0 to 2 years of age.

Material and methods

3D voxel software was used to calculate mandibular body length, mandibular ramus length, bicondylar width, bigonial width and the gonial angle. Intra- and inter-rater reliability was assessed for these measurements. They were found to be sufficient for all distances; intra-class correlation coefficients were all above 0.9. Regression analysis for growth modelling was performed.

Results

In this multi-centre retrospective study, 109 CT scans were found eligible that were performed for various reasons (e.g. trauma, craniosynostosis, craniofacial abscesses). Craniosynostosis patients had larger mandibular measurements compared to non-craniosynostosis patients and were therefore excluded. Fifty-one CT scans were analysed.

Conclusions

Analysis showed that the mandible increases more in size vertically (the mandibular ramus) than horizontally (the mandibular body). Most of the mandibular growth occurs in the first 6 months.

Clinical relevance

These growth models provide insight into normal mandibular development in the first 2 years of life. This reference data facilitates discrimination between normal and abnormal mandibular growth.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-021-03937-1.

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°.

Is Amniotic Fluid Level a Predictor for Syndromic Diagnosis in Robin Sequence?

OBJECTIVE

The purpose of this study was to determine whether gestational amniotic fluid level abnormalities were associated with postnatal syndromic status in a series of patients with Robin sequence (RS).

DESIGN

Retrospective study of participants with RS at Boston Children's Hospital from 1967 to 2017. Participants were divided into syndromic and nonsyndromic groups. The primary predictor variable was postnatal syndromic diagnosis (yes/no). Additional predictor variables included gestational age at birth, birthweight, sex, presence of cleft palate, and other congenital anomalies. The primary outcome variable was amniotic fluid level (normal, oligohydramnios, or polyhydramnios). Descriptive statistics were computed and logistic regression was used to analyze amniotic fluid level as a predictor for syndromic diagnosis. Statistical significance was set at P < .05.

RESULTS

Sixty-five (54%) syndromic and 56 (46%) nonsyndromic RS participants were included. An abnormal amniotic fluid level was seen significantly more frequently in the syndromic group (49.2% vs 25.0%; P = .001). Abnormal amniotic fluid level was associated with a 2.9-fold increased likelihood of a syndromic diagnosis (P = .007). Polyhydramnios, which was seen more frequently than oligohydramnios, predicted a 4.18 times increased likelihood of a syndromic diagnosis (P = .003).

CONCLUSIONS

Abnormal amniotic fluid level, particularly polyhydramnios, is associated with an increased likelihood of a syndromic diagnosis in patients with RS.